Garlic: Nutrition, Health Benefits, and Downsides

Garlic is an excellent flavor-enhancer and contains a range of compounds that may offer benefits. These include sulfur compounds such as allicin, polyphenols, and nutrients like vitamin C, manganese, B vitamins, and selenium.

Extensive research has investigated the potential health effects of garlic, with several large reviews finding it may help lower blood pressure and blood cholesterol. However, much of this research is mixed and was conducted using garlic supplements rather than whole-food garlic.

It is also possible that garlic may have some potential drawbacks when consumed in larger amounts due to its FODMAP content, which may lead to gastrointestinal symptoms in individuals with IBS.

In this article, we examine the full nutritional profile of garlic and tell you exactly what research has found on its potential benefits and downsides.

Health Benefits

Here we’ll list some of the potential health benefits of consuming garlic, and how strong the evidence supporting it is.

Rich in Vitamins and Minerals

Like most vegetables, garlic contains a good range of vitamins and minerals. Per 100 grams, the most notable of these in raw garlic include:

• Vitamin B6: 73% DV
• Manganese: 73% DV
• Vitamin C: 35% of the Daily Value (% DV)
• Copper: 33% DV
• Selenium: 26% DV
• Calcium: 14% DV

Source: USDA – Raw garlic

These may seem like high nutrient levels, but remember that a typical serving size of garlic may be significantly smaller than 100 grams.

This is because garlic is often used in small amounts for flavoring dishes. However, some people do enjoy eating roasted or pan-fried garlic in larger amounts, so the amount of these nutrients you get will depend on the amount of garlic.

May Lower Blood Pressure

Research has indicated that garlic may help to support healthier blood pressure levels:

A 2025 systematic review of 10 randomized controlled trials investigated whether long-term garlic consumption was safe and effective in patients with hypertension. The results indicated that garlic may help reduce blood pressure, particularly in individuals with obesity or high baseline diastolic blood pressure.

The results of this study were similar to those of an earlier meta-analysis of 12 studies, which involved 553 participants with hypertension. The meta-analysis found that garlic supplementation significantly lowered both systolic and diastolic blood pressure.

May Help Improve Blood Sugar Control

Some research has also linked garlic to potential blood sugar benefits, though the evidence is mixed. Here’s what some of the latest studies show:

• A 2026 systematic review of 27 randomized controlled trials found that garlic supplementation modestly reduced fasting blood sugar levels. The average reduction in fasting blood sugar across the studies was 2.76 mg/dL.
• An earlier 2026 systematic review analyzed how garlic supplementation impacted the health of participants with type 2 diabetes. The review found evidence for a “significant decrease” in fasting blood sugar.
• A previous 2024 systematic review of 22 studies had similar findings, noting that garlic supplementation was effective for managing fasting blood glucose levels.

However, it should be noted that garlic supplements were used rather than whole garlic.

Additionally, the authors of these systematic reviews noted the need for high-quality, larger studies with more participants to confirm the results.

Can Garlic Lower Cholesterol?

Recent research has also looked into the effect of garlic on hyperlipidemia, which is otherwise known as high cholesterol.

• A 2024 systematic review found that garlic intake lowered LDL-C, total cholesterol, and triglycerides in participants with high cholesterol levels. However, the effects were more significant from garlic oil and garlic tablets compared to powder.
• A 2023 systematic review also found that garlic had a beneficial impact on several markers of cardiovascular health in patients with coronary artery disease. Most notably, reductions in LDL-C and total cholesterol were observed.

Again, these studies focused on garlic supplementation, and the fact that garlic oil and garlic tablets had significantly different effects to garlic powder shows how the form matters.

It is less clear if simply eating whole garlic can have the same effect. However, the research does show that garlic contains bioactive compounds that may beneficially impact processes involved in cardiovascular health.

May Support Heart Health

Due to positive research on garlic’s influence on cardiovascular risk markers like blood pressure, fasting blood sugar, and LDL-C, it may help to support cardiovascular health.

A 2026 systematic review analyzed results from 108 studies on garlic intake and cardiovascular risk markers. In view of the total evidence analyzed, the review noted that garlic “significantly improves key cardiovascular risk markers” and may support cardiovascular health.

Contains Beneficial Sulfur Compounds

It is thought that some of the potential benefits of garlic may partly come from its allicin content.

Garlic contains numerous sulfur compounds, including S-allylcysteine and alliin, but allicin is among the most well-researched.

In animal research conducted on allicin, it has been found to have antihypertensive properties; it can relax blood vessels, which may lower blood pressure.

Since allicin is thought to also possess antioxidant properties, this compound may play a role in garlic appearing to improve cardiovascular risk markers.

Garlic Intake and Cancer Risk

Garlic is part of the allium family of vegetables, alongside vegetables such as chives, leeks, onions, and shallots.

Some observational research has linked allium vegetables, including garlic, to a lower risk of specific cancers due to the purported anticancer properties of the sulfur compounds they contain.

For example, a 2022 systematic review of observational studies found an association between garlic intake and a lower risk of gastrointestinal cancer. However, the authors noted that further research is necessary to validate the findings, and the study found an association rather than confirming any kind of causal effect.

Notably, another systematic review found no evidence to support allium vegetable intake or garlic supplementation influencing cancer risk.

