Cholesterol-lowering foods - the sum greater than the parts?

Clinical trials of dietary approaches to lowering LDL-cholesterol levels have been reported to be as effective as statin medication. Real-life settings however have favoured the ease and consistency of statins, with diet receiving less focus.

The new study, published in the American Journal of Clinical Nutrition​ (Vol. 83, pp.582-591), followed 45 volunteers with high cholesterol levels for one year, eating a diet with a portfolio (for every 1000 kilocalories) of one gram of plant sterols, about 10 grams of viscous fibres, 22.5 grams of soy protein, and 23 grams of whole almonds.

Enriched margarines were used as the source of the plant sterols, the fibre came from oats, barley, okra and eggplant, and the soy proteins came from soy milk and tofu.

"No long-term studies have reported on combinations of these functional food… We believe that the combination approach may greatly enhance its effectiveness,"​ said lead author David Jenkins from the University of Toronto.

The participants were also instructed to eat five to ten daily servings of fruit and vegetables.

Regular blood tests during the year allowed the researchers to measure total cholesterol, triacylglycerol and HDL cholesterol levels. LDL levels were calculated from these results.

"Application of a diet that combined several cholesterol-lowering foods under free-living real-world conditions resulted in a mean LDL-cholesterol reduction of about 13 per cent,"​ reported the researchers.

However, about 30 per cent of the participants reported reductions of more than 20 per cent, which are similar to results from statin therapy and equivalent to a reduction in death from heart disease of about 30 per cent.

The scientists found that those who best followed the diet reported the highest changes in LDL-cholesterol levels.

"The participants found it easiest to incorporate single items such as the almonds and margarine into their daily lives,"​ said Jenkins.

Compliance with almonds and the plant-sterol enriched margerine was satisfactory, said the researchers, 79 per cent and 67 per cent of volunteers reaching the targets for intake.

"The fibres and vegetable protein were more challenging since they require more planning and preparation, and because these types of niche products are less available,"​ explained Jenkins.

Compliance levels were 55 and 51 per cent for the viscous fibre and soy protein, respectively.

HDL-cholesterol levels were also increased, and a small but significant reduction in blood levels of triacylglycerol was observed (13 per cent).

The researchers also reported a "small but statistically significant" loss of weight amongst the participants.

"The study's findings suggest that the average person can do a lot to improve their health through diet,"​ said Jenkins.

Jenkins and his colleagues predicted that as the availability and variety of soy, viscous fibre, plant sterol, and almond containing foods increased, people would find it easier to follow such diets.

Comparison with statins allowed the scientists to gauge the effects relative to a well-established medicative alternative, but stressed that they were not questioning the benefits of using statins for people with high risks of CVD.

"We don't, however, know the long-term effects of these drugs when used on a large section of the broader population who are at low risk in primary prevention."​

"Emphasizing diet changes in general can boost the success rate of statins while providing additional health benefits and a possible alternative for those for whom drugs are not a viable option,"​ he said.

Lowering LDL-cholesterol levels has been proposed to reduce the risk of cardiovascular disease, the cause of almost 50 per cent of deaths in Europe, and reported to cost the EU economy an estimated €169 billion ($202 billion) per year.

According to the American Heart Association, 34.2 percent of Americans (70.1 million people) suffered from some form of cardiovascular disease (CVD) in 2002.