Marion County Medical Center

Health Shorts

March 2006

Vitamin D Deficit Is Common
Vitamin D is needed to build strong bones and reduce the risk of hypertension, heart disease, diabetes and prostate, breast, ovarian and colorectal cancers. Yet recent research suggests that many Americans have a deficiency of this vitamin.
Half of the women admitted to Brigham and Women’s Hospital for hip fractures were found to have a vitamin D shortage. And a Canadian study that collected blood samples from a random selection of men and women, ages 27 to 89, found that 34 percent had insufficient supplies of vitamin D.

The recommended daily allowance of vitamin D was revised upward to 400 IU a day in 1997, but a recent meta-analysis found that even 600 IU was not enough to reduce the fracture rate in older Americans. Dietary sources include eggs, milk and fatty fish such as salmon and mackerel. Vitamin D is also manufactured by the body through exposure to ultraviolet B rays.
[SOURCE: “Vitamin D’s New Day in the Sun,” Harvard Women’s Health Watch, February, 2004; “Are You Getting Enough Vitamin D To Fight Fractures?” Tufts University Health & Nutrition Letter, December, 2005]

UV Rays–The Good and the Bad
Ultraviolet radiation has been implicated as a major cause of most skin cancers, cataracts and premature aging of the skin. At the same time, death rates from prostate, ovarian and other cancers are only half as high in sunny areas such as Arizona compared to cloudy northeastern states. According to one analysis, too little exposure to ultraviolet B radiation contributes to the premature cancer deaths of 21,700 whites and 1,400 blacks each year.

This increased cancer risk is believed to be due to a deficiency of vitamin D, which is manufactured by the body in response to exposure to ultraviolet B radiation. Only a small amount of sun exposure is needed, however, and vitamin D can also be obtained from diet and supplements.
[SOURCE: W.B. Grant, “An Estimate of Premature Cancer Mortality in the U.S. Due to Inadequate Doses of Solar Vultraviolet-B Radiation,” Cancer, 94(6), 1867; Emil Vernarec, “Sun Exposure, Vitamin D, and Cancer Deaths,” RN, November, 2002]

Skin Color Affects Sensitivity to Sun
Response to the ultraviolet radiation of sunlight may vary more than 100-fold between persons of different skin pigmentation, according to a study published in the American Journal of Human Genetics.

At greatest risk of skin cancer are fair-skinned individuals of northern European descent living in sunny areas. Even among such persons, however, response to ultraviolet radiation may vary four- to five-fold between individuals or even with the same person at different body sites.
[SOURCE: Jonathan L. Rees, “The Genetics of Sun Sensitivity in Human, (Review Article),” American Journal of Human Genetics, November, 2004]

Osteoporosis Risk May Be Set Early
A person’s risk of osteoporosis and bone fractures may be determined in part before birth, according to a study published in The Lancet. Researchers found that a deficiency of vitamin D in the mother during late pregnancy, a common occurrence, was associated with deficits in bone mineral density in the child that persisted until age 9 and increased the risk of adult osteoporosis. The authors concluded: “Vitamin D supplementation of pregnant women, especially during winter months, could lead to long lasting reductions in the risk of osteoporotic fracture in their offspring.”
[SOURCE: M.K. Javaid, et al, “Maternal Vitamin D Status During Pregnancy and Childhood Bone Mass at Age 9 Years: A Longitudinal Study,” The Lancet, January 7, 2006]

Calcium Pills Show Limited Benefit
Calcium and vitamin D supplements failed to show the benefits doctors expected in a seven-year study of 36,282 women ages 50 to 79.
As part of the Women’s Health Initiative, subjects taking 1,200 milligrams of calcium and 400 to 600 IU of vitamin D daily had no statistically significant lower risk of bone fractures than women taking a dummy pill. Subjects taking the supplements showed one percent greater bone density in the hip, however.
[SOURCE: Jeff Donn, “Study Shows Limited Benefits from Calcium,” AP Health, February 14, 2006]

Vitamin D Crucial for Bone Health
Vitamin D may be more important than calcium in promoting strong bones, according to a recent Icelandic study published in the Journal of the American Medical Association.

In a study of 944 adults, ages 30 to 85, researchers found that higher levels of vitamin D were more closely associated with good bone health than high levels of calcium.

