Nuts and peanuts: what the evidence says about cholesterol and the heart

Few foods have been tested as often as nuts. A 2015 meta-analysis pulled together 61 controlled trials with 2,582 participants, covering walnuts, pistachios, macadamias, pecans, cashews, almonds, hazelnuts and Brazil nuts. Each daily 1-ounce (28.4 g) serving lowered total cholesterol by 4.7 mg/dL, LDL by 4.8 mg/dL, apolipoprotein B by 3.7 mg/dL and triglycerides by 2.2 mg/dL Del 2015. The dose mattered more than the type of nut, and effects were stronger at 60 g a day or more.

An earlier pooled analysis of the raw data from 25 trials (583 people not taking cholesterol drugs) found that about 67 g of nuts a day lowered LDL by 10.2 mg/dL, a 7.4% fall. The effect was largest in people who started with higher LDL, and different nuts gave similar results Sabate 2010.

Those are modest changes, smaller than a statin gives, but they are consistent from trial to trial. That consistency is why this page grades the LDL effect strong. Nuts are not a replacement for a cholesterol medicine your clinician has prescribed.

In the Spanish PREDIMED trial, one of three groups followed a Mediterranean diet and received free mixed nuts. Over a median 4.8 years, 3.4% of that group had a heart attack, stroke or cardiovascular death, compared with 4.4% on a reduced-fat control diet Estruch 2018. The trial was republished in 2018 after problems with randomization at some sites came to light, and the results held up in the reanalysis. The olive oil page covers the same trial from the other arm.

Large cohort studies point the same way. A dose-response meta-analysis of 20 prospective studies found each 28 g a day of nuts was linked with lower risk of coronary heart disease, cardiovascular disease and death from any cause, and results were similar for peanuts and tree nuts Aune 2016. These studies cannot fully separate nuts from the healthier habits of people who eat them, so they are graded limited on their own.

Nuts are dense in calories, which puts many people off. The evidence says the worry is overstated. A 2021 meta-analysis of 86 randomized trials (5,873 participants) found no effect of nuts on body weight, rated high-certainty evidence, and six cohort studies with 569,910 people linked nut eating with a slightly lower chance of becoming overweight Nishi 2021. Nuts tend to replace other snacks rather than add to them, and that is the pattern to aim for.

FDA lists qualified health claims, its category for promising but not settled evidence, for nuts and coronary heart disease (2003), walnuts (2004) and macadamia nuts (2017) FDA. It also lists a 2017 qualified claim about feeding ground peanuts to infants and a lower risk of developing peanut allergy, an area where parents should follow their pediatrician's advice FDA.

Supermarket nuts are fine. If you want a wider range of raw or unsalted nuts, iHerb lists raw almonds and other plain nuts.