Digestion | March 1, 2016 | Author: The Super Pharmacist
Vegans, excluding dairy products, eggs and any other animal products from their diets, tend to eat significantly higher levels of particular vitamins and minerals than individuals with standard diets. A typically vegan diet will have much higher levels of Vitamin C, Vitamin E, folic acid, iron, magnesium and dietary fibres. Conversely, they also tend to have a lower calorie count, cholesterol, omega-3 fatty acids, Vitamin D, Vitamin B12, calcium and zinc than diets which contain animal products (1).
The question of the distinct health advantages of being a vegan is a complex one. The question is often framed as being beneficial in comparison to diets that include animal products, yet this is a difficult comparison to evaluate and study due to the wide range of confounding variables that contribute to good health and longer life. It is difficult to separate the health benefits of veganism from other practices such as not smoking, levels of exercise, and not drinking excessively. In comparison to individuals who consume meat, vegans tend to consume much less saturated fat and cholesterol, and eat many more phytochemicals (chemical compounds that occur naturally in plants). As such, vegans tend to have lower levels of low-density lipoprotein (LPL) cholesterol, lower body mass index (BMI) and lower blood pressure, all of which have an evidenced association with longer life and a reduced risk of a wide range of chronic diseases (2). There is some clinical evidence that vegans have a lower risk of heart attack and death from cardiac causes compared to those who have diets including meat. A famous large prospective epidemiological study, comparing vegan and non-vegan Seventh Day Adventists (a religious group that avoid caffeine and don’t drink or smoke), found vegans to have significantly less incidence of cardiovascular disease (3,4). The sample also acknowledged and controlled for additional variables that are protective factors in longer life expectancy such as exercise and tobacco avoidance, as have a wide range of other large cohort studies with similar findings (5).
Although veganism carries significant health benefits, the strict requirements of the diet also place vegans at a higher risk of particular diseases. The EPIC-Oxford study, involving 65,000 research participants, evidenced a reduced risk of cardiovascular disease in vegans but a significantly higher risk of bone fractures and osteoporosis, with less than 75% of vegan participants receiving their recommended daily allowance of calcium (6). This appears to be as a result of a lower mean calcium uptake than both vegetarians and meat and fish eaters. Deficiency in iron can also cause anaemia, and iron deficiency can also manifest itself as an enlarged spleen, frequent infections, brittle nails, and swelling and/or soreness of the tongue. Similarly, a lack of calcium (hypocalcemia), as well as contributing to low bone density, can manifest as muscle cramps, abdominal cramps and a highly irritable nervous system. A lack of Vitamin B12 can also result in folate deficiency anaemia, and is most common in older people. Vitamin D is essential for regulating the amount of calcium and phosphate in our bodies, and ensuring bones and teeth remain healthy. Vegan diets are often low in Vitamin D, and require additional supplementation. This is especially true for vegans living in countries with relatively low levels of sunlight, as the body generates Vitamin D under the skin in response to the sun.
Good planning is essential when following a vegan diet to ensure that it meets all the nutritional and mineral requirements of each individual. The lack of iron, calcium, Vitamin B12 and Vitamin D that is common with many vegan diets can be addressed through a number of non-pharmaceutical methods such as eating plenty of fruit and vegetables, starchy foods, beans, pulses and dairy alternatives such as fortified soya drinks. The lack of certain minerals and vitamins in a vegan diet can have a particularly negative effect on developing children, and many organisations recommend supplementary Vitamin A, C and D for many children (providing they are not drinking more than 500ml of infant formula per day). Children who are solely breastfed are recommended to receive all the vitamin supplements, as vegan parents are also less likely to transmit adequate levels of the requisite minerals and vitamins naturally that a young child requires to develop appropriately (7,8). Fortified soy milk is a popular dietary choice among many vegans as a reliable source of calcium, and is reinforced by a strong body of evidence (9). A lack of Vitamin B12 often results in iron deficiency anaemia. The most commonly prescribed supplement is ferrous sulphate. Individuals who experience significant side effects to this drug can be prescribed ferrous gluconate in its place (10). For individuals with complications such as Chronic Kidney Disease (CKD), B12 injections can be used in place of orally administered tablets (11). It is important that patients discuss B12 deficiency with their Doctors, as vegan diets are not the only contributing factor that result in low levels: pernicious anaemia and certain medications (such as anticonvulsants and proton pump inhibitors) can also affect how many vitamins the body is able to absorb due to their effect on normal gastric acid function (12). It is important that B12 as a dietary component is addressed at the outset of commencing a vegan diet, as prolonged periods of deficiency can result in a number of health problems such as temporary infertility, heart conditions and pregnancy complications (13). This extends to a need for detailed planning and knowledge of plant-based nutrition, and being aware of the consequences of not incorporating all the vitamins and minerals that are required for a healthy, balanced diet.