LDL-Cholesterol-Lowering Effects of a Dietary Supplement Containing Onion and Garlic Extract Used in Healthy Volunteers.

The short version

This randomized trial with 66 healthy volunteers explored whether a daily capsule combining garlic powder and a concentrated onion extract lowers LDL cholesterol, the "bad" cholesterol that builds up in artery walls and drives heart and blood vessel disease. Medicines such as statins are usually kept for people with clearly raised LDL cholesterol or several risk factors, so people with slight elevations are generally pointed toward diet and lifestyle changes. Garlic and onion contain organosulfur compounds (sulfur-rich plant chemicals), which the authors say are linked to cholesterol-lowering, antioxidant and anti-inflammatory effects. To the authors' knowledge, human research had mostly looked at garlic alone, and none had combined the two plants in one capsule. Volunteers living in Granada, Spain, with LDL cholesterol between 100 and 190 mg/dL were split at random into two groups of 33. One group took a capsule called Aliocare daily with lunch, holding 86 mg of onion extract and 14 mg of garlic powder, and the other took an identical-looking placebo of plain cellulose. Neither participants nor researchers knew who received which. Blood samples and blood pressure were checked at the start and after 2, 4 and 8 weeks, including markers of oxidation and inflammation, liver and kidney function. After 8 weeks, LDL cholesterol was 6% lower in the capsule group (4% lower at 4 weeks), and total cholesterol about 6% lower. Among those starting above 110 mg/dL, LDL cholesterol dropped 12% by week 8. Triglycerides (blood fats) also fell, while good HDL cholesterol stayed unchanged and glucose did not differ. Oxidized LDL, a form of LDL damaged by oxidation and linked to artery disease, fell about 32% by week 8. Blood pressure was about 5% lower, and no adverse events were reported, with liver and kidney tests staying in the normal range. Compliance exceeded 95%, and participants did not guess their group assignment. Interleukin-6, an inflammation marker, tended to fall with the capsule without reaching significance, and malondialdehyde, another oxidation marker, did not differ. The authors conclude the capsule was safe and improved several heart-related measures, and they suggest garlic and onion may act together, though the study did not test each plant separately. They state plainly that the volunteers were mostly young with LDL cholesterol at the low end of the range, the pandemic limited recruitment, the sample was small and the 8-week duration short. The authors add that recruiting under different conditions would likely have produced higher baseline values and more robust results. They plan larger, longer studies in people with higher LDL cholesterol.

Key findings

• In an 8-week trial of 66 healthy volunteers in Spain with slightly raised LDL cholesterol (the cholesterol that builds up in artery walls), a daily capsule of garlic powder plus standardized onion extract lowered LDL cholesterol by 4% at week 4 and 6% at week 8 compared with baseline, with no such fall in the placebo group.
• The fall in LDL cholesterol reached 12% by week 8 in volunteers who started above 110 mg/dL, and total cholesterol and triglycerides also fell, while HDL cholesterol was unchanged.
• Oxidized LDL (LDL damaged by oxidation, linked to artery disease) fell about 32% by week 8 and blood pressure fell about 5%, but malondialdehyde did not differ and interleukin-6 fell without reaching statistical significance.
• Liver and kidney tests stayed normal and no adverse events were reported; compliance exceeded 95%.
• The study was small, short, and enrolled mostly young volunteers with LDL cholesterol at the low end of the range; the authors state it did not test garlic and onion separately, so their possible synergy remains unproven.

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