For centuries, garlic (Allium sativum) has been valued by many cultures both as a tasty food and as a traditional remedy. Recent studies have highlighted its heart health-promoting properties.

This article explores garlic’s impact on several aspects of heart and metabolic health. All claims are evidence-based and drawn from published scientific research.

Garlic for Healthier Cholesterol Levels

Improving Cholesterol

Did you know garlic can help manage your cholesterol levels?

Research shows it may decrease your total cholesterol and triglycerides while helping raise “good” HDL cholesterol.

Several clinical trials have demonstrated these benefits (1, 2, 3).

A modest 8% decrease in total serum cholesterol could translate to a 38% reduction in risk of coronary events by around age 50 (3).

Even standardized garlic powder, at approximately 900 mg/day, has been shown to help reduce total cholesterol (4).

Another review found garlic intervention might result in about a 12% reduction in total cholesterol compared to placebo (5).

Furthermore, a combination of garlic and fish oil showed stronger improvements in total cholesterol, triglycerides, LDL (“bad”) cholesterol, and the cholesterol-to-HDL ratio (9).

For those with hyperlipidemia (high cholesterol), garlic may provide additional benefits by improving cholesterol levels, body mass index (BMI), and even blood pressure (11).

Summary
Garlic may help manage cholesterol levels by lowering total cholesterol and triglycerides while raising “good” HDL cholesterol, potentially reducing the risk of heart events.

Caveats in Research

Not all studies show the same results.

Research in particular populations did not find significant cholesterol-lowering effects from garlic (6, 7, 8).

Some reviews conclude that garlic may reduce total cholesterol and triglycerides but leaving LDL and HDL largely unchanged in certain populations (10).

Tip
Consider adding 1-2 cloves of fresh garlic to your daily meals or taking a standardized garlic supplement (about 900 mg daily) after consulting with your healthcare provider, especially if you have elevated cholesterol.

Blood Pressure Regulation

Antihypertensive Effects

Hypertension (high blood pressure) is a major risk factor for cardiovascular disease.

Good news: several studies show that garlic supplementation may reduce your blood pressure for people with hypertension.

Research indicates garlic may help lower both systolic and diastolic blood pressure in people with elevated numbers (12, 13).

Aged garlic extract has been shown to lower systolic blood pressure by about 10 mmHg in patients with uncontrolled hypertension (14).

Multiple reviews and meta-analyses confirm that garlic supplementation can lower systolic blood pressure.

The findings of these studies lowered blood pressure by approximately 5-8 mmHg and diastolic blood pressure by around 3-5 mmHg in hypertensive individuals (15, 16, 17, 18).

Disclaimer
It is important to note that some research shows only modest or no measurable effect in certain populations. Researchers suggest larger, well-controlled studies are needed to further confirm garlic’s potential as a blood-pressure aid (19, 6).

Garlic’s Role in Protecting Arteries

Prevention of Plaque Formation

As plaque accumulates in your arteries over time, it increases your risk of cardiovascular issues.

Research suggests garlic may help slow or even reverse this plaque progression.

One four-year, randomized, double-blind clinical trial found that high-dose garlic powder supplements reduced atherosclerotic plaque volume in the carotid and femoral arteries (20).

Aged garlic extract has been found to offer similar benefits in slowing the progression of atherosclerosis and supporting overall vascular (endothelial) health (21).

Additionally, it helps preserve microvascular circulation, potentially lowering your overall cardiovascular risk (22).

Garlic also may reduce the oxidation of LDL particles, a key factor in plaque buildup (23).

Tip
For potential anti-atherosclerotic benefits, consider aged garlic extract supplements, which have shown promising results in clinical studies. Look for products standardized for S-allylcysteine content and follow the manufacturer’s recommended dosing.

Effects on Coronary Artery Calcification

Calcium deposits in coronary arteries (calcification) raise the risk of heart disease.

Studies suggest that aged garlic extract may help slow or reduce these deposits.

In a prospective randomized, double-blind study involving patients with metabolic syndrome, garlic significantly reduced “low-attenuation plaque,” a particularly harmful type (24).

Garlic powder supplements may also help limit the thickening of the carotid artery wall (25).

Combining aged garlic extract with certain micronutrients may further reduce coronary calcium progression, possibly indicating more stable plaque (26).

Blood Flow Benefits of Garlic

Inhibition of Platelet Aggregation

Platelets are small blood cells that bind together to create clots.

When they aggregate excessively, they can lead to heart attacks or strokes.

Research indicates that garlic’s organosulfur compounds may reduce platelet aggregation (27).

Clinical trials back this up: garlic powder tablets have been shown to reduce the formation of circulating platelet aggregates (28).

