TBD Meeting (5436-21)

Although use of some herbal and dietary supplements show statistically greater weight loss compared with placebo, it is not sufficient to benefit health, according to the joint findings of two systematic reviews, which are the first to comprehensively include all available herbal and dietary supplements for weight loss for over 15 years.

Sally Kubetin/MDedge News

“There is currently insufficient evidence to recommend any of the supplements we included in our reviews for weight loss,” stressed lead author Erica Bessell, a PhD candidate from the University of Sydney.

She added that some products with promising results warrant further investigation in well-conducted randomized controlled trials (RCTs) to determine their efficacy and safety.

But, overall, she would like to see a reduction in the number of products on the market without evidence to support their efficacy, “because, as we found, many of the products currently marketed for weight loss just do not work.

“Herbal and dietary supplements might seem like a quick-fix solution to weight problems, but people need to be aware of how little we actually know about them,” she said in an interview. “We would recommend that people trying to lose weight should save their money and seek out evidence-based care instead,” she emphasized.

The research was presented as two posters at this year’s online European Congress on Obesity (ECO). The meeting was presented by the European Association for the Study of Obesity.
 

Herbal and dietary supplement industry booming

Supplements for weight loss are growing in popularity, sustaining a rapidly expanding business sector globally. In the United States, the herbal and dietary supplements industry was estimated to be worth USD $41 billion in 2020, with 15% of Americans having tried a weight loss supplement in their efforts to shed pounds.

In light of this, Ms. Bessell said it is increasingly important to ensure supplements are efficacious and safe: “The popularity of these products underscores the urgency of conducting larger, more rigorous studies to have reasonable assurance of their safety and effectiveness for weight loss.”

Commenting on the study and the wider issues related to the surge in uptake of herbal and dietary supplements, Susan Arentz, PhD, said the evidence is similar to that for other complex interventions that people attempt for weight loss, including for example exercise, in that it is heterogeneous and low quality.

“One outstanding limitation for herbal medicine was the failure of trialists to validate the contents of interventions. Given the chemical variability of plants grown and harvested in different conditions, and the presence of pharmaceuticals and heavy metals found in some supplements ... future investigations of standardized herbal supplements and RCTs of higher methodological quality are needed,” remarked Dr. Arentz, a board member of the Australasian Integrative Medicine Association and researcher at Western Sydney University.

“Also, further RCTs are warranted due to the consumer preferences for natural treatments, especially in health settings with predominant use of traditional medicines and practices,” said Dr. Arentz.   
 

One review for herbal supplements, one for organic compounds

To accommodate the large number of trials investigating supplements for weight loss, the researchers conducted two systematic reviews, together representing 121 randomized placebo-controlled trials. One of the reviews investigated herbal supplements, and the other examined supplements with isolated organic compounds for example, specific fibers or lipids.  

Many of the included trials had been published in the last decade and had not been previously included in an up-to-date systematic review.

Ms. Bessell added that many studies often had a small sample size or were poorly designed, with insufficient information on the composition of supplements, and often featured little data on long-term effectiveness.

The two reviews primarily analyzed efficacy, not safety, because many of the studies did not report adverse effects.

The first review, published last year in Diabetes, Obesity and Metabolism, looked at 54 placebo-controlled randomized trials up to August 2018 on the effect of herbal supplements on weight loss . The study included 4,331 individuals aged 16 years or older who were overweight or obese. To be clinically meaningful, a weight loss of at least 2.5 kg was required over a period of, most often, 12 weeks or less.

Herbal supplements included in the analysis included green tea, Garcinia cambogia and mangosteen (tropical fruits), white kidney bean, ephedra (a stimulant that increases metabolism), African mango, yerba mate (herbal tea made from the leaves and twigs of the Ilex paraguariensis plant), veld grape (commonly used in Indian traditional medicine), licorice root, and East Indian Globe Thistle (used in Ayurvedic medicine).

The second review analyzed 67 randomized trials up to December 2019 that compared the effect of dietary supplements containing naturally occurring isolated organic compounds to placebo for weight loss in 5,194 individuals aged 16 years or older who were overweight or obese.

Meta-analyses were conducted for chitosan, glucomannan, conjugated linoleic acid, and fructans comparing the mean weight difference post intervention between participants receiving the dietary supplement and those on placebo.
 

No clinically significant results

Commenting on the overall results, Ms. Bessell said: “Though most supplements were safe for use in the short term, very few were found to produce clinically meaningful weight loss. Those that were found to result in clinically meaningful weight loss had only been investigated in one or two trials, so we need more research.”

The first review on herbal supplements found that only Phaseolus vulgaris (white kidney bean) resulted in significant weight loss compared with placebo, with an average weight difference of 1.61 kg (3.5 pounds). The result was not clinically meaningful, however.

For isolated organic compounds, significant weight differences compared with placebo were seen for chitosan, with a mean difference of 1.84 kg (4 pounds), glucomannan at 1.27 kg (2.8 pounds), and conjugated linoleic acid at 1.08 kg (2.4 pounds).

Again, none of these findings met the criteria for clinical significance (weight loss of 2.5 kg [5.5 pounds] or more).

In addition, some combination preparations containing African mango, veld grape, East Indian Globe Thistle, and mangosteen showed promising results with a mean weight difference of 1.85 kg (4 pounds), but were investigated in three or fewer trials, often with poor research methodology or reporting, and the findings should be interpreted with caution, the researchers noted.

Other dietary supplements, including modified cellulose – a plant fiber that expands in the stomach to induce a feeling of fullness – and blood orange juice extract, also showed encouraging results but were investigated in one trial and need more evidence before they can be recommended for weight loss, Ms. Bessell added.

She pointed out that some supplements are banned in some countries, such as ephedra (an extract from the plant Ephedra sinica). “This supplement is already banned in many countries because of the risk of serious adverse effects. The possibility of drug interactions may also be present with some other supplements, so health professionals and consumers should be aware of this.”

The isolated organic compounds supplements review was published in the International Journal of Obesity to coincide with the ECO 2021 conference.

Ms. Bessell has declared no relevant conflicts of interests. Dr. Arentz reviewed the systematic review of RCTs of herbal medicine supplements for weight loss published in Diabetes, Obesity and Metabolism.
 

A version of this article first appeared on Medscape.com.

Although use of some herbal and dietary supplements show statistically greater weight loss compared with placebo, it is not sufficient to benefit health, according to the joint findings of two systematic reviews, which are the first to comprehensively include all available herbal and dietary supplements for weight loss for over 15 years.

