Acarbose and blood glucose after a meal: a small trial mainly shows an early effect

Four conditions compared in the same participants

The randomized, placebo-controlled study used a single-blind crossover design: participants were studied under four conditions. The researchers compared an oligosaccharide-based placebo, ingestion of 50 mg of acarbose, and simultaneous intake of 150 g of rice with either 50 mg or 100 mg of acarbose.

The aim was to examine whether inhibition of salivary alpha-amylase by acarbose altered blood glucose after a meal. The abstract reviewed does not provide enough information to reconstruct all the details of the sessions or the intervals between them.

A blunted early rise, but an important distinction

At 30 minutes, the rise in blood glucose was significantly smaller when acarbose was taken simultaneously with rice, at both doses studied, than in the condition in which 50 mg was swallowed. However, the abstract does not quantify these differences, making their practical significance difficult to assess.

The peak rise in blood glucose occurred at 30 minutes with the placebo and with the swallowed 50 mg dose, compared with 60 minutes when rice and 50 mg of acarbose were taken simultaneously.

However, the area under the blood glucose curve did not differ significantly between these two conditions involving 50 mg of acarbose. This result therefore does not demonstrate a reduction in overall glucose exposure between them, even though the early response was blunted.

An exploratory finding, not a strategy to adopt

The authors interpret their observations as an effect of salivary amylase inhibition on the early rise in blood glucose. However, the abstract alone does not allow a full assessment of the mechanistic measurements supporting this interpretation.

With only 15 participants, all young and healthy women, this trial does not allow the findings to be generalized to men, older people or people with diabetes. Nor does it establish a long-term clinical benefit or, on its own, justify using acarbose to blunt blood glucose rises after meals.

What we can take away

The signal mainly concerns the start of the blood glucose response. A smaller early rise is not enough to demonstrate lower overall exposure or a health benefit.