The paper is signed by Sina Naghshi and a team at Tabriz University of Medical Sciences in Iran, with Ahmad Jayedi and Dagfinn Aune of Imperial College London. Aune also works at the Cancer Registry of Norway. The protocol was registered in advance on PROSPERO, the international register of systematic reviews, as CRD42024565726. The stated funding comes from Tabriz University itself.
The authors count a grain as whole when it keeps all three parts of the kernel, bran, germ and endosperm. They gathered 87 randomised trials reported in 101 publications. In each, one group ate more whole grains and the other stayed on its usual diet, on refined grains or on general advice. The editorial that accompanies the paper puts total enrolment at 6,529. For LDL cholesterol, the outcome with most data, there are 69 trials and 5,932 people.

On the same scale, total cholesterol falls by 0.10 millimoles per litre and LDL by 0.07. Systolic pressure falls by 0.82 millimetres of mercury, with a 95 per cent confidence interval of 0.15 to 1.49. Diastolic pressure falls by the same amount, with an interval that comes close to zero. Waist circumference shrinks by 0.22 centimetres. Triglycerides drop by 0.04 millimoles per litre. Fasting glucose drops by 0.03, with an interval that touches zero. For HDL cholesterol and insulin the intervals cross zero, and the result is undecided.
For each outcome the authors grade their certainty with the GRADE method, which weighs the quality of the evidence, the consistency between trials and the precision of the estimates. Certainty is high for weight, waist, total cholesterol and interleukin-6, an inflammatory molecule. It is moderate for LDL, triglycerides, glucose and blood pressure. It is low for C-reactive protein and for the insulin resistance index.

What is new is the dose. The authors looked for the amount that gives the largest effect. For most measures the benefit peaks between 60 and 100 grams a day, dry weight, and for a few it keeps rising to 180 to 220 grams. The authors warn that data above the usual intakes are sparse and the threshold remains uncertain.
The most serious limitation is stated by the corresponding author, Helda Tutunchi, in the European Society of Cardiology press release. The trials last eight weeks on average. None counted heart attacks, strokes or deaths. The meta-analysis measures risk factors, not disease. The trials also disagree with one another. Heterogeneity, the share of variation between results that chance does not explain, ranges from 40 to 82 per cent depending on the outcome.

The press release leans on the benefits and quotes the researcher calling the diet a simple, cheap strategy. The accompanying editorial, as quoted in the release, gives moderate certainty to the insulin resistance index. The paper’s own table rates it low.
Across a whole population, a few millimetres of mercury and a fraction of a millimole of cholesterol matter, because they add up over millions of people. For a single patient the figures stay small. Two hundred grams of body weight and less than one millimetre of pressure for three servings a day will not change a hypertensive patient’s treatment. Knowing whether whole grains protect the heart needs trials that run for years and count events. Those trials do not yet exist.

Mean change in cardiometabolic risk factors per extra 48 grams a day of whole grains (dry weight), with 95 per cent confidence intervals. Pooled from 87 randomised trials.
Chart produced by ScienceOnline from data in Naghshi S. et al., European Heart Journal 2026, doi 10.1093/eurheartj/ehag519

References
Naghshi S., Kiani S., Ostadrahimi A., Jayedi A., Mobasseri M., Arefhosseini S., Tutunchi H., Aune D., “Whole-grain consumption and cardiometabolic risk: a meta-analysis of randomized trials”, European Heart Journal, article ehag519 (volume and issue not yet assigned), published online 15 September 2026, open access under CC BY 4.0. doi: 10.1093/eurheartj/ehag519
PROSPERO, protocol registration CRD42024565726.
European Society of Cardiology, press release on the meta-analysis, republished by ScienceDaily on 16 September 2026 as “Scientists find the whole grain ‘sweet spot’ for better heart health”.