Sally Kubetin/MDedge News

“There is currently insufficient evidence to recommend any of the supplements we included in our reviews for weight loss,” stressed lead author Erica Bessell, a PhD candidate from the University of Sydney.

She added that some products with promising results warrant further investigation in well-conducted randomized controlled trials (RCTs) to determine their efficacy and safety.

But, overall, she would like to see a reduction in the number of products on the market without evidence to support their efficacy, “because, as we found, many of the products currently marketed for weight loss just do not work.

“Herbal and dietary supplements might seem like a quick-fix solution to weight problems, but people need to be aware of how little we actually know about them,” she said in an interview. “We would recommend that people trying to lose weight should save their money and seek out evidence-based care instead,” she emphasized.

The research was presented as two posters at this year’s online European Congress on Obesity (ECO). The meeting was presented by the European Association for the Study of Obesity.
 

Herbal and dietary supplement industry booming

Supplements for weight loss are growing in popularity, sustaining a rapidly expanding business sector globally. In the United States, the herbal and dietary supplements industry was estimated to be worth USD $41 billion in 2020, with 15% of Americans having tried a weight loss supplement in their efforts to shed pounds.

In light of this, Ms. Bessell said it is increasingly important to ensure supplements are efficacious and safe: “The popularity of these products underscores the urgency of conducting larger, more rigorous studies to have reasonable assurance of their safety and effectiveness for weight loss.”

Commenting on the study and the wider issues related to the surge in uptake of herbal and dietary supplements, Susan Arentz, PhD, said the evidence is similar to that for other complex interventions that people attempt for weight loss, including for example exercise, in that it is heterogeneous and low quality.

“One outstanding limitation for herbal medicine was the failure of trialists to validate the contents of interventions. Given the chemical variability of plants grown and harvested in different conditions, and the presence of pharmaceuticals and heavy metals found in some supplements ... future investigations of standardized herbal supplements and RCTs of higher methodological quality are needed,” remarked Dr. Arentz, a board member of the Australasian Integrative Medicine Association and researcher at Western Sydney University.

“Also, further RCTs are warranted due to the consumer preferences for natural treatments, especially in health settings with predominant use of traditional medicines and practices,” said Dr. Arentz.   
 

One review for herbal supplements, one for organic compounds

To accommodate the large number of trials investigating supplements for weight loss, the researchers conducted two systematic reviews, together representing 121 randomized placebo-controlled trials. One of the reviews investigated herbal supplements, and the other examined supplements with isolated organic compounds for example, specific fibers or lipids.  

Many of the included trials had been published in the last decade and had not been previously included in an up-to-date systematic review.

Ms. Bessell added that many studies often had a small sample size or were poorly designed, with insufficient information on the composition of supplements, and often featured little data on long-term effectiveness.

The two reviews primarily analyzed efficacy, not safety, because many of the studies did not report adverse effects.

The first review, published last year in Diabetes, Obesity and Metabolism, looked at 54 placebo-controlled randomized trials up to August 2018 on the effect of herbal supplements on weight loss . The study included 4,331 individuals aged 16 years or older who were overweight or obese. To be clinically meaningful, a weight loss of at least 2.5 kg was required over a period of, most often, 12 weeks or less.

Herbal supplements included in the analysis included green tea, Garcinia cambogia and mangosteen (tropical fruits), white kidney bean, ephedra (a stimulant that increases metabolism), African mango, yerba mate (herbal tea made from the leaves and twigs of the Ilex paraguariensis plant), veld grape (commonly used in Indian traditional medicine), licorice root, and East Indian Globe Thistle (used in Ayurvedic medicine).

The second review analyzed 67 randomized trials up to December 2019 that compared the effect of dietary supplements containing naturally occurring isolated organic compounds to placebo for weight loss in 5,194 individuals aged 16 years or older who were overweight or obese.

Meta-analyses were conducted for chitosan, glucomannan, conjugated linoleic acid, and fructans comparing the mean weight difference post intervention between participants receiving the dietary supplement and those on placebo.
 

No clinically significant results

Commenting on the overall results, Ms. Bessell said: “Though most supplements were safe for use in the short term, very few were found to produce clinically meaningful weight loss. Those that were found to result in clinically meaningful weight loss had only been investigated in one or two trials, so we need more research.”

The first review on herbal supplements found that only Phaseolus vulgaris (white kidney bean) resulted in significant weight loss compared with placebo, with an average weight difference of 1.61 kg (3.5 pounds). The result was not clinically meaningful, however.

For isolated organic compounds, significant weight differences compared with placebo were seen for chitosan, with a mean difference of 1.84 kg (4 pounds), glucomannan at 1.27 kg (2.8 pounds), and conjugated linoleic acid at 1.08 kg (2.4 pounds).

Again, none of these findings met the criteria for clinical significance (weight loss of 2.5 kg [5.5 pounds] or more).

In addition, some combination preparations containing African mango, veld grape, East Indian Globe Thistle, and mangosteen showed promising results with a mean weight difference of 1.85 kg (4 pounds), but were investigated in three or fewer trials, often with poor research methodology or reporting, and the findings should be interpreted with caution, the researchers noted.

Other dietary supplements, including modified cellulose – a plant fiber that expands in the stomach to induce a feeling of fullness – and blood orange juice extract, also showed encouraging results but were investigated in one trial and need more evidence before they can be recommended for weight loss, Ms. Bessell added.

She pointed out that some supplements are banned in some countries, such as ephedra (an extract from the plant Ephedra sinica). “This supplement is already banned in many countries because of the risk of serious adverse effects. The possibility of drug interactions may also be present with some other supplements, so health professionals and consumers should be aware of this.”

The isolated organic compounds supplements review was published in the International Journal of Obesity to coincide with the ECO 2021 conference.

Ms. Bessell has declared no relevant conflicts of interests. Dr. Arentz reviewed the systematic review of RCTs of herbal medicine supplements for weight loss published in Diabetes, Obesity and Metabolism.
 

A version of this article first appeared on Medscape.com.

Although use of some herbal and dietary supplements show statistically greater weight loss compared with placebo, it is not sufficient to benefit health, according to the joint findings of two systematic reviews, which are the first to comprehensively include all available herbal and dietary supplements for weight loss for over 15 years.

Sally Kubetin/MDedge News

“There is currently insufficient evidence to recommend any of the supplements we included in our reviews for weight loss,” stressed lead author Erica Bessell, a PhD candidate from the University of Sydney.

She added that some products with promising results warrant further investigation in well-conducted randomized controlled trials (RCTs) to determine their efficacy and safety.

