With progressive ripeness there is a decrease in starch and an increase in free sugar content of bananas. The starch also is considered to be poorly digestible. Therefore, we decided to study plasma glucose, serum insulin, C- peptide, and plasma glucagon responses to bananas with increasing degrees of ripeness. Seven male subjects with untreated noninsulin-dependent diabetes mellitus ingested 50 g carbohydrate as bananas of stage 4 (more yellow than green), 5 (yellow with green tip), 6 (all yellow), and 7 (yellow flecked with brown) ripeness. They also received 50 g glucose on two occasions for comparative purposes. On a separate occasion water only was given as a control. The area responses were quantified by determining incremental areas using the water control as baseline. The mean glucose area following the 50 g glucose meals was 15.1 ± 1.9 mM · h. After the ingestion of bananas of 4, 5, 6 and 7 ripeness the glucose area response was 42, 41, 51 and 48% of that after glucose ingestion, respectively. The insulin area response following glucose meals was 888 pM · h. Responses to 4, 5, 6 and 7 bananas were 85, 70, 61, 85%, respectively, of that following glucose ingestion. C-peptide data were similar to the insulin data. The glucagon area response was negative after glucose ingestion but was positive following banana ingestion. In summary, the glucose, insulin, C-peptide, and glucagon area responses varied little with ripeness of the bananas.
Bibliographical noteFunding Information:
This study was supported by a grant from the National Dairy Promotion and Research Board, administered in cooperation with the National Dairy Council and the VA Merit Review Funds from the Department of Veterans Affairs. We thank the patients for participation in this study, and staffs of the Special Diagnostic Treatment Unit, the Metabolic Research Laboratory and the Clinical Chemistry Laboratory for their technical assistance. We also thank Claudia Durand for secretarial expertise.