Throughout the world there are many people who are vegetarians. Currently, most vegetarians choose to be on this type of diet for health or ethical reasons. Of the adult population in the United States, 2.5% or 4.8 million people constantly follow a vegetarian diet. Two percent of children 6-17 years old are also vegetarians.
To accommodate the increased popularity of vegetarian diets, the food industry has pushed for new food products and cookbooks to be put on the market. Also, cafeterias and restaurants have been putting more vegetarian options on their menus. Not all of these options are ideal and vegetarians must be careful of their possible choices.
The majority of the population are non-vegetarians and often have the viewpoint depicted by the cartoonist above. There are many people that are ignorant of all the possibilities of protein sources that can be consumed in the vegetarian diet. Vegans and vegetarians need to be very knowledgeable about how to complement vegetable protein with grain protein to obtain adequate protein (that is complete with all the essential amino acids) for the day. This can be easily achieved with planning if they follow the guidelines and substitute legumes, nuts, soy protein, etc. for meat protein. Non-vegetarians often consume much more protein than needed which can result in weight gain.
The more restricted a vegetarian diet is, the more their diet may be low or absent in vitamin B12, vitamin D, riboflavin, calcium, iron and zinc. Deficiencies in these nutrients can be very serious and even life threatening.
- Vitamin B12 unfortunately is only contained in animal products, including egg & dairy (and in small amounts in fermented vegetable products) therefore vegans should consider taking a supplement to avoid deficiencies such as pernicious anemia and nerve degeneration (and long-term neurological problems for infants with pregnant or breastfeeding vegetarian mothers).
- Vitamin D can be obtained from fatty fish, fortified milk and cereals as well as from sunlight. It is rare for vegetarians to be deficient in vitamin D if they have adequate sun exposure.
- Forty-eight percent of vegans have diets that are low in riboflavin, however, very few vegans were found to have signs of deficiencies (eye and nervous system disorders, confusion, headaches, inflammation of the tongue, mouth and throat, as well as, cracking tissue around the mouth and other skin disorders).
- Although both calcium and iron were low in vegetarian diets when studied, very little effect (low cases of decreased bone mass and anemia) was seen. This may be due to high intakes of vitamin C from fruit and vegetables that increases absorption of both calcium and iron. (Note: generally when calcium and iron are consumed together, they bind, making them both unavailable for absorption).
- Zinc is found in many animal products, however, it is also found in nuts, beans and whole grains that can be consumed by vegetarians to prevent deficiencies.
- Fontana, L., Shew, J. L., Holloszy, J. O., & Villareal, D. T. (2005). Low bone mass in subjects on a long-term raw vegetarian diet. Archives of Internal Medicine, 165, 684-689.
- Leung, S., Lee, R., Sung, R., Luo, H., Lam, C., Yuen, M., et al. (2001). Growth and nutrition of Chinese vegetarian children in Hong Kong. Journal of Paediatrics Child Health, 37, 247-253.
- Mangels, A.R., Messina, V., & Melina, V. (2003). Position of the American Dietetic Association and Dietitians of Canada: Vegetarian Diet. Journal of the American Dietetic Association, 103 (6), 748-765.
- Mangels R. Kavanagh-Prochaska, K. (n.d.). The Vegetarian Resource Group. Nutrition: Vegan nutrition in pregnancy and childhood. Retrieved March 4, 2009 from http://www.vrg.org/nutrition/prenancy.htm
- Waldmann, A., Koschizke J. W., Leitzmann, C., & Hahn, A. (2003). Dietary intakes and lifestyle factors of a vegan population in Germany: results from the German vegan study. European Journal of Clinical Nutrition, 57, 947-955.
- Wardlaw, G. M., & Hampl, J. S. (2007). Perspectives in Nutrition (7th ed.). New York: McGraw-Hill.
- United States Department of Agriculture (2008, October 8). Inside the Pyramid: Vegetarian choices in the meat & bean group. Retrieved March 4, 2009 from http://www.mypyramid.gov/pyramid/vegetarian.html
- Yen, C. E., Yen, C. H. Huang, M. C., Cheng, C. H., & Huang, Y. C. (2008). Dietary intake and nutritional status of vegetarian and omnivorous preschool children and their parents in Taiwan. Nutrition Research, 28, 430-436.