Four weeks of spice consumption lowers plasma proinflammatory cytokines and alters the function of monocytes in adults at risk of cardiometabolic disease: secondary outcome analysis in a 3-period, randomized, crossover, controlled feeding trial

Ester S Oh, Kristina S Petersen, Penny M Kris-Etherton, and Connie J Rogers

Objective
The aim of this study was to examine the effect of longer-term spice consumption on inflammatory cytokines and monocyte subsets [classical (CM), intermediate (IM), nonclassical (NCM)] in adults at risk of cardiometabolic disease.

Methods
A 3-period, randomized, crossover, controlled feeding trial was conducted. Participants (n= 71 recruited; n = 63 completed) randomly consumed diets differing in terms of the quantity of spices: 0.547 g (low-dose spice diet; LSD), 3.285 g (medium-dose spice diet; MSD), or 6.571 g (high-dose spice diet; HSD) per day per 2100 kcal for 4 weeks with a ≥2-week washout between diets. At baseline and after each diet period, proinflammatory cytokines (IL-1β, IL-6, IL-8, monocyte chemoattractant protein-1, and TNF-α) in plasma and LPS-stimulated peripheral blood mononuclear cell culture supernatants, and the phenotype and function of monocyte subsets, were measured in fasted participants. Postprandial proinflammatory cytokines also were quantified at baseline by consumption of a low-spice-dose test meal, and after each diet period by consumption of a test meal containing a spice dose corresponding to daily spice consumption during the preceding 4-week diet period.

Results
Fasting plasma IL-6 was reduced (mean ± SEM: −118.26 ± 50.63 fg/mL; P < 0.05) after MSD compared with baseline. Postprandial plasma IL-1β, IL-8, and TNF-α were lower (mean ± SEM: −9.47 ± 2.70 fg/mL, −0.20 ± 0.05 pg/mL, and −33.28 ± 12.35 fg/mL, respectively) after MSD compared with LSD (main diet effect; P < 0.05). CM adherence was reduced (mean ± SEM: −0.86 ± 0.34; P = 0.034) after HSD compared with LSD. IM migration was reduced after MSD and HSD compared with LSD (mean ± SEM: −0.39 ± 0.09 and −0.56 ± 0.14, respectively; P < 0.05).

Conclusions
Four weeks of consuming a medium-dose spice diet reduced fasting plasma IL-6 and postprandial plasma IL-1β, IL-8, and TNF-α as well as altering monocyte function.

Reference
Oh, ES, Petersen, KS, Kris-Etherton, PM, Rogers, CJ. Four weeks of spice consumption lowers plasma proinflammatory cytokines and alters the function of monocytes in adults at risk of cardiometabolic disease: secondary outcome analysis in a 3-period, randomized, crossover, controlled feeding trial. The American Journal of Clinical Nutrition. 115(1): 61.72. 2022.