A major international study suggests that people who regularly eat garlic have lower odds of several chronic diseases, including cancer, diabetes and cardiovascular disease, while additional research points to potential benefits for liver health, cognitive function and blood pressure.

By yourNEWS Media Newsroom

A common kitchen ingredient used for thousands of years in traditional medicine may offer benefits extending beyond its culinary value, according to research linking regular garlic consumption to lower rates of several major chronic diseases.

A study published in August 2025 in the scientific journal Health Care Science examined dietary patterns and health information from 175,866 participants in China and the United Kingdom. Researchers found that people who consumed garlic frequently generally had lower odds of developing or having conditions including cancer, diabetes, high blood pressure, cardiovascular disease and respiratory illnesses.

The strongest associations emerged from a Chinese longevity study, where participants reporting garlic consumption almost every day had 49% lower odds of cancer, 42% lower odds of diabetes and 31% lower odds of cardiovascular disease compared with those in the reference consumption group.

The findings add to growing scientific interest in garlic’s naturally occurring sulfur compounds, which have demonstrated antioxidant, anti-inflammatory and other biological activities in laboratory research.

However, researchers emphasized that the findings were observational, meaning they identified relationships between dietary habits and health outcomes rather than establishing that garlic directly prevents disease.

The study, titled Dietary Pattern of Garlic and Risk of Chronic Diseases: Evidence From Three Large-Scale Cohorts, was conducted by researchers including Xiaoyu Tai, Tao Luo and Keying Song and published Aug. 3, 2025.

The investigation combined data from three population studies: the Chinese Longitudinal Healthy Longevity Survey, involving 26,524 participants; the Xinjiang Multiethnic Cohort, involving 7,658 participants; and the UK Biobank, which contributed information from 141,684 participants.

By examining populations with different dietary habits, researchers sought to determine whether the relationship between garlic consumption and chronic disease appeared consistently across distinct groups.

The Chinese longevity survey measured how frequently participants ate garlic, while the Xinjiang study evaluated garlic intake. The UK Biobank assessed participants’ reported preference for garlic, an important distinction because enjoying garlic does not necessarily establish how much of it a person consumes.

Researchers used statistical models to examine associations between those dietary measurements and five categories of chronic illness.

In the Chinese longevity group, the results were particularly notable.

Participants who reported eating garlic almost daily had 49% lower odds of cancer, 42% lower odds of diabetes, 32% lower odds of hypertension, 23% lower odds of respiratory disease and 31% lower odds of cardiovascular disease.

Those figures represent relative differences in the study’s statistical estimates, not the absolute probability that an individual will develop a disease. They also do not mean that adding garlic to an otherwise unchanged diet will produce equivalent reductions in risk.

The Xinjiang cohort showed similar associations involving hypertension, respiratory disease and cardiovascular disease, while the UK Biobank results linked a preference for garlic with lower odds of diabetes and cardiovascular disease.

The consistency of several findings across the cohorts suggests a possible connection worth investigating further, although differences in dietary measurements and lifestyle characteristics complicate direct comparisons.

People who regularly consume garlic may also eat more vegetables, follow different overall dietary patterns, exercise more or engage in other health-related behaviors that influence disease risk.

Researchers attempted to account for several such factors through statistical adjustments, but observational studies cannot eliminate every potential source of confounding.

Consequently, the results provide evidence of an association rather than proof that garlic prevents cancer, diabetes or heart disease.

The findings nevertheless contribute to a substantial body of research exploring the biological activity of garlic, scientifically known as Allium sativum.

Garlic contains organosulfur compounds, including alliin, which undergoes chemical changes when a clove is crushed, chopped or chewed.

Breaking the clove’s cellular structure allows the enzyme alliinase to interact with alliin, producing allicin, one of the compounds responsible for garlic’s characteristic aroma.

Allicin is chemically unstable and can transform into other sulfur-containing substances, including diallyl disulfide and diallyl trisulfide.

These compounds have attracted scientific interest because laboratory studies indicate they can influence cellular processes associated with oxidative stress, inflammation and metabolism.

Oxidative stress occurs when reactive molecules accumulate faster than the body’s protective systems can neutralize them, potentially damaging cellular structures.

Inflammation, meanwhile, is a normal component of the immune response but can contribute to disease when it becomes persistent or excessive.

Researchers have investigated whether garlic-derived compounds can affect those processes in ways that might support cardiovascular, metabolic or other aspects of health.

Laboratory findings provide possible explanations for garlic’s biological activity, but they do not automatically establish that consuming ordinary amounts of garlic produces the same effects in humans.

One area receiving particular attention is liver health.

A population-based study published in 2019 examined raw garlic consumption among 24,106 Chinese adults, including 11,326 men and 12,780 women.

The researchers assessed dietary patterns using food-frequency questionnaires and evaluated participants for nonalcoholic fatty liver disease, a condition involving excess fat accumulation in the liver.

According to the study published in the journal European Journal of Endocrinology, men who consumed raw garlic four to six times weekly had approximately 34% lower odds of newly diagnosed fatty liver disease compared with men consuming it less than once a week.

