How we rate
“Strong” = several concordant meta-analyses or systematic reviews. “Moderate” = one synthesis, or several controlled trials. “Limited” = early trials only. The rating is about the quality of the studies, not about how useful the supplement is.
Legumes
A portion of legumes per day (lentils, chickpeas, beans) lowered LDL cholesterol and slightly reduced blood pressure in trials, and improves blood glucose in diabetics. For weight, the effect is minimal: −0.34 kg in six weeks.
Benefits
- LDL cholesterol: in 26 randomized trials (1,037 people), about one portion per day (130 g) lowered LDL by 0.17 mmol/L compared to control diets; another meta-analysis of 10 trials found −8 mg/dL of LDL and −11.8 mg/dL of total cholesterol.
- Canned beans: in adults with high LDL, one cup per day (180 g) for 4 weeks lowered LDL by 8.08% and total cholesterol by 5.46%; half a cup did no better than the control group's rice.
- Lentils: in 38 adults with a high waist circumference, 980 g of cooked green lentils per week for 12 weeks lowered LDL and total cholesterol, as well as the post-meal spike in blood glucose.
- Type 2 diabetes: in one trial, a low glycemic index diet rich in legumes lowered HbA1c by 0.5 points, compared to 0.3 for a diet rich in wheat fiber; across 41 trials, legumes lower fasting blood glucose, insulin, and HbA1c.
- Post-meal blood glucose: replacing half of the rice or mashed potatoes with lentils, or adding black beans or chickpeas to a rice dish, reduced the blood glucose spike in healthy adults.
- Blood pressure: in 8 trials (554 people), legumes eaten in place of other foods, at equal calories, lowered systolic blood pressure by 2.25 mmHg.
- Satiety: in 9 single-meal trials, legumes provided 31% more satiety, without causing people to eat less at the next meal.
- Cohorts: eating the most legumes is associated with 10% fewer cardiovascular and coronary heart diseases (14 studies, 367,000 people) and 6% fewer all-cause deaths (32 cohorts, over one million people).
Precautions
Bloating: in three trials, less than half of the participants reported more gas in the first week with pinto beans or baked beans, only 19% with black-eyed peas, and 3 to 11% reported it even without beans; the discomfort varies depending on the type of legume. Lentils every day: in the 12-week trial, digestive disorders were no more frequent than with meat meals, all rated as none or mild. Limitations: weight: the effect is minimal, −0.34 kg in six weeks on average across 21 trials (940 people). Diabetes: in 15 cohorts (565,810 people), eating more legumes was not associated with less type 2 diabetes; only tofu and soy protein were linked to it. Heart and stroke: no reduction in cardiovascular deaths (32 cohorts) nor in heart attacks and strokes (review of 28 cohorts); the certainty of the observed links is rated as "low" to "very low". Chickpeas: in one trial, the slight decrease in cholesterol was partly due to involuntary changes in the rest of the diet. Trials are short and small, and the effect on blood glucose varies greatly from one study to another.
Recommended dosage
About one portion per day: 130 to 180 g of cooked legumes (150 g median in a review), for 4 to 12 weeks in trials.
How to take it
- Quantity: about one portion per day, 130 g median in meta-analyses on cholesterol and weight, ranging from 54 to 360 g cooked depending on the trials.
- Half a portion is not always enough: in the trial on canned beans, 90 g per day did not significantly lower cholesterol, whereas 180 g did.
- Duration: from 4 weeks to 3 months in the trials; no study in this factsheet measures an effect beyond that.
- Instead of, not in addition to: in the trials on blood pressure, legumes replaced other foods at equal calories; in diabetics, replacing red meat with legumes lowered fasting blood glucose, triglycerides, and LDL.
- At mealtime: mixing lentils, black beans, or chickpeas into rice or potatoes reduces the subsequent blood glucose spike.
- Form: green lentils, canned beans, and chickpea flour were tested; canned foods worked well too.
Did you know?
The fear of gas is exaggerated: in three trials, less than half of the participants reported more during the first week of beans, and 3 to 11% reported it even with a bean-free diet.
What the studies say
This systematic review and meta-analysis, including 32 cohorts and more than 1.1 million participants, evaluated the association between pulse consumption and mortality. Higher pulse consumption was associated with a reduced risk of all-cause mortality and stroke mortality. An increase of 50 g/day of pulses was linked to a 6% reduction in the risk of all-cause mortality.
Zargarzadeh N, Mousavi SM, Santos HO, Aune D, Hasani-Ranjbar S, Larijani B, Esmaillzadeh A. — Advances in nutrition (Bethesda, Md.) (2023) — View the source study
For information only: not a substitute for medical advice. Dietary supplements are not a replacement for a varied, balanced diet. Learn more