Vitamin D: Are You Getting Enough?

Vitamin D may be the new fish oil. If you've followed the research over the past couple of years, it seems that there is very little vitamin D doesn't help. Depending on where you live, you may be heading into the not-so-sunny seasons, so now may be a good time to think about getting enough D.

Why Vitamin D is in the News

The continually-emerging research on vitamin D is that it curbs diseases such as; diabetes, multiple sclerosis, congestive heart failure and some cancers (breast, prostate, colon, leukemia, pancreatic) and has even been shown to extend life. Not too shabby. It has also been shown to have immune-boosting potential - warding off diseases such as; lupus and rheumatoid arthritis as well as skin conditions such as psoriasis. It is also vital for bone formation.

Almost every tissue in the body (brain, bone, breast, colon, intestine, heart, kidneys and prostate) has a receptor for the active form of vitamin D. As the theory goes, the active form of vitamin D is one of the most potent hormones in inhibiting cell proliferation. This means that a wayward cancer cell growth may be inhibited by vitamin D.

Sensible sun Exposure

Vitamin D is especially important for those who do not live in southern climates and hence don't get the sun exposure to manufacture vitamin D. Even a sunscreen with an SPF of 8 reduces the ability of our bodies to make vitamin D by 90%! Michael Holick, director of the vitamin D, Skin and Bone Research Laboratory recommends sensible exposure. He defines "sensible" as no more than 10-20 minutes of sun exposure on the arms, legs or face 2-3 times per week between the hours of 11 and 2. (We don't make as much before or after these times).

How Much?

Newer research is now recommending 1000 International Units (IU's) for older people as well as those with dark skin. Some scientists believe that amounts up to 2000 IU's are warranted for these people. There are reports that safety up to 10,000 IU's has been demonstrated. It is important to consider sun exposure, dietary sources and supplementation and strike the right balance. Many researchers think a 1000 IU daily supplement is warranted and safe, even if there is additional exposure and dietary sources.

Food Sources of Vitamin D

Cod Liver oil (1 tablespoon) 1400 IU's
Salmon (3.5 ounces) 360 IU's
Tuna, canned (3 ounces) 200 IU's
Sardines, canned (1.75 ounces) 250 IU's
Milk, cow's (1 cup) 100 IU's

Are you "D"-ficient?

References

• Yee YK, Chintalacharuvu SR, Lu J, Nagpal S. (2005). "Vitamin D receptor modulators for inflammation and cancer". Mini Rev Med Chem
• van Etten E, Mathieu C. (2005). "Immunoregulation by 1,25-dihydroxyvitamin D3: basic concepts". J Steroid Biochem Mol Biol. 97 (1-2): 93-101
• Holick MF (2004). "Sunlight and vitamin D for bone health and prevention of autoimmune diseases, cancers, and cardiovascular disease". American Journal of Clinical Nutrition Full Text 80 (6): 1678S-88S.
• Holick MF (2005). "The vitamin D epidemic and its health consequences Full Text". J Nutr 135 (11): 2739S-48S
• Grant WB (2002). "An estimate of premature cancer mortality in the U.S. due to inadequate doses of solar ultraviolet-B radiation". Cancer 94 (6): 1867-75.