The health benefits of vegetarian diets are recognized, since they favor maintaining a normal body weight and reduce the risks of chronic diseases, an effect attributed to the high intake of fruits, vegetables, whole foods and low intake of saturated fat.
More and more people are opting for a Veggy diet around human health; due to the high consumption of foods of animal origin and the higher prevalence of the so-called chronic non-communicable diseases (cardiovascular, cancer, type 2 diabetes, obesity) and, on the other hand, linked to the cost, in ecological terms, of the livestock operation.
Well-planned vegetarian diets are appropriate for all stages of the life cycle, including pregnancy, lactation, infancy, childhood and adolescence, as well as for athletes, and can also provide health benefits in prevention and treatment of certain diseases.
Nutritional Considerations for Vegetarians
People who follow these diets are subjected to possible deficiencies of macro and micronutrients, because of this, it is important to obtain consultation with health and nutrition professionals to lead a healthier life rich in essential nutrients.
The critical nutrients in the vegetarian are proteins, omega 3 fatty acids, iron, zinc, iodine, calcium, vitamin D, vitamin B12.
1. Protein
Cereals tend to be low in lysine, an essential amino acid. This may be relevant when evaluating the diets of individuals who do not consume animal protein sources and when the diets are relatively low in protein. Some dietary adjustments, such as consuming more legumes and soy products instead of other protein sources poorer in lysine, or increasing dietary protein of all types, can ensure adequate lysine intake.
Plant protein can meet protein requirements as long as a variety of plant foods are eaten and caloric needs are met.
2. Omega-3 fatty acids
While vegetarian diets are generally high in omega-6 fatty acids, they may contain insufficient amounts of omega-3 fatty acids. Diets that do not include fish, eggs, or generous amounts of algae are generally low in eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two fatty acids important for cardiovascular health and brain and eye development.
Vegetarians, and especially vegans, tend to have lower blood levels of EPA and DHA than non-vegetarians. For the vegan, some microalgae are a source of DHA and brown seaweed oil is a good source of EPA. Rich sources of alpha-linoleic acid (ALA), the precursor to EPA and DHA, include flaxseed (flax seeds), canola, walnuts, chia, and soybeans, however the conversion of ALA to DHA is lower. People with higher omega-3 fatty acid requirements, such as pregnant and breastfeeding women, can take advantage of DHA-rich microalgae.
3. Iron
The iron in plant foods is non-heme iron, which is sensitive to both inhibitors and enhancers of iron absorption.
Some inhibitors of iron absorption are phytates, calcium and polyphenols from tea, coffee, herbal teas and cocoa. Fiber only slightly inhibits iron absorption.
Some food preparation techniques (such as soaking and sprouting legumes, grains and seeds, and fermenting bread) can reduce the amount of phytate and thus improve iron absorption. Other fermentation processes, such as those used to make miso and tempeh, can also improve the bioavailability of iron. Vitamin C and other organic acids present in fruits and vegetables can considerably promote iron absorption and reduce the inhibitory effects of phytates, and thus improve iron status.
Due to the lower bioavailability of iron in a vegetarian diet, the recommended iron intake for vegetarians is 1.8 times that of non-vegetarians.
The incidence of iron deficiency anemia in vegetarians is similar to that of non-vegetarians. Although vegetarian adults have lower iron stores than non-vegetarians, their serum ferritin concentrations are generally within normal limits.
4. Zinc
The bioavailability of zinc in vegetarian diets is lower than in non-vegetarian diets, mainly due to the higher content of phytic acid in vegetarian diets.
Therefore, the zinc requirements for some vegetarians, whose diets consist mainly of legumes and unrefined grains rich in phytates, may exceed the Recommended Daily Allowances.
Food preparation techniques (such as soaking and sprouting legumes, grains, and seeds, and fermenting bread) can reduce the binding of zinc to phytic acid and increase the bioavailability of zinc. Organic acids, such as citric acid, can also improve zinc absorption to some extent.
- Overt zinc deficiency is not evident in Western vegetarians.
- Some sources of zinc are soy products, legumes, cereals, cheese, and nuts.
5. Iodine
Some studies indicate that vegans who do not consume key sources of iodine, such as iodized salt or seaweed, may be at risk for iodine deficiency, because plant-based diets are often low in iodine. Sea salt and kosher salt are usually not iodized, and neither are salty seasonings like tamari.
