The effect on glucagon, glucagon-like peptide-1, total and acyl-ghrelin of dietary fats ingested with and without potato

Abstract

Introduction: We are interested in the metabolic response to ingested macronutrients and the interaction between macronutrients in meals. Recently, we have determined the insulin and glucose response to ingestion of lard, olive oil, or safflower oil, fat sources varying in fatty acid composition and carbohydrate (CHO), in the form of potato.

Objective: Our aim was to determine the effect of these dietary fats ingested alone or with potato on glucagon, glucagon-like peptide-1 (GLP-1) (7-37 and 7-36 amide), and total and acyl-ghrelin concentrations.

Methods: Healthy subjects ingested 25 g fat (lard, olive oil, or safflower oil), 50 g CHO (potato), 25 g fat with 50 g CHO, or water only. Glucagon, GLP-1 (7-37 and 7-36 amide), and total and acyl-ghrelin responses were determined over 4 h.

Results: All fats when ingested alone increased glucagon. Glucagon increases were dramatically attenuated when fats were ingested with the potato. GLP-1 increased after all meals, but was greatest when fats were ingested alone. The fat-stimulated increase was completely negated when fats were ingested with potato. Both acyl and total ghrelin decreased when only fats were ingested, as expected. When potato was ingested with any of the fats, the fat-induced decrease in acyl-ghrelin response also was essentially negated. Paradoxically, ghrelin increased when potato alone was ingested.

Conclusions: The current data indicate that the glucagon, GLP-1 and ghrelin responses to ingested fats, varying in fatty acid composition, are significantly affected by co-ingestion of CHO. Overall, the interaction between ingested foods in general is likely to be complex.

Figures

Figure 1

Time course of serum glucagon concentrations. Time points are means ± sem. Insets, Net integrated areas under the curve after test meal ingestion. Bars with different letters indicate that data are statistically significantly different (P < 0.05).

Figure 2

Time course of serum GLP-1 concentrations. Time points are means ± sem. Insets, Net integrated areas under the curve after test meal ingestion. Bars with different letters indicate that data are statistically significantly different (P < 0.05).

Figure 3

Time course of serum total ghrelin concentrations. Time points are means ± sem. Insets, Net integrated areas under the curve after test meal ingestion. Bars with different letters indicate that data are statistically significantly different (P < 0.05).

Figure 4

Time course of serum acyl-ghrelin concentrations. Time points are means ± sem. Insets, Net integrated areas under the curve after test meal ingestion. Bars with different letters indicate that data are statistically significantly different (P < 0.05).