Individual postprandial glycemic responses to diet in n-of-1 trials: Westlake N-of-1 trials for macronutrient intake (WE-MACNUTR)

Authors: MA, YUE - Westlake University; FU, YUANQING - Westlake University; TIAN, YUNYI - Westlake University; GOU, WANGLONG - Westlake University; MIAO, ZELEI - Westlake University; YANG, MIN - Zhejiang University; ORDOVAS, JOSE - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; ZHENG, JU-SHENG - Westlake University

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/18/2021
Publication Date: 7/13/2021
Citation: Ma, Y., Fu, Y., Tian, Y., Gou, W., Miao, Z., Yang, M., Ordovas, J.M., Zheng, J. 2021. Individual postprandial glycemic responses to diet in n-of-1 trials: Westlake N-of-1 trials for macronutrient intake (WE-MACNUTR). Journal of Nutrition. 151(10):3158-3167. https://doi.org/10.1093/jn/nxab227.
DOI: https://doi.org/10.1093/jn/nxab227

Interpretive Summary: The definition of a healthy diet is still controversial, especially for the individual, given the large inter-individuality in responses to the diet. Scientists at the HNRCA in Boston, in collaboration with Chinese researchers, took a new approach to determine individual glucose responses to diets. The investigators used the so-called 'n-of-1' study design to investigate the individual variability in blood glucose response when eating diets with different levels of fat and carbohydrates. Twenty-eight participants were included in the analysis. Our results demonstrated that N-of-1 trials are optimal to characterize personal blood glucose responses to different diets and opens new possibilities to personalized dietary recommendations to prevent diabetes and cardiovascular diseases.

Technical Abstract: BACKGROUND: The role of different types and quantities of macronutrients on human health has been controversial, and the individual response to dietary macronutrient intake needs more investigation. OBJECTIVES: We aimed to use an 'n-of-1' study design to investigate the individual variability in postprandial glycemic response when eating diets with different macronutrient distributions among apparently healthy adults. METHODS: Thirty apparently healthy young Chinese adults (women, 68%) aged between 22 and 34 y, with BMI between 17.2 and 31.9 kg/m2, were provided with high-fat, low-carbohydrate (HF-LC, 60-70% fat, 15-25% carbohydrate, 15% protein, of total energy) and low-fat, high-carbohydrate (LF-HC, 10-20% fat, 65-75% carbohydrate, 15% protein) diets, for 6 d wearing continuous glucose monitoring systems, respectively, in a randomized sequence, interspersed by a 6-d wash-out period. Three cycles were conducted. The primary outcomes were the differences of maximum postprandial glucose (MPG), mean amplitude of glycemic excursions (MAGE), and AUC24 between intervention periods of LF-HC and HF-LC diets. A Bayesian model was used to predict responders with the posterior probability of any 1 of the 3 outcomes reaching a clinically meaningful difference. RESULTS: Twenty-eight participants were included in the analysis. Posterior probability of reaching a clinically meaningful difference of MPG (0.167 mmol/L), MAGE (0.072 mmol/L), and AUC24 (13.889 mmol/Lh) between LF-HC and HF-LC diets varied among participants, and those with posterior probability more than 80% were identified as high-carbohydrate responders (n = 9) or high-fat responders (n = 6). Analyses of the Bayesian-aggregated n-of-1 trials among all participants showed a relatively low posterior probability of reaching a clinically meaningful difference of the 3 outcomes between LF-HC and HF-LC diets. CONCLUSIONS: N-of-1 trials are feasible to characterize personal response to dietary intervention in young Chinese adults.