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Low vitamin D levels in blacks may explain higher rates of heart disease

January 6, 2010 |  3:06 pm

The disparity in rates of heart disease deaths between blacks and whites can be attributed in large part to low levels of vitamin D in a substantial portion of the black population, researchers have found. Their dark skin cuts down on the production of vitamin D--which is produced primarily by sunlight--particularly among those who live at higher latitudes where sunlight is less intense than it is closer to the equator, said Dr. Kevin Fiscella of the University of Rochester, a co-author of the paper appearing Thursday in the Annals of Family Medicine. In general, blacks require three to five times as much exposure to sunlight as whites to produce the same amount of vitamin D.

The study also found a higher risk of death from heart disease in whites with abnormally low levels of vitamin D.

Low levels of vitamin D have previously been linked to increases in high blood pressure, obesity, diabetes, peripheral artery disease, kidney disease and breast cancer. To further explore the links, Fiscella and Dr. Peter Franks of UC Davis studied vitamin D levels in 15,000 people who participated in the third National Health and Nutrition Survey from 1988 to 1994 and correlated them to deaths reported in the National Death Index through 2001. Overall, they found that the 25% of subjects in the study with the lowest blood levels of vitamin D had a 40% higher risk of dying from heart disease than those in the upper 75%. Blacks in the study had a 38% higher risk of dying from heart disease than whites, they found, but low blood levels of vitamin D accounted for about two-thirds of the increased risk. The rest could be attributed to poverty.

Current federal guidelines for vitamin D call for consumption of 400 International Units (IUs) of vitamin D for most adults and 600 IUs for those over age 70. Fiscella did not make a recommendation for daily intake, but most researchers studying vitamin D now take between 1,500 and 2,000 IUs per day. The general consensus is that no harm is associated with a daily intake of up to 10,000 IUs. And many physicians agree that, when you have your annual visit with your doctor, he or she should measure your vitamin D levels.

-- Thomas H. Maugh II

Twenty minutes of sunlight per day provides most whites with enough vitamin D, but blacks require three to five times as much exposure. Credit: Al Schaben / L.A. Times

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Comments (4)

"Grassrootshealth D Action"
offer postal 25(OH)D3 testing to ensure people monitor their levels to stay above the 55ng/ml associated with least incidence of cardiometabolic disorders.

Nursing and pregnant ladies may like to read the free full text paper available online.

" Circulating 25-Hydroxyvitamin D Levels in Fully Breastfed Infants on Oral Vitamin D Supplementation."

This paper has some interesting graphs showing how 400iu/daily is an effective intake enabling a month old baby (approx 4~5kg 8~11lbs weight) to achieve optimum bone mineral density.

To ensure babies were born with access to vitamin D3 replete breast milk required mothers consume 6400iu/daily/D3, at latitude 32N .

Dr Davis Heartscanblog working at latitude 42N finds his heart patients require 5000~6000iu/daily/D3 to attain 25(OH)D3 around 60ng/ml.
As there is wide variation in response to D3 and/or UVB exposure regular 25(OH)D3 testing is recommended.

The federal guidelines for Vitamind D is mentioned as an "Adequate Intake" (AI). You can find a good list of the Vitamin D intake at

It is broken down in to age groups.

Medical News Today reports: "US researchers investigating the disparity
between blacks and whites in heart and stroke-related deaths have suggested
that vitamin D deficiency may be partly responsible." This will be in the
Annals of Family Medicine, online, January 11. Kevin Fiscella, et al.

This is my explanation of this finding.

Copyright, 2010, James Michael Howard

"A case may be made that blacks exhibit increased cardiomyopathy that may be
explained by the effects of increased testosterone on heart hypertrophy.
Blacks produce more testosterone than whites. The basis being that
testosterone increases calcium effects on heart muscle.

Since vitamin D exerts pleiotropic actions involving calcium, vitamin D
produces an antagonistic effect on the availability of calcium. It is known
that vitamin D is antagonistic to heart hypertrophy.

I suggest these findings may be explained by the foregoing. That is, vitamin
D exerts a protective effect against testosterone-induced cardiomyopathy
which occurs in both races but much more so in blacks."

Blacks have low lactose tolerance which may contribute to a lack of vitamin D since milk products contain Vit. D. I don't kbow if this fact was considered in the study


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