But, overall, she would like to see a reduction in the number of products on the market without evidence to support their efficacy, “because, as we found, many of the products currently marketed for weight loss just do not work.

“Herbal and dietary supplements might seem like a quick-fix solution to weight problems, but people need to be aware of how little we actually know about them,” she said in an interview. “We would recommend that people trying to lose weight should save their money and seek out evidence-based care instead,” she emphasized.

The research was presented as two posters at this year’s online European Congress on Obesity (ECO). The meeting was presented by the European Association for the Study of Obesity.
 

Herbal and dietary supplement industry booming

Supplements for weight loss are growing in popularity, sustaining a rapidly expanding business sector globally. In the United States, the herbal and dietary supplements industry was estimated to be worth USD $41 billion in 2020, with 15% of Americans having tried a weight loss supplement in their efforts to shed pounds.

In light of this, Ms. Bessell said it is increasingly important to ensure supplements are efficacious and safe: “The popularity of these products underscores the urgency of conducting larger, more rigorous studies to have reasonable assurance of their safety and effectiveness for weight loss.”

Commenting on the study and the wider issues related to the surge in uptake of herbal and dietary supplements, Susan Arentz, PhD, said the evidence is similar to that for other complex interventions that people attempt for weight loss, including for example exercise, in that it is heterogeneous and low quality.

“One outstanding limitation for herbal medicine was the failure of trialists to validate the contents of interventions. Given the chemical variability of plants grown and harvested in different conditions, and the presence of pharmaceuticals and heavy metals found in some supplements ... future investigations of standardized herbal supplements and RCTs of higher methodological quality are needed,” remarked Dr. Arentz, a board member of the Australasian Integrative Medicine Association and researcher at Western Sydney University.

“Also, further RCTs are warranted due to the consumer preferences for natural treatments, especially in health settings with predominant use of traditional medicines and practices,” said Dr. Arentz.   
 

One review for herbal supplements, one for organic compounds

To accommodate the large number of trials investigating supplements for weight loss, the researchers conducted two systematic reviews, together representing 121 randomized placebo-controlled trials. One of the reviews investigated herbal supplements, and the other examined supplements with isolated organic compounds for example, specific fibers or lipids.  

Many of the included trials had been published in the last decade and had not been previously included in an up-to-date systematic review.

Ms. Bessell added that many studies often had a small sample size or were poorly designed, with insufficient information on the composition of supplements, and often featured little data on long-term effectiveness.

The two reviews primarily analyzed efficacy, not safety, because many of the studies did not report adverse effects.

The first review, published last year in Diabetes, Obesity and Metabolism, looked at 54 placebo-controlled randomized trials up to August 2018 on the effect of herbal supplements on weight loss . The study included 4,331 individuals aged 16 years or older who were overweight or obese. To be clinically meaningful, a weight loss of at least 2.5 kg was required over a period of, most often, 12 weeks or less.

Herbal supplements included in the analysis included green tea, Garcinia cambogia and mangosteen (tropical fruits), white kidney bean, ephedra (a stimulant that increases metabolism), African mango, yerba mate (herbal tea made from the leaves and twigs of the Ilex paraguariensis plant), veld grape (commonly used in Indian traditional medicine), licorice root, and East Indian Globe Thistle (used in Ayurvedic medicine).

The second review analyzed 67 randomized trials up to December 2019 that compared the effect of dietary supplements containing naturally occurring isolated organic compounds to placebo for weight loss in 5,194 individuals aged 16 years or older who were overweight or obese.

Meta-analyses were conducted for chitosan, glucomannan, conjugated linoleic acid, and fructans comparing the mean weight difference post intervention between participants receiving the dietary supplement and those on placebo.
 

No clinically significant results

Commenting on the overall results, Ms. Bessell said: “Though most supplements were safe for use in the short term, very few were found to produce clinically meaningful weight loss. Those that were found to result in clinically meaningful weight loss had only been investigated in one or two trials, so we need more research.”

The first review on herbal supplements found that only Phaseolus vulgaris (white kidney bean) resulted in significant weight loss compared with placebo, with an average weight difference of 1.61 kg (3.5 pounds). The result was not clinically meaningful, however.

For isolated organic compounds, significant weight differences compared with placebo were seen for chitosan, with a mean difference of 1.84 kg (4 pounds), glucomannan at 1.27 kg (2.8 pounds), and conjugated linoleic acid at 1.08 kg (2.4 pounds).

Again, none of these findings met the criteria for clinical significance (weight loss of 2.5 kg [5.5 pounds] or more).

In addition, some combination preparations containing African mango, veld grape, East Indian Globe Thistle, and mangosteen showed promising results with a mean weight difference of 1.85 kg (4 pounds), but were investigated in three or fewer trials, often with poor research methodology or reporting, and the findings should be interpreted with caution, the researchers noted.

Other dietary supplements, including modified cellulose – a plant fiber that expands in the stomach to induce a feeling of fullness – and blood orange juice extract, also showed encouraging results but were investigated in one trial and need more evidence before they can be recommended for weight loss, Ms. Bessell added.

She pointed out that some supplements are banned in some countries, such as ephedra (an extract from the plant Ephedra sinica). “This supplement is already banned in many countries because of the risk of serious adverse effects. The possibility of drug interactions may also be present with some other supplements, so health professionals and consumers should be aware of this.”

The isolated organic compounds supplements review was published in the International Journal of Obesity to coincide with the ECO 2021 conference.

Ms. Bessell has declared no relevant conflicts of interests. Dr. Arentz reviewed the systematic review of RCTs of herbal medicine supplements for weight loss published in Diabetes, Obesity and Metabolism.
 

A version of this article first appeared on Medscape.com.

Protein complexes referred to as inflammasomes, part of the innate immune system that helps regulate inflammation, appear to be an important contributor to the development of obesity-related colon cancer, if not other cancers, according to new research.

pixologicstudio/Thinkstock

“Population-based studies have shown that individuals who are prone to develop chronic inflammatory diseases are at increased risk of cancer, and inflammasomes play an important role in cancer development showing tumor-promoting or tumor-suppressive actions depending on the type of tumor, the specific inflammasome involved, and downstream effector molecules,” Victoria Catalan, PhD, Navarre Institute of Health Research, Pamplona, Spain, explained in an interview.

“So inflammasomes are not only implicated in obesity-associated colon cancer but their role may be more relevant in patients with obesity,” she added.

The new research was presented during the recent European Congress on Obesity, held virtually because of the pandemic.  The meeting was presented by the European Association for the Study of Obesity.
 

Tissue samples

Tissue samples were obtained from 38 individuals who were lean and 61 individuals who were obese, and further divided into those with or without colon cancer.

