How Much Sunshine or Vitamin D do I Need?

Not long ago, when a joint Canadian-U.S. health panel last studied vitamin D levels in 1997, they concluded that low amounts in people's blood were normal. But at that time there was only speculation that it had an anti-cancer effect.

Since then, study after study showed that low levels are in fact deficiencies leading to a wide variety of diseases including cancer, osteoporosis, heart disease, hypertension, MS, and Crohn's, etc.

Experts are now saying that you need much more of the "sunshine vitamin," depending on: 1) whether you spend time outdoors in the mid day sun, 2) how far north you live, 3) the color of your skin, 4) your age, 5) your diet, and 6) your weight.

How Much Sunshine Do I Need?

• For most people, 10 or 15 minutes in noontime summer sun is enough, and leads to the production of 10,000 IU (International Units) of Vitamin D, according to Dr. John Cannell, head of the Vitamin D Council, a non-profit U.S. organization. Dr. Cannell is concerned that people aren't getting enough of the vitamin, especially when they are advised to avoid the mid day sun.

UV-B rays from the sun on the skin convert cholesterol into the "sunshine vitamin," which, researchers are finding to be a potent anticancer agent.

It is ironic that skin cancer may actually be prevented by what many feel causes it -- sunshine.

In his book, “Naked at Noon,” Krispin Sullivan says that: "One of the known protectors of skin cells from pre-cancerous changes is vitamin D. For most Americans the primary source of this vitamin is sunlight. UV-B, the only band of light producing D, is significantly present only midday during summer months in most of the U.S., the exact time we are advised to avoid sunlight. UV-B is blocked by sunscreen."

HOW BEST TO GET UV-B? The Vitamin D Council suggests wearing a hat to protect your face against sun damage, while exposing other parts of your body to modest amounts of noontime sunlight, stopping before there's even the slightest trace of redness.

How Much Sun You Need Depends On:

People with red or blond hair and blue eyes tend to be more at risk of skin cancer, and should more careful about sun exposure. But as people cover their skin to avoid skin cancer, they reduce their vitamin D.

AIR POLLUTION also interferes with its manufacture because particulate pollution reduces the amount of sunlight people may receive, and also, ozone depletion causes them to minimize exposure to what sunlight there is.

YOUR DIET: Even though we may be spending a short amount of time each day in the sun, dietary sources are still recommended. In the past, people ate a lot more vitamin D-containing foods like butterfat, eggs, liver, organ meats, marine oils and seafood, particularly shrimp and crab, as well as spending more time outdoors. Since we don’t typically these rich foods anymore and stay indoors, experts are advising supplementation.

YOUR AGE: Normal aging involves a reduction in the production of D by sun-exposed skin. Absorption of D precursors from foods and conversion of this vitamin into its active form also diminish as people get older.

YOUR WEIGHT: Supplements, not sunlight, may be necessary for overweight persons because they are less than half as able to utilize vitamin D3 that’s made through the skin, compared to lean persons. Since approximately two-thirds of all Americans are overweight or obese, this is a very significant public health problem. "In obese subjects, oral vitamin D was more bioavailable than D from sunlight exposure.” (Wortsman J et al. Decreased bioavailability of vitamin D in obesity. Am J Clin Nut. 72:690-693. 2000.)

YOUR DOSAGE: Current US Daily Reference Intakes (DRI) this vitamin are:

• Infants 0-12 months, 200 IU (5 micrograms) • Males and females 1-50 years, 200 IU (5 mcg) • 51-70 years, 400 IU (10 mcg)• 71 years and older, 600 IU (15 mcg) • Pregnant or nursing women, 200 IU (5 mcg)

There is evidence that even three times the DRI for an adult is inadequate if a person is not receiving adequate sunlight.

These levels are certainly not therapeutic levels. For instance, it was found that the treatment of rickets generally requires a dose of 1,600 IU/day, and may require a daily dosage of 50,000 to as much as 300,000 IU in resistant cases. (Eguchi M and Kaibara N, Int Orthop. 3:257-264. 1980).

Some experts are now saying that we need ten times the DRI amount.

What Diet or Supplements Do I Need?

NORTHERN LATITUDE: People living in the northern United States, Canada and northern Europe can't make D in winter because the sunlight is too weak.

During the winter in the north, D can only be gotten through food and supplements. Compared to the amount that is made in the skin, amounts in food are very low: A cup of fortified milk has about 100 IU, a typical multivitamin 200 IU.

DEFICIENCY has, however, been found regardless of latitude and season:

Researchers from US, the Netherlands and UK found that in all regions of the world, more than half of postmenopausal women with the crippling bone disease osteoporosis are vitamin D deficient, regardless of age, latitude or season.

A significant number of Australians are deficient in the "sunshine vitamin," once thought to be impossible in sunny Australia. People at the highest risk include the elderly, especially those who are housebound or in residential care.

New Findings for Levels of Supplementation of D

Many leading researchers personally say they are taking supplements ranging from 1,400 to 5,000 IU a day.

Certainly anyone with a chronic illness would be wise to take high doses of D because of its newly discovered importance for immune function.

There is little agreement about what constitutes too much of this vitamin. Most experts agree that amounts up to 2,000 IU a day are safe, while some D researchers say the upper limit should be what humans make when exposed to sunshine, about 10,000 IU a day.

Links:

Best Natural Cancer Cure Is This Vitamin a Miracle Cure-All? US Vitamin D Council, California Naked at Noon, Understanding Sunlight and Vitamin D: SAMPLE CHAPTERS: Deficiency, Diversity and Dosage, Journal Of Orthomolecular Medicine