An easy and effective way to significantly reduce the risk of heart disease in certain populations (those with darker skin or who may not be exposed to sunlight because of lifestyle or culture) may be with the use of vitamin D supplements, according to a recent study. The study’s authors found that young, overweight black individuals who took the highest amount of the supplement (4,000 International Units, IUs) showed the most improvement in a significant risk factor for heart disease.
Vitamin D deficiency is a global problem. The authors of a 2014 review reported that “Vitamin D deficiency is a major public health problem worldwide in all age groups.”
More than 80 percent of Americans have insufficient levels of vitamin D, a nutrient that plays an essential role in heart health, bone integrity, nervous and immune system function, and regulating insulin levels. Heart disease is the number one killer of both men and women in the United States, and the populations studied tend to acquire the disease at an earlier age and die from it at a younger age than the general population.
In a more recent (December 2017) study, a team of researchers explored the effects of vitamin D supplementation on a group of 70 overweight African Americans ages 13 to 45. Black people are at greater risk of vitamin D deficiency than white people because dark skin does not absorb sunlight as well as light skin, so the body does not produce the vitamin as efficiently. In addition, overweight individuals are less able to benefit from vitamin D because fat holds onto the nutrient and it gets trapped in fat rather than utilized.
In the study, some of the participants took a placebo, while others were given either 600 IU, 2,000 IU, or 4,000 IU vitamin D per day for 16 weeks. These dosages are in contrast to those recommended by the National Institute of Health, which recommends 600 IUs for adults (19-70 years) and 800 IUs for those older than 70.
The researchers were looking at the arterial walls of the participants, since the degree of stiffness in these walls is a predictor of cardiovascular disease and death, and a deficiency of vitamin D appears to contribute to this problem. Arterial stiffness was measured both before and after the start of the study.
At the end of 16 weeks, the participants who had taken 4,000 IU vitamin D showed a 10.4 percent decline in the level of arterial stiffness, and the improvement was achieved after only 8 weeks. Subjects in the 2,000 IU group experienced a 2 percent drop in stiffness, while those who took 600 IU showed a 0.1 percent rise. Placebo group participants saw a 2.3 percent rise in arterial stiffness over 16 weeks.
Even though this study involved a relatively small group of individuals, it was significant for several reasons. One, it was the first randomized controlled trial that evaluated the impact of vitamin D supplementation on arterial stiffness in overweight African Americans with a deficiency of vitamin D.
Two, the results of the study prompted the Institutes of Medicine to modify the upper limits of vitamin D supplementation from 2,000 IU to 4,000 IU for everyone age 9 years and older. It should be noted that some other health entities, such as the Vitamin D Council, already advocate taking higher doses of vitamin D (5,000 IU) for adults.
Some of the best food sources of Vitamin D are salmon, sardines, tuna, eggs, and mushrooms.
How much vitamin D are you getting every day? You can learn whether you have a vitamin D deficiency by getting a simple blood test, so talk to your healthcare provider.
Palacios C, Gonzalez L. Is vitamin D deficiency a major global public health problem? Journal of Steroid Biochemical and Molecular Biology 2014 Oct; 144PA: 138-45
Raed A et al. Dose responses of vitamin D3 supplementation on arterial stiffness in overweight African Americans with vitamin D deficiency: a placebo controlled randomized trial. PLoS One 2017 Dec 7
Tovey A. How much vitamin D is needed to achieve optimal levels? Vitamin D Council. 2017 May 22