Our understanding of vitamin D has evolved. Once believed to be a central player only in bone health, vitamin D is now known to be integral to overall well-being.

“There’s a relationship not only with bone health, but with immunity and anti-inflammatory components,” says Cindy Moore, MS, RD, director of nutrition therapy at Cleveland Clinic. “Vitamin D has a role in many different types of actions within the body.”

Though we know more about vitamin D today, as many as 50-90 percent of middle-aged and older adults aren’t getting enough of it, depending on which study you read.

Recent research highlights the benefits of vitamin D intake and the consequences of vitamin D deficiencies. An analysis of studies, published in the Sept. 10 issue of Archives of Internal Medicine, suggested that people who took vitamin D supplements had a seven percent lower risk of death than those who didn’t. Also, a study presented at the American College of Rheumatology’s annual meeting in November found that low vitamin D levels may worsen knee osteoarthritis.

VITAMIN D AND YOU

Vitamin D is available in two forms: D2 (ergocalciferol) and D3 (cholecalciferol), the latter being the better-absorbed form found in most supplements. Your body converts vitamin D into an active form that aids in the absorption of calcium and phosphorus, which are vital to bone growth and repair.

Research also has demonstrated that vitamin D can reduce inflammation, the body’s immune response to injury that some experts suspect is a culprit in heart disease, diabetes, high blood pressure and prostate and colon cancers. Its anti-inflammatory properties may be one reason why some research has linked low vitamin D levels to the risk of these diseases.

HOW YOU GET YOUR D

Several factors may contribute to the burgeoning rates of vitamin D deficiency. It’s not prevalent in our diet, and unless you’re eating a lot of fatty fish or drinking plenty of fortified milk, you’re probably not getting enough from foods.

Vitamin D has been called the “sunshine vitamin” because your body produces it when the sun’s ultraviolet rays penetrate the skin. Sunscreens can hamper this penetration. Many people are getting less sun exposure, and the skin’s ability to make vitamin D from sunlight declines with age.

So, most people need supplements to get their daily vitamin D quota, but questions remain about how much you need. Most multivitamins contain 400-600 international units (IUs). The Institute of Medicine (IOM) recommends that adults ages 51-70 get 400 IUs and those 71 and older get 600 IUs daily. But, those guidelines are based on amounts needed for bone health, Moore says.

“The recommendations, at this point, may be adequate for bone mineralization, but may be inadequate for reducing the risk of some of these chronic diseases, such as diabetes and cardiovascular disease,” she says.

Several studies looking at vitamin D’s effects on these diseases used doses ranging from 300-1,000 IUs, while others have gone as high as 2,000 IUs, the maximum dose (from food and supplements) deemed safe for adults by the IOM. Intakes above this amount can be toxic.

ASK YOUR DOCTOR

Since people process vitamin D differently–for example, people with dark skin synthesize less vitamin D from sunlight–Moore recommends consulting with your doctor about how much you need. You also might ask your physician about testing your vitamin D level.

“People should not self-medicate with vitamin D. There is true danger from exceeding the safe limits,” Moore says.

WHAT YOU CAN DO

* Include more vitamin D-fortified foods (such as milk and cereals) and vitamin D-rich fatty fish (salmon, tuna, mackerel) in your diet.

* Get 10-15 minutes of sun exposure without sunscreen at least twice a week on your face, hands, arms or back.

* If you need a supplement, look for products containing vitamin D3 (cholecalciferol).

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HOW TO GET VITAMIN D FROM FOODS

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Here are some good dietary sources of vitamin D:

Food & serving size                        International    Daily
                                             units per     value %
                                              serving

Cod liver oil (1 tablespoon)                   1,360         340

Cooked salmon (3 1/2 ounces)                    360          90

Cooked mackerel (3 1/2 ounces)                  345          90

Sardines, canned in oil (1 3/4 ounces)          250          70

Tuna, canned in oil (3 ounces)                  200          50

D-fortified milk, all varieties (1 cup)         98           25

Ready-to-eat cereals fortified with 10 %        40           10
of the DV for vitamin D (3/4 to 1 cup)

Source: National Institutes of Health, Office of Dietary Supplements

COPYRIGHT 2008 Belvoir Media Group, LLC
COPYRIGHT 2008 Gale, Cengage Learning

ScienceDaily (Sep. 4, 2008) — Loss of sleep, even for a few short hours during the night, can prompt one’s immune system to turn against healthy tissue and organs.

