Garlic is a plant that grows underground and is beloved worldwide for its potent flavor and distinct smell. Whether it’s being roasted in a Mediterranean-style entree or blended into an Asian-inspired meal, garlic finds its way into many dishes. Beyond taste, garlic is no stranger to both traditional and modern health systems and piques the curiosity of researchers to see how it may support the body.

For centuries, garlic has been cherished not only for food but for its potential medicinal and even mythical purposes. Fast forward to today, garlic is around more than ever, on most kitchen counters and in supplement forms like aged garlic extract, garlic oil capsules, powder tablets, and beyond. Keep reading for an easy-to-digest summary of the history of garlic and its nutrition, top health benefits, tips on buying and storing it, and potential risks/side effects.

Facts & History

Botanically, garlic belongs to the Allium family along with onions, leeks, and shallots. The bulb (or head) of garlic is made up of smaller sections called cloves, all wrapped in a thin, papery skin. Garlic is indigenous to Central Asia (specifically modern-day Iran, Turkmenistan, and Afghanistan). Over time, it spread to other parts of the world through trade and cultural exchange. It became especially popular in regions such as the Mediterranean, the Middle East, India, and China.

Garlic has a rich history beyond the kitchen. The ancient Egyptians buried it with their pharaohs, the Greeks gave it to athletes for endurance, and medieval Europeans even used it to ward off superstitions and ailments. Moving to the present day, garlic’s organosulfur compounds, like allicin, S-allylcysteine, and diallyl disulfide, have captured the interest of many researchers. Once garlic is cut or crushed is how these compounds form (1). Allicin can degrade under high heat, whereas “aged garlic extract” often contains a more stable compound known as S-allylcysteine (2). In addition, diallyl disulfide and diallyl trisulfide have shown anti-inflammatory potential (3).

Beyond being used as a flavoring agent, fresh and processed garlic have been found in various applications across different cultures, especially for potential health-related uses. For many people, daily garlic intake is relatively low, yet research continues to look into how garlic’s unique compounds may support the body (4). Historically, travelers embarking on long journeys often carried garlic, believing it offered them some form of protection.

Nutrition Facts

Macronutrients

Garlic may be a small component of your meal, but it is bursting with flavor and potentially beneficial compounds. One raw clove (about 3 grams) of garlic contains (5):

  • Calories: ~4.47 kcal
  • Protein: 0.19 g
  • Total Fat: 0.015 g
  • Carbohydrate: 0.99 g
  • Fiber: 0.06 g

Each clove is tiny, so it doesn’t drastically affect daily macronutrient goals. Still, it delivers a notable amount of powerful plant compounds.

Vitamins & Minerals

A single 3-gram clove of raw garlic provides approximately (5):

  • Vitamin C: ~0.94 mg (1% DV)
  • Vitamin B-6: 0.037 mg (2% DV)
  • Calcium: ~5.4 mg (<1% DV)
  • Potassium: ~12 mg (<1% DV)
  • Phosphorus: ~4.6 mg (<1% DV)
  • Magnesium: ~0.75 mg (<1% DV)
  • Selenium: ~0.43 µg (1% DV)

In addition to the above, there are trace amounts of iron, zinc, and other minerals in every clove. Even so, garlic is best known for its sulfur-based compounds.

Plant Compounds

Garlic’s core benefits often trace back to its sulfur-containing compounds, with notable examples including:

  • Allicin: Forms when raw garlic is crushed or chopped. Research suggests it may have antibacterial properties and support heart health (1, 6).
  • S-allylcysteine (SAC): Present in aged garlic extract, it’s more stable than allicin and is frequently studied for potential blood pressure and anti-inflammatory benefits (2).
  • Diallyl Disulfide (DADS) & Diallyl Trisulfide (DATS): A major bioactive component of garlic, early research suggests they may help manage inflammation (3).

Garlic also offers antioxidants, such as phenolic acids and flavonoids (7):

  • Total phenolic content: 3.4-10.8 mg gallic acid equivalents (GAE)/g dry matter (dm)
  • Major phenolic acids:
    • Caffeic acid: ~2.9 mg/kg dm
    • Ferulic acid: ~2.6 mg/kg dm
  • Vanillic, p-hydroxybenzoic, and p-coumaric acids: 0.4-0.8 mg/kg dm
Summary
Each garlic clove has several sulfur compounds and trace nutrients that may benefit your body. Allicin and its relative substances are most often linked to garlic’s potential perks.

Garlic Health Benefits

Garlic isn’t just a flavor booster-scientists continue to explore its many possible benefits. Below are some highlights, briefly explained.

