Vitamin D, also know as the "sunshine vitamin," isn't technically a vitamin at all. In its active form, calcitriol, it is a hormone. Synthesis of active vitamin D in our skin is triggered by ultraviolet rays from the sun. In the diet, vitamin D is found naturally in marine foods and eggs. Vegetarians can obtain small amounts from mushrooms, and more from fortified foods such as milk, cereals and juices. The dietary reference intake for adults is 600 IU per day, and 800 IU per day after age 70.
Supplemental Vitamin D
Vitamin D supplements come in two forms, vitamin D2 and Vitamin D3. Both are precursors to calcitriol, functional vitamin D. Vitamin D2, ergocalciferol, is derived from yeast. Vitamin D3, cholecalciferol, is derived from lanolin -- sheep oil -- or fish oil. True vegetarians and vegans typically will not use fish or other animal products and therefore should look for vegetarian ergocalciferol in their supplements.
Vegetarians and Vitamin D Status
Vegetarians are not considered at higher risk for vitamin D deficiency than non-vegetarians, although some studies have linked vegans to a higher risk for vitamin D deficiency. Overt vitamin D deficiency leads to rickets, a softening of the bone matrix. Studies suggest that vitamin D deficiency is more common that previously believed, particularly in the elderly, and may also be linked to cardiovascular disease and cognitive problems, among other health issues. Your overall vitamin D status depends on daily sunlight exposure and vitamin D intake. For sunlight, the NIH recommends five to 30 minutes of sun exposure, without sunscreen, to the face, arms or legs between 10 a.m. and 3 p.m. at least twice per week.
Diet Considerations
Vegetarians and vegans will benefit from choosing nutrient-dense, fortified foods. Many vegetarian food producers fortify their foods with nutrients such as vitamin D, calcium, folic acid and vitamin B12, essential nutrients often low in the Western vegetarian diet. Supplemental vitamin D2 is a good option for any vegetarian or vegan with low vitamin D intake and low sunlight exposure. If you are concerned, a simple blood test from your doctor can assess your circulating vitamin D status.
A Healthy Vegetarian Diet
Although research is ongoing relating to the issues potentially linked to vitamin D deficiency, the important thing for you to do is ensure you have an adequate intake. Consider your diet staples and check for vitamin D in your daily diet. Include more vitamin D containing foods if possible. Consider a supplement if your diet is not adequate in vitamin D.
References
- "Molecular Nutrition and Food Research"; A Review of the Critical Role of Vitamin D in the Functioning of the Immune System and the Clinical Implications of Vitamin D Deficiency; G.K. Schwalfenberg; January 2011
- "American Journal of Clinical Nutrition"; Low Serum 25-hydroxyvitamin D Concentrations and Secondary Hyperparathyroidism in Middle-age White Strict Vegetarians; C. Lamberg-Allartd, et al; November 1993
- "American Journal of Clinical Nutrition"; Serum 25-hydroxyvitamin D status of vegetarians, partial vegetarians, and nonvegetarians: the Adventist Health Study-2; J. Chan, et al; May 2009
- Office of Dietary Supplements: Vitamin D
- "American Journal of Geriatric Pharmacotherapy"; Extraskeletal effects of vitamin D in older adults: cardiovascular disease, mortality, mood, and cognition; K. Barnard K and C. Colón-Emeric; February 2010
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