The health benefits of the vegetarian diet

“ The health benefits of vegetarianism which have been scientifically demonstrated are as follows: fewer obesity problems, fewer cardiovascular diseases, less high blood pressure, less type 2 diabetes, fewer cancers, fewer intellectual disorders in the elderly. When we know that these health problems are real scourges in our society, and constitute the majority of deaths, it makes you want to become vegetarian! », explains Dr Jérôme Bernard-Pellet, vegan doctor.

Less cardiovascular disease

Many studies suggest that vegetarians have better cardiovascular health than their meat-eating counterparts. For what ?

An effective diet against bad cholesterol

Research conducted on the subject consistently states that total cholesterol levels are lower in vegetarians than in non-vegetarians (1). One study even suggests that a vegetarian diet would be more effective than drug treatment (2).

Researchers from the University and St Michel Hospital in Toronto compared the effects on cholesterol of standard treatment with medications to those of a balanced vegetarian diet. Result : a vegetarian diet reduces LDL cholesterol levels by 29% (commonly called “bad” cholesterol), compared to 30.9% for medications. It is important to know that the effect of a vegetarian diet on blood cholesterol depends on the composition of the diet, particularly in relation to saturated and unsaturated fatty acids.

Reduced cardiovascular risk factors

A team of researchers compared cardiovascular risk in 67 vegetarians and 134 omnivores aged 35 to 64. The researchers measured several parameters known to be major risk factors for cardiovascular disease: blood pressure, fasting blood sugar, total cholesterol, LDL cholesterol and triglycerides (3). Result : all indicators are better among vegetarians than among non-vegetarians.

A study also shows that a vegetarian diet preserves the cardiovascular health of patients with rheumatoid arthritis (4).

A particularly interesting effect on tension

A well-known risk factor for cardiovascular diseases, high blood pressure is one of the metabolic parameters to monitor carefully, because it has no particular symptoms.

In a 2020 meta-analysis, researchers attempted to gather evidence for a potential protective effect of vegetarian diets on increased blood pressure (5). This work brought together 15 randomized controlled trials with 856 participants.

Result: vegetarian diets, particularly the vegan diet, are associated with significant reductions in blood pressure compared to omnivorous diets, suggesting that they may play a key role in the prevention and overall management of hypertension.

Lower risk of stroke

Vegetarian diet may reduce risk of stroke, study finds Neurology (6). The study focused on two groups of people from Buddhist communities in Taiwan, where vegetarian diets are encouraged, for 6 to 9 years. Around 30% of the 130,000 participants were vegetarian with an average age of 50 years. None had had a stroke before.

Result : vegetarians had only about half the risk of having a stroke compared to non-vegetarians (even when researchers took into account known risk factors such as high blood pressure, high cholesterol and triglyceride levels, and diabetes).

Beware of homocysteine

High levels of homocysteine ​​(a sulfur-containing amino acid) are associated with an increased risk of cardiovascular disease. This rate is influenced by eating habits: it increases during a deficiency in vitamins B12 (common among vegetarians), B9 and B6.

One study (7) compared the homocysteine ​​levels of 26 vegetarians and 26 omnivores. The goal? To determine the effects of vegetarian diet on homocysteinemia in women. Result : Vegetarians have more homocysteine ​​than omnivores.

Hyperhomocysteinemia in vegetarians reduces the protective effect of their diet on cardiovascular disease. The results of several studies suggest that an increase of 5 µmol/L in homocysteine ​​increases the risk of coronary heart disease by 60% in men and 80% in women.

Fewer colon cancers

There is little data on cancer rates among vegetarians, but some information is available for colon cancer. This information suggests that followers of a vegetarian diet have a lower risk of suffering from this cancer.

Meat eaters eat a diet less rich in fiber than vegetarians. These find proteins in foods of plant origin such as cereals and legumes. These foods being also rich in fiber, they ensure the health of our intestines. This is why, unlike meat eaters, vegetarians are less affected by constipation and colon cancer.

A team of British researchers from the University of Oxford monitored the diets of 10,998 men and women for 17 years (8). The results show that vegetarians slightly reduce their risk of colon cancer: they have 15% less risk than non-vegetarians. But it is especially fruits that seem to provide a real protective effect. Vegetarians who eat the most fruit, five or more per week, then reduce their risk of cancer by 40%.

Fruits and vegetables are particularly rich in antioxidant substances

According to Miguel Sanjoaquin, author of the study, “ fruits and vegetables are particularly rich in antioxidant substances which protect the body from free radical damage. On the other hand, it is known that red meat, rich in saturated fats, increases the excretion of bile acids which in turn produce substances that can encourage the growth of tumors “. Several dozen studies (9) have already been carried out on the impact of a vegetarian diet on the occurrence of cancer. Although the results are sometimes mixed, scientists agree that a vegetarian diet generally reduces the risk of cancer, to a greater or lesser extent depending on the study. This is particularly linked to the fact that diet is not the only factor involved in the development of this disease.

Less diabetes

Type 2 diabetes is rarer and is less likely to be a cause of death in vegetarians than in non-vegetarians. This could be explained by the fact that the weight of vegetarians is closer to their healthy weight, which improves glucose tolerance. The higher proportion of foods with a low glycemic index and dietary fiber would also improve carbohydrate metabolism and reduce blood sugar levels.

While there is no significant result among vegetarians, one study suggests that a vegan diet improves blood sugar control in type 2 diabetics (10). American researchers followed, for 22 weeks, 99 type 2 diabetics, 49 of whom received a vegan diet and the other 50 followed a normal diabetic diet. Result : 43% of vegans and 26% of individuals in the control group reduced their medication for diabetes.

Conclusion: the vegan diet improves blood sugar control.

A negative point: bone health

In March 2025, ANSES published an analysis of epidemiological studies on vegetarian diets. Compared to non-vegetarians, vegetarians have a lower risk of developing type 2 diabetes and other pathologies such as: ischemic heart disease, ovulatory disorders, certain cancers (prostate, stomach, blood) and certain ophthalmological and gastrointestinal diseases. But vegetarians have a higher risk of bone fractures (11).

“If confirmed, the higher fracture risk when avoiding animal products may be explained by factors I describe in The Secret to Strong Bones, particularly muscle masscomments Thierry Souccar. Indeed, muscle mass is important in preventing fractures. “In terms of diet (not to mention resistance exercises), muscle mass depends on the amount of protein we ingest, recalls Thierry Souccar. However, people who follow vegetarian/vegan diets tend to consume less protein than others.

In the 2016 EPIC study, meat eaters obtained an average of 90 g of protein per day, compared with 70 g for lacto-ovo vegetarians and 64 g for vegans (12). In the 2017 French NutriNet-Santé study, meat eaters consumed 84 g of protein per day, but vegans only 60 g (13).

“Moreover, the bioavailability of plant proteins is a little lower, and above all they may lack leucine, an amino acid which activates muscle and bone growth factors, as I explain in my book. This does not mean that a diet without animal products necessarily lacks protein, but that it must be well designed to provide sufficient protein, and of good quality.”