VeganismVeganism is a type of vegetarian diet that excludes meat, eggs, dairy products and all other animal-derived ingredients. Many vegans also do not eat foods that are processed using animal products, such as refined white sugar and some wines. Most vegans also avoid the use of all products tested on animals, as well as animal-derived non-food products, such as leather, fur and wool.
Vegan refers to either a person who follows this way of eating, or to the diet itself.
Veganism is a philosophy and lifestyle that seeks to exclude the use of animals for food, clothing, or any other purpose. Vegans endeavor not to use or consume animal products of any kind. The most common reasons for becoming a vegan are human health, ethical commitment or moral conviction concerning animal rights or welfare, the environment, and spiritual or religious concerns. Of particular concern to many vegans are the practices involved in factory farming and animal testing, and the intensive use of land and other resources for animal farming.
Vegan diets (also called "pure" or "completely" vegetarian diets) are a form of vegetarianism. Properly planned vegan diets are healthful and have been found to satisfy nutritional needs. Poorly planned vegan diets can be low in levels of calcium, iodine, vitamin B12, iron and vitamin D. Vegans are therefore encouraged to plan their diet and take dietary supplements as appropriate.
Vegan Nutritional BenefitsScientists such as Roger Segelken and T. Colin Campbell believe that some diets (such as the standard American diet) are detrimental to health, and they believe that a vegan diet represents an improvement, in part because vegan diets are often high enough in fruit and vegetables to meet or exceed the recommended fruit and vegetable intakes.
According to the American Dietetic Association and Dietitians of Canada, diets that avoid meat tend to have lower levels of saturated fat, cholesterol, and animal protein, and higher levels of carbohydrates, fiber, magnesium, potassium, folate, and antioxidants, such as vitamins C and E, and phytochemicals. People who avoid meat are reported to have lower body mass index than those following the average Canadian diet; from this follows lower death rates from ischemic heart disease; lower blood cholesterol levels; lower blood pressure; and lower rates of hypertension, type 2 diabetes, and prostate and colon cancer.
A 1999 meta-study of five studies comparing vegetarian and non-vegetarian mortality rates in western countries found the mortality rate due to ischemic heart disease 26% lower among vegans compared to regular meat eaters, but 34% lower among ovolactovegetarians and those who ate fish but no other meat. No significant difference in mortality was found from other causes. A 2003 review of three studies comparing mortality rates among British vegetarians and non-vegetarians found only a nonsignificant reduction in mortality from ischemic heart disease, but noted that the findings were compatible with the significant reduction found in the 1999 review.
A 2006 study found that in people with type 2 diabetes a low-fat vegan diet reduced weight, BMI, total cholesterol, and LDL cholesterol and did so to a greater extent than the diet prescribed by the American Diabetes Association.
Nutritional concernsVarious fruits, vegetables, nuts, and grains; some basic ingredients of a vegan diet.
Specific nutrients
The American Dietetic Association considers "appropriately planned" vegan diets "nutritionally adequate", but poorly planned vegan diets can be deficient in nutrients such as vitamin B12, iron, vitamin D, calcium, iodine and omega-3 fatty acids. These deficiencies have potentially serious consequences, including anemia, rickets and cretinism in children, and osteomalacia and hypothyroidism in adults.
Vitamin B12
Deficiencies in Vitamin B12, a bacterial product that cannot be reliably found in plant foods, can have serious health consequences, including megaloblastic anemia and neurodegenerative disease (including subacute combined degeneration of the cord). Although clinical B12 deficiency is rare in vegans, if a person has not eaten more than the daily needed amount of B12 over a long period before becoming a vegan then they may not have built up any significant store of the vitamin. In a 2002 laboratory study, more of the strict vegan participants' B12 and iron levels were compromised than those of lacto- or lacto-ovo-vegetarian participants.
The Vegan Society and Vegan Outreach, among others, recommend that vegans either consistently eat foods fortified with B12 or take a B12 supplement. Tempeh, seaweed, spirulina, organic produce, soil on unwashed vegetables, and intestinal bacteria have not been shown to be reliable sources of B12 for the dietary needs of vegans.
Iron
Iron deficiency may lead to iron deficiency anaemia. Vegans and other vegetarians—especially menstruating, pregnant and breastfeeding women—are at increased risk of developing iron deficiency. Iron is less well absorbed from vegetarian diets (approximately ten percent absorption from vegetarian diets, versus approximately 18 percent absorption from an omnivorous diet); vegetarians who exclude all animal products may need almost twice as much dietary iron each day than non-vegetarians. On the other hand, the iron status of omnivores and vegans appears to be similar, and body absorption processes may adjust to low intakes over time by enhancing absorption efficiency. Molasses are a high-iron food source and many vegans take them in spoonfuls as an iron supplement.
Calcium, vitamin D
It is recommended that vegans eat three servings per day of a high calcium food, such as fortified soy milk, almonds, hazelnuts, and take a calcium supplement as necessary. The EPIC-Oxford study showed that vegans have an increased risk of bone fractures over both meat eaters and vegetarians, likely due to lower dietary calcium intake, but that vegans consuming more than the UK's estimated average requirements for calcium of 525 mg/day had risk of bone fractures similar to other groups. A study of bone density found that vegans have bones 6% less dense than omnivores but that this difference was "clinically insignificant". Another study by the same researchers examined over 100 vegan post-menopausal women and found that “…although vegans have much lower intakes of dietary calcium and protein than omnivores, veganism does not have (an) adverse effect on bone mineral density (BMD) and does not alter body composition.”
The authors of The China Study argue that osteoporosis is linked to the consumption of animal protein because animal protein, unlike plant protein, increases the acidity of blood and tissues which is then neutralized by calcium pulled from the bones. The authors add that "in our rural China Study, where the animal to plant ratio [for protein] was about 10%, the fracture rate is only one-fifth that of the U.S.," where consumption of animal products including dairy, is higher.
For light-skinned people, adequate amounts of vitamin D may also be obtained by spending 15 to 30 minutes in the sunlight every few days. Dark-skinned people need significantly more sunlight to obtain the same amount of vitamin D, and sunlight exposure may be difficult for vegans in areas with low levels of sunlight during winter; in these cases supplementation is recommended.
Iodine
Iodine supplementation may be necessary for vegans in countries where salt is not typically iodized, where it is iodized at low levels, or where, as in Britain or Ireland, animal products are used for iodine delivery. Iodine can be obtained from most vegan multivitamins or from regular consumption of seaweeds, such as kelp.
