Dr. Adam Murphy, a clinical instructor in urology at Northwestern University Feinberg School in Chicago and a physician at Jesse Brown VA Medical Center, said vitamin D deficiency causes brittle bones and has been linked to prostate cancer, diabetes, rheumatoid arthritis and multiple sclerosis.
In African-American men, the increased melanin in darker skin blocks the ultraviolet rays necessary for the body to produce the vitamin and it might require as much as six times more sun exposure than Caucasian men need to produce adequate vitamin D levels.
The Institute of Medicine recommends adults and children take 600 International Units of vitamin D daily, but Murphy said that's way too low.
African-American men living in Chicago would need to take nearly 2,500 International Units of vitamin D to reach normal, healthy levels, Murphy said.
"It takes a dark-skinned male like myself 90 minutes three times a week to absorb enough sunlight to produce the recommended amount of vitamin D compared to just 15 minutes three times a week for a Caucasian male," he said.
The degrees to which African-American men need to increase their vitamin D supplementation likely varies depending on how sunny the area is and how long people spend outside.
The findings were presented at the American Association of Cancer Researchers Health Disparities Conference in Washington.