People often get confused over the difference between whole grains and refined grains. Whole grains contain most of the original grain intact, as grown by the grain plant. Refined grains are processed to remove some of the outer casing or inner seed. Whole grains also tend to be higher in dietary fiber, minerals, vitamins, and essential fatty acids than refined grains.
Previous studies have found that whole-grain intake is associated with a lower risk of cardiovascular disease and death, but no clear links were found for refined grains. This is the reason why researchers decided to take on this new study.
For the study, data were analyzed for 137,130 people aged 35 to 70 years across 21 low-, middle-, and high-income countries who had no history of heart disease. All participants were taking part in the Prospective Urban and Rural Epidemiological (PURE) study.
Food questionnaires were used to assess intake of refined grains, whole grains, and white rice. White rice was examined separately from all other refined grains because more than 60% of the PURE population live in Asia, where rice is a staple food.
For an average of 9.4 years, deaths from cardiovascular causes or serious cardiovascular events, including heart attack, stroke, and heart failure were tracked.
Higher Risk of Death
It was found that the highest category of intake of refined grains (at least 350 g or about seven servings per day) was linked with a 27% higher risk of death and a 33% higher risk of serious cardiovascular events compared with the lowest category of intake (less than 50 g per day).
Higher intake of refined grains was also related to higher blood pressure. However, no significant associations were found between intake of whole grains or white rice and health outcomes.
Although this is only an observational study, so it can’t establish cause, researchers were able to analyze broad patterns of diet from across 21 countries. This means that the results are likely to be widely applicable to populations across the world.
The suggestion coming out of this study is that globally, a lower intake of refined products should be encouraged, and there should be an emphasis on promoting a higher intake of whole grains.
The researchers concluded, “Reduction in quantity and improvement in the quality of carbohydrate is essential for better health outcomes.”