Effect of animal protein intake on meeting recommendations for nutrient intake among US adults, What We Eat in America, NHANES 2015-2018

Authors: Hoy, M Katherine; Murayi, Theophile; Moshfegh, Alanna

Submitted to: Current Developments in Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/28/2022
Publication Date: 12/30/2022
Citation: Hoy, M.K., Murayi, T., Moshfegh, A.J. 2022. Effect of animal protein intake on meeting recommendations for nutrient intake among US adults, What We Eat in America, NHANES 2015-2018. Current Developments in Nutrition. https://doi.org/10.1016/j.cdnut.2022.100027.
DOI: https://doi.org/10.1016/j.cdnut.2022.100027

Interpretive Summary: Dietary guidance encourages replacing some animal sources of protein with plant foods. It is unclear what effect changes in protein source has on adequacy of nutrient intake, but this has not been evaluated in U.S. adults. The objective of this study was to compare food consumption, and nutrient intake and adequacy of U.S. adults by level of percent animal protein (AP) intake of the diet. Dietary intake data of adults 19+ years (N=9,706) from What We Eat In America, NHANES 2015-2018 were used. Proportions of protein from animal and plant sources were estimated from the ingredients in the Food and Nutrient Database for Dietary Studies 2015-2018, then applied to the dietary intakes. Intakes were classified into five levels of AP intake. Food intake was described using the USDA Food Patterns (FP) components. Usual nutrient intakes were estimated and compared to age and gender specific Dietary Reference Intakes (DRI). Comparisons between the five AP levels were made using t-tests. Results were considered significant at P<0.01. Total protein intake was higher as level of AP intake increased. Among the highest three levels of percent AP, <1% did not meet their DRI for protein compared to 17% and 5% in the lowest two levels. In levels with lower AP intake, there were significantly higher percentages not meeting DRIs for vitamins A, B12, choline, zinc, and calcium, but meeting recommendations for folate, vitamin C, saturated fat, cholesterol, and fiber. Regardless of protein source, over one-third of adults did not meet DRIs for fiber, vitamins A, C, D, E, K, choline, calcium, and potassium. Those with lower AP intake consumed more legumes, nuts and seeds, total grains, and total fruit (P<0.01) whereas consumption of meat, poultry, seafood, and dairy increased with higher AP intake (P<0.01). There were no differences between the five levels in intake of total vegetables, soy products, and oils. Replacing protein from animal sources with plant foods may result in lower intakes of protein and some nutrients, but better intake of dietary components associated with reducing chronic disease risk. Current intake of U.S. adults indicates dietary improvements are needed, regardless of protein source.

Technical Abstract: Dietary guidance encourages replacing some animal sources of protein with plant foods. It is unclear what effect changes in protein source has on adequacy of nutrient intake, but this has not been evaluated in U.S. adults. The objective of this study was to compare food consumption, and nutrient intake and adequacy of U.S. adults by quintile of percent animal protein (AP) intake. Dietary intake data of adults 19+ years (N=9,706) from What We Eat In America, NHANES 2015-2018 were used. Proportions of protein from animal and plant sources were estimated from the ingredients in the Food and Nutrient Database for Dietary Studies 2015-2018, then applied to the dietary intakes. Intakes were classified by quintile of percent AP. Food intake was described using the USDA Food Patterns (FP) components. Usual nutrient intakes were estimated using the NCI Method and compared to age and gender specific Dietary Reference Intakes (DRI). Comparisons between quintiles were made using t-tests. Results were considered significant at P<0.01. Total protein intake was higher as quintile of AP intake increased. Among the higher quintiles of percent AP, <1% did not meet their DRI for protein compared to 17% in Q1 and 5% in Q2. Generally, differences between Q1 and Q5 were significant, while values among Q2 through Q4 were intermediate between Q1 and Q5, with some significant differences. There were significantly higher percentages not meeting DRIs among those with lower percent AP for vitamins A, B12, choline, zinc, and calcium, but meeting recommendations for folate, vitamin C, saturated fat, cholesterol, and fiber. Regardless of protein source, over one-third of adults did not meet DRIs for fiber, vitamins A, C, D, E, K, choline, calcium, and potassium. Those with lower AP intake consumed more legumes, nuts and seeds, total grains, and total fruit (P<0.01) whereas consumption of meat, poultry, seafood, and dairy increased with higher AP intake (P<0.01). There were no differences between quintiles in intake of total vegetables, soy products, and oils. Replacing protein from animal sources with plant foods may result in lower intakes of protein and some nutrients, but better intake of dietary components associated with reducing chronic disease risk. Current intake of U.S. adults indicates dietary improvements are needed, regardless of protein source.