Calcium alginate and blood sugar after starchy meals in rats
What it found
In rats, calcium alginate at 5% of the diet with fine particles worked best at lowering the blood sugar rise after a starchy meal.
Lab tests suggest it slows starch digestion by blocking one digestive enzyme.
What they found
Animal and lab studies
Enzyme blocking in lab
In lab tests, calcium alginate barely blocked alpha-amylase but clearly blocked alpha-glucosidase, an enzyme involved in starch digestion.
Glucose binding and uptake
Calcium alginate bound little glucose directly and had essentially no effect on how easily glucose crossed a membrane.
How it may work
The authors suggest the blood sugar lowering comes mainly from less efficient starch digestion, possibly because the gut contents become more viscous.
Best dose and particle size
In rats given a starchy meal, 5% by weight of calcium alginate that passed through a 270-mesh sieve was the most effective at reducing the after-meal blood sugar rise.
What the authors conclude
“Therefore, we considered that the suppression of blood glucose by Ca-Alg is predominantly due to a decrease in the efficiency of starch digestion as a result of inhibition of α-glucosidase, possibly due to increased viscosity of the gastrointestinal contents.”
Also in their conclusions
- They conclude that the suppression of blood glucose by calcium alginate is predominantly due to a decrease in the efficiency of starch digestion as a result of inhibition of alpha-glucosidase.
- They suggest this may be due to increased viscosity of the gastrointestinal contents.
- They found that 5% by weight of 270-mesh-pass calcium alginate was most effective in rats.
How it was done
Calcium alginate is known to reduce the rise in blood sugar after eating, so it might help prevent lifestyle-related diseases such as diabetes. The authors wanted to find out how it does this.
They ran lab tests on the enzyme-blocking and glucose-binding actions of calcium alginate. They then fed rats a starchy diet containing different amounts and particle sizes of calcium alginate and measured the blood sugar rise.
What it can’t tell you
- We summarised it from the abstract only.
- These are rat and lab tests. They can't show what happens in people.
- The study looked at one starchy meal, not long-term blood sugar control or diabetes risk.
The paper
- Title
- Mechanism of Suppression of Blood Glucose Level by Calcium Alginate in Rats
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Abstract only
- Cite
- Idota Y, Kato T, Shiragami K, et al (2018). Mechanism of Suppression of Blood Glucose Level by Calcium Alginate in Rats. Biological & pharmaceutical bulletin. doi:10.1248/bpb.b18-00155PubMed 29973436DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error