Peter Loescher, MD
Posted June 30th, 2010
A pill is currently available over the counter that will make you feel younger, stronger, more alert, more alive, and more enthused. It can also reduce by one third to one half your risk of diabetes, multiple sclerosis, inflammatory bowel disease, breast, colon, and prostate cancer, and lower your risk of hypertension, congestive heart failure, and heart attack. Sound too good to be true? Wait… there’s more… Studies show that it will improve your immune system, decrease risk of depression and schizophrenia, and decrease your risk of osteoarthritis and asthma. Best of all, it’s not a banned performance-enhancing drug!
Believe it or not, I am talking about good old vitamin D, the stuff that has fortified your milk since you were a kid, the stuff that your incredibly smart body can make, simply by you going out in the sun and exposing your (gasp!) unprotected skin for five to thirty minutes twice a week.
Experts recognized many years ago that vitamin D protects against rickets, a childhood disease of poor bone mineralization. This led to vitamin D-fortified milk, cereal, and other foods, which largely eradicated rickets from our population. With this problem solved, vitamin D was largely forgotten and thought to be adequately supplemented in western society. More recent research has revealed that despite these food fortifications, vitamin D levels in this country and around the world are surprisingly low. Somewhere between 25 to 40 percent of the U.S. population is vitamin D deficient, and worldwide an estimated 1 billion people have inadequate levels of this important nutrient.
VITAMIN D SOURCES AND AMOUNTS
People get vitamin D from their diet and from sunlight. Oily fish, shiitake mushrooms, and cod liver oil are excellent dietary sources of vitamin D. Many foods are fortified with vitamin D, such as milk, yogurt, cheese, cereals, breads, and orange juice. Exposure to direct sunlight, with arms and legs exposed without sunscreen for long enough to create a slight reddening of the skin (5-10 minutes, depending on the strength and angle of the sun’s rays, time of day, and skin sensitivity) can allow the body to synthesize up to 3 days worth of vitamin D.
Vitamin D comes in two forms: D2 and D3, which have different chemical structures. The important fact to remember is that D3 is roughly three times more potent than D2. Once in the body, both vitamin Ds are processed by the liver to its circulating form in the bloodstream, and then activated when needed by the kidney to perform one or more of its many functions throughout the body.
Historically, experts have determined vitamin D deficiency to be a level below 20 ng/dl, and recommended daily intake to be 400 IU. Many experts now feel that the preferred range for health is 30 to 60 ng/dl, and daily intake should be 800 to 2000 IU per day. Vitamin D has the potential to cause problems at levels above 150 ng/dl. To achieve such levels, one would have to take more than 10,000 IU per day for more than five weeks.
Best estimates in this country show that often 100 percent of nursing home residents are vitamin deficient, up to 50 percent or more of elderly men and women in the U.S. and Europe are deficient, 42 percent of African American women age 15-49 are deficient, and 32 percent of Boston area medical students, residents, and physicians were found in a recent study to be deficient in vitamin D, even after drinking fortified milk daily, taking daily multivitamin with 400 IU vitamin D and eating salmon once per week.
Calcium and phosphorous are important for bone health. Without adequate vitamin D, absorption of calcium and phosphorous is decreased by up to 50 percent, increasing risk of osteoporosis and fractures. A study in France of 3,700 elderly women who were given 1200 IU calcium and 800 IU vitamin D per day for three years showed a 43 percent reduction in hip fracture compared to controls. Vitamin D also seems to improve muscular function. A recent study of over 1,200 nursing home residents demonstrated a 72 percent decrease in falls in a group given 800 IU vitamin D per day, along with 1,200 mg calcium.
We are starting to recognize the role that vitamin D plays in gene expression and control of cellular function in our bodies. Vitamin D helps cells to know when to replicate and when to self terminate. Proper expression of these and other cell functions can protect us from everything from tuberculosis infection and autoimmune diseases like psoriasis to colon, breast, prostate, pancreatic and ovarian cancer, and lymphoma. It has long been recognized that people living above 35 degrees latitude (i.e north of Los Angeles, Dallas, Phoenix, Atlanta) are far more likely to get, and to die from, the above list of diseases. Large studies have also shown that patients with vitamin D levels below 20 ng/dl are up to 50 percent more likely to contract the above diseases, and more likely to die from them than those with vitamin D levels above 30 ng/dl. Diabetes, Crohn’s disease, cardiovascular disease, hypertension, schizophrenia, depression, asthma, rheumatoid arthritis, and osteoarthritis also all show substantial declines in prevalence among people who have adequate vitamin D levels.
A number of factors can lead to vitamin D deficiency. Sunscreen (SPF 15+) impairs vitamin D synthesis by the skin by up to 99 percent. Dark skin decreases vitamin D synthesis by up to 99 percent. Aged skin (70 years +) can have decreased synthesis ability up to 75 percent. Latitude, time of year, and time of day can impair vitamin D synthesis from sunlight. There is almost no ability to create vitamin D from sunlight between November and February above 35 degrees latitude. Obesity, digestive problems, kidney failure, and certain medications can also increase risk for vitamin D deficiency.
Vitamin D deficiency can be diagnosed with a simple blood test. The test is expensive (about $250) and only a few major institutions around the country do the test. No one in Vermont does this test; at Gifford Hospital in Randolph, we send our samples to the Mayo Clinic in Minnesota for vitamin D levels. Because of the cost, many doctors will not test patients, but rather will simply recommend supplementing vitamin D at the 800, 1000, or even 2000 IU per day level. For a patient having symptoms which may be directly related to vitamin D deficiency, obtaining a baseline level is warranted. As more cost-effective tests are developed and more centers do the test in house, more widespread testing will probably become the norm, perhaps even a routine.
Because of the high prevalence of vitamin D deficiency, the health risks of being deficient, the skin cancer risks of prolonged sun exposure, and the relative ease of supplementation, it is advisable to consider supplementing with either 1000 IU of vitamin D3 or 3000 IU of vitamin D2 daily. Ask your doctor if vitamin D is right for you. It could help prevent some deadly diseases, make you feel and perform better at the same time, and you won’t fail any performance enhancing drug tests for taking it.
Peter Loescher is a board-certified family practitioner and sports medicine physician at the Sharon Health Center in Sharon, VT, an affiliate of Gifford Medical Center. He completed a residency in family practice at Dartmouth Hitchcock Medical Center and a fellowship in sports medicine at the University of Oklahoma and Eastern Oklahoma Orthopedic Center, Tulsa. He is the sports medicine director at The Cardigan Mountain School and provides medical coverage at many local athletic events. When not at the office, he can be found running, biking, and skiing the byways and trails of northern New England. You can reach him at [email protected].