Excess vitamin intake: An unrecognized risk factor for obesity

Figure 5 Proposed mechanism of excess vitamins-induced obesity. The absorption of sugar stimulates the release of insulin, while absorbed excess vitamins (from vitamin-fortified foods and drinks) generate ROS, leading to a decrease in the sensitivity of peripheral tissues to insulin (i.e., insulin resistance). To compensate the insulin resistance, additional insulin has to be secreted, resulting in a high blood insulin level. Then, the sensitivity of peripheral tissues recovered with the rapid clearance of ROS, consequently, relatively high insulin level causes a rapid decrease in blood glucose due to increased glucose uptake, which may trigger excess energy intake. The conversion of glucose to fat in adipose tissue is promoted by high levels of B vitamins. Therefore, long-term consumption of vitamin fortified foods (including formulas) and drinks may cause fat accumulation in the body and subsequent obesity. ROS: Reactive oxygen species; RSS: ROS scavenging system.