Eating more refined grains increases risk of heart disease, death: study

Bread is seen in this stock photo. (Mariana Kurnyk/Pexels)

TORONTO — A new study has found that consuming a high number of refined grains, such as white bread, cereal and croissants, can be associated with a higher risk of major cardiovascular disease, stroke and death.

The Prospective Urban Rural Epidemiology (PURE) study looked at participants in 21 countries, including Canada, and reported that the intake of refined grains and added sugars have "greatly increased" in peoples’ diets over the years.

"This study re-affirms previous work indicating a healthy diet includes limiting overly processed and refined foods," study co-author and Simon Fraser University health sciences professor Scott Lear said in a press release.

The prospective cohort study, published Friday in The British Medical Journal, examined diets from populations in low, middle and high-income countries over 16 years.

In addition to Canada, other countries involved in the study included regions of the United States, Europe, South America, Africa, the Middle East, South Asia, South East Asia and China.

According to the study, the analysis consisted of 137,130 participants aged 35 to 70 years old who had no history of heart disease. The participants used "food frequency questionnaires" to assess their intakes of refined grains, whole grains and white rice with follow-up conducted every three years.

The study reported that refined grains included products made with refined flour, such as white bread, pasta or noodles, breakfast cereals, crackers, bakery products and desserts. Whole grains included whole grain flours such as buckwheat, and intact or cracked whole grains, including steel cut oats.

According to researchers, the questionnaires were used to evaluate grain intake in association with cardiovascular disease, total mortality, blood lipids and blood pressure.

The study found that having more than seven servings of refined grains per day was associated with a 27 per cent greater risk of early death, a 33 per cent increased risk of heart disease, and 47 per cent greater risk for stroke.

Higher intakes of refined grains were also linked to higher systolic blood pressure, according to the study.

The study reported that the consumption of refined grains was highest in China followed by South East Asia. Intake of white rice was highest in South Asia while countries in Africa reported the highest intake of whole grains.

"High intake of refined grains was associated with higher risk of mortality and major cardiovascular disease events. Globally, lower consumption of refined grains should be considered," the study's authors wrote.

According to researchers, the study "observed no significant association between intake of whole grains or white rice and clinical outcomes."

To help combat the study's findings, researchers suggest eating whole grain foods like brown rice and barley, as well as having fewer high-sugar cereal grains and refined wheat products in one's diet.

"Intakes of a combination of cereal grains with a lower intake of refined wheat products should be encouraged while promoting a higher intake of whole grains. Reduction in quantity and improvement in quality of carbohydrate is essential for better health outcomes," the study said.