Foods such as soybeans, cruciferous vegetables, and sweet potatoes contain natural goitrogens. These foods have not been associated with thyroid insufficiency in healthy individuals as long as iodine intake is adequate.
Vegetarian diets have recognized benefits, favor maintaining a normal weight and reduce the risk of chronic diseases. Properly planned they are healthy.
6. Calcium
Data from the Oxford Center for the European Prospective Study on Cancer and Nutrition (EPIC-Oxford) showed that the risk of fractures was similar in lacto-ovo-vegetarians and meat eaters, while vegans had 30% increased risk of fractures. bones. possibly because their mean calcium intake was significantly lower.
7. Vitamin D
Vitamin D status depends on exposure to sunlight and the intake of foods fortified with vitamin D or supplements. The degree of skin synthesis of vitamin D after exposure to sunlight is highly variable and depends on various factors, such as time of day, season, latitude, skin pigmentation, use of sunscreen, and age.
Low intakes of vitamin D, low serum concentrations of 25-hydroxyvitamin D, and lower bone mass have been observed in some vegan groups that did not take vitamin D supplements or fortified foods.
Foods fortified with vitamin D include cow’s milk, some brands of soy drink, rice drink and orange juice, and some breakfast cereals and margarines. Both vitamin D2 and vitamin D3 are used in supplements and to enrich food. Vitamin D3 (cholecalciferol) is of animal origin and is obtained by ultraviolet irradiation of lanolin 7-dehydrocholesterol. Vitamin D2 (ergocalciferol) is obtained from the ultraviolet irradiation of ergosterol from yeast and is considered acceptable for vegans.
Although some studies indicate that vitamin D2 is less effective than D3 in maintaining serum 25-hydroxyvitamin D, others show that vitamin D2 and vitamin D3 are just as effective.
Low-oxalate vegetables (eg, Chinese cabbage, broccoli, Chinese cabbage, collard greens, and kale) and fortified fruit juices are good sources of highly bioavailable calcium (50-60% and 40-50%, respectively), while calcium-enriched tofu and cow’s milk have good calcium bioavailability (around 30-35%), sesame seeds, almonds and dried beans have lower bioavailability (21-27 %).
Fortified foods such as fruit juices, soy and rice drinks, and breakfast cereals can provide significant amounts of dietary calcium for vegans.
The oxalates in some foods, such as spinach and Swiss chard, greatly reduce calcium absorption, making these vegetables poor sources of usable calcium. Foods rich in phytates can also inhibit calcium absorption.
8. B12 vitamin
Lacto-ovo-vegetarians can obtain adequate amounts of vitamin B12 from dairy products, eggs, or other reliable sources of vitamin B12 (fortified foods and supplements), if they consume them regularly. For vegans, vitamin B12 must be obtained through regular consumption of foods fortified with vitamin B12, such as fortified soy and rice drinks, some breakfast cereals, and some meat substitutes; otherwise, a daily vitamin B12 supplement is needed.
However, it is currently being investigated whether other non-animal but bioavailable sources of vitamin B12 can be used, including Chlorella pyrenoidosa. In vegans with vitamin B12 deficiency, who were given 9 g of Chlorella pyrenoidosa for 2 months, showed an increase in serum levels of this vitamin.
Vitamin B12 can also be found, for example, in vegetables grown with organic fertilizer, however, the amount of vitamin B12 present in these foods is low. Due to bacterial contamination, tempeh, a food product obtained from the fermentation of soybeans, contains a considerable amount of vitamin B12 (0.7-8.0 μg / 100 g).
Other foods that have an interesting amount of vitamin B12 are wild mushrooms, being the shiitake mushroom (Lentinula edode) one of those that contain the most and that in addition, its consumption is massive among vegetarians, however, more than 50 g of mushroom are needed dry to meet the requirements of this vitamin.
Finally, some edible algae such as nori seaweed, present a non-negligible amount of this vitamin and with good bioavailability. Consumption of 4 g of dried purple algae (77.6 μg dry weight vitamin B12 / 100 g) provides the recommended daily dose of 2.4 μg / day,
According to the World Health Organization and FAO, vegetarians have a lower risk of obesity, hypertension, cardiovascular diseases, diabetes, arthritis, cancer (especially colon and prostate), and heart disease
Professional nutritionists should educate individuals who take the option of starting any type of vegetarian diet and help implement it properly, to cover all the macro and micronutrients required according to their age and metabolic status, to promote normal growth and development.
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