The American diet — particularly its emphasis on added sugars, processed grains and other refined carbohydrates — may be to blame, at least in part, for why so many American adults struggle with insomnia, according to a study published in the American Journal of Clinical Nutrition.

The study found that older women who ate the highest amount of refined carbohydrates were most likely to report having difficulty getting a good night’s sleep.

Women who ate the highest amount of whole fruit, vegetables and fiber, on the other, were least likely to report problems with insomnia.

Because of the way foods interact with the human body, these findings are likely applicable to other people, the study’s authors add.

“Insomnia is often treated with cognitive behavioral therapy or medications, but these can be expensive or carry side effects,” says James Gangwisch, the study’s senior author and an assistant professor of clinical psychology at Columbia University, in a released statement.

“By identifying other factors that lead to insomnia, we may find straightforward and low-cost interventions with fewer potential side effects,” he adds.

A major health concern

Insomnia is a widespread health problem in the United States. One in four American adults experiences acute insomnia (difficulty falling or staying asleep for at least three nights a week) each year, researchers have found. About a quarter of those individuals have recurring bouts of insomnia or go on to develop chronic insomnia (when the problem continues for more than three months).

Getting less than the recommended seven hours of sleep each night is harmful to our health. Insufficient sleep has been linked to obesity and a variety of negative health outcomes, including heart disease, diabetes and depression. Insufficient sleep also increases the risk of injuries from accidents and mental errors, both on and off the job.

Several previous studies have examined a possible link between a high-carb diet and insomnia. The results of those studies were inconsistent, however. Nor were the studies able to clearly determine if a high-carb diet led to insomnia, or whether insomnia caused individuals to crave — and eat — more sugary foods.

Why would diet make a difference?

“When blood sugar is raised quickly, your body reacts by releasing insulin, and the resulting drop in blood sugar can lead to the release of hormones such as adrenaline and cortisol, which can interfere with sleep.

And, yes, fruits contain sugar. “But the fiber in them slows the rate of absorption to help prevent spikes in blood sugar. “This suggests that the dietary culprit triggering the women’s insomnia was the highly processed foods that contain larger amounts of refined sugars that aren’t found naturally in food.”