Vegetarians need to plan meals to include sources of protein, iron, calcium, vitamin B-12 and vitamin D in order to meet nutritional needs. Well-planned vegetarian diets are healthful, provide adequate nutrition and potentially lower the risk for certain chronic diseases, according to the American Dietetic Association. However, without careful planning, vegetarians could be at risk for vitamin D deficiency.
Vitamin D naturally occurs in only a few foods, including cod liver oil, salmon, mackerel, tuna, beef liver and egg yolks, according to the National Institutes of Health. Sources of vitamin D for vegetarians include exposure to sunlight and fortified foods such as soy milk, cow's milk, juice, cereal and margarine. Fortified foods either contain vitamin D2, a vegan form, or vitamin D3, derived from sheep's wool, according to the Vegetarian Resource Group.
The American Journal of Clinical Nutrition reports that vitamin D deficiency is now considered a pandemic. Vitamin D deficiency leads to increased risk for certain cancers, hypertension, autoimmune diseases and osteoporosis, according to the journal. The recommended intake of vitamin D for men and women ages 19 to 50 is 5 mcg or 200 IU, according to the NIH. Adults 51 to 70 years of age need 10 mcg or 400 IU, and adults over 70 need 15 mcg or 600 IU daily.
Lacto-vegetarians consume dairy products and get vitamin-D from foods such as fortified milk and margarine. Ovo-vegetarians get vitamin D from eggs. One cup of fortified milk contains more than 100 IU of vitamin D, 1 tbsp. of fortified margarine provides 60 IU and one egg contains 25 IU, according to the NIH. A serving of fortified cereal provides 40 IU and fortified orange juice contains 100 IU, per NIH. Besides exposure to sunlight, vegans get vitamin D exclusively from fortified soy, rice, almond and hemp milk, which provide from 40 to 160 IU per serving, according to the Vegetarian Resource Group.
Most people get adequate amounts of vitamin D from sun exposure, according to the NIH. People in the deep south typically benefit from sunlight-induced vitamin D production year round. Those in latitudes above 34 degrees north lose the benefit from November to February, and sometimes longer in the extreme northern U.S., according to the NIH. The general prescription for vitamin D production is exposure to sunlight at least twice a week between the hours of 10 a.m. and 3 p.m. Other factors that affect exposure and vitamin D synthesis include cloud cover, season, skin melanin content, smog and sunscreen. Although exposure to UV rays promotes vitamin D production, limiting exposure is important to reduce the risk of skin cancer and melanoma.
Even though meeting the dietary requirements of vitamin D is possible through a well-planned diet, supplements are available for vegetarians with vitamin D deficiency. Look for vegetarian or vegan supplements with a maximum of 2,000 IU. If you have a history of kidney stones or if you're a lactating mother, the Vegetarian Resource Group recommends consulting a physician to determine the appropriate supplementation.