) Phytosterols are plant sterols which are structurally similar to cholesterol. In experimental studies, phytosterols and in particular b-sitosterol showed anti-carcinogenic properties. Phytosterols are abundant in fat soluble fractions of plants: seeds, nuts, cereals, beans, and legumes are rich sources of phytosterols. Several case-control and cohort studies showed a decreased breast cancer risk with increasing consumption of vegetables and fruits. The protective effect of vegetables and fruits may be, at least in part, explained by the anti-cancerogenic effect of phytosterols. Phytosterols are not endogenously synthesized in human body: the phytosterols present in human blood derive solely from diet via intestinal absorption. B-sitosterol and campesterol are the predominant phytosterols in blood. However, up to this time, there is not clear information on how diet may influence serum phytosterol levels in human beings. Thus, the aim of the proposed study is to assess the effect of a diet rich in vegetables and low in animal fat on serum levels of b-sitosterol and campesterol in comparison with a typical Western (North-European) diet. The specific objective of the proposed study is to evaluate if a diet rich in seeds, nuts, beans, legumes and other vegetables can actually modify serum phytosterols, in particular b-sitosterol and campesterol. The proposed study plans to use data and stored blood samples collected in a randomized controlled trial on effect of a diet rich in vegetables and low in animal fat on hormonal profile conducted at the Istituto Nazionale Tumori (Italian National Cancer Institute) in Milan (Northern Italy) between 1995-1996. The study, known as DIANA study, involved 99 healthy free-living postmenopausal women aged 50-65, half of whom were randomly assigned to the intervention group characterized by intensive dietary counseling and common group meals using Mediterranean and macrobiotic recipes over a period of 4.5 months.
| Muti, Paola; Awad, Atif B; Schunemann, Holger et al. (2003) A plant food-based diet modifies the serum beta-sitosterol concentration in hyperandrogenic postmenopausal women. J Nutr 133:4252-5 |
