Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/29/2013
Publication Date: 3/24/2014
Citation: Makarem, N., Scott, M., Quatromoni, P., Jacques, P., Parekh, N. 2014. Trends in dietary carbohydrate consumption from 1991 to 2008 in the Framingham Heart Study Offspring Cohort. British Journal of Nutrition. DOI:10.1017/S0007114513004443. Interpretive Summary: The quantity and quality of carbohydrates that individuals consume have been reported to be associated with the risk and progression of a number of chronic diseases including cancer, cardiovascular disease (CVD), and type 2 diabetes. While refined grains, sugars and sugar-sweetened beverages have been shown to be associated with an increased risk of cancer, CVD, type 2 diabetes, and weight gain, whole grains and fiber may protect against chronic disease. Few studies, however, have examined intake and sources of carbohydrates in the American diet. In particular, no study has looked at trends in consumption of carbohydrates, sugars, and fiber over time. The aim of this study was to examine trends in the intake of dietary carbohydrates and their major food sources over a 17 year period. We examined data on approximately 2,800 participants in the Framingham Heart study from 1991 to 2008. During the 17 year study period, dietary guidelines and messaging had placed an increased emphasis on eating more whole grains and decreasing sugar intake. Over the 17 year follow-up period, the percentage of total calories consumed from carbohydrates and sugars decreased. Dietary fiber intake increased. The number of weekly servings of yeast bread, soft drinks/soda, cakes/cookies/quick breads/doughnuts, potatoes, milk, pasta, rice and cooked grains, fruit juice/drinks, potato chips/maize chips/popcorn, and lunch foods (e.g. pizzas and burgers) decreased significantly, while the intake of ready-to-eat cereals, legumes, fruits, dairy products, candy and ice cream/sherbet/frozen yogurt increased significantly. This decrease in intake of processed carbohydrates (i.e. chips, cookies, etc) and increase in healthier carbohydrates such as legumes and fruits showed a positive trend. Despite this, fiber, fruit, and vegetable intakes were still at levels lower than what is recommended by the current dietary guidelines.
Technical Abstract: The intake of carbohydrates has been evaluated cross-sectionally, but not longitudinally in an ageing American adult population. The aim of the present study was to examine trends in the intake of dietary carbohydrates and their major food sources among the Framingham Heart Study Offspring (FOS) cohort, which had been uniquely tracked for 17 years in the study. The FOS cohort was recruited in 1971-1975. Follow-up examinations were conducted, on average, every 4 years. Dietary data collection began in 1991 (examination 5) using a validated semi-quantitative FFQ. The study included 2894 adults aged = 25 years with complete dietary data in at least three examinations from 1991 to 2008. Descriptive statistics were generated using SAS version 9.3, and a repeated-measures model was used to examine trends in the intake of carbohydrates and their food sources in the whole sample, and by sex and BMI category. Over 17 years of follow-up, the percentage of energy from total carbohydrates (51.0-46.8 %; P for trend < 0.001) and total sugars (18.2-16.6 %; P for trend < 0.001) decreased. There was a decrease in the percentage of energy from fructose (5.4-4.7 %; P for trend < 0.001) and sucrose (9.8-8.8 %; P for trend < 0.001). Dietary fibre intake increased (18.0-19.2 g/d; P for trend < 0.001). The number of weekly servings of yeast bread, soft drinks/soda, cakes/cookies/quick breads/doughnuts, potatoes, milk, pasta, rice and cooked grains, fruit juice/drinks, potato chips/maize chips/popcorn, and lunch foods (e.g. pizzas and burgers) decreased significantly (P for trend < 0.001), while the intake of ready-to-eat cereals, legumes, fruits, dairy products, candy and ice cream/sherbet/frozen yogurt increased significantly (P for trend<0.04). Similar trends were observed when the analyses were stratified by sex and BMI. The present results suggest favourable trends in dietary carbohydrate consumption, but dietary guidelines for fruits, vegetables and fibre were not met in this cohort.