Low Vitamin D Tied to Estrogen Decline
Reported November 17, 2009
(Ivanhoe Newswire) — Ill effects of vitamin D deficiency in men are amplified by lower levels of estrogen, but not by testosterone.
Vitamin D is essential to good health, and can be obtained from fortified foods such as milk and cereals, and by exposure to sunlight. Previous studies showed that deficiencies in vitamin D and low levels of estrogen were independent risk factors for hardened and narrowed arteries and weakened bones.
Researchers conducted a national study of 1,010 men to investigate the relationship between Vitamin D and heart and bone health. “Our results confirm a long-suspected link and suggest that vitamin D supplements, which are already prescribed to treat osteoporosis, may also be useful in preventing heart disease,” lead investigator and cardiologist Erin Michos, M.D., M.H.S., Johns Hopkins University School of Medicine and its Heart and Vascular Institute, was quoted as saying.
“All three steroid hormones – vitamin D, estrogen and testosterone – are produced from cholesterol, whose blood levels are known to influence arterial and bone health,” said Michos. “Our study gives us a much better understanding of how the three work in concert to affect cardiovascular and bone health.”
Michos says the overall biological relationship continues to puzzle scientists because studies of the long-term effects of adding estrogen in the form of hormone replacement therapy in women failed to show fewer deaths from heart disease. Indeed, results showed that in some women, an actual increase in heart disease and stroke rates occurred, although bone fractures declined.
The men in the study had their hormone levels measured for both chemical forms of testosterone and estrogen found in blood.
Initial results showed no link between vitamin D deficiency and depressed blood levels of either hormone. And despite finding a harmful relationship between depressed testosterone levels and rates of heart disease, stroke, high blood pressure, and osteopenia in men, researchers found that it was independent of deficiencies in vitamin D.
When researchers compared ratios of estrogen to sex hormone binding globulin (SHBG) levels, however, they found that rates of both diseases, especially osteopenia, were higher when both estrogen and vitamin D levels were depressed.
Using the same measure of estrogen levels, men low in vitamin D were also at heightened risk of cardiovascular diseases. Michos explained, “These results reinforce the message of how important proper quantities of vitamin D are to good bone health, and that a man’s risk of developing osteoporosis and heart disease is heavily weighted on the complex and combined interaction of how any such vitamin deficits interact with both their sex hormones, in particular, estrogen.”
SOURCE: Presented at the American Heart Association Annual Scientific Sessions, Orlando, FL, November 15, 2009