Can so call cholesterol-lowering foods actually lower your cholesterol. New study says it can but its not any easy route.
The results come from a six-month trial carried out by researchers from the Clinical Nutrition and Risk Factor Modification Centre in Toronto, Canada.
345 people were chosen who had high cholesterol but no risk of heart disease, did not have diabetes or was on cholesterol lowering drugs. They were split into two groups. One group was separated into two sections; the first section had intense counselling involving dietary advice on the consumption of cholesterol lowering foods such as nuts, oats and Soya and the other section had even more intense counselling with more guidance and more sessions going into much greater detail. The second group was asked to follow a low fat diet and this was the ‘control group’. Dieticians gave all participants similar advice on healthy foods.
The control group advice focused on consuming low-fat dairy and wholegrain cereals together with fruit and vegetables. It avoided mentioning the foods recommended to the ‘intense’ group.
The ‘intense’ groups were advised to eat foods high in plant sterols, soy protein, fibre and nuts. Consumption of peas, beans and lentils was also encouraged.
All participants were assessed at a clinic before the trial began and then again after week three and finally six months after starting the trial. Blood samples were taken as was blood pressure and weight.
Although the dietician and participants knew which diet they were on and the participants had some say in which diet they followed the researchers and the study’s statistician did not.
The results showed that all participants in both groups lowered their cholesterol, proving that just a low fat diet can have a beneficial effect but the ‘intense’ group loss much more than the ‘control group’. However less that half of those in the intense group could adhere to the diet over the six month period concluding that to have such a strict diet in the real world is very difficult to maintain and may not be a realistic option.
Here is a summary of the results:
1) All participants lost weight. On average between 1.2 –1.7kg over six months
2) In the ‘control group ’Low Density Lipoproteins (LDL the bad cholesterol) fell by 8mg/dl. A 3% decrease from the baseline.
3) In the intense group they lowered their LDL by 24mg/dl. A 13.1% decrease.
4) In the more intense group LDL fell by 26mg/dl. A 13.8% decrease.
5) Blood pressure did not change significantly in any of the participants.
6) The ones who decreased their LDL the most was the ones who stuck most closely to the diet concluding that it was intervention of the diet that caused the reduction.
The study showed that diet would lower cholesterol. The strength of this study compared to others was that the participants had a say in the diet they chose giving a more real world scenario.
However there are a number of points that need to be considered.
1) Less that half of those on low cholesterol foods could stick to the diet which means that in the real world most people would not be able to stay on it for more than that time so no longer maintaining their reduced cholesterol levels.
2) Physical activity was not part of the process, which could have an even greater effect during the diet process.
3) Participants on cholesterol lowering drugs were excluded from the study. Therefore it is not known if people being treated would have similar or more reduced levels. Also, the effectiveness of dietary change cannot be compared to that of cholesterol-lowering medications based on this particular study
4) It is not known if the diet and the decrease in LDL would decrease the chances of heart disease in these subjects. A back up study of the subjects would be required.
Finally it is worth pointing out that funding for this study came from the Federal Government of Canada with additional funding coming from industry sponsors including Loblaw Brands a supermarket chain, Solae a Soya manufacturer and Unilever. Some of the authors declared that they worked for nut and cereal companies including Quaker Oats and Kellogs. The authors state that the industrial sponsors played no role in the design, conduct or analysis of the study.
This kind of industrial sponsorship on such a study always makes the results feel a little uncomfortable even though there is no suggestion of impropriety. It is a shame that such interesting and important studies can only be financed this way because there will always be a reaction of cynicism from some quarter.
What do you think?