Adding more of one type of food to your diet could improve both your heart health and your waistline, according to a new study.
Researchers from Tabriz University of Medical Sciences in Iran, and Imperial College, London, found that a higher intake of whole grains was associated with a lower risk of cardiometabolic diseases and a reduction in body weight. The study was published in the European Heart Journal on September 15.
Helda Tutunchi, study lead and researcher at Tabriz University of Medical Sciences said in a statement: “Our findings provide a practical indication of the amount of wholegrain that may be needed to achieve meaningful improvements in cardiovascular risk factors. Increasing wholegrain intake is a relatively simple, accessible and affordable dietary strategy that can complement other lifestyle and medical interventions.”
Other studies have found similar associations, Kathleen Melanson, a professor of nutrition science at the University of Rhode Island, told Newsweek. She said that the findings suggest measures are needed to improve whole grain intake in America, as less than 2 percent of the population currently consumes the recommended amount daily.
She added that while whole grains are shown to be beneficial, “it should not be forgotten that the entirety of the diet matters, so other dietary components such as vegetables, legumes, fruits, and healthy sources of proteins and lipids should be taken into account.”
Cardiometabolic diseases, which include both metabolic diseases like diabetes and cardiovascular diseases, affect a substantial proportion of adults in the U.S., according to the Centers for Disease Control and Prevention (CDC). Collectively, cardiometabolic diseases are believed to have been responsible for over 4.8 million deaths among the U.S. working-age population (those aged between 25 to 64) between 1990 and 2017.
What Are Whole Grains?
Grains are the seeds of grasses grown for food, like wheat, oats and rice. These plants also are called cereals. Whole grains have all the parts of the grain—unlike refined or fortified grains where some parts are removed. Examples of whole-grain food include brown rice, quinoa, corn, oatmeal, buckwheat, spelt, and whole-grain breads and pastas.
The American Heart Association recommends eating three or more servings of fiber-rich whole grains every day, but most U.S. adults and children have been found to eat below that amount.
What The Study Found
The study was a systematic review, including data from 87 clinical trials that tested the effects of eating whole grains on risk factors for cardiovascular disease, and more than 6,500 people were involved from across Asia, Europe, the U.S., Canada, Australia and Brazil.
The findings showed that higher whole-grain intake was associated with reductions in body weight, waist circumference and blood pressure, as well as lower levels of total cholesterol, low-density lipoprotein (LDL or “bad”) cholesterol, triglycerides, glucose and interleukin-6 (a marker of inflammation) in the 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—which corresponds to four to six servings of whole grains daily, for example, a bowl of oatmeal, a sandwich made with wholegrain bread, and a serving of brown rice.
Tutunchi told Newsweek that around 60 to 100 grams a day of whole grains could “correspond to approximately a 10 to 15 percent lower risk of coronary heart disease and cardiovascular disease, assuming that the effects across the different risk factors are additive,” but emphasized that the estimate was approximate and indirect rather than a “directly demonstrated reduction in cardiovascular events.”
She also said that “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,” adding the main message is that whole grains “may support cardiometabolic health through a combination of relatively modest improvements across several risk factors, rather than through one dramatic effect.”
As the study also focused on trials with a median duration of eight weeks, further research is needed to better understand the impact of whole grains on human health in the long-term. It is also not clear whether adding more whole grains or swapping whole grains in place of other grains is most beneficial.
Dr Frank Hu, a professor of nutrition at Harvard University, told Newsweek that while the effects on “individual intermediate risk factors are generally modest,” they are “directionally consistent across several pathways—lipids, blood pressure, glycemia, adiposity, and inflammation,” and the findings support “replacing refined grains with whole grains as a routine part of a heart-healthy diet, rather than focusing on individual nutrients such as fiber alone.”
José Ordovás, a professor of nutrition science and policy at Tufts University, told Newsweek that the average effects of higher whole grain intake on risk factors were “modest,” but that small improvements “may still contribute to health when sustained.” Nevertheless, he added it was important to note the study “measured risk factors; they did not directly demonstrate fewer heart attacks, strokes, or new cases of diabetes.”
Chris Blesso, a professor of nutritional sciences at the University of Connecticut, told Newsweek that going forward, longer randomized trials are needed to “compare different grain types and examine if certain individuals respond better than others, since there may be differences in grain type fibers and phytochemical contents which may interact with an individual’s gut microbiome composition.”
David Jacobs, a professor of public health at the University of Minnesota, told Newsweek that he believed the “modest short-term effects attributable to the couple servings a day of whole grain foods enhance the effect of making nutritionally rich plant foods a preponderance of food eaten throughout adulthood.”
He said in his 25 years of research, he believed “an excellent lifetime diet (considering both enjoyment of the food and risk of developing or worsening chronic diseases) for most people includes a lot of nutritionally rich plant foods, without regard to fat or carbohydrate content,” as that minimizes intake of ultra-processed food, but includes nutritionally rich whole grain foods that have been highly processed.
Why Can Whole Grains Affect Heart Health?
Ordovás said that whole grains retain fiber and other components lost during refining, and that certain soluble fibers, particularly beta-glucan in oats and barley, can help lower LDL cholesterol.
Blesso said that the fiber and phytochemicals in whole grains are also thought to influence blood pressure, adiposity (prevalence of fatty tissue) and inflammation.
He said another possible explanation is fiber fermentation, as “whole grains can increase short-chain fatty acid production by gut microbes, which may affect metabolism.”
Ordovás noted that “the replacement food matters as well,” as substituting whole grains for refined grains “changes dietary quality,” while “simply adding whole-grain foods to an otherwise unchanged diet is a different intervention.”
He also said that impacts will differ between people as “baseline metabolic health, habitual diet, medications, genetics, and the gut microbiome could influence individual responses.”
Reference
Sina Naghshi, Sevil Kiani, Alireza Ostadrahimi, Ahmad Jayedi, Majid Mobasseri, Sara Arefhosseini, Helda Tutunchi, Dagfinn Aune (2026) Whole-grain consumption and cardiometabolic risk: a meta-analysis of randomized trials. European Heart Journal. https://doi.org/10.1093/eurheartj/ehag519
Contact Newsweek editors on this story: Kara Dolman and Tony Phillips.
Update 9/25/26, 10:57 a.m. ET: This article has been updated with comment from Helda Tutunchi.
