Citrus Bergamot

Foundational bergamot polyphenol study showing that BPF administered orally for 30 days reduced total cholesterol, LDL cholesterol, and triglycerides while raising HDL cholesterol in patients with hyperlipidemia. The 500 mg dose produced significant reductions in the pure hyperlipidemia group, and the 1000 mg dose produced additional benefit in patients with concurrent hyperglycemia. BPF also reduced blood glucose in the hyperglycemia subgroup. In the animal model, BPF inhibited HMG-CoA reductase activity and enhanced reactive vasodilation. This trial established the initial dose-response framework for bergamot polyphenol supplementation in lipid management.

First comprehensive systematic review of bergamot effects on lipid profile in humans. Twelve qualifying studies showed that 75% reported significant reductions in total cholesterol, LDL cholesterol, and triglycerides. LDL reductions ranged from 7.6% to 40.8%, total cholesterol reductions from 12.3% to 31.3%, and triglyceride reductions from 11.5% to 39.5%. Eight of twelve studies also reported significant HDL improvements. The review noted substantial heterogeneity in bergamot formulations, doses, and study designs across the included trials. Most studies originated from Italian research groups, raising concerns about limited geographic and investigator diversity. The authors emphasized the need for larger, well-designed, multicenter RCTs with standardized bergamot preparations to confirm these findings.

Combined mechanistic and clinical study demonstrating that a standardized whole-fruit bergamot extract reduces cholesterol through AMPK activation. In vitro, the extract stimulated AMPK phosphorylation at Thr172 in HepG2 liver cells, reducing intracellular cholesterol and triglyceride content and downregulating key lipid synthesis genes including HMG-CoA reductase (HMGCR), SREBF1c, SREBF2, and fatty acid synthase (FASN). In the human RCT component, 50 moderately hypercholesterolemic adults taking 400 mg/day for 12 weeks showed significant reductions in total and LDL cholesterol compared with placebo. This study is notable for directly linking in vitro AMPK-mediated mechanism with clinical lipid outcomes in the same investigation, strengthening the mechanistic rationale for bergamot polyphenol supplementation.

Most recent well-designed RCT of bergamot extract for lipid management. In 64 hypercholesterolemic adults, a standardized bergamot flavonoid extract at 150 mg/day produced progressive LDL cholesterol reductions of 7.2% at 2 months, 8.8% at 3 months, and 11.5% at 4 months. Total cholesterol decreased by 8.8% at 4 months. The study also measured oxidized LDL and paraoxonase (PON1) activity as markers of LDL oxidation burden. Safety markers including hepatic and renal function were monitored throughout. The progressive dose-time response pattern is consistent with HMG-CoA reductase inhibition building over weeks. The magnitude of LDL reduction at the 150 mg flavonoid dose is more modest than earlier studies using higher BPF doses (500-1000 mg), which is consistent with dose-dependent effects. The study used rigorous double-blind placebo-controlled design and monthly monitoring, which adds confidence despite the modest sample size.

This small RCT tested a nutraceutical combining bergamot polyphenol fraction and Cynara cardunculus (artichoke) extract at 300 mg/day versus placebo for 12 weeks in 32 adults with NAFLD and endothelial dysfunction. The treatment group showed significantly greater improvement in reactive hyperemia index (0.58 vs 0.13, P=0.02), indicating improved endothelial function. The study is limited by its small sample size and combination product design, which makes it impossible to attribute the effect to bergamot alone. However, it adds to the broader evidence that bergamot polyphenols may support vascular health beyond lipid effects.