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Healthnotes Newswire (July 31, 2008)—Low levels of vitamin D in the blood may increase risk of cardiovascular events such as a heart attack, according to two recent studies published in the Archives of Internal Medicine.

In addition to its critical role in bone development and maintenance, recent research has shown that vitamin D may be far more important for other aspects of health and disease prevention than was previously realized. In fact, research has linked low levels of vitamin D with chronic diseases such as cancer and multiple sclerosis. Now, new research suggests that inadequate vitamin D may increase the risk of heart attacks and death due to cardiovascular disease and other causes.

Investigating diet’s impact on heart health

In the Health Professionals Follow-up study, a study evaluating the associations between diet and the incidence of chronic disease, 18,225 men ages 40 to 75 were evaluated for their blood levels of vitamin D (measured as 25-hydroxyvitamin D [25(OH)D]) and subsequent risk of heart attack. After ten years of follow-up, 454 men had a heart attack or died from coronary artery disease. Men who had less than 15 nanograms per milliliter of the vitamin D measure had a 50% increased risk of having a heart attack compared with men whose blood levels were 30 nanograms per milliliter or higher.

In another study, 3,258 men and women (average age 62) who were scheduled for angiography because of suspected coronary artery disease were followed for subsequent cardiovascular death or death by another cause. People in the study had blood levels of vitamin D drawn at the time of angiography. After 7.7 years of follow-up, 737 people died and 463 of those people died from cardiovascular disease. People with the lowest levels of vitamin D—less than 13.3 nanograms per milliliter—had a higher risk of death from any cause, and a higher risk of death from cardiovascular disease compared with those people whose levels were greater than 28.3 nanograms per milliliter.

Vitamin D may help prevent heart disease by lowering blood pressure, decreasing calcification in the heart vessels, or by other mechanisms. However, the optimal daily level of vitamin D to prevent chronic disease and maintain health is still not known.

“Vitamin D deficiency has been related to an increasing number of conditions and to total mortality,” said Edward Giovannucci, MD, ScD, and his colleagues from the Harvard School of Public Health, Boston, Massachusetts. Dr. Giovannucci comments that the amount of vitamin D required for optimal health may be much higher than the current daily recommendation of 200 to 600 IU per day. This would be especially true for those with minimal sun exposure, added Dr. Giovannucci.

Getting enough vitamin D

Sources of vitamin D include the sun, food, and dietary supplements. People who live in sunny climates who wear less clothing and therefore allow more daily exposure of their arms and legs usually have higher levels of vitamin D compared with people who live in more northern or more cloudy climates.

Food sources of vitamin D are limited but include some fish such as salmon, mackerel, and tuna; cod liver oil; fortified milk; and fortified cereal products. Eggs, fortified margarine, some cheese, and other foods have small amounts of vitamin D.

Ask your doctor about how to get enough vitamin D from appropriate dietary changes or supplements based on your current health.

(Arch Intern Med 2008;168:1174–80; Arch Intern Med 2008;168:1340–9)

Healthnotes Newswire (July 3, 2008)—It’s well known that vitamin D is needed for proper bone growth in children and general bone health in children and adults, but it appears that adolescents worldwide are vitamin D deficient, and that current recommendations for daily D may not be enough for health and disease prevention. The good news: a recent study finds that giving teens higher amounts of vitamin D can raise them to healthy levels after one year of treatment.

The value of the “sunshine vitamin”

Vitamin D deficiency may lead to abnormal bone growth and development and to the development of chronic diseases in adulthood such as osteoporosis, cancer, and multiple sclerosis, and research suggests that the recommended daily intake of 200 IU of vitamin D may not be enough to prevent deficiency. The authors of this new long-term study suggest that a vitamin D blood level of 30 ng/ml (measured as 25-hydroxyvitamin D) is desirable based on expert recommendations, but many people have much lower levels. They tested a higher dose of vitamin D to see if it was safe for teens and effective in raising vitamin D levels.