Supports Heart Health

Garlic may be good for your heart in the following ways:

  • Helps Lower Blood Pressure: Studies have shown that garlic supplements can lower blood pressure more than a placebo, particularly improving the systolic (top number) pressure in those with hypertension (8, 4).
  • Improves Cholesterol Levels: Certain garlic supplements (like aged garlic extract) have been shown to help reduce total and LDL (“bad”) cholesterol (9, 10).
  • Reduces Inflammation: Chronic inflammation can contribute to heart disease, and garlic contains compounds that appear to help lessen inflammatory markers (11, 2, 3).
  • Better Blood Flow & Platelet Function: Garlic can help reduce platelet aggregation, potentially lowering the risk of harmful clot formation (12, 13).

Boosts Immune System

Garlic may reinforce the body’s defenses in a few ways:

  • Stimulating Immune Cells: Research suggests aged garlic extract can activate cells like natural killer (NK) cells and certain T cells, which promote immunity (14, 15).
  • Less Severe Colds & Flu: A few trials report that people taking garlic supplements may have fewer colds or experience milder symptoms of illnesses (14, 16).
  • Reducing Inflammation in Obesity: In individuals who are overweight or obese (and thus prone to higher inflammation), garlic has been shown to reduce certain inflammatory markers (15).

Helps Manage Blood Sugar

If you’re looking for better blood sugar control, garlic may assist by:

  • Improving Insulin Sensitivity: Garlic may enhance the body’s response to insulin, which is especially helpful for those with insulin resistance or Type 2 Diabetes Mellitus (17, 18).
  • Lowering Fasting Blood Glucose & HbA1c: Some studies indicate that garlic may help reduce fasting blood sugar and improve long-term glucose balance (19).
  • Supporting Hormone Balance: Consuming garlic may raise levels of adiponectin in the body, a hormone tied to better insulin sensitivity and lower inflammation (20).

Antimicrobial & Antifungal Properties

Garlic’s sulfur compounds appear to combat microbes by:

  • Killing Harmful Bacteria: Research suggests garlic may slow or inhibit certain bacteria, including H. pylori (linked to stomach ulcers) and some oral bacteria (21, 22, 23).
  • Fighting Fungal Infections: Topical gels containing ajoene (derived from garlic) can match traditional creams for certain fungal skin infections and may also help reduce oral yeast overgrowth (24, 24).
  • Promotes Oral Health: Gargling garlic extracts has been noted to help prevent plaque-forming bacteria in the mouth, supporting healthier gums and teeth (25, 26).

May Help Prevent Some Cancers

While more studies are needed, there is some evidence linking garlic to reduced cancer risk, particularly in the digestive tract:

  • Lower Risk for Gastric & Colorectal Cancers: Those who eat garlic regularly could have a lower risk of certain stomach or colon cancers (27, 28).
  • Immune & Anti-Tumor Effects: Certain compounds in garlic may help the immune system target abnormal cells and limit tumor growth (29).
  • Possible Mechanisms: Garlic may assist in detoxification, boosting antioxidants, and promoting normal cell growth. Results vary, so further studies are underway, but garlic remains a popular topic in cancer research.
Summary
From heart health and immunity to blood sugar balance, infection defense, and potentially reduced cancer risks, the sulfur-based compounds and antioxidants in garlic have drawn considerable attention. Adding it to your meals is a delicious way to try out some of its studied benefits.

May Support Bone & Joint Health

Garlic may also be helpful for bone and joint health, which is less commonly discussed. Some research shows that certain garlic extracts lower inflammatory markers tied to joint pain. For example, garlic supplementation has been found to reduce osteoarthritis symptoms in overweight or obese adults (30).

In that study, participants with knee osteoarthritis noted less stiffness and pain after 12 weeks of taking garlic. Researchers suspect garlic’s anti-inflammatory and antioxidant properties could help safeguard joint tissues. While it shouldn’t replace standard treatments, including garlic in the diet may give extra support for musculoskeletal health.

Risks & Side Effects

Garlic is considered to be safe when used in the amounts found in food. Note the following:

  • Digestive Upset: Some may find that consuming raw garlic or high doses of garlic may end in stomach irritation, which may cause gas or bloating. Cooked or aged garlic may be easier on the stomach.
  • Allergies & Skin Burns: In rare cases, some individuals may experience an allergic reaction (such as rash and/or trouble breathing). Topical use of raw garlic has even resulted in skin burns in some cases (31).
  • Bleeding Risks: Garlic may slightly thin the blood (12), so those on blood-thinning medications or undergoing surgery should check with their doctor first (32). One systematic review found that moderate consumption of dietary garlic does not typically seem to result in severe bleeding complications (33), but in general it is a good idea to remain cautious.
  • Mixed Cancer Risk Findings: While many studies suggest potential benefits, several observational studies have found the use of certain garlic pills to be associated with a potential increase in colorectal cancer risk (34). Further study is necessary to understand it more clearly.
  • Drug Interactions: Garlic has the potential to interact with various medications such as antiretrovirals (35) or those involving intestinal transport mechanisms (36). Consult a healthcare provider before starting new supplements.
  • Lingering Odor: Garlic can leave a smell behind that lingers on the breath or skin. Roasting the garlic and pairing it with fresh herbs or citrus can minimize the after-odor effects.
Summary
For most, garlic consumption is safe in regular food quantities. At higher doses or in raw form, it may cause digestive upset or skin irritation. Additionally, it can mildly thin the blood and interact with certain medications. Thus, individuals on blood thinners or other medications should consult a healthcare provider before taking concentrated garlic supplements.

