Maltose consumption exacerbates high-fat diet-induced overweight and related parameters in mice

Background: Maltose is a disaccharide formed from two units of glucose. The amount of maltose in raw sweet potatoes reportedly increased by more than 40-fold after baking. We aimed to investigate the effects of maltose consumption on diet-induced obesity using a mouse model.Methods: Male C57BL/6J mice were divided into three dietary groups: a control diet of American Institute of Nutrition (AIN)-93 (CD), an AIN-93-based 30% high-fat diet (HFD), or an HFD diet containing 7.0% maltose (HFD+Mal). After 13 weeks, body mass index, blood glucose, lipid parameters, including total cholesterol and triglyceride, and hepatic fatty acid content were evaluated. Results: After 6 weeks on the special diet, weight gain was significantly higher in the HFD+Mal group than in the HFD group. The body mass index rose steadily and was significantly higher in the HFD+Mal group (5.03 ± 0.22), compared to the CD (3.32 ± 0.30) and HFD (4.57 ± 0.40) groups at 12 weeks. The relative liver weight per weight was also significantly higher in the HFD+Mal group than in the other two groups. The increases in blood glucose levels were more significant in the HFD+Mal group compared to the HFD group, as were the plasma levels of total cholesterol, high-density lipoprotein (HDL)-cholesterol and non-HDL-cholesterol. In the liver, levels of the following fatty acids increased in both the HFD and HFD+Mal groups relative to those in the CD group: C14:0 (myristic acid), C16:0 (palmitic acid), C18:0 (stearic acid), C18:1 (oleic acid), C18:2 (linoleic acid) and C18:3 (α-linolenic acid). Additionally, the C16:0 content in the HFD+Mal group was significantly higher than that in the HFD group.  Conclusion: The results of this study suggest that daily consumption of maltose exacerbated the development of obesity and related parameters, including body mass index and plasma cholesterol levels, under the high-fat diet consumption. It is possible that the consumption of maltose-rich cooked sweet potatoes, as part of an overall HFD, might exacerbate HFD-induced overweight.Keywords: high-fat diet-induced obesity, maltose, mice, roasting, sweet potato