A new finding from the study was that both obesity and colon cancer increase gene expression levels of the proteins NLRP3, NLRP6, ASC, and NOD2 in visceral adipose tissue (VAT), “suggesting that obesity-associated visceral adipose tissue inflammation creates a microenvironment favorable for colon cancer development,” Dr. Catalan elaborated.

Investigators also found upregulated levels of IL-1-beta in VAT from individuals who were obese as well as those with colon cancer, an observation that strengthens the hypothesis that inflammasome-dependent production of these cytokines may influence colon tumorigenesis, she added.

Dr. Catalan noted that her team has previously shown that blocking the expression of NLRP3 reduces VAT inflammation and significantly attenuates fibrosis that contributes to the development of obesity-associated comorbidities including type 2 diabetes and nonalcoholic fatty liver disease.  

“Whether obesity has an impact on colon cancer through the enhancement of inflammation or via a direct mechanism is largely unclear, and the role of inflammasomes in cancer development is still controversial,” Dr. Catalan cautioned.

Nevertheless, the study showed that tissue samples from patients with colon cancer were associated with reduced expression of NLRP6 and IL-18. Dr. Catalan explained that NLRP6 is an important factor in the intestinal injury response which regulates aspects of healing inflammation. The same protein is also linked to epithelial integrity and the loss of NLRP6, and IL-18 – its main effector in the intestine – has been associated with increased mortality in colorectal cancer.

“Thus, reduced expression of NLRP6 and IL-18 in the colon from patients with colon cancer suggests an impaired regulation in the inflammatory cascade and a decrease in the integrity of the intestinal barrier,” Dr. Catalan suggested. The same experiment revealed that gene expression levels of adiponectin, an anti-inflammatory protein produced by adipose tissue, were similarly reduced in VAT in individuals who were obese as well as those with colon cancer.  

Low levels of adiponectin have, in turn, been linked to a higher risk of colorectal cancer, Dr. Catalan noted. But it has also been recently shown that normal levels of adiponectin inhibit colorectal cancer cell growth. “It is very important to take into account that inflammasomes have contrasting roles in tumorigenesis, demonstrating both detrimental and beneficial effects,” Dr. Catalan observed.

The researchers speculated that NLRP3 agonists may enhance immune function and help reverse the immunosuppressive microenvironment promoted by VAT inflammation. For instance, activation of IL-18 signaling by inflammasomes regulates intestinal tissue repair following the development of colon cancer by triggering the process of re-epithelialization. Development of NLRP3 antagonists that can block the signaling pathway of IL-1-beta is currently an important area of research.

Similarly, the recombinant IL-1 receptor antagonist anakinra (Kineret, Amgen), the neutralizing IL-1-beta antibody canakinumab (Ilaris, Novartis), and the soluble decoy IL-1-beta receptor rilonacept (Arcalyst, Regeneron) are all being evaluated as a strategy to block IL-1-beta signaling, Dr. Catalan pointed out.

Various NLRP3 inflammasome inhibitors are also being developed. “Pharmacological inhibitors of the NLRP3 pathway could offer a [viable] treatment option in a wide array of chronic and autoinflammatory diseases for which no adequate therapies currently exist,” Dr. Catalan speculated.

“Strategies to restore the functions of immunosurveillance of inflammasome components could represent an interesting target to identify and treat patients with obesity at increased risk for developing colon cancer,” the researchers said.
 

A version of this article first appeared on Medscape.com.

Protein complexes referred to as inflammasomes, part of the innate immune system that helps regulate inflammation, appear to be an important contributor to the development of obesity-related colon cancer, if not other cancers, according to new research.

pixologicstudio/Thinkstock

“Population-based studies have shown that individuals who are prone to develop chronic inflammatory diseases are at increased risk of cancer, and inflammasomes play an important role in cancer development showing tumor-promoting or tumor-suppressive actions depending on the type of tumor, the specific inflammasome involved, and downstream effector molecules,” Victoria Catalan, PhD, Navarre Institute of Health Research, Pamplona, Spain, explained in an interview.

“So inflammasomes are not only implicated in obesity-associated colon cancer but their role may be more relevant in patients with obesity,” she added.

The new research was presented during the recent European Congress on Obesity, held virtually because of the pandemic.  The meeting was presented by the European Association for the Study of Obesity.
 

Tissue samples

Tissue samples were obtained from 38 individuals who were lean and 61 individuals who were obese, and further divided into those with or without colon cancer.

A new finding from the study was that both obesity and colon cancer increase gene expression levels of the proteins NLRP3, NLRP6, ASC, and NOD2 in visceral adipose tissue (VAT), “suggesting that obesity-associated visceral adipose tissue inflammation creates a microenvironment favorable for colon cancer development,” Dr. Catalan elaborated.

Investigators also found upregulated levels of IL-1-beta in VAT from individuals who were obese as well as those with colon cancer, an observation that strengthens the hypothesis that inflammasome-dependent production of these cytokines may influence colon tumorigenesis, she added.

Dr. Catalan noted that her team has previously shown that blocking the expression of NLRP3 reduces VAT inflammation and significantly attenuates fibrosis that contributes to the development of obesity-associated comorbidities including type 2 diabetes and nonalcoholic fatty liver disease.  

“Whether obesity has an impact on colon cancer through the enhancement of inflammation or via a direct mechanism is largely unclear, and the role of inflammasomes in cancer development is still controversial,” Dr. Catalan cautioned.

Nevertheless, the study showed that tissue samples from patients with colon cancer were associated with reduced expression of NLRP6 and IL-18. Dr. Catalan explained that NLRP6 is an important factor in the intestinal injury response which regulates aspects of healing inflammation. The same protein is also linked to epithelial integrity and the loss of NLRP6, and IL-18 – its main effector in the intestine – has been associated with increased mortality in colorectal cancer.

“Thus, reduced expression of NLRP6 and IL-18 in the colon from patients with colon cancer suggests an impaired regulation in the inflammatory cascade and a decrease in the integrity of the intestinal barrier,” Dr. Catalan suggested. The same experiment revealed that gene expression levels of adiponectin, an anti-inflammatory protein produced by adipose tissue, were similarly reduced in VAT in individuals who were obese as well as those with colon cancer.  

Low levels of adiponectin have, in turn, been linked to a higher risk of colorectal cancer, Dr. Catalan noted. But it has also been recently shown that normal levels of adiponectin inhibit colorectal cancer cell growth. “It is very important to take into account that inflammasomes have contrasting roles in tumorigenesis, demonstrating both detrimental and beneficial effects,” Dr. Catalan observed.

