After Kaare Bursell, a macrobiotic counselor, adopted a rice-based diet, he wrote that "the first change occurring is my insomnia disappears in about three weeks and I am sleeping like a baby for the first time in several months." There are many anecdotes about rice diets and improved sleep, but anecdotes are not proof. The important question is whether or not scientific evidence lends weight to these claims.
Rice Is a High-Glycemic Food
The glycemic index is a measure of how various foods affect blood glucose levels. A 1992 study published in the "American Journal of Clinical Nutrition" determined glycemic index values for 12 varieties of rice, including brown rice, white rice, converted rice and quick-cooking rice. Glycemic indices ranged from 63 to 93. By comparison, glucose has a score of 100. These results suggest that all varieties of rice except those with high amylose, which is a component of starch, should be considered a high glycemic-index food.
Rice and Sleep
In a study published in the February 2007 issue of the "American Journal of Clinical Nutrition," researchers gave 12 healthy men a meal of either starchy rice with a relatively low glycemic index or Jasmine rice, which has a glycemic index of 109. The meal was given either one hour or four hours before bedtime. Sleep quality was measured objectively in a sleep lab. Results showed that Jasmine rice eaten four hours before bedtime significantly decreased the time it took to fall asleep.
Children and Sleep
If you want your toddler to sleep longer at night, try feeding him rice in the evening. A 2011 study of 594 toddlers published in the journal "Clinical Nutrition" found that larger meals, especially if they were rich in carbohydrates, are associated with longer sleep times in toddlers. Carbohydrates were particularly effective if they had high glycemic-index scores. The authors caution that for healthy toddlers between 1.5 and 2 years of age, the sleep-promoting effects of carbohydrates, while statistically significant, were modest.
Possible Mechanisms
Tryptophan is the amino acid precursor of serotonin and melatonin, both of which promote sleep. A study published in the March 1988 issue of the "American Journal of Clinical Nutrition" found that meals high in either starch or sugar increase the ratio of tryptophan to other amino acids. In contrast, meals high in fat and protein decreased this ratio. These results suggest that high-carbohydrate meals increase the rate of serotonin synthesis and that this effect would be greater with high glycemic-index foods like rice.
References
- "American Journal of Clinical Nutrition"; Rice: A High Or Low Glycemic Index Food?; J.B. Miller, et al.; December 1992
- "American Journal of Clinical Nutrition"; High-glycemic-index Carbohydrate Meals Shorten Sleep Onset; A. Afaghi, et al.; February 2007
- "American Journal of Clinical Nutrition" Serotonin Precursor Influenced By Type of Carbohydrate Meal In Healthy Adults; P.M. Lyons, et al.; March 1988
- "Clinical Nutrition"; Associations Between the Macronutrient Composition Of the Evening Meal and Average Sleep Duration in Early Childhood; K. Diethelm, et al.; June 3, 2011
- Alchemy Pages: Some Observations on the some Benefits of a Macrobiotic Life
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