The researchers concluded that persons getting sufficient vitamin D may not need more than 800 milligrams daily of calcium. On the other hand, no amount of calcium can make up for a deficit of vitamin D. They recommended at least 500 milligrams daily of vitamin D through diet or supplements and 700 milligrams for persons living in northern climes or with minimal exposure to sunlight.
[SOURCE: “Vitamin D Drives Bone Health–And You May Not Be Getting Enough,” Tufts University Health & Nutrition Letter, February, 2006; JAMA, November 9, 2005]

Skin Cancers Up Sharply in Youth
Doctors are reporting a sharp increase in non-melanoma skin cancers among young adults. While these cancers are readily treatable and not as dangerous as melanoma, they have previously been considered a problem mainly for persons age 60 and over.

A person who develops one non-melanoma tumor has a 50 percent risk of having a second within two to three years and a 75 percent risk of developing a third.

The major risk factor is exposure to ultraviolet rays, and 80 to 90 percent of non-melanoma skin cancers develop on sun-exposed areas of the body.
[SOURCE: J. Raloff, “Sun Struck: Data Suggest Skin Cancer Epidemic Looms,” Science News, August 13, 2005]

Melanoma Invades Dark Skin Too
Melanoma occurs about 10 times more frequently in white than in black Americans, but African Americans and Hispanics should not ignore warnings regarding exposure to sunlight, use of sunscreen and skin self examinations.

Melanoma and other skin cancers are more likely to be discovered at a later date in dark-skinned persons, and the survival rate is significantly lower. One study found that for blacks 40 percent of melanomas were on the feet and only 33 percent on sun-exposed skin.
[SOURCE: Michele G. Sullivan, “Dark-Skinned Patients Are Still at Risk for Skin Cancers,” Family Practice News, May 1, 2005]

Be Sure Kids Wear Helmets Correctly
About 73 percent of American children are now wearing a helmet when they ride a bicycle compared to only 18 percent 15 years ago, according to a Massachusetts study. To protect the frontal region of the child’s skull, the most common site of impact, the helmet must fit well and be adjusted so that the helmet does not rest too high on the forehead or slide too easily forward or backward.
[SOURCE: “Helmets Help,” Vibrant Life, November-December, 2003]

Sunscreen: Don’t Go Out Without It
Even in small amounts, sun damages the skin, causing premature wrinkles, sags, sun spots and skin cancer. Various wave lengths of ultraviolet radiation have different ways of harming skin cells. Radiation is believed to release oxidants which damage the collagen fibers and elastin that give the skin strength, firmness and elasticity.

To protect the skin, dermatologists recommend the use of sunscreen with an SPF of 15 or greater that protects against both ultraviolet A and ultraviolet B radiation. About two tablespoons is usually sufficient to cover exposed areas of the body. It should be re-applied every two hours or after swimming.
[SOURCE: “Sun Is the Skin’s Greatest Enemy,” Harvard Women’s Health Watch, April, 2002]

Building Bone as Well as Muscle
For building strong bones, weight bearing activity is recommended, and bicycling does not ordinarily qualify despite its benefits for developing cardiovascular fitness and muscle. Trail riding, however, because of the bouncing and jostling, can strengthen bones.

One small study of high-mileage male bicyclists found that trail riders had above average bone density while road riders had below average. As an adjunct to any aerobic exercise, strength training can help maintain and improve bone density.
[SOURCE: “Build Bones on a Bike,” Prevention, October, 2002]

Vegan Diet Can Promote Bone Density
A person following a vegan diet (consuming no animal foods) can get calcium from beans, chick peas, lentils, nuts and seeds, calcium-fortified orange juice and green, leafy vegetables. But vitamin D is necessary for proper utilization of calcium, and there are few plant foods with significant amounts of vitamin D.

To maintain strong bones, vegans are advised to seek vitamin D from fortified foods and supplements plus a limited amount of sun exposure, engage in regular weight-bearing exercise and limit use of sodium and caffeine which can cause loss of calcium in urine.
[SOURCE: Reed Mangels, “Preventing Osteoporosis: Building Strong Bones over a Lifetime,” Vegetarian Journal, March-April, 2005]

Don’t Push Young Bikers
Biking is good for a child’s motor development, but introducing it too early in life may have the opposite effect. One study found that kids who started biking at ages three to five had more injuries of all kinds than those starting at age six or seven.
[SOURCE: “Stay on the Trike,” Psychology Today, January-February, 2005]

Health Shorts

March 2006

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