In the study, 340 students, ages 10 to 17, were randomly assigned to take low-dose vitamin D3 (1,400 IU per week), high-dose vitamin D3 (14,000 IU per week), or placebo. After one year of treatment, adolescents who received the high-dose vitamin D had significantly higher blood levels (average, 38 ng/ml of 25-hydroxyvitamin D) compared with the levels in the low-dose vitamin D (17 ng/ml) and placebo groups (16 ng/ml).

The authors claim that vitamin D deficiency “is prevalent in children and adolescents worldwide.” They add that the high worldwide prevalence of vitamin D deficiency, the fact that many adult diseases begin in childhood because of vitamin deficiencies, and increasing evidence for the safety of higher doses of vitamin D should prompt a change in the current recommendations for an adequate daily amount. More research is needed to determine the safety of taking higher daily doses of vitamin D and to determine optimal levels for health and disease prevention.

Get your daily D

A person gets vitamin D several ways:

• Modest sun exposure (approximately 20 minutes per day)—people who get very little sun exposure, such as those who live in cloudy climates and at northern latitudes, may need to rely on diet and supplements to achieve adequate vitamin D levels

• Supplements such as vitamin D3 and cod liver oil—1 teaspoon of some brands provides 400 IU of natural vitamin D

• Some foods and beverages—fortified milk and cereal, fatty fish such as salmon and mackerel, and, to a lesser extent, eggs, beef, some cheeses, and other foods

According to the American Academy of Dermatology, most people get the current recommended amounts of vitamin D through incidental sun exposure. They recommend using sunscreen when outdoors in the sun and obtaining needed amounts of vitamin D through foods and supplementation. However, for those not likely to take supplements or deliberately get enough D in the diet, it is important to weigh the risks and benefits of sun exposure against your risks for bone disease and other health issues. Talk to your doctor about your vitamin D needs and what combination of sources might be best for you.

(J Clin Endocrin Metab 2008:doi:10.1210/jc.2007-2530)

Healthnotes Newswire (June 19, 2008)—Older women with low back pain might benefit by getting some extra vitamin D, reports a study in the Journal of the American Geriatrics Society. Low levels of vitamin D can lead to weakened bones, lowered immune function, and sometimes pain.

The new study included 958 people over age 65 who gave information about the location of their pain, from their midback to their feet. Blood samples were taken to measure vitamin D levels.

Women were more likely than men to have moderate or severe pain in some part of their bodies, and women who were vitamin D deficient were almost twice as likely to suffer from low back pain as were people with normal vitamin D levels. Vitamin D status didn’t seem to affect low back pain in men, nor did it influence pain in other parts of the bodies of men or women.

How (and how much) do you D?

The “sunshine vitamin” is produced in the body after exposure of the skin to sunlight. Exposing the face, arms, and hands to sunlight for 15 minutes three times per week year-round can help boost vitamin D levels. Vitamin D also occurs naturally in a few foods like egg yolks and fatty fish such as salmon and mackerel. Dairy products, juices, and cereal products are often fortified with vitamin D.

Just how much vitamin D is best for optimal health is a hot topic. A growing body of evidence suggests that 400 IU per day, the amount found in many multivitamin products, is not enough to maintain optimal levels. Many people appear to need 1,000 IU per day and in some cases even more. The body’s ability to synthesize vitamin D diminishes with age, putting older people at increased risk for deficiency.

The Institute of Medicine has concluded that long-term intake of 2,000 IU per day is safe for most people. Some doctors recommend even more, such as 2,000 to 4,000 IU per day depending on the season, but people taking those amounts should be monitored by a doctor.

Along with the many other benefits adequate D offers the body, such as supporting calcium absorption that keeps bones strong, the authors of the new study conclude that the new study’s “findings suggest it may be worthwhile to question older adults about their pain and screen older women with significant back pain for vitamin D deficiency.”

(J Am Geriatr Soc 2008;56:785–91)