Relationship Between Animal Protein Intake and Meeting Recommendations for Protein Intake Among U.S. Adults, What We Eat in America, NHANES 2015–2018

OBJECTIVES: To describe protein intake and percentage of adults who met protein recommendations by level of animal: plant protein intake. METHODS: Usual protein intake was estimated using two days of dietary intake data from adults 19+ years (N = 9707) in What We Eat in America (WWEIA), NHANES 2015–2018. Those who did not have height and weight data were excluded, as well as pregnant and lactating women. Proportions of protein from animal and plant sources were estimated for each food in the Food and Nutrient Database for Dietary Studies 2015–2018, then applied to the dietary intakes to determine the population intake of protein from animal and plant sources. Adults were classified by quintile (Q) of animal: plant protein intake by age and sex to determine the percentages who met or exceeded their Dietary Reference Intake (DRI) for protein (grams/kilogram body weight). Mean protein intakes and percentages who met their DRIs for each quintile were compared using t-tests. Results were considered significant at P < 0.001. RESULTS: The percentages of total protein from animal sources for each quintile were Q1: < 42.6; Q2: 42.6 - < 59.5; Q3: 59.5 - < 68.6; Q4: 68.9 - < 78.1; Q5: ≥78.1. Mean (SE) protein intakes (grams) were Q1: 61 (1.7); Q2: 75 (1.5); Q3: 86 (1.3); Q4: 99 (1.7); Q5: 110 (2.2); mean intakes of all quintiles differed significantly from each other(P < 0.001). Percentages meeting or above their DRIs for protein intake were Q1: 83 (4.2); Q2: 95 (1.1); Q3: 99 (0.6); Q4: 100 (0.4); and Q5: 99 (0.3). Percentage meeting DRIs for protein in Q1 was significantly lower than Q3, Q4, and Q5. The percentage meeting DRIs in Q5 was significantly higher than Q1 and Q2 (P < 0.001); Q3, Q4 and Q5 did not differ from each other. CONCLUSIONS: Higher levels of animal protein intake were associated with a greater likelihood of adults meeting recommendations for protein intake. Evaluating food choices of those who met protein recommendations with lower animal protein intake may inform nutrition education about how protein recommendations for protein intake can be met when including more plant sources in the diet. FUNDING SOURCES: ARS-USDA.