Low levels of vitamin D circulating in the blood may be a risk factor for cardiovascular disease, suggests a new study from Harvard School of Public Health.

For their analyses, Giovannucci and colleagues used data from a subset of 18225 men participating in the prospective Health Professionals Follow-up Study. Participants were free of diagnosed cardiovascular disease at blood sampling (between 1993, and 1999), and over the course of a 10-year follow up 454 experienced a non-fatal heart attack or fatal coronary heart disease. To examine the link between blood vitamin D levels and heart disease risk, another 900 men with no cardiovascular events during follow-up were randomly selected among participants. The precursor of the active form of vitamin D, 25-hydroxyvitamin D (25 OH D), was used to assess vitamin D status.

Men who were considered deficient in vitamin D (25 OH D ≤15 ng/ml) had an up to 2.5-fold higher risk for heart attack compared to men with vitamin D sufficiency (25 OH D ≥30 ng/ml). Even intermediate vitamin D levels (25 OH D of 15.0 29.9 ng/ml) were linked with a 1.5-fold increased risk. Although those with a deficiency in vitamin D also had other risk factors for cardiovascular disease, vitamin D levels appeared to be an independent factor.

The authors conclude that low vitamin D levels are associated with higher heart attack risk. This adds to growing evidence relating vitamin D deficiency to a number of conditions and to total mortality. If further scientific research proves this relationship, current recommendations for vitamin D intake may need to be amended.

Good dietary sources of vitamin D are oily fish or fortified products including milk and breakfast cereals.

For more information, see:
Giovannucci et al (2008) 25-Hydroxyvitamin D and Risk of Myocardial Infarction in Men: A Prospective Study. Arch Intern Med 168:1174-1180

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Nutrition - Vitamins, Minerals & Phytonutrients