Canadian study indicates that quality of nutritional supplements is still a concern

In a new study, researchers discovered that more than half of the nutritional supplements tested did not disintegrate properly. Included in the test were 39 tablets and 10 capsules containing minerals and vitamins commercially available on the Canadian market. The first disintegration stage was performed using Simulated Intestinal Fluid (SIF) pH 6.8 for 20 minutes. Products which did not disintegrate were further analyzed using USP disintegration conditions for dietary supplements. Of the 39 tablets tested, only 18 products disintegrated fully at the first stage. The 21 tablets that did not pass the first stage were then tested for disintegration using USP conditions. Nine tablets still failed to disintegrate, including all three timed-release products tested. Forty-percent of the capsules also failed the first stage, although all ten eventually passed when subjected to USP testing conditions.

This study illustrates that disintegration, one basic indicator of product quality, is still a concern for dietary supplements.

J Pharm Pharmaceut Sci (www.cspsCanada.org) 9(1):40-49, 2006 http://www.ualberta.ca/~csps/JPPS9(1)/Loebenberg.R/tablets.pdf

Low Vitamin D Levels Linked to Insulin Resistance

Vitamin D intake may be linked to insulin resistance. Researchers administered oral glucose tolerance tests to 126 healthy volunteers who had no obvious symptoms of glucose intolerance. Blood glucose levels declined more slowly in test subjects with low vitamin D levels. These subjects were also more likely than their peers to show signs of metabolic syndrome including obesity, hypertension and insulin resistance. The results from this study suggest that people with low vitamin D levels have a higher risk of developing insulin resistance and metabolic syndrome.

Am J Clin Nutr 2004 May;79(5):820-5.

Supplemental vitamin D and calcium reduces risk of diabetes

The incidence of type-2 diabetes is lower among women who get adequate calcium and supplement with vitamin D. Researchers used data from the Nurses Health Study, which includes over 83,000 women, to study the relationship of calcium and vitamin D intake to type-2 diabetes.

After 20 years of follow-up, it was concluded that a combined daily intake of over 1,200 mg of calcium and more than 800 IU of vitamin D was associated with a 33 percent lower risk of type-2 diabetes. Interestingly, dietary vitamin D intake did not appear to provide any statistically significant benefit. But the women who supplemented with at least 400 IU of vitamin D had a 13% lower risk of diabetes when compared to those who took less than 100 IU per day. Both dietary and supplemental calcium resulted in decreased risk of type-2 diabetes, and those with overall intakes above 1,200 mg had a 21% lower risk than those who got less than 600 mg per day.

Elevated intakes of calcium and vitamin D, especially from supplements, are significantly associated with lower incidence of type-2 diabetes.

Diabetes Care 29:650-656, 2006