Archief Roodbont

Clinical Context

Hyperlipidemia is a common clinical problem, and all patients with hyperlipidemia should receive dietary advice to reduce lipid levels. However, can dietary changes match statins in improving the lipid profile? Some of the authors of the current study performed a trial comparing a dietary portfolio featuring plant sterols, soy protein, viscous fiber, and almonds vs a low-fat diet, with or without lovastatin. Their results, which were published in the July 23, 2003, issue of the Journal of the American Medical Association, demonstrated that the diet portfolio group experienced similar decreases in low-density lipoprotein (LDL) cholesterol and C-reactive protein (CRP) levels at 4 weeks vs the lovastatin plus low-fat diet group.

The best means to implement a dietary portfolio to reduce serum lipids are largely unknown. The current study by Jenkins and colleagues examines the effect of intensity of dietary advice on serum lipid outcomes among adults with hyperlipidemia.

Study Synopsis and Perspective

A diet rich in foods with proven heart-healthy benefits is significantly better than a diet low in saturated fat for reducing LDL-cholesterol levels in patients with hyperlipidemia, according to the results of a new study [1]. The "dietary portfolio" of cholesterol-lowering foods reduced LDL-cholesterol levels by 26 mg/dL, nearly as large a reduction as was observed in some of the earliest statin trials, according to researchers.

"The four major components of the dietary portfolio are foods that the Food and Drug Administration has recognized as being able to carry a heart-healthy claim for their ability to lower serum cholesterol levels," said lead investigator Dr David Jenkins (University of Toronto, ON). "These include soy proteins, sticky types of fibers like oats, barley, and psyllium, vegetables, viscous fibers, nuts, and plant sterols. We basically looked for ways in which these components were enriched in foods obtainable from the supermarket and encouraged people with support and help to look after themselves."

Speaking with heartwire, Jenkins said the foods included in the diet have been shown to reduce serum LDL-cholesterol levels by as much as 28% to 35%. Unknown, however, was how effective the dietary portfolio would be in real-world conditions or how effective the diet would be compared with a standard diet low in saturated fat.

Portfolio Diet vs Diet Low in Saturated Fat

Published in the August 24, 2011 issue of the Journal of the American Medical Association, the 24-week, parallel-design study included 351 patients with hyperlipidemia from four academic medical centers in Canada. Patients were randomized to one of two dietary interventions: a standard diet low in saturated fat; and the portfolio diet consisting of plant sterols, soy protein, viscous fibers, and nuts. In addition to the portfolio diet, the patients eating the heart-healthy foods received dietary advice for six months, with intensive-treatment patients receiving seven 40-minute counseling sessions and the routine-treatment portfolio patients receiving two counseling sessions.

The purpose of the different intensities of dietary counseling was to determine whether the routine dietary portfolio, which would be considered manageable by physicians in that it required just two counseling sessions, would be as effective as a more intensive treatment arm requiring multiple office visits.

Intensive therapy with the portfolio diet reduced LDL-cholesterol levels 13.8% from baseline, a reduction of 26 mg/dL (p<0.001). Similarly, patients treated with the portfolio diet who received just two counseling sessions also had significant reductions in LDL cholesterol, which was reduced 13.1% from baseline, or down 24 mg/dL. The reductions in LDL cholesterol were not statistically different in the two dietary-portfolio treatment arms.

Overall, individuals who followed more of a plant-based diet within the dietary portfolio had the lowest reduction in LDL-cholesterol levels, noted Jenkins.

Comparatively, patients in the control arm eating a standard low-saturated-fat diet reduced their LDL cholesterol levels 3%, down 8 mg/dL from baseline. The percentage reduction in LDL cholesterol was significantly greater in both portfolio diets compared with the low-saturated-fat diet (p<0.001).

To Treat or Not to Treat With a Statin

To heartwire , Jenkins noted that patients in the study had an average LDL-cholesterol level of 171 mg/dL at baseline, so they were considered hyperlipidemic but were not taking any medication to lower their cholesterol levels. The next step for the researchers is to test the effectiveness of the heart-healthy portfolio diet in patients with increased cardiovascular risk or those taking medications to lower their LDL-cholesterol levels. The hope is that eating a diet rich in soy proteins, viscous fibers, nuts, and vegetables can incrementally add to the benefit offered by LDL-lowering medications.

"We don't regard this as the end of the line by any means in terms of where we have to go with this diet," said Jenkins. "We have to see what this diet does in combination with statins, how much of an advance we can get, and whether we can actually lower the dose of statin therapy. More important, we need to know if the diet is applied over a long period of time, do we actually see a cardiovascular-outcome benefit, initially in ultrasound and magnetic-resonance imaging of the arteries, and in the longer term, in improvements in cardiovascular events."

Jenkins added that patients in the present analysis are typically patients that cause some problems for doctors, mainly in the sense that "they can be scratching their heads" about whether or not they should be treated with a statin. These results showed that the diet can help pull patients out of a middle-risk category to one that is lower risk. For example, the diet resulted in a 10% reduction in the Framingham risk score, which is sufficient to take a patient from moderate risk to low risk, he said.