Men who ate raw garlic at least seven times weekly also showed an inverse association, although the estimated difference was somewhat smaller.

The same statistically significant relationship was not observed among women.

The researchers did not establish why the associations differed by sex, and the findings do not demonstrate that garlic can prevent or reverse fatty liver disease.

Nevertheless, they raised the possibility that garlic consumption may relate to metabolic processes involved in liver fat accumulation.

Separate clinical research has investigated garlic powder supplements among patients with fatty liver disease, including whether supplementation affects blood measurements commonly used to assess liver injury.

Some studies have reported improvements in alanine aminotransferase, or ALT, and aspartate aminotransferase, or AST.

These enzymes can become elevated when liver cells are injured, although abnormal levels may have multiple causes and do not independently establish the severity of liver disease.

Researchers have proposed that garlic’s effects on lipid metabolism, insulin sensitivity and inflammation could help explain favorable changes observed in some investigations.

However, clinical studies have generally involved relatively small groups or limited treatment periods, making it premature to conclude that garlic supplements are an established treatment for fatty liver disease.

Garlic’s possible effects on the digestive system have also attracted attention.

Certain sulfur-containing compounds, including diallyl disulfide, have demonstrated anti-inflammatory activity in laboratory experiments.

Researchers studying inflammatory bowel disease have examined whether these substances could influence pathways associated with intestinal inflammation.

Inflammatory bowel disease includes conditions such as Crohn’s disease and ulcerative colitis, which involve chronic inflammation of the digestive tract.

Although experimental research has identified potential mechanisms worth exploring, evidence from human clinical trials remains insufficient to establish garlic as a treatment for either condition.

Furthermore, garlic can aggravate gastrointestinal symptoms in some individuals, particularly those sensitive to fermentable carbohydrates.

Garlic contains fructans, a type of carbohydrate that can contribute to gas, bloating and abdominal discomfort in susceptible people.

Individuals with irritable bowel syndrome or related digestive sensitivities may therefore experience symptoms after eating garlic even though the ingredient contains compounds being studied for possible health benefits.

The relationship between garlic and cardiovascular health is better studied.

High blood pressure and elevated LDL cholesterol are important risk factors for cardiovascular disease, and multiple clinical trials have examined whether garlic preparations can improve either measurement.

The National Institutes of Health’s National Center for Complementary and Integrative Health reports that garlic supplements may produce small reductions in total cholesterol and LDL cholesterol among individuals whose levels are elevated.

Limited evidence also suggests that garlic supplements may modestly reduce blood pressure in people with hypertension.

The effects, however, are generally smaller than those achieved with established medications, and available studies vary in their methods, participant characteristics and supplement formulations.

A separate NIH review of natural products for cholesterol management noted that garlic supplementation for more than two months may improve certain cholesterol measurements, but the benefits are modest compared with prescription cholesterol-lowering drugs.

Some studies have also examined aged garlic extract and fermented black garlic, which contain different combinations of sulfur compounds from fresh garlic.

Aged preparations have been investigated for possible effects on blood pressure and vascular function, including changes in diastolic blood pressure among individuals with hypertension.

Results have varied, and researchers have not established that any particular garlic preparation reliably prevents heart attacks or strokes.

This distinction is important because lowering a risk factor does not necessarily prove that a supplement prevents the disease associated with that factor.

The NIH notes that evidence remains insufficient to conclude that garlic supplements prevent cardiovascular disease, despite some favorable findings involving cholesterol and blood pressure.

Garlic’s potential effects on blood clotting have also received attention.

Certain garlic-derived compounds can influence platelet activity in laboratory studies, suggesting possible effects on the processes involved in clot formation.

However, consuming garlic should not be regarded as a proven method of preventing dangerous blood clots.

High-dose garlic supplements may increase bleeding risk, particularly among people taking anticoagulants or medications that affect platelet function.

The possible interaction becomes especially important before surgery or other medical procedures, when abnormal bleeding can create serious complications.

Beyond cardiovascular and metabolic health, researchers have explored possible relationships between garlic consumption and cognitive function.

Population studies have reported that older adults who consume garlic frequently may have lower rates of cognitive impairment and, in some analyses, greater longevity.

One investigation found that people reporting garlic consumption at least five times weekly were less likely to experience cognitive impairment than participants who consumed it less frequently.

Researchers have suggested that antioxidant and anti-inflammatory compounds in garlic could contribute to protecting nerve cells from certain forms of damage.

Some small supplementation studies have also investigated possible changes in memory, attention and related cognitive functions.

However, the available evidence does not establish that garlic prevents dementia or substantially improves cognitive performance in otherwise healthy adults.

The observed associations may be influenced by broader dietary habits, socioeconomic circumstances, general health and other lifestyle factors.

More rigorous clinical trials would be necessary to determine whether garlic itself produces measurable, lasting neurological benefits.

The relationship between garlic preparation and the formation of allicin has generated considerable interest among both scientists and home cooks.

Because alliinase becomes active when garlic cells are damaged, crushing or chopping a clove allows the chemical reaction that produces allicin to begin.

