If you’re coming up short on shuteye, you’ll want to train your tired eyes on this: research has discovered an association between isoflavones found in soybeans and better sleep. The study was published in Nutrition Journal and included 1,076 Japanese participants, ages 20 to 78. To assess their isoflavone intake, researchers asked the participants to estimate how often they had eaten tofu, fried tofu, and natto (fermented soybeans)—all soy-based foods typically rich in isoflavones—over the previous month. The participants also answered a survey regarding their sleep duration and quality (such as whether they felt refreshed after sleep) in that same month. After evaluating their answers and adjusting for factors such as age, sex, occupation, and coffee intake, researchers found that:
On average, people with the highest daily isoflavone intakes were 84% more likely to get an optimal amount of sleep (7 to 8 hours per day) and 78% more likely to have sufficient sleep quality than people with the lowest isoflavone intakes.
These findings are supported by previous research in which isoflavone supplements improved sleep in post-menopausal women with insomnia; however, more research is needed before a direct link can be drawn between dietary isoflavones and better sleep. In addition to containing isoflavones that may promote better sleep, soy products are generally high in protein and low in fat, and may help prevent heart disease, diabetes, and metabolic syndrome. To boost your soy isoflavone intake, look for whole soybeans, roasted soy nuts, tofu, tempeh, soy flour, and soy milk.
Source: Nutrition Journal