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Baobab Fruit May Improve Markers of Postprandial Glycemia in Healthy Adults

Date 03-31-2022
HC# 022241-685
Keywords:
Baobab (Adansonia digitata, Malvaceae)
Blood Glucose
Glycemic Response

Rita K, Bernardo MA, Silva ML, et al. Adansonia digitata L. (baobab fruit) effect on postprandial glycemia in healthy adults: a randomized controlled trial. Nutrients. January 17, 2022;14(2):398. doi: 10.3390/nu14020398.

Baobab (Adansonia digitata, Malvaceae) trees, native to Africa and widely distributed in Africa and India, are an emblematic and cultural species of increasing interest for their medicinal properties. In vivo, baobab fruit pulp ethanolic extract had hypoglycemic effects. In humans, baobab fruit aqueous extract (BAE) significantly reduced (P < 0.05) blood glucose (BG) area under the curve (AUC). In healthy adults, a baobab polyphenol extract added to white bread significantly reduced (P < 0.05) insulin response but not BG. A 2021 clinical trial did not find significant benefits in hemoglobin levels in a baobab fruit pulp group vs. controls. Baobab fruit may have antioxidant effects due to its polyphenol content. To date, several procyanidins, including epicatechin and quercetin, have been identified in baobab fruit extracts, along with tannins, phytic acid, trypsin inhibitors, N-benzoyl-DL-arginine-P-nitroanilide (BAPA), trypsin type III, oxalates, hydrocyanic acid, and high levels of soluble fiber.

The authors hypothesized that BAE would improve glycemic response in adults. They conducted a randomized, single-blind, controlled clinical trial (RCT) with participants recruited at the Campus Universitário Egas Moniz (Monte de Caparica, Portugal). Dates of the RCT are not reported.

BAE was made with baobab fruit from Luanda, Angola. About 40 g pulp, seeds, and red filaments were boiled in 300 mL water for five minutes. After cooling, the liquid was strained to remove seeds and filaments and filtered for homogeneity. BAE used in the RCT and in chemical analysis had 0.1333 g baobab/mL extract fresh weight. In assays, BAE had high levels of total phenolics, proanthocyanins, and hydrolyzable tannins. Total antioxidant capacity, radical inhibition power, radical scavenging capacity, and inhibition of superoxide anion (O2•- anion) and nitric oxide (NO) radical formation were also high.

Men and women aged 18-40 years who had fasting BG < 126 ml/dl, no history or symptoms of gastrointestinal, hepatic, or cardiovascular diseases, or baobab allergy, and were not pregnant or lactating were eligible for the RCT. Exclusion criteria were fasting < eight or > 10 hours before the intervention, use of any drug or supplement that could influence BG, or ingesting water, baobab, alcohol, or coffee (Coffea arabica, Rubiaceae) or smoking tobacco (Nicotiana tabacum, Solanaceae) < eight hours before the intervention. Of 43 individuals assessed, 12 did not meet criteria, and 31 were randomized to BAE (n = 15) or control (n = 16). There were more women in BAE than control (12 vs. 9). Anthropometric measures were made at baseline. Participants also completed an assisted 24-h food recall questionnaire to identify all foods and estimate amounts eaten. Intake was analyzed for total energy, carbohydrates, proteins, and lipids. After 8-10 hours fasting, BG was assessed via capillary blood drop and an oral glucose tolerance test (OGTT) was administered. The BAE group then drank 250 mL BAE. BG was re-measured at 30, 60, 90, and 120 m after the OGTT. BG incremental AUC (AUCi) was defined for each participant. Maximum concentration (Cmax) and variation of Cmax (ΔCmax) were determined by comparison with baseline levels. At baseline, there were no significant differences between groups, including in dietary intake at the last meal eaten before the intervention or in capillary BG levels (P = 0.115). All participants completed the RCT. In statistical analyses, significance was set at P < 0.05.

Analysis found no interaction between independent and repeated measures (P = 0.092) so it was not possible to infer any differences in BG at different time points; however, BAE produced slightly lower BG levels at different points. There was also no significant difference in ΔCmax variation between groups (P = 0.054), but Cmax and AUCi mean levels were significantly lower in BAE 120 m post-ingestion (P = 0.012 and 0.029, respectively), indicating a positive effect on BG control in healthy adults.

Effects of BAE on insulin secretion and glucagon-like peptide 1 were not assessed but should be considered in future studies to clarify BAE's hypoglycemic activities. Effects of baobab's polyphenol content on enterocyte glucose transporters may underlie its hypoglycemic action. Baobab's high dietary fiber content may also help reduce BG. BAE polyphenols likely contribute to its antioxidant effects. Procyanidin B2, for example, prevents the formation of advanced glycation end products in pancreatic β-cells that occurs with hyperglycemia. BAE inhibition of O2- anion and NO radical formation is also a relevant result, as oxidative stress is a major factor in the endothelial dysfunction seen in postprandial hyperglycemia in healthy participants.

Future studies should include larger study groups with better gender balance and address BAE effects for longer periods and as part of mixed-meal daily intake.

The authors state that they had no financial conflicts of interest.

—Mariann Garner-Wizard