Phytosterols, otherwise known as plant sterols, are similar structurally to cholesterol and just as cholesterol is a structural component of our cell membranes, they play a similar role in the cell membranes of plants.
More than 40 sterols have been identified from plants of which beta-sitosterol, stigmasterol and campesterol are the most abundant. Indeed, beta-sitosterol comprises 50% of all dietary phytosterols
Which foods are high in phytosterols?
Phytosterols are found naturally in a variety of wholegrains, legumes, nuts, seeds, fruits, vegetables and vegetable oils but in very small amounts. Additionally there arc a variety of fortified foods available, such as margarines, yoghurts, and drinks, to which phytosterols have been added.
The average daily intake of phytosterols is 250 mg, although vegetarians tend to consume more. One would have to consume more than 20 kg of fruit and vegetables to gain 1 gram of phytosterols.
How do phytosterols work?
Phytosterols appear to reduce cholesterol by inhibiting the absorption of dietary cholesterol within the intestines. The actual mechanism by which this occurs is not understood fully but it appears likely that as the molecular structure of phytosterols is almost identical to cholesterol, the body is unable to tell the difference. Phytosterols arc therefore able to attach to cholesterol receptors in the intestines and be absorbed in place of cholesterol. As there arc limited numbers of receptors for cholesterol attachment and absorption, phytosterols arc able to physically block the cholesterol and prevent the body from absorbing it«
The blood LDL cholesterol-lowering effect of phytosterols appears to be established within the first 2-3 weeks of use and appear to be effective both in the short and long term, with studies as short as 3 weeks and as long as 85 weeks showing a significant reduction in cholesterol after supplementation with phytosterols •
What’s the Ideal dally Intake?
While a range of doses has been studied, the beneficial effect of phytosterols appears to taper off at intakes of over 2,5 g daily, with little additional benefit being found at intakes higher than 2 g daily.