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For the last several months, Vitamin D research has dominated health headlines. This week is no exception as two studies were released touting the importance of Vitamin D. In one study, the level of Vitamin D in the blood has been identified as a marker for childhood asthma, while the second found that Vitamin D supplements, taken during a weight-loss program, improved several cardiovascular risk markers for overweight subjects.
A research team led by John M. Brehm, Channing Laboratory, Department of Medicine, Brigham and Women’s Hospital, Boston, compared blood levels of Vitamin D with markers for allergy and asthma severity among children in Costa Rica. Their ground-breaking study, published in the American Journal of Respiratory and Clinical Care Medicine, examined the relationship between the levels of the major blood-circulating form of Vitamin D, known as 25-hydroxyvitamin D, and markers of allergy and asthma severity among 616 Costa Rican children between the ages of 6 and 14.
The researchers found that among the asthma sufferers, more than one-quarter (28 percent) had <30 ng/ml of circulating Vitamin D, considered to be an insufficient level. They also determined that increases in Vitamin D levels were associated with reduced odds of hospitalization and the use of anti-inflammatory medications over the previous year. Participants with increased levels of Vitamin D also demonstrated increased airway responsiveness.
In a second study published in The American Journal of Clinical Nutrition, a research team, headed by Armin Zittermann from the Klinik für Thorax und Kardiovaskularchirurgie Ruhr-Universität Bochum in Germany, examined the impact that Vitamin D has on weight loss and risk markers for cardiovascular disease in overweight subjects.
The study looked at 200 overweight participants with average levels of Vitamin D metabolites of 30 nmol/L (12 ng/mL). Randomly assigned to receive either a placebo or 83 µg/day of Vitamin D (approximately 3,500 IU per day) for one year, each subject also participated in a weight-loss program.
At the end of the study, the levels of circulating Vitamin D increased in the supplemented group by 55.5 nmol/L, while the placebo group only increased by 11.8 nmol/L. Furthermore, the participants taking supplements recorded a 13.5 percent reduction in triglyceride levels compared to 3.0 in the placebo group, and a significant 26.5 percent reduction (compared to 18.7 percent in the placebo group) in the level of parathyroid hormone, which is considered a new risk marker for cardiovascular disease. According to the research team, Vitamin D did not have a negative impact on weight loss or fat reduction, regardless of gender.
Perhaps most interesting, the participants taking Vitamin D, when compared to the placebo group, exhibited a threefold reduction in the markers for inflammation. Inflammation is a subject of tremendous research interest because of its role in initiating many chronic diseases.
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