TORONTO — Findings from a meta-analysis of 26 randomized controlled trials suggest eating dietary pulses such as beans, chickpeas, lentils and peas significantly reduces L.D.L. or “bad” cholesterol levels. Results appeared on-line April 7 in the Canadian Medical Association Journal.
The pooled analysis suggested a reduction in L.D.L. cholesterol of 0.17 mmol/L (equivalent to about a 5% reduction from baseline) at a median dose of 130 grams of pulses per day. The median fiber intake was 20 grams per day in the control diets and 26 grams per day in the interventional diets. Most of the studies reported gastrointestinal symptoms improved over the course of the dietary invention.
The researchers said a dietary pulse intake of 130 grams per day, or about one serving per day, may prove difficult to achieve in the United States, where the median intake is 0.2 servings per day, and in Canada, where only 13% of the population consume dietary pulses on a given day.
“However, this intake level is reasonable and is currently consumed by many cultures without reports of adverse effects that would limit consumption,” the researchers said.
The meta-analysis involved researchers from both the United States and Canada, including the University of Toronto, the University of Saskatchewan, the University of Guelph, the American Heart Association, the Harvard School of Public Health, the Wellness Institute of Cleveland Clinic and Pennsylvania State University. Loblaw Cos. Ltd. and a Canadian Institutes of Health Research knowledge synthesis grant provided funding.
The researchers initially identified 3,080 reports and then selected 22 reports (26 randomized-controlled trials) for the meta-analysis.
The follow-up period in the studies had to have been at least three weeks, which satisfies the minimum follow-up requirement of the U.S. Food and Drug Administration used in the scientific evaluation of lipid-lowering health claims. Studies that examined only whole dietary non-oilseed pulses were included. Trials of peanuts and soybeans were excluded because they have high oil content. Studies of pulse extracts also were excluded.
The median age of people in the studies was 51.1 years. The number of women and the number of men were about equal. At baseline, the median L.D.L. was 3.50 mmol/L.
Beans were used in the intervention diets in 14 trials. Other pulses included peas (2 trials), chickpeas (2 trials), lentils (1 trial) and mixed pulses (8 trials). Dietary pulses were administered as flour in 3 trials, as whole foods in 18 trials and in a mixed format (flour and whole foods) in 3 trials.