People who ate garlic almost every day had significantly lower odds of cancer, diabetes, hypertension, respiratory disease and cardiovascular disease than those who rarely ate it. The finding comes from a three-cohort study published in Health Care Science in August 2025, pooling data from nearly 176,000 adults across China and the United Kingdom.
In the Chinese Longitudinal Healthy Longevity Survey, daily garlic eaters had about 32 percent lower odds of hypertension and 31 percent lower odds of cardiovascular disease compared with those who rarely or never ate it.
Cancer odds were roughly halved, and diabetes odds were 42 percent lower. Effects were smaller in the UK Biobank arm, which measured how much people liked garlic rather than how often they ate it.
These are observational associations. They cannot prove that garlic itself drives the lower risk, only that regular eaters differ from non-eaters in these outcomes. Still, controlled trials help explain why the link keeps showing up.
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What garlic may do for your blood pressure
Randomized trials point to a modest effect on blood pressure. A 2025 meta-analysis of 10 trials in Frontiers in Nutrition found that garlic supplementation lowered systolic blood pressure by an average of 4.21 mmHg and diastolic pressure by 3.13 mmHg compared with control groups. HDL cholesterol, the type linked to lower heart risk, rose slightly across three trials. The inflammatory marker TNF-alpha also fell.
The scale of the effect matches what the National Center for Complementary and Integrative Health reports: limited evidence that garlic supplements may reduce blood pressure and total cholesterol to a small extent in people whose levels are already elevated. Welltica has previously covered garlic's blood-pressure effect in more depth.
What it may do for your immune system
A small randomized trial published in Nutrients in May 2023 gave 65 elderly volunteers either a daily capsule of concentrated garlic and onion extract or a placebo for 36 weeks. According to the authors, consumption of the Alliaceae mixture induced a significant decrease in respiratory infections, especially for influenza-like illness and the common cold, and the severity of episodes was several times lower in the treatment group.
The study is small and used a concentrated extract, not raw garlic, so the effect should not be overstated. But it fits a broader pattern in the cohort data on respiratory disease.
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What it may do for your gut
Garlic is rich in fructans, a fiber that the small intestine cannot break down. When the fibers reach the colon, certain beneficial bacteria ferment them. In a 2024 study in Nutrients, garlic treatment led to an increase in Bifidobacterium, and the researchers confirmed the prebiotic potential in laboratory cultures with Bifidobacterium adolescentis.
A practical tip and a caution
Allicin, the compound behind many of garlic's proposed effects, forms when an enzyme called alliinase acts on crushed cloves. Heat inactivates the enzyme quickly. A 1999 study by researchers at Penn State found that letting crushed garlic sit for about 10 minutes before cooking preserved more of its bioactive compounds.
There is one plain caution. NCCIH warns that garlic supplements may increase the risk of bleeding, which matters for anyone on anticoagulants or aspirin, or preparing for surgery. Anyone in that situation should talk to their doctor before adding daily garlic in supplement form.
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This article is made and published by Jesper Bengtson, who may have used AI in the preparation.