Vitamin D comes in two forms: vitamin D-2 and vitamin D-3. Your body naturally produces vitamin D-3 from sunlight and also absorbs it better than vitamin D-2. As such, vitamin D-3 is the better of the two sources. Although most natural sources of vitamin D-3 are non-vegetarian, you can easily meet your daily needs with a combination of sunlight, egg yolks and fortified foods. However, as excessive amounts of vitamin D-3 can cause kidney damage, you should be careful not to exceed your recommended daily intake.
Very few foods naturally contain significant amounts of vitamin D. Most of these foods, such as fish and seafood, are not suitable for vegetarians. Eggs are the sole exception to this, being both vegetarian-friendly and naturally high in vitamin D-3. One whole, large egg contains 1 milligram of vitamin D, or approximately 6.7 percent of your recommended daily 15-milligram intake. As almost all of the vitamin D-3 in eggs is in the yolk, you can boost your intake by removing their whites. For example, three large egg yolks weigh the same as one large egg and contain approximately 18.7 percent of your daily vitamin D-3. However, as they are not suitable for vegan and lacto-vegetarian diets, eggs are not a good source of vitamin D-3 for all vegetarians.
Aside from eggs, all vegetarian dietary sources of vitamin D-3 are fortified foods. The source of this fortification is vegetarian and involves the use of ultraviolet light to increase the vitamin D-3 content of a compound present in sheep's wool. Foods fortified with vitamin D-3 that are suitable for all vegetarian diets include orange juice, dairy alternatives and breakfast cereals. Although not vegan-friendly, other fortified vegetarian sources of vitamin D-3 include margarine and dairy products. According to the Vegetarian Resource Group and Office of Dietary Supplements, one serving of these foods can provide between 10 and 40 percent of your daily vitamin D-3 intake.
You body is capable of producing all of your daily vitamin D-3 with adequate exposure to sunlight. Under ideal conditions, you can meet your body's vitamin D-3 needs by exposing your arms and legs to sunlight for as little as five to 30 minutes each week. However, your body's ability to produce vitamin D-3 changes with your age, skin pigmentation, sunscreen use, clothing and the amount of pollution in the air. In addition, you can only produce vitamin D-3 from ultraviolet-B rays. These rays peak between 10 a.m. and 3 p.m. in the summer and do not reach the Earth's surface during the winter months at high northern or southern latitudes. As such, you should not rely entirely on exposure to sunlight for your vitamin D-3 needs.
It is not possible for your body to produce excessive amounts of vitamin D-3 from sunlight. However, exceeding your daily intake with fortified foods or dietary supplements can lead your body to absorb too much calcium, resulting in kidney stones and kidney damage. Although the human body may be able to tolerate as much as 25 times the recommended daily intake, you should not exceed 75 milligrams of vitamin D-3 per day. Because of the potential damage to your kidneys, this suggestion drops to a maximum of 37.5 milligrams per day if you have a history of kidney stones.
- Office of Dietary Supplements: Vitamin D
- The Vegetarian Resource Group: FAQs About Vitamin D
- U.S. Department of Agriculture National Nutrient Database for Standard Reference: Egg, Whole, Raw, Fresh
- U.S. Department of Agriculture National Nutrient Database for Standard Reference: Egg, Yolk, Raw, Fresh
Matthew Lee has been writing professionally since 2007. Past and current research projects have explored the effect of a diagnosis of breast cancer on lifestyle and mental health and adherence to lifestyle-based (i.e. nutrition and exercise) and drug therapy treatment programs. He holds a Master of Arts in psychology from Carleton University and is working toward his doctorate in health psychology.