vegan

vegan diets comprise only plant foods and exclude all meat, poultry, fish, dairy products, eggs, and honey. Although many poor peasant agriculturalist populations have diets based on plant foods with only small amounts of animal food, there are no traditional societies which follow a completely vegan diet. The word was coined by Donald Watson as ‘the beginning and end of vegetarian’, and the first vegan society was formed in Britain in 1944.

The reasons for choosing a vegan diet are similar to those for choosing a vegetarian diet, but the philosophy is more logical because dairy foods, which are included in vegetarian diets, cannot be produced efficiently without the slaughter of cattle. To produce milk a cow must give birth to a calf: most of these calves are reared and slaughtered for meat, and the cows themselves are also slaughtered for meat as soon as they fail to conceive or develop other health problems. The production of eggs involves the slaughter of male chicks and of old laying hens.

Unfortified plant foods contain all the nutrients needed by humans except for vitamin B12 and vitamin D. Animals used for meat obtain vitamin B12 from bacteria in the rumen (cattle and sheep), bacteria in the soil (pigs), or by eating their own faeces (rabbits). Vitamin B12 is now synthesized cheaply and added to many foods including breakfast cereals, yeast extracts, and various soya-based foods. Vitamin D is synthesized in the skin in response to sunlight, and is also added to several foods including margarine. Therefore, with fortification and sunlight, vegan diets can supply all the nutrients needed by humans. Vegan diets are usually higher than non-vegetarian diets in some nutrients such as fibre, vitamin C, vitamin E, potassium, and magnesium, and lower than non-vegetarian diets in protein, riboflavin, vitamin B₁₂, and calcium. Vegan diets can be low in iodine and selenium, but this depends on the soil in which the plants are grown.

The nutritional status and health of vegans has been investigated in a number of small studies. These have shown that most vegans are adequately nourished and in satisfactory health, and that vegans are thinner and have lower blood cholesterol concentrations than comparable non-vegetarians. Vegan children grow normally provided that they receive well planned diets. There have been some cases of nutritional deficiency in vegans, notably vitamin B12 deficiency in vegans who were not eating foods fortified with this vitamin (or taking a vitamin B12 supplement).

There is little information on the long-term health of vegans. Epidemiological studies of mortality in vegetarians have included some vegans, and the mortality rate of these vegans has been similar to that of the vegetarians, but the total number studied throughout the world is still far too small to be able to draw any firm conclusions. A diet comprised largely or entirely of plants has several potential advantages for health, land use, and ecological impact, and looking further ahead may be the diet of choice for the extended exploration of space. Further scientific research on plant-based diets and the health of vegans is therefore a priority for the future.

Tim Key

Bibliography

Langley, G. R. (1995). Vegan nutrition. The Vegan Society, St Leonards-on-Sea.