The Sunshine Vitamin
Once experts believed rickets to be conquered, vitamin D sat in the shadows of other nutritional superstars like vitamins C and E for years. Foods were fortified with the vitamin, and we moved on to other things. The problem is that we also moved in, indoors that is with our love of our computers and televisions growing as quickly as our fears of the sun and its harmful UV rays. Experts now say that half of the world's population are D deficient and that this deficiency could be taking a serious toll on our health.
So, are you getting enough vitamin D, especially on gloomy days? If you are not munching on such vitamin D rich foods as wild salmon and sardines, the answer is probably no.
Vitamin D has been called 'the sunshine vitamin' because our bodies can actually produce and store it with UVB exposure. Although it is well known for its role in bone health and prevention of rickets, it also has shown to potentially reduce the risk of such ailments as multiple sclerosis, autoimmune disorders, diabetes, rheumatoid arthritis, and various types of cancer. In fact, a European study published by scientists at the International Agency for Research on Cancer and the Institute of Oncology concluded that adequate vitamin D levels may decrease mortality from virtually any health condition.
A Fish a Day?
James Fleet, professor of nutrition and vitamin D researcher at Purdue University says that northern folks, even if they are munching on salmon and sardines, probably are still lacking in vitamin D during the fall and winter months. In fact adds Fleet, "It is nearly impossible to get enough [vitamin D] from food." The recommended allowance for vitamin D is currently 200 to 600 IU's (International Units) depending on a person's age, but with all of the new research, many experts are recommending at least 1,000 IU's a day.
Fleet explains that outside of sunshine, fatty fish provide the main natural source of one form of D-D3. However, getting 1,000 units from fish would mean consuming as much as 3 to 6 ounces of wild fresh salmon every day. Of course, Fleet notes, that with fish you have to keep in mind mercury content and exposure. He explains that vitamin D2 can be found in plant and fortified foods but only in small amounts. And relying on your fortified milk would require drinking about ten cups daily.
To Sun or Not to Sun?
Unfortunately, mercury in our fish is not the only danger lurking in our pursuit of D. We're all quite familiar with the repercussions of overdoing our sun exposure, namely premature aging or even skin cancer.
For years, we have been urged to avoid the sun or to protect ourselves with sunscreen. Although sunscreen does block the more dangerous UVA rays, it also blocks UVB, which is necessary to manufacture vitamin D. Therefore experts are beginning to rethink the 'no sun' message. In fact, a controversial study done by researchers at the University of New Mexico in 2005 concluded that some sun actually increased the lifespan of patients with the deadliest form of skin cancer, melanoma.
James Leyden, dermatologist and researcher at the University of Pennsylvania School of Medicine, says that he believes that we intuitively know that we need some sun. He further adds that the warnings about sun should really be tailored to the individual. For example, a redhead with freckles and a family history of melanoma should take different precautions than an African American with no family history of skin cancer.
Michael Holick, M.D., a seasoned researcher and professor at Boston University Medical School made waves in the dermatology community when he penned his book, The UV Advantage (ibooks, Inc., 2004). Holick explains that when our skin is exposed to UVB rays, our bodies are very efficient at producing vitamin D3.
In his book, Holick states that one reason that half of us are deficient is that UVB rays do not even reach us above around thirty-five degrees latitude between November and February. So, he says that during these months if you live anywhere north of Atlanta, Georgia, you essentially cannot produce D from the sun.
Like Leyden, Holick advocates an individually tailored prescription for sun protection. But he says that for the purpose of getting enough vitamin D, 10 to 15 minutes of midday exposure to the arms and legs 2 to 3 times per week should provide enough for the average healthy adult. However, he explains individuals that are older or have darker skin tones require more exposure.
Of course, Holick says that for people who cannot get UVB, a dietary supplement can provide some reassurance. In fact, he personally supplements with 1,000 IU's daily and gets 400 IU's from his multivitamin. He adds that for those who live north of Atlanta and have absorption issues, a Sperti Lamp or a tanning bed can be used. But Holick warns, the bed must be a UVB bed, and that users should tan for only 50 percent of the recommended time, and only after applying sunscreen to their faces.
The Do's and Don'ts of D
Katherine Tallmadge, M.A., R.D., is a speaker, author, and national spokesperson for the American Dietetic Association. She agrees with Holick's urgency regarding vitamin D and explains that rickets has even begun to show up in certain populations of dark-skinned children. She now recommends that all of her clients request a vitamin D analysis as part of their physical.
Tallmadge concurs that 1,000 IU's per day is generally agreed upon but that many are saying that up to 4,000 IU's is safe. She personally takes 2,000 IU's per day because she uses a sunscreen. But, she also explains that individuals should remember that the vitamin is fat-soluble and stays in the body. So, you can accumulate too much.
Elizabeth Somer, M.A., R.D., author of several books including Age-Proof Your Body (McGraw-Hill, 2006) believes that it is nearly impossible to get enough vitamin D from our diets. However, she isn't ready to recommend taking much more than the current allowances until there is more of an official consensus. But this decision should be made fairly soon. The Canadian Cancer Society is already urging adults to supplement with vitamin D this winter and it is expected that a committee will soon be formed in the U.S. to officially change recommendations for Americans.
Know Better, D Better
Fleet admits that with all of the new research, he is going to be shopping for a good supplement. He goes on to warn, however, that as important as it is to get enough D, we need to keep in mind that it is only one piece of the nutritional puzzle.
Victoria Maizes, M.D., executive director of the Program in Integrative Medicine at the University of Arizona, says that vitamin D is a critical piece of the puzzle. Her advice, however, simplifies things a bit: "Get a blood test to see if you are lacking. If so, work with your physician or nutritionist to find the right dose for you."
So, keep munching on vitamin D rich foods as many provide a wealth of nutritional benefits, including omega-3s and other essentials. But in your pursuit of D, you may need to give Mother Nature a little help this winter. And, of course, when the sun comes back out, go and enjoy! Just don't forget to stop and put on the sunscreen if you stay too long. Leyden says that a little bit of sun is not only good for D but is good for the soul.
Natural Sources of D
Wild Salmon (3.5 oz) about 600-1000 IU of D3
Farmed Salmon (3.5 oz) about 100-250 IU of D3 or D2
Sardines, canned (3.5 oz) about 300 IU of D3
Mackerel, canned (3.5 oz) about 250 IU of D3
Tuna, canned (3.6 oz) about 230 IU of D3
Cod Liver Oil (1 tsp) about 400-1000 IU of D3
Shitake mushrooms: Fresh (3.5 oz) about 100 IU of D2, Sun-dried (3.5 oz) about 1600 IU of D2
Egg Yolks about 20 IU of D2 or D3
Sunlight: 5-10 minutes of direct UVB to arms and legs about 3,000 IU of D3
Foods currently fortified include milk, orange juice, infant formula, yogurts, butter, margarine, cheeses, and cereals. Check the labels.