Excluding whole grain-containing foods from the Nova ultraprocessed food category: a cross-sectional analysis of the impact on associations with cardiometabolic risk measures

Am J Clin Nutr. 2024 Feb 28:S0002-9165(24)00163-1. doi: 10.1016/j.ajcnut.2024.02.017. Online ahead of print.

Abstract

Background: Whole grain (WG) consumption is linked with a reduced risk of chronic disease. However, the recommendations of the Nova classification system tend to contradict this evidence as high WG-containing foods, such as bread and cereals, are considered ultraprocessed, and intake is discouraged.

Objectives: This study aimed to explore associations of cardiometabolic risk measures with ultraprocessed food (UPF) intake as classified by Nova compared with when foods with ≥25% and ≥50% WG are removed from the Nova UPF category.

Methods: A cross-sectional analysis of the 2015-18 National Health and Nutrition Examination Survey. Nova was used to identify UPFs, and the WG Initiative's definition of a WG food and front-of-pack labeling requirements was used to identify high WG foods. Regression models were used to explore impacts on the association of UPF intake (quintiles) and cardiometabolic risk measures when high WG foods were excluded from the Nova UPF category.

Results: Participants in the highest quintile of UPF intake had significantly higher weight [83.6 kg (0.8)], BMI (in kg/m2) [30.6 (0.3)], waist circumference [103.1 cm (0.6)], and weight-to-height ratio [0.63 (0.003)] compared to those in the lowest quintile (P < 0.0001 for all). The same was found when foods with ≥25% and ≥50% WG were removed. Positive associations for C-reactive protein were found when ≥25% and ≥50% WG-containing foods were removed only [2.32 mg/L (0.1), P = 0.0209; 2.37 mg/L (0.1), P = 0.0179, respectively]. Participants in the highest quintile had significantly lower total cholesterol after adjustment when foods with ≥50% WG were removed [4.98 mmol/L (0.04), P = 0.0292]. Adjusted R2 values remained relatively unchanged across each approach for all outcomes.

Conclusions: Foods high in WG may not significantly contribute to the deleterious associations previously observed between UPF intake and cardiometabolic risk factors. Consideration of their contribution to healthful dietary patterns and diet quality in the United States population should be made prior to the endorsement of Nova.

Keywords: NHANES; Nova; cardiometabolic risk; ultraprocessed food; whole grain.