Health risks arising from following a vegetarian or vegan diet

Introduction: According to data from the World Health Organization (WHO), alternative diets such as veganism and vegetarianism are gaining more and more popularity. At the same time, the low level of awareness among the public about the complications that could arise from improper diet control is worrying. Aim: The aim of this study is to summarize the possible risks arising from alternative nutrition as well as the ways of its safe application in healthy people and risk groups of patients. Materials and methods: Research articles and reports published in Google Scholar, PubMed, and MDPI were reviewed. Data were also taken from the website of the WHO European Regional Office. Results: Vegan and vegetarian diets are usually rich in folic acid, ω-6 fatty acids, vitamin E and vitamin C, carbohydrates, fiber, carotenoids, and magnesium. Some beneficial effects are observed on cardiovascular and some kidney diseases, the intestinal microbiome, and metabolism. On the other hand, a poorly balanced vegan diet can lead to serious deficiencies in proteins, fatty acids, iron, iodine, zinc, calcium, and vitamins, especially vitamin B12 and vitamin D. Pregnancy and lactation could proceed under a similar nutritional regime as veganism or vegetarianism, but studies show that this is quite difficult to achieve and is a process that must be closely monitored by a specialist, according to the needs of the mother and the baby. For the same reasons, alternative feeding regimes are not recommended for children. Conclusion: Veganism and vegetarianism appear to be applicable, but with caution and adequate supplementation of deficient nutrients, which must be monitored by a specialist. It is most reasonable to consume a moderate amount of meat against a high intake of fruits, vegetables, dairy products, and fish.