The researchers speculated that NLRP3 agonists may enhance immune function and help reverse the immunosuppressive microenvironment promoted by VAT inflammation. For instance, activation of IL-18 signaling by inflammasomes regulates intestinal tissue repair following the development of colon cancer by triggering the process of re-epithelialization. Development of NLRP3 antagonists that can block the signaling pathway of IL-1-beta is currently an important area of research.

Similarly, the recombinant IL-1 receptor antagonist anakinra (Kineret, Amgen), the neutralizing IL-1-beta antibody canakinumab (Ilaris, Novartis), and the soluble decoy IL-1-beta receptor rilonacept (Arcalyst, Regeneron) are all being evaluated as a strategy to block IL-1-beta signaling, Dr. Catalan pointed out.

Various NLRP3 inflammasome inhibitors are also being developed. “Pharmacological inhibitors of the NLRP3 pathway could offer a [viable] treatment option in a wide array of chronic and autoinflammatory diseases for which no adequate therapies currently exist,” Dr. Catalan speculated.

“Strategies to restore the functions of immunosurveillance of inflammasome components could represent an interesting target to identify and treat patients with obesity at increased risk for developing colon cancer,” the researchers said.
 

A version of this article first appeared on Medscape.com.

Protein complexes referred to as inflammasomes, part of the innate immune system that helps regulate inflammation, appear to be an important contributor to the development of obesity-related colon cancer, if not other cancers, according to new research.

pixologicstudio/Thinkstock

“Population-based studies have shown that individuals who are prone to develop chronic inflammatory diseases are at increased risk of cancer, and inflammasomes play an important role in cancer development showing tumor-promoting or tumor-suppressive actions depending on the type of tumor, the specific inflammasome involved, and downstream effector molecules,” Victoria Catalan, PhD, Navarre Institute of Health Research, Pamplona, Spain, explained in an interview.

“So inflammasomes are not only implicated in obesity-associated colon cancer but their role may be more relevant in patients with obesity,” she added.

The new research was presented during the recent European Congress on Obesity, held virtually because of the pandemic.  The meeting was presented by the European Association for the Study of Obesity.
 

Tissue samples

Tissue samples were obtained from 38 individuals who were lean and 61 individuals who were obese, and further divided into those with or without colon cancer.

A new finding from the study was that both obesity and colon cancer increase gene expression levels of the proteins NLRP3, NLRP6, ASC, and NOD2 in visceral adipose tissue (VAT), “suggesting that obesity-associated visceral adipose tissue inflammation creates a microenvironment favorable for colon cancer development,” Dr. Catalan elaborated.

Investigators also found upregulated levels of IL-1-beta in VAT from individuals who were obese as well as those with colon cancer, an observation that strengthens the hypothesis that inflammasome-dependent production of these cytokines may influence colon tumorigenesis, she added.

Dr. Catalan noted that her team has previously shown that blocking the expression of NLRP3 reduces VAT inflammation and significantly attenuates fibrosis that contributes to the development of obesity-associated comorbidities including type 2 diabetes and nonalcoholic fatty liver disease.  

“Whether obesity has an impact on colon cancer through the enhancement of inflammation or via a direct mechanism is largely unclear, and the role of inflammasomes in cancer development is still controversial,” Dr. Catalan cautioned.

Nevertheless, the study showed that tissue samples from patients with colon cancer were associated with reduced expression of NLRP6 and IL-18. Dr. Catalan explained that NLRP6 is an important factor in the intestinal injury response which regulates aspects of healing inflammation. The same protein is also linked to epithelial integrity and the loss of NLRP6, and IL-18 – its main effector in the intestine – has been associated with increased mortality in colorectal cancer.

“Thus, reduced expression of NLRP6 and IL-18 in the colon from patients with colon cancer suggests an impaired regulation in the inflammatory cascade and a decrease in the integrity of the intestinal barrier,” Dr. Catalan suggested. The same experiment revealed that gene expression levels of adiponectin, an anti-inflammatory protein produced by adipose tissue, were similarly reduced in VAT in individuals who were obese as well as those with colon cancer.  

Low levels of adiponectin have, in turn, been linked to a higher risk of colorectal cancer, Dr. Catalan noted. But it has also been recently shown that normal levels of adiponectin inhibit colorectal cancer cell growth. “It is very important to take into account that inflammasomes have contrasting roles in tumorigenesis, demonstrating both detrimental and beneficial effects,” Dr. Catalan observed.

The researchers speculated that NLRP3 agonists may enhance immune function and help reverse the immunosuppressive microenvironment promoted by VAT inflammation. For instance, activation of IL-18 signaling by inflammasomes regulates intestinal tissue repair following the development of colon cancer by triggering the process of re-epithelialization. Development of NLRP3 antagonists that can block the signaling pathway of IL-1-beta is currently an important area of research.

Similarly, the recombinant IL-1 receptor antagonist anakinra (Kineret, Amgen), the neutralizing IL-1-beta antibody canakinumab (Ilaris, Novartis), and the soluble decoy IL-1-beta receptor rilonacept (Arcalyst, Regeneron) are all being evaluated as a strategy to block IL-1-beta signaling, Dr. Catalan pointed out.

Various NLRP3 inflammasome inhibitors are also being developed. “Pharmacological inhibitors of the NLRP3 pathway could offer a [viable] treatment option in a wide array of chronic and autoinflammatory diseases for which no adequate therapies currently exist,” Dr. Catalan speculated.

“Strategies to restore the functions of immunosurveillance of inflammasome components could represent an interesting target to identify and treat patients with obesity at increased risk for developing colon cancer,” the researchers said.
 

A version of this article first appeared on Medscape.com.

Vegetarians have more favorable levels of a number of biomarkers including cardiovascular-linked ones – total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein A and B – than meat eaters, according to results of the largest study of its kind to date.

Results of the cross-sectional, observational study of 178,000 participants were presented as an electronic poster at this year’s online European Congress on Obesity by Jirapitcha Boonpor of the Institute of Cardiovascular & Medical Sciences, University of Glasgow (Scotland).

“We found that the health benefits of becoming a vegetarian were independent of adiposity and other sociodemographic and lifestyle-related confounding factors,” senior author Carlos Celis-Morales, PhD, also from the University of Glasgow, said in an interview.

Total cholesterol and LDL cholesterol concentrations for vegetarians were 21% and 16.4% lower than in meat eaters. But some biomarkers considered beneficial – including vitamin D concentrations – were lower in vegetarians, while some considered unhealthy – including triglycerides and cystatin-C levels – were higher.  

