Vitamin D is a critical factor in the maintenance of good health, and it also helps to prevent chronic disease such as diabetes and cancer; in fact, more than 800 studies demonstrate vitamin D’s effectiveness against cancer. With flu season upon us, it is wise to pay attention to the large and growing body of evidence documenting the key role played by vitamin D in preventing seasonal flu.
Our bodies naturally produce vitamin D in response to sunlight (UVB radiation) exposure. According to the Vitamin D Council, Caucasian skin produces approximately 10,000 International Units (“IU”) of vitamin D3 (cholecalciferol) in response to 20–30 minutes of summer sun exposure. But during the winter months, those who live in the northern latitudes are unlikely to get sufficient sun exposure to produce adequate levels of vitamin D. For the longest time, natural health advocates have warned that the official “Recommended Dietary Allowance” of Vitamin D (400 IU per day) is far too low, and that the amount we actually need is much higher. The problem, however, is that while it is impossible to get too much vitamin D from sun exposure, excessive supplementation can be toxic.
To sort out the “conflicting messages” that we receive about vitamin D, the governments of Canada and the United States jointly asked the U.S. Institute of Medicine (“IOM”), the health arm of the National Academy of Sciences, to assess current data on health outcomes associated with vitamin D and calcium, and to update the nutrient reference values known as “Dietary Reference Intakes”. The proposed new reference values published by the IOM in November 2010 are astonishingly low, with the report even suggesting that we do not need to take vitamin D supplements. The new IOM “Recommended Dietary Allowance” is 600 IU of vitamin D per day for children and adults, including pregnant and lactating women, and 400 IU per day for infants from 0 to 12 months.
Moreover, without producing any evidence to support the assertion, the IOM study warns that taking 10,000 IU or more per day could be toxic, and proposes an “Upper Level Intake” of 1,000 – 4,000 IU per day. In direct contrast, a recent study from the University of California, San Diego School of Medicine and Creighton University School of Medicine in Omaha, published by the International Institute of Anticancer Research, confirms that adults actually require 4,000 – 8,000 I.U. daily to maintain a vitamin D level adequate to prevent chronic disease, and concludes that universal intake of up to 40,000 IU of vitamin D per day is unlikely to result in vitamin D toxicity: Anticancer Research | February 2011. This study clearly supports the Vitamin D Council recommendation that healthy adolescents and adults without adequate sun exposure should supplement with at least 5,000 IU of vitamin D3 daily. Natural health practitioners similarly recommend that otherwise healthy adults should supplement with 5,000 IU of Vitamin D3 daily, children should take 2,000 IU per day, infants should be given 35 IU per pound of body weight (or 400-1,000 IU depending on weight) daily, and they suggest using appropriate blood tests to keep regular tabs on vitamin D serum levels.
While quantity is crucial, the quality of the vitamin D supplement is also important. A recent study confirms that vitamin D3 is approximately 87% more effective at raising vitamin D blood levels than vitamin D2, and produces 2- to 3-fold greater storage of vitamin D: Journal of Clinical Endocrinology & Metabolism | December 22, 2010.
One further point worth mentioning is that many people are unaware that sunscreen can interfere with our innate ability to produce vitamin D, and that the regular use of a strong sunscreen can lead to vitamin D deficiency. For a 12-year-old girl named Tyler Attrill, her severe vitamin D deficiency was only recognized when she failed to recover properly from surgery. This young girl’s regular habit of using factor 50 sunblock likely deprived her of vitamin D and caused her to develop the bone disease rickets: BBC News | January 19, 2011.
Is there a hidden agenda behind the ultra-low IOM recommendations? Personally, I find it difficult not to be cynical, especially given the fact that the IOM recommendation committee spurned the advice of many vitamin D experts. Those who heed the IOM advice and either inadequately supplement or fail to supplement with vitamin D will likely be more susceptible to seasonal flu and, unfortunately, more prone to develop chronic illness.