Selecting Fresh Garlic

To maximize flavor and possible health advantages, seek fresh garlic:

  • Firm Bulbs: Steer clear of bulbs that have soft spots or cloves falling off.
  • Clean, Dry Exterior: Avoid bulbs that have mold, moisture, or shriveled skin.
  • Outer Paper Mostly Intact: The cloves should be well covered with the papery skin.
  • Weight: The heavier the bulb, the fresher the cloves.

In addition to these tips, purchasing from stores that have a quick turnover of fresh produce may have fresher garlic.

How to Store Garlic

To maximize the shelf life of garlic, proper storage is the key:

  • Cool, Dry Spot: Store whole, unpeeled bulbs in a well-ventilated container out of direct light.
  • Do Not Refrigerate Whole Bulbs: The refrigeration can promote sprouting or molds. After peeling or cutting, it can be stored for a short time in the refrigerator in an airtight container.
  • Use Quickly: Once the head is broken into individual cloves, their shelf life decreases. Use them promptly.

How to Lessen Intense Garlic Smell

To reduce the intensity of garlic:

  1. Germ-Free: The germ is the green sprout found in the middle of the clove. It can have a bitter flavor.
  2. Roast or Simmer: Using medium heat with garlic can mellow out the taste.
  3. Pair with Fresh Herbs & Acid: The addition of parsley, lemon juice, or vinegar to garlic has a great way of minimizing the aftertaste.
  4. Try Lemon or Milk: Consuming lemon water or milk around the same time of having garlic may reduce the smell lingering.

Keep in mind that garlic’s intensity can differ depending on the variety, freshness, and how it is cooked.

Is It Safe to Eat Raw Garlic?

Most people that consume garlic raw do so in salads or dips. Eating raw garlic is always an option. However, raw garlic tends to be more pungent and can irritate sensitive stomachs more. Cooking it typically tends to mellow out the garlic and decrease its harsh smell.

Do Different Garlic Varieties Taste Different?

Yes. Generally speaking, the softneck varieties that are usually bought at the supermarket tend to be less pungent than the rest. Typically, softneck garlic is milder than hardneck garlic. Additionally, some specialty or heirloom varieties are sweeter and have distinct flavors.

Can Garlic Be Frozen?

Some people prefer to mince it and freeze it, or roast it and freeze it as a paste into small portions. Freezing may affect the texture and if you’re looking for a crisp bite, use fresh garlic.

What makes garlic spicy?

Allicin is the compound responsible for the “hot” sensation you may get when eating garlic alone or in certain foods. It is present in the garlic naturally and gets stronger once the garlic is crushed or chopped. If you want to mellow out the spiciness, try cooking the garlic or adding some cream. This will remove some of the allicin.

Why is my garlic turning blue?

You may notice garlic turning blue-green in certain scenarios. One of the most common ways this can happen is when cooking with certain ingredients like lemon, for example. Because garlic contains sulfur, when it comes into contact with an acidic environment like lemon, the garlic interacts with it causing a change in color to greenish blue. This can also happen when pickling garlic. If this ever happens to you, just remember it is still perfectly safe to eat.

Conclusion

Garlic is known worldwide for its pungent flavor and potential medicinal qualities. While each clove contains only trace amounts of common nutrients, its sulfur compounds may help support heart health, immune health, blood sugar regulation, and more (6). There is ongoing research for potential protection against some infections and cancers (37). More recent research even suggests garlic may help support joint health in some people with overweight or obesity.

Garlic may be eaten raw for a more potent bite and cooked for a sweeter, more subtle one. It is in sauces, soups, marinades, and roasted veggies. So, the next time you pick up a clove of garlic, think about its lengthy history and the mountain of research surrounding it.

As with everything else, consume garlic in moderation. Some people may have issues with digestive upset, allergy, or interaction with their medication. Individuals on blood thinners or other medications should consult a healthcare professional before starting garlic supplements. However, for most folks, incorporating a bit of garlic into your everyday diet is a delicious way to try out its possible health benefits.

From its historical origins across different cultures to modern-day scientific research, garlic continues to remain a kitchen staple around the world and the subject of research to come.

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