Vitamins and minerals supplements aren't automatic sure wins on the health front. Too much selenium might boost the risk for the form of diabetes that makes cells resistant to the effects of insulin.
PHILADELPHIA -- A new analysis of data from a large national study found that people who took a 200 microgram selenium supplement each day for almost eight years had an increased risk of developing type 2 diabetes than those who took a placebo or dummy pill.
The data came from the Nutritional Prevention of Cancer Trial (NPC), a large randomized, multi-center, clinical trial from the eastern United States, designed to evaluate whether selenium supplements prevent skin cancer. In the study being published, researchers selected 1,202 participants who did not have diabetes when they were enrolled in the NPC Trial. Half received a 200 microgram selenium supplement and half received a placebo pill for an average of 7.7 years.
Saverio Stranges, MD, PhD, lead author of the study, says that the findings from this study suggest that selenium supplements do not prevent diabetes and that they might be harmful. “At this time, the evidence that people should take selenium supplements is extremely limited. We have observed an increased risk for diabetes over the long term in the group of participants who took selenium supplements.”
Overweight people did not experience a boost in type 2 diabetes risk from taking selenium.
In the current study, 58 out of 600 participants in the selenium group and 39 out of 602 participants in the placebo group developed type 2 diabetes. After 7.7 years of follow-up, the relative risk rate was approximately 50 percent higher among those randomly selected for the selenium group than among those randomly placed in the placebo group.
The results consistently showed higher risks of disease among participants receiving selenium across subgroups of baseline age, gender, and smoking status. However, the selenium supplements had no impact on the most overweight participants. The risk of developing diabetes tended to be higher in people who had higher blood selenium levels at the start of the study.
Whether a selenium supplement would help or hurt you probably depends on how much selenium you have in your body from your diet. People who eat Brazil nuts already are getting lots of selenium and shouldn't take a supplement.
The lack of increased risk from selenium for those who are overweight suggests that selenium works to boost type 2 diabetes by the same mechanism which fat cells boost that risk. Maybe the fat cells already flip some molecular switches to the same position selenium causes the switches to get set to and therefore when selenium comes along it can't flip the switches.
We need implanted sensors that'll tell us when we are getting too much or two little of each nutrient. We also need nutritional genomics: genetic tests that will tell us what levels of nutrients are ideal for our individual bodies.
|Share |||Randall Parker, 2007 July 15 02:40 PM Aging Diet Studies|