Posted by Alpha-cyclodextrin (αCD) is a bacterial product that is widely used as a food ingredient. In the EU, αCD is regulated as a “dietary fiber” with an authorized health claim that it contributes to the reduction of post-prandial glycemic responses. In the US αCD is GRAS (generally recognized as save), but the FDA recently rejected the inclusion of αCD in the list of “dietary fibers”, because “the strength of the scientific evidence does not support a finding of a beneficial effect of αCD on postprandial blood glucose …”. The meta-analysis presented here provides a review of studies conducted on the effect of αCD on the rise of blood glucose levels after consumption of ~50 g of starch.
This meta-analysis is based on five published clinical trials on the efficacy of αCD to reduce glucose excursions after a high-carb meal containing ~50g starch from white bread or rice in subjects aged 18–41 years. Two additional publications either had the majority of calories came from fat. Hence, these two studies were excluded from the meta-analysis. There were strong indications that the published P-values suffered from loss of power due to errors in the statistical methodology, including the cross-over design not being reflected in the statistical method used. Still, a formal meta-analysis using Fisher’s combined probability test confirmed the EMA’s 2012 health claim that, when taken with a high-carb meal containing ~50g of starch, 5–10 g of the dietary fiber αCD reduce post-prandial glucose excursions.
Knut M Wittkowski (2022) The effect of alpha-cyclodextrin on post-prandial glucose excursions, a systematic meta analysis. medRxiv September 6, 2022
doi: https://doi.org/10.1101/2022.09.04.22279468
Featured image: Bär et al. Foods. 2020 Jan 7;9(1):62. doi: https://doi.org/10.3390/foods9010062.
In the EU, but not the US, the soluble fiber alpha-cyclodextrin (aCD) is currently a “dietary fiber” with an authorized health claim to “reduce postprandial glucose excursions”. The above systematic review has been updated to clarify some of the issues that have contributed to the current difference in regulations:
(1) High-fat meals do not cause glucose excursions. Hence, the effect of aCD with a high-fat meal can be seen on lipid profiles, but not on glucose profiles.
(2) The dose of aCD should reflect the amount of carbohydrates in the meal. The EU recommends 5 g aCD per 50 g carbohydrates.
(3) aCD acts independently of insulin (resistance).
After accounting for the above issues, the EU position is confirmed: at least 5 g aCD per 50 g of carbohydrates reduces postprandial glucose excursion and also the need for the pancreas to release more insulin.