Vegetarian diets have recently become much more popular, but there is insufficient information about the health benefits. Prior reports of associations between biomarkers and a vegetarian diet were unclear, including evidence of any metabolic benefits, noted Dr. Celis-Morales.

Importantly, participants in the study had followed a vegetarian or meat-eater diet for at least 5 years before their biomarkers in blood and urine were assessed.

“If you modify your diet, then, 2 weeks later, you can see changes in some metabolic markers, but changes in markers of cardiovascular disease will take 5-10 years,” he explained.
 

No single biomarker can assess health

Asked to comment on the findings, John C. Mathers, PhD, noted that they clearly confirm the importance of not reading any biomarker result in isolation.

Health is complex and individual markers tell you just part of the story,” said Dr. Mathers of the Human Nutrition Research Centre, Newcastle (England) University.

He says a vegetarian diet can be nourishing but cautioned that “just because someone excludes meat from their diet does not mean necessarily that they will be eating a healthy diet.”

“Some of the biomarker differences seen in this work – such as the lower concentrations of total cholesterol and LDL cholesterol, GGT [gamma-glutamyl transferase], and ALT [alanine transaminase] – are indicators that the vegetarians were healthier than the meat eaters. However, other differences were less encouraging, including the lower concentrations of vitamin D and higher concentrations of triglycerides and cystatin-C.”

Also reflecting on the results, Jose Lara Gallegos, PhD, senior lecturer in human nutrition at Northumbria University, Newcastle upon Tyne, England, said they support previous evidence from large studies such as the European Prospective Investigation into Cancer and Nutrition (EPIC), which showed that a vegetarian diet is associated with a lower risk of heart disease.

“A vegetarian diet might also be associated with lower risk for liver diseases such as nonalcoholic fatty liver disease,” Dr. Gallegos said, but added that some levels of biomarkers considered to be “healthy” were lower in the vegetarians, and it is important to remember that strictly restricted diets might be associated with potential risks of nutritional inadequacies.

“Other, less restrictive dietary patterns, such as a Mediterranean diet, are also associated with ... health benefits,” he observed.
 

Large data sample from the UK Biobank study

“Specifically, we wanted to know if vegetarians were healthier because they are generally leaner and lead healthier lives, or whether their diet specifically was responsible for their improved metabolic and cardiovascular health,” Dr. Celis-Morales explained.

Data were included from 177,723 healthy participants from the UK Biobank study who were aged 37-73 years and had reported no major dietary changes over the last 5 years. In total, 4,111 participants were self-reported vegetarians who followed a diet without red meat, poultry, or fish, and 166,516 participants were meat eaters.

Nineteen biomarkers related to diabetes, hypertension, cardiovascular diseases, cancer, and liver and renal function were included, and the associations between vegetarian diet and biomarkers, compared with meat eaters, were examined.

To minimize confounding, the findings were adjusted for age, sex, deprivation, education, ethnicity, smoking, total sedentary time, type of physical activity, alcohol intake, body mass index, and waist circumference.

Compared with meat eaters, vegetarians had significantly lower concentrations of 14 biomarkers, including total cholesterol (21% lower); LDL (16% lower); lipoprotein A (1% lower), lipoprotein B (4% lower), and liver function markers (GGT: 354% lower, and ALT: 153% lower), IGF-1 (134% lower), urate (122% lower), total protein (29% lower), creatinine (607% lower), and C-reactive protein (10% lower).

However, the researchers found that, compared with meat eaters, vegetarians had significantly higher concentrations of some unhealthy biomarkers, including triglycerides (15% higher) and cystatin-C (4% higher), and lower levels of some beneficial biomarkers including high-density lipoprotein (HDL) cholesterol (5% lower), vitamin D (635% lower), and calcium (0.7% lower).

No associations were found for hemoglobin A1c, systolic blood pressure, and aminotransferase.

“Some biomarkers, for example urate, were very low in vegetarians, and this served to verify our results because we expected meat eaters to have higher levels of urate,” remarked Dr. Celis-Morales.
 

Diet commitment and cardiovascular outcomes

Many people, whether vegetarians or meat-eaters, follow short-term diets, for example, the Atkins or the 5:2 diet, and often lack continuity switching from one diet to the next, or back to regular eating.  

“They are healthy, but they do not commit for long enough to make a difference to metabolic markers or potentially long-term health. In contrast, vegetarians are usually fully committed but the reasons behind this commitment might be a concern for the environment or animal welfare, for example,” Dr. Celis-Morales pointed out.

However, he added that many vegetarians replace the meat in their diet with unhealthy alternatives. “They often eat too much pasta or potatoes, or other high-energy food with low nutritional value.”

Having identified metabolic markers specific to long-term vegetarian diets, Dr. Celis-Morales wanted to know what happens to vegetarians’ long-term cardiovascular health. He analyzed and published these outcomes in a separate study published in December 2020.

“Over 9 years of follow-up, we have found that vegetarians have a lower risk in terms of myocardial infarction in the long-term, as well as other cardiovascular disease,” he reported.

Asked whether there was an optimum age or time in life to become a vegetarian to improve health, Dr. Celis-Morales explained that the healthier you are, the less likely you will reap the health benefits of dietary changes – for example to being a vegetarian.

“It is more likely that those people who have unhealthy lifestyle risk factors, such as smoking, and high consumption of high-energy foods or processed meat are more likely to see positive health effects,” he said.  

Lifestyle changes to improve cardiovascular outcomes are usually more likely to be required at 40 or 50 years old than at younger ages. He also noted that metabolic markers tend to show clear improvement at around 3 months after adopting a particular diet but improvements in disease outcomes take a lot longer to become evident.

Dr. Celis-Morales and his team are currently conducting a further analysis to understand if the vegetarian diet is also associated with a lower risk of cancer, depression, and dementia, compared with meat-eaters.

Dr. Celis-Morales, Dr. Mathers, and Dr. Gallegos have reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Vegetarians have more favorable levels of a number of biomarkers including cardiovascular-linked ones – total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein A and B – than meat eaters, according to results of the largest study of its kind to date.

Results of the cross-sectional, observational study of 178,000 participants were presented as an electronic poster at this year’s online European Congress on Obesity by Jirapitcha Boonpor of the Institute of Cardiovascular & Medical Sciences, University of Glasgow (Scotland).

“We found that the health benefits of becoming a vegetarian were independent of adiposity and other sociodemographic and lifestyle-related confounding factors,” senior author Carlos Celis-Morales, PhD, also from the University of Glasgow, said in an interview.

