Comparison of indices of carbohydrate quality and food sources of dietary fiber on longitudinal changes in waist circumference in the Framingham offspring cohort

Authors: SAWICKI, CALEIGH - Tufts University; LICHTENSTEIN, ALICE - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; ROGERS, GAIL - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; JACQUES, PAUL - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; MA, JIANTAO - Framingham Heart Study; SALTZMAN, EDWARD - Tufts University; MCKEOWN, NICOLA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University

Submitted to: Nutrients
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/16/2021
Publication Date: 3/19/2021
Citation: Sawicki, C., Lichtenstein, A.H., Rogers, G., Jacques, P.F., Ma, J., Saltzman, E., McKeown, N.M. 2021. Comparison of indices of carbohydrate quality and food sources of dietary fiber on longitudinal changes in waist circumference in the Framingham offspring cohort. Nutrients. 13(3):997. https://doi.org/10.3390/nu13030997.
DOI: https://doi.org/10.3390/nu13030997

Interpretive Summary: The aim of this study was to examine the long-term relation between different measures of dietary carbohydrate sources and overall carbohydrate quality and changes in waist circumference. We used data collected from 3,101 middle-age adults every 4 years over a total of 18 years. We found that participants who ate a diet with a higher ratio of total carbohydrate to fiber or total carbohydrate to cereal fiber (i.e. fiber from grains) experienced a greater increase in waist circumference on average compared to those who ate a diet with a lower ratio of carbohydrate to fiber or carbohydrate to cereal fiber. We also observed that participants who ate a diet higher in total fiber, cereal fiber, or fruit fiber experienced a smaller increase in waist circumference on average compared to those who ate less fiber. However, this relationship was not observed among participants who consumed a high carbohydrate diet overall. Therefore, improving the ratio of carbohydrate to fiber in the diet may help to maintain waist circumference over time.

Technical Abstract: Background: The long-term impact of carbohydrate quality and different sources of dietary fiber on abdominal weight gain is not fully understood. Objective: We aimed to examine the prospective relation of a carbohydrate quality index (CQI) and other carbohydrate quality measures with changes in waist circumference (WC) as surrogate marker of abdominal adiposity. Design: Subjects were participants in the Framingham Offspring cohort (n = 3,101 subjects), with mean baseline age 54.9 +/- 0.2 years (mean +/- SE) and BMI 27.2 +/- 0.1 kg/m2. Health and lifestyle data were collected approximately every 4 years over a median total of 18 years. Dietary exposures estimated from food frequency questionnaires included a CQI, total fiber, cereal, vegetable, and fruit fiber, carbohydrate-to-total fiber ratio, and carbohydrate-to-cereal fiber ratio. The CQI was defined by four criteria: dietary fiber, glycemic index, whole grain-to-total grain ratio, and solid-to-total carbohydrate ratio. Estimates of WC were standardized to four-year change and examined across energy-adjusted quartiles of carbohydrate quality variables using mixed models accounting for repeated measures. Results: No significant association was observed between the CQI and changes in WC. Higher ratios of carbohydrate-to-fiber and carbohydrate-to-cereal fiber were significantly associated with greater increases in WC per 4-year period (p-trend = 0.003 for both respectively); whereas higher intake of total fiber, cereal fiber, and fruit fiber were significantly associated with smaller increases in WC (p-trend < 0.001 for total and cereal fiber, p-trend = 0.002 for fruit fiber). There was a significant interaction between total fiber and total carbohydrate (as % of total energy intake). After stratification, the association between fiber intake and change in WC was not maintained in the context of a high carbohydrate diet. Conclusion: Better carbohydrate quality, primarily higher fiber intake and lower carbohydrate-to-fiber ratios, may help attenuate increases in abdominal adiposity over time.