Regulating Hypothalamus Gene Expression in Food Intake: Dietary Composition or Calorie Density?

BACKGROUND: The proportion of saturated fatty acids/unsaturated fatty acids in the diet seems to act as a physiological regulation on obesity, cardiovascular diseases, and diabetes. Differently composed fatty acid diets may induce satiety of the hypothalamus in different ways. However, the direct effect of the different fatty acid diets on satiety in the hypothalamus is not clear. METHODS: Three experiments in mice were conducted to determine whether: different compositions of fatty acids affects gene mRNA expression of the hypothalamus over time; different types of fatty acids administered into the stomach directly affect gene mRNA expression of the hypothalamus; and fat composition changes in the diet affects gene mRNA expression of the hypothalamus. RESULTS: The type of fat in cases of purified fatty acid administration directly into the stomach may cause changes of gene expressions in the hypothalamus. Gene expression by dietary fat may be regulated by calorie amount ingested rather than weight amount or type of fat. CONCLUSION: Therefore, the calorie density factor of the diet in regulating hypothalamic gene in food intake may be detrimental, although the possibility of type of fat cannot be ruled out.