![]() However, all these human studies were either not placebo controlled ( 22, 24– 27), not blinded ( 19– 21, 24), not randomized ( 23, 24), or used a “before and after” design ( 22). In 2 other studies, 100–500 mg/d glucosyl-hesperidin in tablets had either no effect on LDL-C ( 26) or lowered it significantly only in hypertriglyceridemic individuals and after 8 wk of consumption ( 27). A study with pure naringin (400 mg/d in capsules consumed with meals) showed reductions in TC (−14%), LDL-C (−17%), and TG (−14%) concentrations in hypercholesterolemic participants ( 25). Three studies in which hypercholesterolemic ( 22, 23) or healthy individuals ( 24) consumed between 240 and 750 mL/d of orange juice (a source of hesperidin), however, did not show an effect on TC and LDL-C concentrations. The consumption of 1–2 peeled Jaffa grapefruits or Sweeties or 100–200 mL fresh Sweetie juice/d reduced plasma TC (−8 to −16%), LDL-cholesterol (LDL-C) (−11 to −21%), and TG (−12 to −27%) and increased HDL-cholesterol (HDL-C) (+2 to +3%) in coronary atherosclerosis patients ( 19– 21). The evidence in humans comes mainly from studies in which citrus fruits/juices rich in hesperidin or naringin were tested for their lipid-lowering properties. In vitro experiments did not confirm a direct effect of hesperidin or naringin on hydroxy-3-methylglutaryl-CoA reductase activity ( 9, 10, 16) but did suggest that hesperidin and naringin may reduce acyl-CoA: cholesterol acyltransferase-2 and microsomal triglyceride (TG) transfer protein mRNA ( 16) as well as the secretion of apolipoprotein B-100 (the apolipoprotein of LDL particles) ( 14, 17), while increasing LDL receptor mRNA ( 16, 18). Studies in animal models showed a depressing effect on 3-hydroxy-3-methylglutaryl-CoA reductase and acyl-CoA: cholesterol acyltransferase activities in the liver ( 3, 5, 9, 10, 12, 15), an upregulation of gene expression of key regulators of liver β-oxidation ( 13, 14), and an increase in the excretion of bile acids ( 3, 5– 7), whereas effects on neutral sterol excretion were inconsistent ( 3, 4, 6, 7, 9, 10, 12). The pathways involved in the potential hypolipidemic properties of hesperidin/hesperetin and naringin/naringenin are not yet fully understood. The evidence for the cholesterol-lowering effect of hesperidin/hesperetin in animal models is scarcer ( 9, 12). Pure naringin or naringenin, naringin-rich grapefruit juices, peels, or peeled grapefruits reduced plasma total cholesterol (TC) 4 (−14 to −55%) and hepatic cholesterol concentrations in various animal models ( 3– 14). The colon microflora has the ability to hydrolyze the flavonoid glycosides hesperidin and naringin to generate the corresponding aglycones called naringenin and hesperetin, respectively ( 2). Naringin is mainly present in grapefruits and sour oranges, and hesperidin is present in sweet oranges, mandarins and lemons ( 1). These flavonoids exist mainly in their glycoside form in plants. In conclusion, pure hesperidin and naringin consumed in capsules at mealtime do not lower serum TC and LDL-C concentrations in moderately hypercholesterolemic men and women.Ĭitrus flavonoids such as naringin and hesperidin have been proposed in the literature as potential blood cholesterol-lowering ingredients. These citrus flavonoids also did not affect serum HDL-cholesterol and triglyceride concentrations. Hesperidin and naringin did not affect TC or LDL-C, with endpoint LDL-C concentrations (adjusted for baseline) of 4.00 ± 0.04, 3.99 ± 0.04, and 3.99 ± 0.04 mmol/L for control, hesperidin, and naringin groups, respectively. In all groups, the mean consumption of scheduled capsules was gt 99%. They maintained their prestudy body weights (mean changes lt 0.2 kg in all groups). ![]() One hundred ninety-four participants completed the study. ![]() Blood samples to measure serum lipids were taken on 2 consecutive days at the beginning and end of the intervention phase. During the 4-wk intervention, the participants applied the same dietary restrictions and consumed 4 capsules/d providing either placebo (cellulose) or a daily dose of 800 mg hesperidin or 500 mg naringin. A 4-wk preintervention period during which participants refrained from consuming hesperidin and naringin sources preceded the intervention. A total of 204 healthy men and women with a serum TC concentration of 5.0–8.0 mmol/L participated in a randomized, placebo-controlled, parallel trial with 3 groups. This study evaluated the LDL-C–lowering efficacy of pure hesperidin and naringin in moderately hypercholesterolemic individuals. However, the evidence from previous studies in humans is not convincing. The citrus flavonoids hesperidin and naringin have been suggested to lower blood total (TC) and LDL-cholesterol (LDL-C) both in animal models and humans. ![]()
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