A new article in the September 15th issue of Biological Psychiatry, by the UCLA Cousins Center research team, reports that losing sleep for even part of one night can trigger the key cellular pathway that produces tissue-damaging inflammation. The findings suggest a good night’s sleep can ease the risk of both heart disease and autoimmune disorders such as rheumatoid arthritis.

Specifically, the researchers measured the levels of nuclear factor (NF)-?B, a transcription factor that serves a vital role in the body’s inflammatory signaling, in healthy adults. These measurements were repeatedly assessed, including in the morning after baseline (or normal) sleep, after partial sleep deprivation (where the volunteers were awake from 11 pm to 3:00 am), and after recovery sleep. In the morning after sleep loss, they discovered that activation of (NF)-?B signaling was significantly greater than after baseline or recovery sleep. It’s important to note that they found this increase in inflammatory response in only the female subjects.

These data close an important gap in understanding the cellular mechanisms by which sleep loss enhances inflammatory biology in humans, with implications for understanding the association between sleep disturbance and risk of a wide spectrum of medical conditions including cardiovascular disease, arthritis, diabetes, certain cancers, and obesity. John H. Krystal, M.D., Editor of Biological Psychiatry and affiliated with both Yale University School of Medicine and the VA Connecticut Healthcare System, comments: “The closer that we look at sleep, the more that we learn about the benefits of sleeping. In this case, Irwin and colleagues provide evidence that sleep deprivation is associated with enhancement of pro-inflammatory processes in the body.”

“Physical and psychological stress brought on in part by grinding work, school and social schedules is keeping millions of Americans up at night,” said Dr. Irwin, lead author and director of the Cousins Center for Psychoneuroimmunology at the Semel Institute. “America’s sleep habits are simply not healthy. Our findings suggest even modest sleep loss may play a role in common disorders that affect sweeping segments of the population.” In other words, sleep is vitally important to maintaining a healthy body. And as Dr. Krystal notes, “these findings provide a potential mechanistic avenue through which addressing sleep disturbance might improve health.”

ScienceDaily (Dec. 8, 2007) — Scientists have known which genes are linked to inflammation, but now researchers at Wake Forest University Baptist Medical Center have organized this information to develop a powerful tool to aid investigators in studying the genetics of inflammatory diseases.

Using complex web-based software called Ingenuity Pathway Analysis®, the researchers were able to systematically map out pathways, or chains of genes, and subpathways that contribute to various aspects of inflammation.

“We basically organized the inflammation-associated genes in a systematic way,” said Matthew Loza, Ph.D., of the Center for Human Genomics at Wake Forest University School of Medicine, and lead author of the study. “Before, a random list of genes involved in inflammation was all you had. We started with that same list, but then built these networks to bring all these different genes together.”

The study, which was recently published by the Public Library of Science in its online journal PLoS One, has also led to the development of two customized panels for analyzing genetic variations in the inflammation pathways — one for European and one for African descent populations. In a laboratory, these panels are analyzed using special laboratory equipment and computer systems. Researchers can obtain the custom inflammation panel through Affymetrix Corporation.

“This is so significant because inflammation is a very hot topic, and many research groups want to study it,” said Bao-Li Chang, Ph.D., assistant professor of pediatrics at Wake Forest and senior author for the study. “We have provided researchers with the tool to effectively and efficiently accomplish their goals.”

Inflammation is the immune system’s response to pathogens and tissue damage. Chronic inflammation is linked to numerous diseases, including rheumatoid arthritis, cardiovascular disease, and many cancers.

This study is part of a larger study through the Women’s Health Initiative that explores the role of inflammation in colon, breast and lung cancer. It’s sponsored by the National Heart, Lung and Blood Institute of the National Institutes of Health.

Co-researchers were Charles McCall, M.D., and Jianfeng Xu, Dr. P.H., of Wake Forest, Liwu Li, Ph.D., of the Virginia Polytechnic Institute and State University, and William Isaacs, Ph.D., of Johns Hopkins University Medical Institutions.