Dec. 12 (UPI) -- Women may be able to rest easier, simply by eating more fruit, vegetables and fiber, a new study suggests.
Published Wednesday in the American Journal of Clinical Nutrition, the analysis found that post-menopausal women who consumed a diet high in refined carbohydrates, including added sugars, were more likely to develop insomnia than those whose diets included higher amounts of vegetables, fiber and whole fruit.
The researchers believe that rapid spikes and troughs in blood sugar after eating refined carbs may trigger the sleeping disorder.
"Insomnia is often treated with cognitive behavioral therapy or medications, but these can be expensive or carry side effects," senior author James Gangwisch, assistant professor at Columbia University Vagelos College of Physicians and Surgeons, said in a statement. "By identifying other factors that lead to insomnia, we may find straightforward and low-cost interventions with fewer potential side effects."
Some 30 percent of American adults experience insomnia.
For the study, Gangwisch and his team collected data from more than 50,000 participants in the Women's Health Initiative Observational Study. All of the participants had completed food diaries, and the researchers assessed whether those reporting diets with higher amounts of high-carbohydrate foods also experienced symptoms of insomnia.
In general, highly refined carbohydrates -- such as added sugars, white bread, white rice and soda -- have a higher glycemic index. Consuming foods with these carbs can cause more rapid increases in blood sugar levels.
The authors found that those consuming foods with higher dietary glycemic index -- particularly those with added sugars and processed grains -- were up to 15 percent more likely to develop insomnia. They noted that earlier studies have explored a possible link between refined carbohydrates and insomnia, but results have been inconsistent.
"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," Gangwisch noted. "Whole fruits contain sugar, but the fiber in them slow 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."