Associations Between Usual Plant & Animal Protein Intake and Select Serum Biomarkers of Chronic Disease Risk

Abstract

Background:The prevalence of lifestyle-related chronic diseases has increased significantly in the U.S. over the last two decades, and nutrition interventions may help reduce disease risk. However, studies linking diet with chronic disease risk factors have yet to confirm optimal proportions and sources of certain dietary components such as protein. The purpose of this analysis was to identify associations between usual intake of plant and animal protein and standard clinical chemistries relevant to chronic disease risk. Methods:This analysis of baseline screening data from an ongoing study within the Seattle Dietary Biomarker Development Consortium included a subset of adult participants screened for the first trial of the study. Screening data included usual diet and fasting blood measures of common clinical chemistries. Using linear regression models, animal- and plant-based protein intake were assessed relative to serum concentrations of select biomarkers, including LDL cholesterol, triglycerides, hematocrit, and albumin. Additionally, mean biomarker concentrations were compared between tertiles of intake of select protein foods using ANOVA and post-hoc Tukey models. Results:Data associated with a total of 33 participants were analyzed. The linear regression revealed a significant inverse relationship between plant-based protein intake as a percent of total calories and hematocrit (p=0.02). A significant positive relationship between animal-based protein intake as a percent of total calories and hematocrit (p=0.004) was also identified after adjustments. ANOVA tests revealed a significant difference in mean triglyceride concentrations between protein intake tertiles in terms of servings per week of poultry (p=0.04) as well as a significant difference in mean hematocrit in terms of servings per week of green beans and peas (p=0.007). Conclusion:These results suggest that the proportions of plant and animal-based protein in the diet may meaningfully influence hematocrit levels and may be important considerations in addressing iron-deficiency anemia or mitigating CVD risk. However, large, randomized controlled trials are needed to confirm these findings.