Table 7. Overview of recent clinical trials testing quercetin with respect to diabetic and inflammatory markers .

Treatment group	Dose; duration	Ref.	Effect of quercetin
20 athletes	1000 mg quercetin t.w. 1000 mg Vitamin C, 40 mg niacinamide 120 etc.; once	(133)	No postexercise inflammation or immune changes
334/333 non-smoking, un-treated sarcoidosis patients	500/1000 mg quercetin (t.w. 125/250 mg Vit. C and 5/10 mg niacin)/d; 2 w	(134)	Little reduction in HDL cholesterol level and IL-6
12 sarcoidosis patients	2000 mg quercetin within 24 h	(135)	Increase in TAC, decrease in serum MDA, TNFa/IL- 10 and IL-8/IL-10 ratio, no effect on serum glutathione
6 healthy females	150 mg quercetin; once	(136)	No changes for respiratory quotient, resting energy expenditure, pulse or blood pressure
38/40 healthy females	500/1000 mg quercetin/d; 12 w	(137)	No influence on innate immune function or inflammatory markers IL-6 and TNF-α or body fat
93 ow patients with MetS	150 mg quercetin/d; 6 w	(138)	Reduction of blood pressure, plasma oxidized LDL, and TNF-α (dependent on apolipoprotein E genotype)
20 rheumatoid arthritis patients	498 mg quercetin (t.w. 399 mg Vit. C)/d; 4 w	(139)	No significant change of inflammation markers in blood
93 ow with MetS	150 mg quercetin/d; 6 w	(140)	Reduction of blood pressure, serum HDL-cholesterol, and oxidized LDL plasma concentration; no effect on TNF-α
35 healthy participants	50–150 mg quercetin/d; 2 w	(141)	No effect on TNF-α and oxidized LDL- concentration; no significant change of body composition, resting energy expenditure serum lipids, and lipoproteins
47 T2DM patients	Received oral quercetin (250 mg/d) or identical placebo (cellulose) capsules for 8 w	(142)	Improvement of TAC and reduction of serum concentration of atherogenic oxidized LDL

Ow: overweight; MetS: metabolic syndrome; T2DM: Type 2 diabetes mellitus; d: days; w: weeks; t.w.: together with; IL: interleukin; TNFα: tumor necrosis factor α; TAC: total antioxidant capacity; MDA: Malondialdehyde