Effects of vegetarian and vegan diets on the gastrointestinal tract

In 2018, an interesting study was published, which involved 1209 anonymous adult volunteers from Poland (886 people) and the United States of America (323 people). 702 people adhered to a vegetarian diet, and 365 people adhered to a vegan diet. The control group included 142 people who did not use any dietary restrictions. A questionnaire was used on demographic data, socioeconomic status, chronic diseases, and gastrointestinal complaints.

Veganism is the strictest type of diet 1

Volunteers followed the diet for at least 1 year, after which their health status was analyzed and the following conclusions were made:

Vegetarians and vegans had lower body mass index (BMI) than the standard diet group.

Chronic diseases occurred with the same frequency in all study groups.

After changing the diet, an improvement in well-being was noticed in more than half of vegetarians and vegans – 74%, 84%, deterioration – 4% and 3% and no change – 22% and 13%, respectively.

Before the change in diet, half of vegetarians and almost 2/3 of vegans experienced bloating, a feeling of heaviness and fullness in the stomach; about 1/3 suffered from heartburn, nausea and a tendency to constipation; 11% of subjects in both groups had poor appetite; 2% of vegetarians and 3% of vegans had dermatological problems.

After changing the diet, a significant proportion of participants noted a decrease in the frequency of symptoms from the digestive system. Bloating and a feeling of fullness in the stomach were noted only by 12% of vegetarians and 13% of vegans; heartburn, nausea – 4% and 2%, a tendency to constipation – 4% and 8%, poor appetite – 3% and 2%.

It was found that the frequency of dermatological problems (such as hair loss, acne, brittle nails) increased significantly to 16% in vegetarians and 10% in vegans.

This study demonstrated a beneficial effect of diet on intestinal motility, which is associated with a higher fiber intake.

The reduction in bloating after switching to a vegetarian diet is more difficult to explain, as many plant foods have potentially gas-producing properties. In vegans, improvements may be due to the exclusion of lactose, as lactose intolerance occurs in about 20-25% of adult Poles.

There is an assumption that a plant-based diet changes the composition of the intestinal microbiota, which contributes to the formation of short-chain fatty acids and the suppression of the growth of pathogenic flora.

Fatty foods can help relax the lower esophageal sphincter and act as a reflux trigger. The reduction in heartburn is likely due to the replacement of fat-rich foods with fiber-rich foods. In addition, weight loss also favorably affects the course of GERD by reducing intra-abdominal pressure.

A vegetarian diet is characterized by a lower calorie content and stimulation of gastrointestinal motility. This likely resulted in improved appetite in the subjects.

Veganism is the strictest type of diet 2

What conclusion would you like to draw from the above? It is possible to stick to a vegetarian diet in the long run with health benefits, but only if the person is willing to devote some amount of time and attention to planning their diet. When switching to a plant-based diet, there are risks of deficiencies in nutrients such as protein, vitamin B12, iron, zinc, calcium, omega-3, iodine. That is why the decision to switch to a vegetarian / vegan diet should be approached responsibly, in consultation with a doctor. It must be understood that periodically it may be necessary to take tests, take vitamins or trace elements in supplements, and adjust the diet together with a dietitian.

In addition, it is important to emphasize that a vegetarian/vegan diet is not the only correct type of diet. This is just one of the options and does not outperform a standard diet that includes animal products in terms of health benefits. For example, the so-called Mediterranean type of diet, which implies the use of a large amount of plant foods, carries the same health benefits that can be obtained from a vegetarian diet, but does not exclude the use of meat, fish, eggs and dairy products.