A large new analysis of clinical trials suggests Americans may need to eat more whole grains than federal dietary guidelines currently recommend to get the biggest benefits for heart health, weight and blood sugar.
The meta-analysis, published in the European Heart Journal, pooled data from 87 randomized controlled trials involving more than 6,500 people across Asia, Europe, the United States, Canada, Australia and Brazil. Researchers found that eating four to six servings of whole grains daily — roughly 60 to 100 grams, the equivalent of a bowl of oatmeal, two slices of whole-grain bread and a serving of brown rice — produced the greatest improvements in body weight, cholesterol, blood sugar and blood pressure.
That range exceeds the two to four servings a day recommended under the current Dietary Guidelines for Americans, a federal standard many Americans don’t even meet.
“This is the largest and most comprehensive meta-analysis of randomized controlled trials on whole-grain intake and cardiovascular risk factors,” lead author Helda Tutunchi, of Tabriz University of Medical Sciences in Iran, said in a statement.
People who ate more whole grains showed lower body weight, waist circumference, blood pressure, total cholesterol, LDL (“bad”) cholesterol, triglycerides, blood glucose and interleukin-6, a marker of inflammation, according to the study. Tutunchi said the benefit did not come from any single mechanism but from “several modest improvements acting together, rather than through one large effect on a single factor.”
The researchers acknowledged limits to the data: most of the trials reviewed were short in duration and did not directly track heart attacks or strokes, meaning longer-term research is still needed to confirm the findings.
A South Carolina Dietitian’s Take
Lauren Manaker, a South Carolina-based registered dietitian nutritionist who was not involved in the study, cautioned that jumping straight to six servings a day is unrealistic for most people currently eating little or no whole grain.
“Going from zero to six is a lot,” Manaker told Fox News Digital. “My recommendation is to start slow. Two servings is better than zero servings.”
She suggested starting the day with oatmeal or overnight oats, or swapping refined-grain sides for whole-grain alternatives such as sorghum or brown rice.
Manaker also warned shoppers not to assume a brown-colored loaf of bread is automatically whole grain. “We want to look at the ingredient list and make sure one of the first ingredients is a whole grain,” she said. “We also want to look at the nutrition panel and make sure there’s some fiber in there.”
Whole grains, the researchers noted, retain all three parts of the kernel — the bran, germ and endosperm — unlike refined grains that have parts removed during processing.
Despite the caveats, the study’s authors concluded that boosting whole-grain intake is “a relatively simple, accessible and affordable dietary strategy” that can work alongside other heart-healthy habits.
In an editorial accompanying the report, Cecilie Kyro of the Danish Cancer Institute in Copenhagen and colleagues called for policies that make minimally processed whole-grain staples affordable and culturally acceptable, while “avoiding a drift towards ultra-processed products.”
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