Chemical and microbiological considerations of phytosterols and their relative efficacies in functional foods for the lowering of serum cholesterol levels in humans: A review

The controversy of the relative efficacies of sterols and stanols in the lowering of blood cholesterol in humans continues without resolution. Basic physical, chemical and microbiological characteristics of phytosterols were reviewed in the context of the animal physiology and study design. Not all sterols are alike chemically. Shape and size of the test molecule do matter. Involuntary microbial transformation of sterols into stanols in the human gut would inevitably afford different outcome, even if clonal humans were available as test subjects. The current discourse on the relative merits of different forms of phytosterols for the lowering serum cholesterol levels in humans might be a futile exercise if the different physical, chemical and microbiological reactivities of the molecule being studied were ignored. Theoretical considerations and clinical-study evidence suggest that stanol would be the principal bio-reactive species to cause the lowering of serum cholesterol in humans.