Vitamin D

When we talk about vitamin D, we think of bone. Vitamin D is very important for bone health, as it is essential for promoting calcium absorption in the stomach. Typical diseases caused by vitamin D deficiency are Rickets in children and osteomalacia (soft bones) in adults.

Vitamin D deficiency is associated with increased risk for cancer (particularly colon, prostate, and breast); hypertension, and autoimmune diseases (e.g., multiple sclerosis and type I diabetes). It is also related to depression, fatigue, muscle weakness, and chronic pain syndrome. A study in older patients showed that vitamin D3 supplements (700 IU-1000 IU/day) lowered the risk of falls by 19%. The protective effect of vitamin D appears to be linear: as vitamin D3 levels increase (within the therapeutic range), there is an associated decrease in morbidity. In other words, Vitamin D enhances overall wellness.


What causes Vitamin D deficiency or insufficiency? Lack of dietary intake, insufficient sunlight (especially since concerns about skin cancer result in avoidance of sun exposure and/or use of sunblock), malabsorption diseases (such as celiac disease and short bowel syndrome), use of some medications, and end stage liver disease are all risk factors for vitamin D deficiency or insufficiency.


The simple and effective way to correct vitamin D is oral vitamin D3 supplement. For prevention of vitamin D deficiency, the American Academy of Pediatrics currently recommends 400 IU/day for breast-fed infants; for children and adolescents at risk of vitamin D deficiency (dark skin or inadequate sun exposure), a daily supplement of 400-1000 IU/day of vitamin D3 is recommended; for adults at risk (older than 50, pregnant, or lactating), 800-1000 IU/day is recommended.

Relatively few foods naturally contain vitamin D, the most abundant being oily fish like salmon, sardines, and mackerel, or old-fashioned cod liver oil. To give you an idea of the amount of vitamin D in various foods, a serving of salmon contains about 360 IU, a glass of fortified milk about 100 IU, an egg about 25 IU, and a tablespoon of cod liver oil 1300+ IU.


Casual sun exposure should meet vitamin-D needs. Approximately 5-30 minutes of sun exposure between 10:00pm and 3:00pm at least twice a week to the face, arms, legs, or back without sunscreen usually leads to sufficient vitamin D synthesis.

Certain groups are particularly predisposed to vitamin D deficiency. When exposed to the same amount of sunlight, elderly individuals produce only 20% of the vitamin-D produced by young adults. As a result, more than half of individuals older than 65 are vitamin-D deficient. Due to their skin pigmentation, African Americans require much more sun to produce the same levels of vitamin D than do fair-skinned Caucasians. At least 50% of African Americans, who are also less likely to drink fortified milk due to lactose intolerance, are vitamin-D deficient sometime during the year.


Vitamin D toxicity is a concern—as is vitamin D hypersensitivity—with inappropriate use or monitoring of vitamin D supplementation. Therefore, it’s wise to discuss vitamin D3 supplementation with your physician before starting, and to follow-up with your physician as recommended.