Due to the lack of strong evidence, any claims that garlic lowers cancer risk should be viewed with caution.

Does Garlic Have Any Downsides?

Garlic may have some potential drawbacks that affect a small subset of people, as detailed in the following sections.

Rare Allergies

Genuine allergies to garlic are very rare, but they do exist.

A study published in the Journal of Allergy and Clinical Immunology found that 132 people out of 13,000 people recorded in an allergy register reported an allergy to garlic. Among these people, 74% tested positive for a garlic allergy by a skin prick test.

This was less than 1% of people out of a group with reported allergies, so the true prevalence rate in the general public is likely to be lower.

As with any suspected allergy, seek advice from your healthcare provider if you suspect an allergy to garlic.

Gastrointestinal Distress

Garlic is one of several FODMAP vegetables:

• FODMAP meaning: The abbreviation stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols (FODMAP).
• What are FODMAPs: They are types of carbohydrates and sugars that are not digested in the same way as typical starches and sugars, instead being fermented by bacteria in the gut. Fructans are the main FODMAP in garlic.
• Why this matters: Some people, particularly those with irritable bowel syndrome (IBS), can experience gastrointestinal discomfort from gases produced by the fermentation of FODMAP foods. This can include symptoms such as bloating, abdominal pain, and diarrhea.

It is unlikely that a small amount (like a clove or two) of garlic used for flavoring would cause notable issues. However, larger intakes of garlic would be more likely to affect susceptible individuals.

Anyone experiencing gastrointestinal distress following garlic consumption should seek guidance from their healthcare provider.

Complete Nutrition Facts

For anyone who wishes to know the full nutritional profile of garlic, the following information shows the typical amount of each macronutrient, vitamin, and mineral.

The data is presented per 100g and per 3 cloves (9g), and we have calculated Percent Daily Values (% DV) rounded to the nearest whole percent for each nutrient.

Source: USDA – Garlic, raw

Calories and Macronutrients

Nutrient	Per 100g (% DV)	Per 3 cloves (9g) (% DV)
Calories	149 kcal	13 kcal
Carbohydrates	33.1g (12%)	2.98g (1%)
Fiber	2.1g (8%)	0.19g (1%)
Sugars	1.0g	0.09g
Fat	0.5g (1%)	0.05g (<1%)
Saturated fat	0.09g (<1%)	0.01g (<1%)
Monounsaturated fat	0.01g	<0.01g
Polyunsaturated fat	0.25g	0.02g
Omega-3	0.02g	<0.01g
Omega-6	0.23g	0.02g
Protein	6.36g (13%)	0.57g (1%)
Cholesterol	0 mg (0%)	0 mg (0%)

Vitamins

Vitamin	Per 100g (% DV)	Per 3 cloves (9g) (% DV)
Vitamin A (RAE)	0 mcg (0%)	0 mcg (0%)
Vitamin C	31.2 mg (35%)	2.81 mg (3%)
Vitamin D	0 mcg (0%)	0 mcg
Vitamin E	0.08 mg (<1%)	<0.01 mg (<1%)
Vitamin K	1.7 mcg (1%)	0.15 mcg (<1%)
Thiamin (B1)	0.2 mg (17%)	0.02 mg (2%)
Riboflavin (B2)	0.11 mg (8%)	0.01 mg (1%)
Niacin (B3)	0.7 mg (4%)	0.06 mg (<1%)
Pantothenic acid (B5)	0.60 mg (12%)	0.05 mg (1%)
Vitamin B6	1.24 mg (73%)	0.11 mg (6%)
Folate (B9)	3 mcg (1%)	0.27 mcg (<1%)
Vitamin B12	0 mcg (0%)	0 mcg (0%)
Choline	23.2 mg (4%)	2.09 mg (<1%)

Mineral	Per 100g (% DV)	Per 3 cloves (9g) (% DV)
Calcium	181 mg (14%)	16.3 mg (1%)
Iron	1.7 mg (9%)	0.15 mg (1%)
Magnesium	25 mg (6%)	2.25 mg (1%)
Phosphorus	153 mg (12%)	13.8 mg (1%)
Potassium	401 mg (9%)	36.1 mg (1%)
Sodium	17 mg (1%)	1.53 mg (<1%)
Zinc	1.16 mg (11%)	0.10 mg (1%)
Copper	0.30 mg (33%)	0.03 mg (3%)
Manganese	1.67 mg (73%)	0.15 mg (7%)
Selenium	14.2 mcg (26%)	1.28 mcg (2%)

Is Garlic a Healthy Choice?

As we’ve discussed in this article, garlic supplementation has been linked to potential benefits for reducing blood pressure in people with hypertension, lowering blood cholesterol, and helping to maintain lower fasting blood sugar levels.

It is possible that whole garlic, which contains many of the same bioactive sulfur compounds, may provide some of these benefits. There is a lack of evidence to clearly show this, though, and in absence of such evidence, we should not assume whole garlic has the same effects as concentrated supplements.

For those who can consume FODMAPs without digestive difficulties, larger amounts of garlic may also provide a wide range of vitamins and minerals.

Given the evidence, garlic should be viewed as a flavor-enhancer that contains essential nutrients, with uncertain evidence for further health benefits.

References