Four to six servings of whole grain per day lower risk factors for heart disease

by European Society of Cardiology

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Eating four to six servings of whole grains each day reduces several major risk factors for cardiovascular disease, according to a new study published in the European Heart Journal. The study is a systematic review and meta-analysis, meaning it brings together the results of all existing research in this area. It includes data from 87 clinical trials that tested the effects of eating whole-grain foods on risk factors for cardiovascular disease.

It shows that eating a diet rich in whole-grain foods is likely to prevent heart disease by reducing body weight, blood pressure and levels of cholesterol and glucose in the blood.

The research was led by Dr. Helda Tutunchi from Tabriz University of Medical Sciences, Iran. She said, "Although higher whole-grain intake has long been linked to better heart health in population studies, clinical trials have produced mixed findings. This left an important practical question unanswered: How much whole grain should people eat to meaningfully improve cardiovascular health?

"To address this, we systematically combined and analyzed all available randomized controlled trials to identify the amount of whole grain associated with the greatest benefits."

The analysis included more than 6,500 people from trials conducted across Asia, Europe, the United States, Canada, Australia and Brazil. It showed that eating more whole grains reduced people's body weight, waist circumference and blood pressure, as well as levels of total cholesterol and low-density lipoprotein cholesterol (LDL or 'bad' cholesterol), triglycerides, glucose and interleukin-6 (a sign of inflammation) in people's blood.

These benefits could be seen in people eating 30 to 40 grams of whole grains per day (dry weight), but the greatest benefits were found in people eating 60 to 100 grams per day. This corresponds to four to six servings of whole grains daily, for example, a bowl of oatmeal, a sandwich made with whole-grain bread and a serving of brown rice.

Tutunchi said, "This is the largest and most comprehensive meta-analysis of randomized controlled trials on whole-grain intake and cardiovascular risk factors. Unlike previous reviews, we looked specifically at how much whole grain people need to eat to get the greatest benefits.

"We also evaluated the certainty of the evidence and found high-certainty evidence for improvements in several outcomes, including body weight, waist circumference and total cholesterol.

"However, most of the trials we included were relatively short, with an average duration of about eight weeks. As a result, we cannot determine whether these benefits are maintained over the long term. In addition, relatively few studies evaluated very high whole-grain intakes, above 140 grams per day, so the effects at those intake levels remain uncertain.

"Our findings provide a practical indication of the amount of whole grain that may be needed to achieve meaningful improvements in cardiovascular risk factors. Increasing whole-grain intake is a relatively simple, accessible and affordable dietary strategy that can complement other lifestyle and medical interventions.

"We found that most benefits occur at intakes of approximately 60 to 100 grams per day, toward the upper end of current dietary recommendations. These findings do not necessarily call for major changes to existing guidelines, but they support public health strategies that help people increase their whole-grain intake and move toward the higher end of current targets.

"One important finding is that whole grains may benefit cardiovascular health through several modest improvements acting together, rather than through one large effect on a single risk factor. We observed improvements across multiple pathways, including blood lipids, blood pressure, glucose regulation, body fat and some markers of inflammation.

"Although the change in each individual risk factor was generally modest, improving several risk factors simultaneously could contribute to a greater reduction in long-term cardiovascular risk. However, the included trials did not assess cardiovascular events directly, so longer-term studies are needed to confirm this."

In an accompanying editorial, Dr. Cecilie Kyrø from the Danish Cancer Institute, Copenhagen, and colleagues said, "More than half a century ago, Sir Denis Burkitt and colleagues proposed that the refining of staple carbohydrates, with the accompanying removal of cereal fiber (i.e. from whole to refined grains), underpinned a broad spectrum of 'Western' diseases via effects on stool bulk, transit time and the colonic milieu.

"Whole grains refer to cereal grains in which the three main parts—bran, germ and endosperm—are all retained in the same proportions as in the intact kernel, whether consumed as whole kernels, flakes or milled into flour and used in bread and other foods.

"A meta-analysis of trials investigating the effect of whole grains on cardiometabolic risk markers by Naghshi et al. is published in this issue of the European Heart Journal and includes 87 trials of 6,529 study participants in total.

"The meta-analysis shows high-certainty evidence for reductions in body weight, waist circumference, total cholesterol and interleukin-6 (IL-6), and moderate-certainty evidence for improvements in LDL cholesterol, triglycerides, systolic blood pressure, fasting plasma glucose and insulin resistance (HOMA-IR).

"Importantly, the meta-analysis includes dose–response analyses, addressing differences in whole-grain intake between trials and providing quantitative evidence to inform food-based dietary guidelines. Overall, intakes of 60–100 g/day dry weight (∼4–6 servings) were found to be clearly related to relevant cardiometabolic improvements.

"For clinicians, the message from Naghshi et al. is reassuringly simple: Encouraging patients to replace refined grain foods with minimally processed whole grains is likely to yield modest but meaningful improvements in body weight, waist circumference and blood lipids, perhaps particularly in individuals with type 2 diabetes.

"At the population level, even small shifts in these markers can translate into substantial reductions in cardiometabolic events. Adding evidence from research into other disease endpoints indicates that the beneficial effects of whole-grain foods go substantially beyond cardiometabolic disease.

"The dose–response analyses by Naghshi et al. suggest that intakes of around 60–100 g/day whole grains (∼4–6 servings) are needed to achieve measurable cardiometabolic benefits. Current U.S. dietary guidelines recommend 2–4 servings of whole grains per day within an overall pattern that emphasizes 'real food' and reduced intake of ultra-processed products.

"While this is an important step in the right direction, the trial evidence indicates that higher whole-grain intakes than presently recommended in some guidelines may be optimal for cardiometabolic health.

"From a policy perspective, the challenge is to make minimally processed whole-grain staples accessible, affordable and culturally acceptable, while avoiding a drift toward ultra-processed products that merely add whole grains to otherwise highly processed formulations."

Publication details

Whole-grain consumption and cardiometabolic risk: a meta-analysis of randomized trials, European Heart Journal (2026). DOI: 10.1093/eurheartj/ehag519

Journal information: European Heart Journal

Key medical concepts

Cardiovascular DiseasesBody WeightBlood Pressure

Clinical categories

CardiologyNutrition & Healthy eatingPreventive medicineHealthy living Provided by European Society of Cardiology Who's behind this story?

Sadie Harley

BSc Life Sciences & Ecology. Microbiology lab background with pharmaceutical news experience in oil, gas, and renewable industries. Full profile →

Andrew Zinin

Master's in physics with research experience. Long-time science news enthusiast. Plays key role in Science X's editorial success. Full profile →

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