Spice diet lowers proinflammatory cytokines, alters monocyte function in adults

Adherence to medium-dose spice diet (MSD) for 4 weeks results in a reduction of fasting plasma interleukin (IL)-6 and postprandial plasma IL-11β, IL-8, and tumour necrosis factor alpha (TNF-α) as well as changes in monocyte function in adults at risk of cardiometabolic disease, a study has shown.

A team of investigators conducted a three-period, randomized, crossover, controlled feeding trial. Seventy-one participants randomly consumed diets differing in terms of the quantity of spices (0.547 g [low-dose spice diet; LSD], 3.285 g [MSD], or 6.571 g [high-dose spice diet; HSD] · d⁻¹ · 2,100 kcal⁻¹) for 4 weeks, with a ≥2-wk washout between diets.

Among fasted participants, proinflammatory cytokines (IL-1β, IL-6, IL-8, monocyte chemoattractant protein-1, and TNF-α) in plasma and lipopolysaccharide-stimulated peripheral blood mononuclear cell culture supernatants and the phenotype and function of monocyte subsets were measured at baseline and after each diet period.

The investigators also quantified postprandial proinflammatory cytokines at baseline by consumption of an LSD 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.

Fasting plasma IL-6 decreased (mean, ‒118.26 fg/mL; p<0.05) after MSD relative to baseline. Postprandial plasma IL-1β (mean, ‒9.47 fg/mL), IL-8 (mean, ‒0.20 pg/mL), and TNF-α (mean, ‒33.28 fg/mL) were also lower after MSD than after LSD (main diet effect; p<0.05).

Classical monocyte adherence was lower (mean, ‒0.86; p=0.034) after HSD compared with LSD. Intermediate monocyte migration also decreased following MSD and HSD compared with LSD (mean, ‒0.39 and ‒0.56, respectively; p<0.05).