- Help boost your immune system
- Reduce your risk of high blood pressure
- Lower your blood pressure if it’s high
- Reduce your risk of depression
- Reduce your risk of coronary heart disease, type 2 diabetes, stroke, and several kinds of cancer
- Help delay, even prevent, cognitive decline, generally, and Alzheimer’s, specifically
Vitamin D deficiency doubles your risk of dying too youngA 2014 study found that people with vitamin D deficiency were twice as likely to die prematurely—from all causes. In the US and Europe, it's estimated that more than two-thirds of the population is D-deficient, and that roughly 13 percent of all deaths in the US, and 9 percent in Europe, could be attributed to D-deficiency. This is staggering. So many people dying before their time, so many probably ill, miserable, and at risk of sudden catastrophic events, like stroke and heart attack, in their last years. And it’s such a simple problem to correct.
How much vitamin D is enough?First things first: one of the central players in defining vitamin D sufficiency is the Food and Nutrition Board (FNB) at the Institute of Medicine of The National Academies (formerly National Academy of Sciences). Their recommended daily allowance (RDA) for males and females from age 1 year to age 70 years is 600 IUs. What? No nuances, gradations, or variants accounting for age, general health, environmental factors, or current meds? Nope—it’s 600 IUs, straight across the board. I think they're living in the past—in a time when all your body needed to produce sufficient vitamin D was good food and healthy sunlight. Unfortunately, for most Americans, bad food is either the only option or the much easier option. As for healthy sunlight, many Americans live under polluted skies, which block some of the D-producing UV rays your body needs. Add to that our inclination to spend more time indoors or slather on the sunblock when we do go out…it’s no wonder we’re so D-deficient.
How I manage vitamin D for all patientsIn my practice, the first step is to determine the extent of D-deficiency, if any. I start with a simple blood test and repeat it every six months to assess the patient’s levels. The result should ideally show a blood serum level between 50-70 ng/ml (nanograms per milliliter). For those within the ideal range, I recommend that every man, woman, and child take a daily dose of 1,500 IUs per day. If the result is less than 50 ng/ml, I recommend up to 4,000 IUs of vitamin D daily, and up to 30 minutes of direct sunlight. (Some doctors recommend up to 10,000 IUs—too much, in my opinion, and not supported by sufficient long-term study.) Your body needs the sun’s UV rays to create vitamin D, so my personalized RDA would depend not only on the degree of deficiency, but also on the location and season, and, hence, the potency of local sunlight. In northern climes, for example, sunlight is weaker throughout the year, and even moreso in winter, so I might recommend longer exposure or a higher RDA.
Are you at risk for D-deficiency?With D-deficiency, diet and sun exposure aside, the usual risk factors are in full force:
- Over-consumption of alcohol
- Lack of exercise/sedentary lifestyle
- Social isolation
A D-helpful dietVitamin D is so important, I'll flex on what's acceptable in your diet. In a rare case of my agreeing with Big Food, products that are "fortified" with vitamin D—milk and bread, for example—are OK, if not too adulterated otherwise. Food sources of natural vitamin D are few. They include wild-caught fish—salmon is champ, with mackerel, tuna, and sardines also good—but fish once a week only, thanks to
- Theodoratou, E., I. Tzoulaki, L. Zgaga, and J. P. A. Ioannidis. "Vitamin D and Multiple Health Outcomes: Umbrella Review of Systematic Reviews and Meta-analyses of Observational Studies and Randomised Trials." Bmj 348, no. Apr01 2 (2014).
- Schild A, Herter-Aeberli I, Fattinger K, Anderegg S, Schulze-König T, Vockenhuber C, Synal H-A, Bischoff-Ferrari H, Weber P, von Eckardstein A, Zimmermann MB: Oral Vitamin D Supplements Increase Serum 25-Hydroxyvitamin D in Postmenopausal Women and Reduce Bone Calcium Flux Measured by 41Ca Skeletal Labeling. Journal of Nutrition 2015, 145: 2333-2340, doi: 10.3945/jn.115.215004
- Heaney, R.; Garland, C.; Baggerly, C.; French, C.; Gorham, E. Letter to Veugelers, P.J. and Ekwaru, J.P., A Statistical Error in the Estimation of the Recommended Dietary Allowance for Vitamin D. Nutrients 2014, 6, 4472–4475; doi:10.3390/nu6104472. Nutrients 2015, 7, 1688-1690.
- Cranney C, Horsely T, O'Donnell S, Weiler H, Ooi D, Atkinson S, et al. Effectiveness and safety of vitamin D. Evidence Report/Technology Assessment No. 158 prepared by the University of Ottawa Evidence-based Practice Center under Contract No. 290-02.0021. AHRQ Publication No. 07-E013. Rockville, MD: Agency for Healthcare Research and Quality, 2007.
- Cedric F. Garland, June Jiwon Kim, Sharif Burgette Mohr, Edward Doerr Gorham, William B. Grant, Edward L. Giovannucci, Leo Baggerly, Heather Hofflich, Joe Wesley Ramsdell, Kenneth Zeng, and Robert P. Heaney. Meta-analysis of All-Cause Mortality According to Serum 25-Hydroxyvitamin D. American Journal of Public Health: August 2014, Vol. 104, No. 8, pp. e43-e50. doi: 10.2105/AJPH.2014.302034