Several epidemiologic studies have found that
magnesium ion (Mg²⁺) is related to
obesity and
type 2 diabetes mellitus. However, there have been almost no reports on the effects of a combination of excessive food intake and Mg²⁺ supplementation on
metabolic syndrome and various blood tests values for
diabetes mellitus. In this study, we investigated changes in
body weight and blood test values for
diabetes mellitus of Otsuka Long-Evans Tokushima Fatty (OLETF) rats, a model for human
type 2 diabetes mellitus via
metabolic syndrome, under conditions of combined excessive food intake and Mg²⁺ supplementation. The rats received Mg²⁺ supplementation by drinking
magnesium water (Mg²⁺; 200 mg/l). No significant differences were observed in the levels of food or water intake between OLETF rats drinking purified water (PW) or
magnesium water (MW).
Type 2 diabetes mellitus with
metabolic syndrome developed at 30 weeks of age, and the
body weights and plasma
insulin levels of OLETF rats at 60 weeks of age were lower than those of normal rats. The plasma
glucose (PG) levels in 38-week-old OLETF rats drinking MW were significantly lower than in those of rats drinking PW, while the
body weights and the levels of
triglycerides (TG) and
insulin of 38-week-old MW-drinking OLETF rats were significantly higher than those of their PW-drinking counterparts. On the other hand, the decreases in
body weight and
insulin levels in 60-week-old OLETF rats were suppressed by MW supplementation. The present study demonstrates that Mg²⁺ supplementation delays the development of
diabetes mellitus in OLETF rats under conditions of excessive food intake. In addition,
obesity and high blood TG levels were observed in OLETF rats receiving Mg²⁺ supplementation in conjunction with excessive food intake.