Blackmores Institute

The prospective cohort study of post-menopausal women who participated in the Women’s Health Initiative Observational Study, found that insomnia was associated with higher glycaemic index (GI), higher body mass index and less physical activity among other factors.“The results from the three-year longitudinal multivariable analyses (n = 53,069) showed subjects with higher dietary GI and glycaemic load and higher consumption of added sugars, starch, and non-whole/refined grains were more likely to have insomnia after three years in energy-adjusted analyses,” the researchers reported.Despite variations in the different models analysed, the researchers found a significant linear trend toward higher insomnia incidence for higher glycaemic load while higher consumption of fibre, whole grains, non-juice fruit and vegetables were significantly associated with decreased odds of insomnia.“There was a significant linear trend toward lower insomnia incidence for increasing non-juice fruit consumption in all three models. There were no associations of dietary total sugar, total carbohydrate, whole grains, or dairy products with insomnia incidence in fully adjusted models,” the authors said.“Cross-sectional analyses did not demonstrate a relation between the consumption of starch and the prevalence of insomnia, but prospective analyses showed that individuals with higher starch consumption were progressively and significantly more likely to have developed insomnia incidence after three years.“Although starches are complex carbohydrates, sources such as refined white bread and boiled potatoes have high GIs, whereas other fibre-rich sources including legumes, nuts/seeds, and yams generally have low GIs. When we examined different types of starches according to fibre content, we found that progressively higher consumption of whole grains was associated with lower insomnia prevalence, whereas the opposite was true for non-whole/refined grains, with progressively higher consumption associated with higher insomnia prevalence and incidence.”The study also found that increased vegetable consumption was also associated with decreased insomnia prevalence and incidence with the authors noting that the most commonly consumed vegetable in the United States is potatoes with most varieties and methods of cooking resulting in high GIs, whereas the next six most commonly consumed vegetables (onions, tomatoes, head lettuce, romaine and leaf lettuce, bell peppers, and cucumbers) all have low GI.“A plausible mechanism by which a high-GI diet may increase the risk of insomnia is through acute spikes and troughs in blood glucose. GI and glycemic load have been shown to provide physiologically valid estimates of postprandial glycaemia and insulin demand in healthy individuals.“Hypoglycaemia has been shown to produce arousal from sleep and substantially reduce sleep efficiency in non-diabetic adults. High blood sugar from carbohydrate consumption can initially make one drowsy, helping one to fall asleep, but the compensatory hyperinsulinaemia and counter-regulatory hormone responses can awaken one from sleep.“Higher-GI diets have also been shown to stimulate inflammatory immune responses, which could function to increase the risk of insomnia through anti-inflammatory cytokines that inhibit sleep. Added sugars could also negatively affect sleep quality by compromising the intestinal microbiome,” the authors explained.“High-GI diets could be a risk factor for insomnia in postmenopausal women, whereas dietary fiber, nonjuice fruit, and vegetables reduce its risk. If high-GI diets increase the risk of insomnia, then dietary interventions that promote the consumption of whole unprocessed carbohydrates that are high in fiber and have low GIs could serve as potential treatments of, and primary preventive measures for, insomnia in postmenopausal women,” the study concluded. Source: 
 AmJ Clin Nutr 2019; 00: 1-11. DOI: <a href="https://academic.oup.com/ajcn/advance-article-abstract/doi/10.1093/ajcn/nqz275/5673520">10.1093/ajcn/nqz275</a>

Insomnia in post-menopausal women may be linked to high glycaemic index diets, new research in the American Journal of Clinical Nutrition, reports.

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