Cooking garlic immediately after chopping it can reduce the opportunity for that reaction to occur before heat begins changing the enzyme’s activity.

For that reason, some food researchers recommend allowing chopped or crushed garlic to stand for approximately 10 minutes before cooking.

The resting period can permit additional allicin formation before the garlic is exposed to high temperatures.

Heat affects alliinase activity and accelerates the transformation of allicin into other sulfur compounds, meaning the composition of garlic changes during cooking.

However, the claim that allicin is completely destroyed at a single temperature or that a particular cooking time eliminates all useful garlic compounds oversimplifies a complex chemical process.

Allicin is only one of several biologically active substances found in garlic, and cooked garlic still contains other sulfur compounds.

There is also insufficient human evidence to establish that waiting exactly 10 minutes before cooking leads to better long-term health outcomes.

The technique may help preserve certain compounds under particular conditions, but it should not be confused with a clinically proven disease-prevention method.

People who prefer uncooked garlic can incorporate it into foods such as salad dressings, chimichurri, dips or other cold preparations.

Cooked garlic remains useful in soups, sauces, roasted vegetables and other dishes, particularly when it helps add flavor without excessive salt.

Fermented garlic preparations, including black garlic and garlic preserved in honey, have also become popular because fermentation can alter flavor and chemical composition.

However, claims that fermentation reliably preserves allicin are not well established. Different fermentation and aging processes can substantially change the concentrations of individual sulfur compounds.

There are also food-safety considerations. Garlic preserved in oil or homemade fermented preparations must be handled and stored appropriately to reduce the risk of bacterial contamination.

The findings do not mean that people need to consume garlic supplements to benefit from eating garlic-containing foods.

For most adults, culinary garlic can be incorporated into a balanced diet without significant risk.

Dietary garlic is generally well tolerated, although large amounts, particularly when eaten raw, can cause heartburn, nausea, abdominal discomfort and increased gas.

Some people also experience allergic reactions.

The NIH advises particular caution with concentrated garlic supplements because these products can deliver substantially different quantities of active compounds from those normally consumed in food.

Individuals using aspirin, warfarin or other medications affecting blood clotting should consult their health care providers before taking garlic supplements.

The same advice applies to people preparing for surgery or managing conditions that increase bleeding risk.

Pregnant and breastfeeding women can generally consume normal culinary amounts of garlic, but the safety of larger medicinal doses is less certain.

People with known garlic allergies should avoid garlic-containing products, and individuals with digestive sensitivities may need to limit intake according to their tolerance.

Those precautions underscore another important distinction in the research: studies involving ordinary dietary garlic cannot necessarily be used to justify taking high-dose garlic supplements.

The chemical composition, amount consumed and biological effects can differ substantially among fresh cloves, cooked garlic, aged extracts, powders and concentrated capsules.

Some studies also rely on self-reported consumption, which can introduce errors because participants may not accurately remember how frequently they eat a particular food.

The 2025 investigation involving nearly 176,000 participants represents a substantial contribution to understanding garlic’s possible health associations, but its findings must be considered within those limitations.

The study was not a randomized clinical trial in which participants were assigned to consume specific amounts of garlic over time and then monitored for differences in disease outcomes.

Instead, it examined existing dietary patterns and health information, allowing researchers to identify statistical relationships.

Although the analysis accounted for multiple factors, it could not establish whether garlic consumption itself caused the lower disease rates.

The evidence concerning cancer is especially important to interpret carefully.

While the Chinese longevity cohort found substantially lower odds of cancer among frequent garlic consumers, other investigations have produced mixed results.

The NIH reports that consuming garlic does not appear to reduce stomach cancer risk and that its potential effect on colorectal cancer remains uncertain.

The large differences reported in one population therefore should not be interpreted as proof that garlic provides broad protection against cancer.

Similarly, the association with diabetes does not establish that eating garlic can replace blood glucose monitoring, prescribed medications, regular physical activity or other established approaches to diabetes prevention and management.

Researchers remain interested in garlic because its diverse chemical compounds provide plausible biological mechanisms for some of the associations observed in population studies.

Further investigations may clarify which preparations are most active, how much garlic would be needed to produce meaningful effects and whether particular groups benefit more than others.

Large randomized studies would also help determine whether improvements in biological markers translate into fewer cases of chronic disease.

For now, the research supports a measured conclusion.

Garlic is an accessible, flavorful food that may contribute beneficial compounds to a varied diet. Population studies have linked frequent consumption with several favorable health outcomes, while clinical trials suggest that certain garlic preparations can modestly improve blood pressure, cholesterol and other measurements.

Those findings are promising but do not establish garlic as a substitute for medical treatment or as a proven means of preventing cancer, diabetes, heart disease or dementia.

As scientists continue investigating the relationship between garlic and long-term health, its most practical role remains as part of a balanced eating pattern that includes vegetables, fruits, whole grains and other nutrient-rich foods.

The familiar bulb may offer more than flavor, but the strongest evidence favors considering it one component of an overall healthy lifestyle rather than a stand-alone preventive medicine.

Source: Natural News

Original article