Brown Seaweeds Prove to Normalize Insulin and Glucose Levels
Irish researchers have confirmed that brown seaweed safely slows glucose release from the gut, while other research has shown that brown seaweeds increase insulin sensitivity and helps balance and normalize insulin levels and blood glucose levels.
The research from Ireland analyzed extracts from 15 different seaweeds including five brown seaweed species. They tested extracted seaweeds from both ethanol or cold water extract methods.
The research found that Ascophyllum nodosum – a long brown seaweed also called Norwegian kelp – significantly inhibited alpha-amylase.
They also found that extracts from another brown seaweed species – Fucus vesiculosus Linnaeus (also called Bladderwrack) – was able to significantly inhibit alpha-glucosidase.
The ability to inhibit these two enzymes slows down digestion and absorption of glucose into the bloodstream. This is because both amylase and alpha-glucosidase break down carbohydrates (starches) into their most basic components, notably glucose.
“Overall, our findings suggest that brown seaweed extracts may limit the release of simple sugars from the gut and thereby alleviate postprandial hyperglycemia,” concluded the resarchers.
This is not the first study that has found that brown seaweeds normalize insulin and glucose levels.
In a study from Canada’s Laval University, researchers studied 23 adults in a double-blind placebo-controlled study.
After a week-long washout period, the subjects were given either 500 milligrams of brown seaweed in capsules or a placebo before consuming a small meal of carbohydrates. The seaweed combination consisted of Ascophyllum nodosum and Fucus vesiculosus.
After taking the seaweed or the placebo, the subjects were tested over a three-hour period for their glucose and insulin responses.
After another week-long washout cycle, the groups were switched and given the placebo or seaweed supplement. This was followed by another three-hour glucose and insulin test.
The researchers found that the seaweed supplement produced a 12% reduction of insulin incremental area under the curve. He also found an 8% increase in insulin sensitivity among those who consumed the seaweed supplement prior to eating.
The researchers concluded:
“These data suggest that brown seaweed may alter the insulin homeostasis in response to carbohydrate ingestion.”
Other research has confirmed similar findings and seaweeds potential medical application for diabetics and people with other glucose metabolism issues.
Active Constituent Found?
There is evidence that a component of algae called diphlorethohydroxycarmalol (DPHC) may be at least partially responsible for these effects. DPHC is considered a phlorotannin, and brown algae contains several other phlorotannins, including eckol, diekol, phloroglucinol, and dioxinodehydroeckol.
Phlorotannins in general have been found to modulate the production of proteins within cells. Enzymes like amylase and glucosidase are both essentially proteins.
In one study, diabetic mice were given an isolated extract of DPHC, extracted from the brown algae called Ishige okamurae. The diphlorethohydroxycarmalol was found to inhibit both alpha-glucosidase and alpha-amylase in the mice. And it normalized blood glucose levels within the diabetic mice given the compound compared to those not given the extract. It also normalized insulin sensitivity as well.
Seaweed’s ability to help normalize insulin and glucose metabolism has been studied by others. Many have concluded that the fucoidins within brown seaweed and other types of seaweeds can help with metabolic syndrome and even weight loss.
Lordan S, Smyth TJ, Soler-Vila A, Stanton C, Ross RP. The α-amylase and α-glucosidase inhibitory effects of Irish seaweed extracts. Food Chem. 2013 Dec 1;141(3):2170-6.
Paradis ME, Couture P, Lamarche B. A randomised crossover placebo-controlled trial investigating the effect of brown seaweed (Ascophyllum nodosum and Fucus vesiculosus) on postchallenge plasma glucose and insulin levels in men and women. Appl Physiol Nutr Metab. 2011 Dec;36(6):913-9.
Heo SJ, Hwang JY, Choi JI, Han JS, Kim HJ, Jeon YJ. Diphlorethohydroxycarmalol isolated from Ishige okamurae, a brown algae, a potent alpha-glucosidase and alpha-amylase inhibitor, alleviates postprandial hyperglycemia in diabetic mice. Eur J Pharmacol. 2009 Aug 1;615(1-3):252-6.