Consumption of a plant sterol-enriched rye bread for two weeks was associated with a 5 percent reduction in total cholesterol levels, and an 8 percent reduction in LDL cholesterol levels, according to findings published in Nutrition, Metabolism and Cardiovascular Diseases.
“High-fiber rye bread enriched with both 2 g/d and 4 g/d of nonesterified plant sterol during two weeks is sufficient to induce significant beneficial changes in major serum lipid and apolipoprotein risk factors compared to control treatment,” said the researchers, led by Päivi Söderholm from the University of Helsinki, Finland.
They added that such benefits, coupled with rye breads own health-promoting properties, means that the combination of plant sterol and high fiber bread is an attractive dietary modification that can easily be put into practice as a functional food.
Risk factors
The authors said that high serum levels of LDL cholesterol is a well established risk factor for cardiovascular disease, and thus an important target in drug and dietary treatment trials.
However they noted that consumers with normal cholesterol levels (normocholesterolemic) are also likely to purchase functional foods with the aim of reducing LDL cholesterol and total cholesterol.
Plant sterols occur naturally in vegetable oils, nuts, seeds and grains, and possess serum cholesterol-lowering properties. Among the food industry they are widely used ingredients for functional foods aimed at reducing cholesterol.
Numerous clinical trials in controlled settings have reported that daily consumption of 1.5 to 3 grams of phytosterols/-stanols from foods can reduce total cholesterol levels by eight to 17 per cent, representing a significant reduction in the risk of cardiovascular disease.
High fiber, whole grain cereals also may also possess certain cardiovascular health benefits, which according to the researchers include serum LDL and total cholesterol lowering properties.
Söderholm and colleagues said that low-fat foods have been successfully introduced as carriers for such nonesterified plant sterols. They said that if high-fiber cereals are shown to be effective vehicles for enrichment with plant sterols, the resulting products could provide improved cardiovascular protection and health benefits.
“We explored the influence of two doses of high-fiber rye bread enriched with nonesterified plant sterol … on serum lipid risk factors,” said the researchers.
They added that in healthy subjects a measurement of serum apolipoprotein B/apolipoprotein A1 (apoB/apoA1) ratio – the balance between pro-atherogenic and anti-atherogenic lipoproteins – provides more predictive power than conventional lipid risk factors.
Study details
The dietary intervention trial subjects were randomized to receive a rye bread with added plant sterols (in either 2 grams per day or 4 grams per day) or without any plant sterol (control group).
According to the study, intake of rye bread enriched with 2 g/d of plant sterols significantly reduced serum total (5.1 percent reduction) and LDL cholesterol (8.1 percent), apoB/apoA1 (8.3 percent), and total cholesterol/HDL cholesterol ratios (7.2 percent reduction).
The authors reported that four grams per day led to reductions of over 10 percent in LDL cholesterol levels, and significantly reduced all other measures of lipid risk factors.
“Rye bread alone did not decrease cholesterol levels in the control group,” said the researchers. However, they noted that by utilizing rye bread as a food carrier for plant sterols, significant benefits could be achieved.
“These results indicate that rye bread as vehicle is able to deliver and release plant sterols into the intestine and the marked reduction in LDL- cholesterol suggests no significant interaction between rye fiber and plant sterols,” said the researchers.
Source: Nutrition, Metabolism and Cardiovascular Diseases
Published online ahead of print, doi: 10.1016/j.numecd.2010.09.011
“The effect of high-fiber rye bread enriched with nonesterified plant sterols on major serum lipids and apolipoproteins in normocholesterolemic individuals”
Authors: P.P. Söderholm, G. Alfthan, A.H. Koskela, H. Adlercreutz, M.J. Tikkanen