Total cholesterol and LDL cholesterol concentrations for vegetarians were 21% and 16.4% lower than in meat eaters. But some biomarkers considered beneficial – including vitamin D concentrations – were lower in vegetarians, while some considered unhealthy – including triglycerides and cystatin-C levels – were higher.  

Vegetarian diets have recently become much more popular, but there is insufficient information about the health benefits. Prior reports of associations between biomarkers and a vegetarian diet were unclear, including evidence of any metabolic benefits, noted Dr. Celis-Morales.

Importantly, participants in the study had followed a vegetarian or meat-eater diet for at least 5 years before their biomarkers in blood and urine were assessed.

“If you modify your diet, then, 2 weeks later, you can see changes in some metabolic markers, but changes in markers of cardiovascular disease will take 5-10 years,” he explained.
 

No single biomarker can assess health

Asked to comment on the findings, John C. Mathers, PhD, noted that they clearly confirm the importance of not reading any biomarker result in isolation.

Health is complex and individual markers tell you just part of the story,” said Dr. Mathers of the Human Nutrition Research Centre, Newcastle (England) University.

He says a vegetarian diet can be nourishing but cautioned that “just because someone excludes meat from their diet does not mean necessarily that they will be eating a healthy diet.”

“Some of the biomarker differences seen in this work – such as the lower concentrations of total cholesterol and LDL cholesterol, GGT [gamma-glutamyl transferase], and ALT [alanine transaminase] – are indicators that the vegetarians were healthier than the meat eaters. However, other differences were less encouraging, including the lower concentrations of vitamin D and higher concentrations of triglycerides and cystatin-C.”

Also reflecting on the results, Jose Lara Gallegos, PhD, senior lecturer in human nutrition at Northumbria University, Newcastle upon Tyne, England, said they support previous evidence from large studies such as the European Prospective Investigation into Cancer and Nutrition (EPIC), which showed that a vegetarian diet is associated with a lower risk of heart disease.

“A vegetarian diet might also be associated with lower risk for liver diseases such as nonalcoholic fatty liver disease,” Dr. Gallegos said, but added that some levels of biomarkers considered to be “healthy” were lower in the vegetarians, and it is important to remember that strictly restricted diets might be associated with potential risks of nutritional inadequacies.

“Other, less restrictive dietary patterns, such as a Mediterranean diet, are also associated with ... health benefits,” he observed.
 

Large data sample from the UK Biobank study

“Specifically, we wanted to know if vegetarians were healthier because they are generally leaner and lead healthier lives, or whether their diet specifically was responsible for their improved metabolic and cardiovascular health,” Dr. Celis-Morales explained.

Data were included from 177,723 healthy participants from the UK Biobank study who were aged 37-73 years and had reported no major dietary changes over the last 5 years. In total, 4,111 participants were self-reported vegetarians who followed a diet without red meat, poultry, or fish, and 166,516 participants were meat eaters.

Nineteen biomarkers related to diabetes, hypertension, cardiovascular diseases, cancer, and liver and renal function were included, and the associations between vegetarian diet and biomarkers, compared with meat eaters, were examined.

To minimize confounding, the findings were adjusted for age, sex, deprivation, education, ethnicity, smoking, total sedentary time, type of physical activity, alcohol intake, body mass index, and waist circumference.

Compared with meat eaters, vegetarians had significantly lower concentrations of 14 biomarkers, including total cholesterol (21% lower); LDL (16% lower); lipoprotein A (1% lower), lipoprotein B (4% lower), and liver function markers (GGT: 354% lower, and ALT: 153% lower), IGF-1 (134% lower), urate (122% lower), total protein (29% lower), creatinine (607% lower), and C-reactive protein (10% lower).

However, the researchers found that, compared with meat eaters, vegetarians had significantly higher concentrations of some unhealthy biomarkers, including triglycerides (15% higher) and cystatin-C (4% higher), and lower levels of some beneficial biomarkers including high-density lipoprotein (HDL) cholesterol (5% lower), vitamin D (635% lower), and calcium (0.7% lower).

No associations were found for hemoglobin A1c, systolic blood pressure, and aminotransferase.

“Some biomarkers, for example urate, were very low in vegetarians, and this served to verify our results because we expected meat eaters to have higher levels of urate,” remarked Dr. Celis-Morales.
 

Diet commitment and cardiovascular outcomes

Many people, whether vegetarians or meat-eaters, follow short-term diets, for example, the Atkins or the 5:2 diet, and often lack continuity switching from one diet to the next, or back to regular eating.  

“They are healthy, but they do not commit for long enough to make a difference to metabolic markers or potentially long-term health. In contrast, vegetarians are usually fully committed but the reasons behind this commitment might be a concern for the environment or animal welfare, for example,” Dr. Celis-Morales pointed out.

However, he added that many vegetarians replace the meat in their diet with unhealthy alternatives. “They often eat too much pasta or potatoes, or other high-energy food with low nutritional value.”

Having identified metabolic markers specific to long-term vegetarian diets, Dr. Celis-Morales wanted to know what happens to vegetarians’ long-term cardiovascular health. He analyzed and published these outcomes in a separate study published in December 2020.

“Over 9 years of follow-up, we have found that vegetarians have a lower risk in terms of myocardial infarction in the long-term, as well as other cardiovascular disease,” he reported.

Asked whether there was an optimum age or time in life to become a vegetarian to improve health, Dr. Celis-Morales explained that the healthier you are, the less likely you will reap the health benefits of dietary changes – for example to being a vegetarian.

“It is more likely that those people who have unhealthy lifestyle risk factors, such as smoking, and high consumption of high-energy foods or processed meat are more likely to see positive health effects,” he said.  

Lifestyle changes to improve cardiovascular outcomes are usually more likely to be required at 40 or 50 years old than at younger ages. He also noted that metabolic markers tend to show clear improvement at around 3 months after adopting a particular diet but improvements in disease outcomes take a lot longer to become evident.

Dr. Celis-Morales and his team are currently conducting a further analysis to understand if the vegetarian diet is also associated with a lower risk of cancer, depression, and dementia, compared with meat-eaters.

Dr. Celis-Morales, Dr. Mathers, and Dr. Gallegos have reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.

Vegetarians have more favorable levels of a number of biomarkers including cardiovascular-linked ones – total cholesterol, low-density lipoprotein cholesterol, and apolipoprotein A and B – than meat eaters, according to results of the largest study of its kind to date.

Results of the cross-sectional, observational study of 178,000 participants were presented as an electronic poster at this year’s online European Congress on Obesity by Jirapitcha Boonpor of the Institute of Cardiovascular & Medical Sciences, University of Glasgow (Scotland).

