Paleolithic and Mediterranean Diet Pattern Scores Are Inversely Associated with Biomarkers of Inflammation and Oxidative Balance in Adults

Abstract

Background: Chronic inflammation and oxidative balance are associated with poor diet quality and risk of cancer and other chronic diseases. A diet-inflammation/oxidative balance association may relate to evolutionary discordance.

Objective: We investigated associations between 2 diet pattern scores, the Paleolithic and the Mediterranean, and circulating concentrations of 2 related biomarkers, high-sensitivity C-reactive protein (hsCRP), an acute inflammatory protein, and F2-isoprostane, a reliable marker of in vivo lipid peroxidation.

Methods: In a pooled cross-sectional study of 30- to 74-y-old men and women in an elective outpatient colonoscopy population (n = 646), we created diet scores from responses on Willett food-frequency questionnaires and measured plasma hsCRP and F2-isoprostane concentrations by ELISA and gas chromatography-mass spectrometry, respectively. Both diet scores were calculated and categorized into quintiles, and their associations with biomarker concentrations were estimated with the use of general linear models to calculate and compare adjusted geometric means, and via unconditional ordinal logistic regression.

Results: There were statistically significant trends for decreasing geometric mean plasma hsCRP and F2-isoprostane concentrations with increasing quintiles of the Paleolithic and Mediterranean diet scores. The multivariable-adjusted ORs comparing those in the highest with those in the lowest quintiles of the Paleolithic and Mediterranean diet scores were 0.61 (95% CI: 0.36, 1.05; P-trend = 0.06) and 0.71 (95% CI: 0.42, 1.20; P-trend = 0.01), respectively, for a higher hsCRP concentration, and 0.51 (95% CI: 0.27, 0.95; P-trend 0.01) and 0.39 (95% CI: 0.21, 0.73; P-trend = 0.01), respectively, for a higher F2-isoprostane concentration.

Conclusion: These findings suggest that diets that are more Paleolithic- or Mediterranean-like may be associated with lower levels of systemic inflammation and oxidative stress in humans.

Keywords: C-reactive protein; F2-isoprostanes; Mediterranean diet; Paleolithic diet; cross-sectional study; diet patterns; inflammation; oxidative balance.

FIGURE 1

Inclusion criteria and sample availability, pooled MAPI and MAPII studies. hsCRP, high-senstivity C-reactive protein; MAPI, Markers of Adenomatous Polyps I; MAPII, Markers of Adenomatous Polyps II.

FIGURE 2

Associations of the Paleolithic (A) and Mediterranean (B) diet scores with plasma hsCRP concentrations, according to selected participant characteristics; pooled MAPI and MAPII studies. From an unconditional ordinal logistic regression model; only the comparison of quintile 5 relative to quintile 1 of each diet score with the sex-specific quintiles of the biomarkers is shown. Model covariates included study (MAPI or MAPII), regular NSAID or aspirin use (≥4 times/wk), age, total energy intake (kilocalories), current hormone replacement use (in women), sex, smoking (current or former and never), BMI (in kg/m²; categorized by WHO criteria into underweight, normal, overweight, and obese), education level (no college education or some college education), physical activity level (high or low based on the median weekly metabolic equivalent task–h/wk expenditure in the pooled population), regular multivitamin use (≥3 times/wk), and season of the year the FFQ was completed. hsCRP is categorized into sex-specific quintiles from the pooled study population. P-trend was calculated by assigning the median of each diet score quintile to each quintile, and treating this quintile exposure as continuous. For each quintile of each diet score, e^β is the odds that the biomarker concentration is greater than the quintile cutoff if the diet score is in the nonreferent category compared with the odds if it is in the referent category. hsCRP, high-sensitivity C-reactive protein; MAPI, Markers of Adenomatous Polyps I; MAPII, Markers of Adenomatous Polyps II; NSAID, nonsteroidal anti-inflammatory drug.

FIGURE 3

Associations of the Paleolithic (A) and Mediterranean (B) diet scores with FIP concentrations, according to selected participant characteristics; pooled MAPI and MAPII studies. From an unconditional ordinal logistic regression model; only the comparison of quintile 5 relative to quintile 1 of each diet score with the sex-specific quintiles of the biomarkers is shown. Model covariates included study (MAPI or MAPII), regular NSAID or aspirin use (≥4 times/wk), age, total energy intake (kilocalories), current hormone replacement use (in women), sex, smoking (current or former and never), BMI (in kg/m²; categorized by WHO criteria into underweight, normal, overweight, and obese), education level (no college education or some college education), physical activity level (high or low based on the median weekly metabolic task equivalent–h/wk expenditure in the pooled population), regular multivitamin use (≥3 times/wk), and season of the year the FFQ was completed. FIPs are categorized into sex-specific quintiles from the pooled study population. P-trend was calculated by assigning the median of each diet score quintile to each quintile, and treating this quintile exposure as continuous. For each quintile of each diet score, e^β is the odds that the biomarker concentration is greater than the quintile cutoff if the diet score is in the nonreferent category compared with the odds if it is in the referent category. FIP, F₂-isoprostane; MAPI, Markers of Adenomatous Polyps I; MAPII, Markers of Adenomatous Polyps II; NSAID, nonsteroidal anti-inflammatory drug.