Study: Whole Grain Consumption Lowers Death Risk

Just weeks after JAMA published a National Institutes of Health study refuting the idea that there are “good carbs” and “bad carbs’ a new study in the journal finds eating whole grains is associated with lower overall mortality and death from heart disease. Writing in JAMA Internal Medicine, Harvard School of Public Health nutritionist Hongyu Wu, PhD and colleagues report on the dietary habits of 74,341 women from the Nurses’ Health Study and 43,744 men from the Health Professionals Follow-Up Study.

They documented 26,920 deaths during 2,727,006 person-years of follow-up.

The team found that those who ate more whole grains lived longer.

“Every serving of whole grain (28 grams daily) was associated with a 5% lower total mortality or a 9% lower cardiovascular disease (CVD) mortality,” they found.

The NIH study focused on the glycemic index and the belief that refined carbohydrates cause spikes in blood sugar and insulin. But the NIH researchers found that low glycemic foods like whole grains did not lower cholesterol and other heart disease risk factors compared to diets with mostly high glycemic foods, like white bread.

The Harvard study noted that there are likely health benefits in eating whole grains because they contain beneficial nutrients and phytochemicals that are removed when the grains are refined.

“In laboratory research and human feeding trials, whole grains, as well as constituents of whole grains, such as insoluble fiber, magnesium and phytochemicals consistently have beneficial effects on glucose metabolism, blood lipids, endothelial function, antioxidant activity, and inflammation,” the researchers wrote in the article.

“In addition epidemiologic studies have consistently found inverse associates between whole grain intake and lower risk of type 2 diabetes mellitus, and CVDs.

The Harvard researchers found no association with whole grain consumption and lower cancer mortality.

They also found that adding bran or wheat germ to the total whole grains did not appear to have any benefit when it came to overall mortality, but that bran consumption appeared to be associated with lower heart disease rates.

But they noted that not many people in the study ate wheat germ so there could have been a positive association that went undetected.

Though bran has been promoted as having a health benefit due mostly to its fiber, the researchers noted that its favorable effects also include B-group vitamins, vitamin E, magnesium and phytochemicals. These antioxidant phytochemicals include phenolic acids and alkylresorcinols which “may modulate cellular oxidative status and prevent oxidative damage to biologically important molecules, such as DNA, proteins, and membrane lipids,” they wrote.

The authors acknowledge that most of the study participants were middle aged people of European ancestry, so the team did not know whether its findings could be generalized to other demographic or ethnic groups.