A comparison of different practical indices for assessing carbohydrate quality among carbohydrate-rich processed products in the US

Authors: LIU, JUNXIU - Tufts University; REHM, COLIN - Albert Einstein College Of Medicine; SHI, PEILIN - Tufts University; MCKEOWN, NICOLA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University; MOZAFFARIAN, DARIUSH - Tufts University; MICHA, RENATA - Tufts University

Submitted to: PLOS ONE
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/23/2020
Publication Date: 5/21/2020
Citation: Liu, J., Rehm, C.D., Shi, P., McKeown, N.M., Mozaffarian, D., Micha, R. 2020. A comparison of different practical indices for assessing carbohydrate quality among carbohydrate-rich processed products in the US. PLoS ONE. 15(5):e0231572. https://doi.org/10.1371/journal.pone.0231572.
DOI: https://doi.org/10.1371/journal.pone.0231572

Interpretive Summary: Identifying healthy carbohydrate food products can be difficult for consumers. Even products that are labeled as 'whole grain' can sometimes contain added sugar, little fiber, or a mix of whole and refined grains. This study looked at four different metrics for identifying the nutritional quality of carbohydrate-rich foods. We found two potentially promising metrics that may be useful for identifying carbohydrate foods of better nutritional quality. These metrics focus on ensuring adequate dietary fiber and low added sugar, and these metrics may allow consumers to quickly identify higher quality carbohydrate products.

Technical Abstract: Healthier carbohydrate (carb)-rich foods are essential for health, but practical, validated indices for their identification are not established. We compared four pragmatic metrics, based on, per 10g of carb:(a) >/=1g fiber (10:1 carb:fiber), (b) >/=1g fiber and <1g free sugars (10:1:1 carb:fiber:free sugars), (c) >/=1g fiber and <2g free sugars (10:1:2 carb:fiber:free sugars); and (d) >/=1g fiber and, per each 1 g of fiber, <2g free sugars (10:1 carb:fiber, 1:2 fiber:free sugars; or 10:1|1:2). Using 2013-2016 National Health and Nutrition Examination Survey /Food and Nutrient Database for Dietary Studies, we assessed, overall and for 12 food categories, whether each metric discriminated carb-rich products higher or lower (per 100g) in calories, total fat, saturated fat, protein, sugar, fiber, sodium, potassium, magnesium, folate, and 8 vitamins/minerals. Among 2,208 carb-rich products, more met 10:1 (23.2%) and 10:1|1:2 (21.3%), followed by 10:1:2 (19.2%) and 10:1:1 (16.4%) ratios, with variation by product sub-categories. The 10:1 and 10:1|1:2 ratios similarly identified products with lower calories, fat, free sugars, and sodium; and higher protein, fiber, potassium, magnesium, iron, vitamin B6, vitamin E, zinc and iron. The 10:1:2 and 10:1:1 ratios identified products with even larger differences in calories and free sugars, but smaller differences in other nutrients above and lower folate, thiamine, riboflavin, and niacin; the latter findings were attenuated after excluding breakfast cereals (~9% of products). These novel findings inform dietary guidance for consumers, policy, and industry to identify and promote the development of the healthier carb-rich foods.