The researchers measured the effects of activated vitamin D (1,25 dihydroxyvitamin D3, a form called calcitriol) in rats given a normal diet or a high-salt diet, compared to control group rats given either of the same two diets, but no vitamin D treatment. The rats on the high-salt diet were likely to develop heart failure within months.
The rats on the high-salt diet, comparable to the fast food that many humans feast on, quickly revealed the difference vitamin D could make.
"From these animals, we have obtained exciting and very important results," Simpson says.
After 13 weeks, the researchers found that the heart failure-prone rats on the high-salt diet that were given the calcitriol treatment had significantly lower levels of several key indicators of heart failure than the untreated high-salt diet rats in the study. The treated rats had lower heart weight. Also, the left ventricles of the treated rats' hearts were smaller and their hearts worked less for each beat while blood pressure was maintained, indicating that their heart function did not deteriorate as it did in the untreated rats. Decreased heart weight, meaning that enlargement was not occurring, also showed up in the treated rats fed a normal diet, compared to their untreated counterparts.
Simpson and his colleagues have explored vitamin D's effects on heart muscle and the cardiovascular system for more than 20 years. In 1987, when Simpson showed the link between vitamin D and heart health, the idea seemed far-fetched and research funding was scarce. Now, a number of studies worldwide attest to the vitamin D-heart health link (see citations below).
The new heart insights add to the growing awareness that widespread vitamin D deficiencythought to affect one-third to one-half of U.S. adults middle-aged and
|Contact: Anne Rueter|
University of Michigan Health System