Monday, June 18, 2007

15 Min of Sun a Day Keeps the Doctor Away

Summarized from

Harvard Health Letter | June 2007

A more D-manding diet

Some experts say we should have a lot more vitamin D in our diets because it’s protective against several diseases.

Vitamin D has long been recognized as vital to bone health because the body needs the vitamin to absorb calcium. But research has suggested that it may be good for a lot more than just bones. Ample intake of vitamin D may help fend off a wide range of conditions, including colon cancer, diabetes, and physical weakness in old age. Meanwhile, another batch of studies has found that many people, especially as they grow older, have low levels of vitamin D in their blood. Our skin has an amazing ability to produce vitamin D when it’s exposed to sunlight, but with age, the skin becomes less productive. The problem is made worse by older people spending more time indoors. Rickets is the classic children’s disease caused by vitamin D deficiency. It has re-emerged as a problem in some African American communities.

Because of the evidence for shortfalls and the possibility of added benefits, some experts think the recommendations for vitamin D are set way too low. The vitamin D enthusiasts say adults should be getting at least 1,000 IU (International Units) a day. The committees of experts convened by the Institute of Medicine to set daily nutrition requirements also calculate an upper limit (the technical term is Tolerable Upper Intake Level). It’s the too-much-of-a-good-thing level at which a normally healthful nutrient becomes possibly toxic.

The experts — who include Dr. Walter C. Willett, chair of the Harvard School of Public Health’s nutrition department — noted that 400 IU doesn’t increase the amount of vitamin D circulating in the blood very much. Depending on how much a person started out with, they said a daily intake of about 2,000 IU — the upper limit — is necessary before blood levels get high enough for vitamin D to have its full disease-fighting effects.

Current vitamin D guidelines

Ages 19–50

200 IU


400 IU

71 and older

600 IU

The daily intake for adults recommended by some experts is 800–1,000 IU.

the Sun as a Source of Vit D

That’s a lot of vitamin D. Expanding and increasing fortification would be one way to increase intake. In the United States, almost all milk (but generally not other dairy foods) is fortified with vitamin D. The actual amount may vary, but the standard is 100 IU per cup. Putting more D into multivitamins would be another way to go and helpful for older people, who tend to drink less milk and are among the biggest consumers of vitamin pills. Many of the major brands of multivitamins, like Centrum Silver, contain 400 IU of vitamin D. Some of the Dr. Andrew Weil products contain 1,000 IU, but they are expensive. Finally calcium supplements often include some vitamin D or you can buy separate vitamin D pills that contain 1,000 IU or more.

Now getting more sun exposure is another, more controversial, way to increase vitamin D levels, because it means changing the advice to avoid sun and wear sunscreen to protect against skin cancer and other forms of skin damage. Some analysis shows that any increase in skin cancer from adding a small amount of unprotected sun exposure would be offset by declines in other forms of cancer that it might reduce.

Some vitamin D researchers want to see “safe sun” recommendations that would actively encourage people to get 15 minutes or so of sun a few times a week — without sunscreen, which blocks the UV radiation that triggers vitamin D production in the skin.

The pressure to revise vitamin D recommendations is building. The American Cancer Society is preparing its first comprehensive set of guidelines for skin cancer prevention. So stay tuned.
There’s been a lot of disappointing news about vitamins, but vitamin D stands out as a bright spot.


It looks like we need to start thinking about short exposures to Sun as another factor on our healthy lifestyle list. It seems almost intuitive that the Sun, being an integral element of energy in our world, much like water, should have a part in keeping us healthy. So start asking yourself the following questions every so often:

  • How often are you getting Sun exposure per week?
  • Is it more than 15 minutes?
  • Are you protecting your skin if its more than 15 minutes?
So take your lunch outside, walk the dog, read in the park, etc. but if your going to be out for longer durations like softball games, beach days, yard work, etc. lather up good and ward off wrinkles and skin cancer!!!

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