“We found that the health benefits of becoming a vegetarian were independent of adiposity and other sociodemographic and lifestyle-related confounding factors,” senior author Carlos Celis-Morales, PhD, also from the University of Glasgow, said in an interview.

Total cholesterol and LDL cholesterol concentrations for vegetarians were 21% and 16.4% lower than in meat eaters. But some biomarkers considered beneficial – including vitamin D concentrations – were lower in vegetarians, while some considered unhealthy – including triglycerides and cystatin-C levels – were higher.  

Vegetarian diets have recently become much more popular, but there is insufficient information about the health benefits. Prior reports of associations between biomarkers and a vegetarian diet were unclear, including evidence of any metabolic benefits, noted Dr. Celis-Morales.

Importantly, participants in the study had followed a vegetarian or meat-eater diet for at least 5 years before their biomarkers in blood and urine were assessed.

“If you modify your diet, then, 2 weeks later, you can see changes in some metabolic markers, but changes in markers of cardiovascular disease will take 5-10 years,” he explained.
 

No single biomarker can assess health

Asked to comment on the findings, John C. Mathers, PhD, noted that they clearly confirm the importance of not reading any biomarker result in isolation.

Health is complex and individual markers tell you just part of the story,” said Dr. Mathers of the Human Nutrition Research Centre, Newcastle (England) University.

He says a vegetarian diet can be nourishing but cautioned that “just because someone excludes meat from their diet does not mean necessarily that they will be eating a healthy diet.”

“Some of the biomarker differences seen in this work – such as the lower concentrations of total cholesterol and LDL cholesterol, GGT [gamma-glutamyl transferase], and ALT [alanine transaminase] – are indicators that the vegetarians were healthier than the meat eaters. However, other differences were less encouraging, including the lower concentrations of vitamin D and higher concentrations of triglycerides and cystatin-C.”

Also reflecting on the results, Jose Lara Gallegos, PhD, senior lecturer in human nutrition at Northumbria University, Newcastle upon Tyne, England, said they support previous evidence from large studies such as the European Prospective Investigation into Cancer and Nutrition (EPIC), which showed that a vegetarian diet is associated with a lower risk of heart disease.

“A vegetarian diet might also be associated with lower risk for liver diseases such as nonalcoholic fatty liver disease,” Dr. Gallegos said, but added that some levels of biomarkers considered to be “healthy” were lower in the vegetarians, and it is important to remember that strictly restricted diets might be associated with potential risks of nutritional inadequacies.

“Other, less restrictive dietary patterns, such as a Mediterranean diet, are also associated with ... health benefits,” he observed.
 

Large data sample from the UK Biobank study

“Specifically, we wanted to know if vegetarians were healthier because they are generally leaner and lead healthier lives, or whether their diet specifically was responsible for their improved metabolic and cardiovascular health,” Dr. Celis-Morales explained.

Data were included from 177,723 healthy participants from the UK Biobank study who were aged 37-73 years and had reported no major dietary changes over the last 5 years. In total, 4,111 participants were self-reported vegetarians who followed a diet without red meat, poultry, or fish, and 166,516 participants were meat eaters.

Nineteen biomarkers related to diabetes, hypertension, cardiovascular diseases, cancer, and liver and renal function were included, and the associations between vegetarian diet and biomarkers, compared with meat eaters, were examined.

To minimize confounding, the findings were adjusted for age, sex, deprivation, education, ethnicity, smoking, total sedentary time, type of physical activity, alcohol intake, body mass index, and waist circumference.

Compared with meat eaters, vegetarians had significantly lower concentrations of 14 biomarkers, including total cholesterol (21% lower); LDL (16% lower); lipoprotein A (1% lower), lipoprotein B (4% lower), and liver function markers (GGT: 354% lower, and ALT: 153% lower), IGF-1 (134% lower), urate (122% lower), total protein (29% lower), creatinine (607% lower), and C-reactive protein (10% lower).

However, the researchers found that, compared with meat eaters, vegetarians had significantly higher concentrations of some unhealthy biomarkers, including triglycerides (15% higher) and cystatin-C (4% higher), and lower levels of some beneficial biomarkers including high-density lipoprotein (HDL) cholesterol (5% lower), vitamin D (635% lower), and calcium (0.7% lower).

No associations were found for hemoglobin A1c, systolic blood pressure, and aminotransferase.

“Some biomarkers, for example urate, were very low in vegetarians, and this served to verify our results because we expected meat eaters to have higher levels of urate,” remarked Dr. Celis-Morales.
 

Diet commitment and cardiovascular outcomes

Many people, whether vegetarians or meat-eaters, follow short-term diets, for example, the Atkins or the 5:2 diet, and often lack continuity switching from one diet to the next, or back to regular eating.  

“They are healthy, but they do not commit for long enough to make a difference to metabolic markers or potentially long-term health. In contrast, vegetarians are usually fully committed but the reasons behind this commitment might be a concern for the environment or animal welfare, for example,” Dr. Celis-Morales pointed out.

However, he added that many vegetarians replace the meat in their diet with unhealthy alternatives. “They often eat too much pasta or potatoes, or other high-energy food with low nutritional value.”

Having identified metabolic markers specific to long-term vegetarian diets, Dr. Celis-Morales wanted to know what happens to vegetarians’ long-term cardiovascular health. He analyzed and published these outcomes in a separate study published in December 2020.

“Over 9 years of follow-up, we have found that vegetarians have a lower risk in terms of myocardial infarction in the long-term, as well as other cardiovascular disease,” he reported.

Asked whether there was an optimum age or time in life to become a vegetarian to improve health, Dr. Celis-Morales explained that the healthier you are, the less likely you will reap the health benefits of dietary changes – for example to being a vegetarian.

“It is more likely that those people who have unhealthy lifestyle risk factors, such as smoking, and high consumption of high-energy foods or processed meat are more likely to see positive health effects,” he said.  

Lifestyle changes to improve cardiovascular outcomes are usually more likely to be required at 40 or 50 years old than at younger ages. He also noted that metabolic markers tend to show clear improvement at around 3 months after adopting a particular diet but improvements in disease outcomes take a lot longer to become evident.

Dr. Celis-Morales and his team are currently conducting a further analysis to understand if the vegetarian diet is also associated with a lower risk of cancer, depression, and dementia, compared with meat-eaters.

Dr. Celis-Morales, Dr. Mathers, and Dr. Gallegos have reported no relevant financial relationships.

A version of this article first appeared on Medscape.com.