**2. Vegan diet: risks**

*Veganism - a Fashion Trend or Food as a Medicine*

animals.

People become vegan for many reasons, including ethical care for animals and the natural environment, as well as circumstances related to health, spirituality, and religion [1]. As far as ethical principles are concerned, a vegan diet prevents the mass breeding and systematic slaughter of large numbers of animals on farms. Vegan food contains lower levels of cholesterol and fat than the usual diet. From the ecological point of view, the meat industry participates in the pollution of air, land and water, contributes to the exploitation and deforestation of forests and large land areas for the cultivation of crops intended for feeding a large number of farmed

The basis of a healthy vegan diet is all vegetables, vegetable proteins, good fats and whole grains. However, vegans should pay attention to the intake of calcium, magnesium and vitamin D. Adequate intake of vitamin B12 is especially important, which is available in certain types of herbal drinks such as herbal drinks that do not contain lactose or added sugars and are especially suitable for vegans. A wellplanned vegan diet can meet all the needs of the body. A poorly organized vegan diet can cause a lack of calcium, iodine, iron, vitamin B12 and vitamin D, which

According to surveys, vegans make up between 0.2% and 1.3% of the American

The benefits of a vegan diet are great - it reduces the risk of cancer, cardiovascular disease, myocardial infarction, stroke, rheumatoid arthritis, high blood pressure,

Many studies suggest a link between cancer and diet [4]. More than half of these

Vegetarians and vegans generally include greater amounts of plant foods, avoid

the intake of meat, and often adopt other healthy lifestyles compared to nonvegetarians [9]. Thus there is reason to suspect that vegetarian diets may protect against cancer. Factors associated with the high fiber content in vegetarian diets promote increased insulin sensitivity [10]. Plant-based diet is associated with lower circulating levels of total IGF-I and higher levels of IGFBP-I and IGFBP-2 compared with a meat-eating or even a lacto-ovo-vegetarian diet [11]. Insulin and IGF-I act as promoters for most normal and pre-neoplastic tissues. Therefore, their down- regulation may reduce cancer rates [12]. The strongest evidence linking specific foods to decrease risk of certain cancers includes the consumption of fruits and vegetables and whole grains [13]. Studies show a strong inverse relationship between dietary fiber intake and colon cancer in populations at low risk for the disease [14]. Several hypotheses have been postulated to explain this effect, 2 of which are outlined as follows. First, fiber increases the bulk of the stool, which decreases transit time and, in turn, could decrease the time colonic epithelial cells are exposed to potential fecal carcinogens. Second, bacteria in the gut can ferment fiber to short-chain fatty acids such as butyrate. These fatty acids may promote colonic cell differentiation and normal cell apoptosis [15]. It is estimated that an

cancer cases are potentially preventable. Diet affects approximately 30% of all

The diet enables the assessment of the connection between the disease and the intake of certain foods in relation to the usual diet [6]. Several studies have been published that deal with the relationship between dietary factors and overall cancer risk. The vegan diet is thought to be inversely related to the overall incidence of cancer. There are studies whose results for certain cancers are not in line with the diet. This lack of clarity may result from the heterogeneity of vegetarian diets among respondents in different countries, as they may vary widely in relation to the ratio of animal and plant foods eaten, food quality, cooking methods, limitations of measures used to quantify dietary nutrition, and other factors may affect the

must then be taken from vitamin and mineral supplements [2].

asthma, allergies and kidney stones.

development of cancer [7, 8].

population and between 0.25% and 7% of the general population [3].

cancers in developed countries and 20% in developing countries [5].

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Most of the data on the vegan diet is based on the adult population. Less is known about the vegan diet of newborns and children. Children have a greater need for energy and protein, which is met by vegetables, tofu, beans, whole grains, nuts and seeds. It is recommended for 10% more protein in childhood than in adult vegans. For this reason, alternatives rich in low-fiber vegan proteins, such as tofu and seitan, may be desirable, as these foods usually result in high satiety and can support adequate protein intake. Because animal foods such as meat, dairy, eggs, fish and fowl are among the best sources of protein, vegans can sometimes lack sufficient protein in their diets. The American Dietetic Association, however, notes that protein requirements can be met if a variety of plant proteins are consumed. Complementary proteins, specifically, can be very helpful in providing all the essential amino acids required by the body. Complementary proteins are made up by two incomplete proteins, such as beans and rice, that, when combined, form a complete protein. These proteins do not need to be consumed at the same meal, just during the same day [18]. Though vegan diets are often rich in omega-6 fatty acids, they can lack sufficient amounts of omega-3 due to the restriction of omega-3-rich foods, including eggs, fish and other seafood. The omega-3 fatty acids found in animal sources, which include eicosapentaenoic acid and docosahexaenoic acid, are important for cardiovascular, brain and eye health. Plant foods rich in omega-3, such as flaxseed, only contain another type of fatty acid, known as alpha-linolenic acid. Vegans can purchase soy milk and breakfast bars fortified with DHA, as well as DHA supplements derived from microalgae. Because DHA can be retroconverted to EPA, sources containing DHA are sufficient for vegan diets. Vitamin D is important for bone health, and low levels have been linked to reduced bone mass. Sunlight exposure is best source of vitamin D. Therefore, vegans who do not get regular sun exposure need to consume dietary vitamin D through either fortified foods or supplements, since vitamin D occurs naturally in very few foods. Vegan sources of vitamin D that are often fortified include soy milk, rice milk and orange juice. Lack of vitamin B-12 is one of the biggest concerns with vegan diets, especially because vegan diets are typically rich in folacin, which can mask B-12 deficiency symptoms [6]. Severe B-12 deficiencies can result in both anemia and dementia, notes Harvard Medical School. So, if you are a vegan, be sure to consume B-12 fortified foods such as soy and rice beverages and breakfast cereals, or supplements. Because the bioavailability of iron in vegan diets is lower than in traditional diets, vegans should consume 1.8 times the amount of iron consumed by nonvegans. Good sources of iron for vegans include dried beans and dark, leafy green vegetables. Zinc is another mineral whose bioavailability is lower in vegans than in nonvegans. Vegan sources of zinc include legumes, soy products, grains and nuts. Some research suggests that because plant-based diets are low in iodine, vegans who do not consume key sources of iodine, including iodized salt and sea vegetables, are more likely to be deficient in the mineral. The American Dietetic Association notes that vegans tend to fall below the recommended intake of calcium. The calcium in certain calcium-rich vegetables, such as Swiss chard and spinach, is not absorbed well, making fortified foods such as fruit juices, breakfast cereal and soy and rice milk among the best choices for vegans [2].
