The study, published online in the journal Clinical Nutrition , is one of the first studies to consider alipoprotein levels as a measure of the benefits of phytosterols, and adds to a body of science supporting the efficacy of the ingredients for heart health.
Numerous clinical trials in controlled settings have reported that daily consumption of 1.5 to 3 grams of phytosterols/-stanols can reduce total cholesterol levels by eight to 17 per cent, representing a significant reduction in the risk of cardiovascular disease.
The new study, led by Martin Madsena from Arhus University Hospitals, looked at the effects of supplementing 46 people (average age 50.6) with 20 g low-fat margarine (35 per cent fat) and 250 ml low-fat milk (0.7 per cent fat), giving a total plant sterol dose of 2.3 g per day.
The subjects were classed as mildly hypercholesterolemic (LDL cholesterol 3.0 to 5.5 mmol/l).
"
There is a growing body of evidence suggesting that apolipoprotein B/apolipoprotein A-I (apo B/apo A-I) ratio is a better marker of CHD risk than lipid concentrations per se and lipid ratios such as LDL:HDL cholesterol and total:HDL cholesterol," wrote the researchers.
"The objective of the present study was therefore to evaluate the impact of combining two different plant sterol-enriched foods as part of a low-fat diet on CHD risk, with a particular attention to emerging risk factors for CHD such as apo B/apo A-I ratio and [C-reactive protein] CRP," they said.
The researchers report that the daily dose of 2.3 g plant sterols from enriched margarine and milk led to LDL cholesterol reductions of 7.7 per cent.
The patients were eating according to the National Cholesterol Education Program (NCEP) step 1 diet.
In addition, they report levels of apo B were significantly reduced by 4.6 per cent and the ratio of apo B:
apo
A-I decreased significantly by 3.4 per cent.
No changes to levels of the inflammation marker CRP were observed.
"The apo B to apo A-I ratio decreased by 3.4 per cent and, interestingly, this ratio has recently been proposed the strongest marker of risk for vascular disease," stated the researchers.
The study, partly funded by Unilever Denmark, is the second study to evaluate the effect of phytosterols on these markers, with the only other study reporting similar results, said the researchers.
"Our study showed that a combination of dietary intervention and low-fat margarine and milk enriched with plant sterols significantly reduced LDL cholesterol, apo B and the apo B to apo A-I ratio," said the researchers.
"Low-fat products enriched with plant sterols may therefore play a role in managing higher than desirable cholesterol levels."
High cholesterol levels, hypercholesterolaemia, have a long association with many diseases, particularly cardiovascular disease (CVD), the cause of almost 50 per cent of deaths in Europe, and are reported to cost the EU economy an estimated €169bn ($202bn) per year.
Source: Clinical Nutrition (Elsevier) Published on-line ahead of print, doi:10.1016/j.clnu.2007.05.008
"The effect of a combination of plant sterol-enriched foods in mildly hypercholesterolemic subjects" Authors: M.B. Madsena, A.-M. Jensena and E.B. Schmidt