Effects of Calcium Fortified Beverage Intake on Insulin Sensitivity and Antioxidant Metabolism in Healthy Elderly

Calcium, one of the most important nutrients, determines the quality of life of the elderly. It has been reported that 7 out of 10 people over the age of 60 have insufficient calcium intake. The purpose of this study was to evaluate the effect of calcium fortified beverage (CFB) intake on insulin sensitivity and antioxidant metabolism in healthy elderly. A crossover clinical trial was performed and antioxidant status of healthy elderly (age above 65 years, n = 8) was analyzed. Subjects did not take CFB for 0–3 weeks. They then took it for 3–6 weeks. CFB supplementation decreased insulin levels (Δ3–6 weeks: 1.19 ± 0.65 μ IU/mL → Δ0–3 weeks: −0.58 ± 0.38 μ IU/mL). Increasing degree of fasting blood glucose level was suppressed by intake of CFB, although the suppression was not statistically significant. Except for insulin, there were no significant differences in results of biochemical analysis between 0–3 weeks and 3–6 weeks. Catalase activity was significantly increased by CFB supplementation (Δ3–6 weeks: 3.50 ± 5.30 K g/Hb) compared to the no CFB supplementation period (Δ0–3 weeks: −12.48 ± 4.37 K g/Hb). However, the activity of superoxide dismutase and glutathione-peroxidase were not significantly different between 0–3 weeks and 3–6 weeks. H(2)O(2)-induced DNA oxidative damage was also decreased significantly by CFB supplementation. Taken together, these results indicate that CFB has beneficial effect on insulin sensitivity and some antioxidant enzymes in healthy elderly.