Note
A systematic review concluded that while many studies show garlic helps inhibit platelet aggregation, findings vary, suggesting a need for more uniform research (29).

Circulation Enhancement

Garlic may further promote healthy circulation by boosting the body’s ability to dissolve blood clots.

One study found that garlic supplementation improved overall blood fluidity and elevated natural clot-dissolving activity (30).

Another study showed that dried garlic powder significantly increased a key enzyme in breaking down blood clots, while reducing harmful platelet-release markers (31).

Note
If you’re looking to improve your circulation naturally, adding garlic to your diet may help. However, if you’re taking blood-thinning medications, always consult your doctor before starting garlic supplements as they may enhance the effect of these drugs.

Antioxidant and Anti-Inflammatory Properties

Reduction of Oxidative Stress

Oxidative stress and excess free radicals can harm blood vessels.

Garlic has demonstrated antioxidant effects in many studies.

One systematic review and meta-analysis reported that garlic supplementation significantly increased total antioxidant capacity and lowered markers of oxidative stress (32).

In patients with type 2 diabetes, aged garlic extract demonstrated notable antioxidant properties, though some findings were mixed (33).

By limiting LDL oxidation and scavenging free radicals, garlic may reduce the risk of plaque buildup (23).

Anti-Inflammatory Effects

Chronic inflammation is a known contributor to heart disease.

Multiple studies link garlic intake to lower levels of inflammatory markers.

These include C-reactive protein (CRP) and cytokines, both of which signal the immune system to do its job.

These improvements have been observed in diverse groups, including pregnant women at risk for pre-eclampsia (34).

A systematic review of 16 randomized controlled trials reported that garlic supplementation significantly lowered CRP and other cytokines in adults (35).

Higher doses of garlic (≥1200 mg/day) were most effective at lowering CRP according to another meta-analysis (36).

Even in patients with serious conditions like those on dialysis, garlic extract supplementation significantly reduced inflammatory markers (37).

Tip
To harness garlic’s antioxidant and anti-inflammatory properties, aim to include fresh garlic in cooking regularly or consider taking a high-quality garlic supplement. For maximum benefit, crush or chop fresh garlic and let it sit for 10-15 minutes before cooking to allow the beneficial compounds to form.

Management of Metabolic Syndrome and Diabetes

Garlic has been found to assist in managing metabolic concerns like high cholesterol, high blood pressure, and weight management (11).

For those with type 2 diabetes, studies show garlic may lower fasting blood sugar, total cholesterol, and LDL while sometimes raising HDL (38, 39).

One study noted an 11.6% drop in fasting blood glucose and improved blood pressure among subjects taking garlic (40).

In another trial, time-released garlic tablets decreased fasting blood sugar, fructosamine, and serum triglycerides in patients with type 2 diabetes (41).

Tip
For those with diabetes or metabolic syndrome, adding garlic to your management plan might be beneficial. Aim for 2 grams of fresh garlic daily (about 1-2 cloves) or ask your healthcare provider about garlic supplements. Remember that garlic should complement, not replace, your prescribed medications.

Risks and Side Effects

Adverse Effects

Garlic is generally well-tolerated, with only mild side effects in most cases.

In a study of patients on warfarin, aged garlic extract did not cause serious bleeding events.

Some participants, however, reported minor complaints such as headaches or fatigue, which were comparable to placebo (42).

Some people notice a garlic odor when taking supplements.

One trial reported that around 21% of users experienced this smell, though very few quit taking garlic tablets because of it (43, 7).

Drug Interactions

Garlic can interact with certain medications for cardiovascular conditions, such as blood thinners and cholesterol-lowering drugs.

Researchers have pointed out that many dietary supplements, including garlic, may change how the body absorbs and metabolizes these medications (44, 45, 46).

Conclusion

A wide body of research shows that garlic can promote heart health through several mechanisms.

It produces modest but significant improvements in total and LDL cholesterol levels.

It supports blood pressure control, particularly in hypertension.

Garlic may help slow plaque buildup in the arteries.

It also provides beneficial effects on platelet function, oxidative stress, and inflammation.

Individual responses to garlic vary, as do the benefits from different garlic preparations.

Larger-scale studies are needed to clarify which forms of garlic are best for particular cardiovascular benefits.

Garlic is considered safe and well-tolerated for most people.

Some might experience minor issues like garlic odor or mild stomach upset.

If taking medications, especially blood thinners, consult your healthcare provider before adding garlic supplements to your daily routine.

With its long history of culinary and medicinal use and growing scientific support, garlic deserves consideration as part of a heart-healthy lifestyle.

Was this article helpful?