Marginal Impact of Brown Seaweed Ascophyllum nodosum and Fucus vesiculosus Extract on Metabolic and Inflammatory Response in Overweight and Obese Prediabetic Subjects

Abstract

The objective of the present study was to test whether a brown seaweed extract rich in polyphenols combined with a low-calorie diet would induce additional weight loss and improve blood glucose homeostasis in association with a metabolic and inflammatory response in overweight/obese prediabetic subjects. Fifty-six overweight/obese, dysglycemic, and insulin-resistant men and women completed a randomized, placebo-controlled, double-blind, and parallel clinical trial. Subjects were administrated 500 mg/d of either brown seaweed extract or placebo combined with individualized nutritional advice for moderate weight loss over a period of 12 weeks. Glycemic, anthropometric, blood pressure, heart rate, body composition, lipid profile, gut integrity, and oxidative and inflammatory markers were measured before and at the end of the trial. No effect was observed on blood glucose. We observed significant but small decreases in plasma C-peptide at 120 min during 2 h-OGTT (3218 ± 181 at pre-intervention vs. 2865 ± 186 pmol/L at post-intervention in the brown seaweed group; 3004 ± 199 at pre-intervention vs. 2954 ± 179 pmol/L at post-intervention in the placebo group; changes between the two groups, p = 0.002), heart rate (72 ± 10 at pre-intervention vs. 69 ± 9 (n/min) at post-intervention in the brown seaweed group; 68 ± 9 at pre-intervention vs. 68 ± 8 (n/min) at post-intervention in the placebo group; changes between the two groups, p = 0.01), and an inhibition in the increase of pro-inflammatory interleukin-6 (IL-6) (1.3 ± 0.7 at pre-intervention vs. 1.5 ± 0.7 pg/L at post-intervention in the brown seaweed group; 1.4 ± 1.1 at pre-intervention vs. 2.2 ± 1.6 pg/L at post-intervention in the placebo group; changes between the two groups, p = 0.02) following brown seaweed consumption compared with placebo in the context of moderate weight loss. Although consumption of brown seaweed extract had no effect on body weight or blood glucose, an early attenuation of the inflammatory response was observed in association with marginal changes in metabolic parameters related to the prevention of diabetes type 2.

Updated Information of the Effects of (Poly)phenols against Type-2 Diabetes Mellitus in Humans: Reinforcing the Recommendations for Future Research

“…Once more, the test product contained a mixture of compounds making the attribution of the observed properties to the (poly)phenols impossible. One additional study evaluated the potential of a brown (poly)phenol-rich seaweed extract (Ascophyllum nodosum and Fucus vesiculosus; 0.5 g/day for 12 weeks) in combination with a low-calorie diet in overweight/obese individuals with prediabetes [30]. Although some inflammatory markers were attenuated, the authors did not detect significant changes in blood glucose, insulin levels or glycated hemoglobin in the brown seaweed intervention group (N = 27) when compared with the placebo group (N = 29).…”

Ascophyllum nodosum and Fucus vesiculosus Extracts Improved Lipid Metabolism and Inflammation in High-Energy Diet–Induced Hyperlipidemia Rats

“…Both in vitro [ 38 ] and in vivo [ 39 ] experiments have indicated that A. nodosum extract has antioxidant and anti-inflammatory properties; therefore, long-term consumption of A. nodosum extract polyphenols may have health benefits. Vodouhè et al [ 44 ] reported that consumption of brown algae crude extract of A. nodosum and F. vesiculosus at a dosage of 500 mg/day for 12 weeks had no effect on body weight or blood glucose; however, early attenuation of the inflammatory response was observed in individuals with overweight/obesity, dysglycemia, and insulin resistance.…”

The effects of macro‐algae supplementation on serum lipid, glycaemic control and anthropometric indices: A systematic review and meta‐analysis of clinical trials

“…For example, regular consumption of fruits and vegetables as rich sources of natural antioxidants were reported to decline the risk of DM. In addition, antioxidant compounds like polyphenols have hypoglycaemic effects through the inhibition of carbohydrate digestive enzymes and improving the sensitivity of tissues to insulin hormone 8–10 . Finding alternative functional supplements such as antioxidant compounds to improve the quality of clinical therapies may have beneficial effects against the side effects of chemical drugs.…”

“…Recent studies indicated that seaweed polyphenols may have higher biological and pharmacological properties in comparison with other plant‐derived phenolic compounds 10–13 . Algae polyphenol‐rich extracts (APREs) were reported to improve the blood glucose and serum lipids levels in a concentration‐dependent manner 14–16 .…”