Which is good, onion or garlic? A comparative guide to health and flavour

December 13, 2025 •

3 min read

According to nutritional data, garlic is denser in many vitamins and minerals like B6 and C, but which is good, onion or garlic, ultimately depends on your specific health objectives and culinary application. The two Allium family members offer a potent combination of benefits.

Quick Summary

A comparison of onion and garlic reveals distinct nutritional and health benefits, from varying antioxidant profiles to different levels of vitamins and minerals. The best choice hinges on taste preference and specific health goals.

Key Points

Garlic is Denser in Nutrients: It packs significantly higher amounts of vitamins like B6 and C, and minerals such as iron and potassium, per serving compared to onion.
Onion Excels in Antioxidants: Onions are a top source of the powerful antioxidant quercetin, which has strong anti-inflammatory properties.
Both Benefit Heart Health: Garlic is noted for lowering cholesterol and blood pressure, while onions' quercetin helps regulate blood pressure.
Prebiotic Power: Onions provide a richer source of prebiotics, fibers essential for nourishing beneficial gut bacteria and supporting digestive health.
Distinct Culinary Roles: Onions create a sweet, foundational flavor base when cooked, whereas garlic adds a pungent, intense kick that mellows when heated.
Cooking Matters: For maximum allicin, crush raw garlic and let it rest. Cooked onions develop sweetness, but raw provide more vitamin C.
Best Used Together: Incorporating both into your diet leverages their complementary nutritional profiles and distinct flavor contributions for optimal health and taste.

Nutritional Showdown: Onion vs. Garlic

Both onion and garlic, members of the Allium family, provide unique nutritional benefits. Garlic is generally denser in vitamins and minerals, containing higher amounts of vitamins C and B6, and minerals like iron, phosphorus, potassium, zinc, and copper compared to onion on a per-gram basis. Onion, however, is a better source of folate and is lower in calories. While garlic is a medium-calorie food, onions are low in calories. Onions also provide prebiotic fiber, important for gut health.

Key Nutritional Takeaways

Garlic: Higher in many vitamins (C, B6, etc.) and minerals (iron, potassium, zinc, copper). Higher in protein and carbs.
Onion: Higher in folate. Good source of Vitamin C and B6. Rich in prebiotic fiber.

Health Benefits: A Head-to-Head Comparison

The health benefits of onion and garlic stem from their organosulfur compounds and antioxidants, which are studied for their roles in protecting against diseases like cancer and cardiovascular conditions.

Garlic's Health Advantages

Garlic is particularly recognized for its positive impact on cardiovascular health, potentially reducing cholesterol and blood pressure. Its compound, allicin, offers antibacterial and antiviral properties supporting immune function. Garlic may also protect against cognitive decline and improve bone density in postmenopausal women.

Onion's Health Advantages

Onions are rich in antioxidants like quercetin, known for anti-inflammatory effects. Red onions contain anthocyanins with anti-cancer and anti-diabetic properties. Onions are also a good source of prebiotics that support gut health. Quercetin in onions may also contribute to heart health by helping to lower blood pressure.

Culinary Uses and Flavor Profiles

Beyond health benefits, onion and garlic play distinct roles in cooking due to their different flavors and how they react to heat.

Flavor and Cooking Differences

Onions offer a flavor range from sharp when raw to sweet and caramelized when cooked, providing a foundational depth. Their higher water content means they need longer to cook. Garlic has a strong, pungent flavor raw that mellows when cooked, adding a distinct kick. It burns quickly and is typically added later in cooking.

Raw vs. Cooked: Maximizing Benefits

The preparation of onion and garlic affects their health compounds.

Garlic: Crushing raw garlic and letting it sit helps maximize the beneficial compound allicin. Heat can reduce some benefits.
Onion: Cooking can concentrate certain enzymes, while raw onions offer more vitamin C.

Potential Considerations and Side Effects

Both onion and garlic contain FODMAPs, which can cause digestive issues for sensitive individuals or those with IBS. Some may find relief with garlic-infused oil. Certain traditional beliefs also associate their pungent nature with specific effects.

Conclusion: The Final Verdict

Neither onion nor garlic is definitively "better"; both are valuable for health and cooking. Garlic provides higher nutrient density and specific benefits for heart health and immunity. Onions offer powerful antioxidants like quercetin and significant prebiotic fiber for gut health. The best approach is to include both regularly in your diet to benefit from their complementary properties and diverse flavors.

For more detailed information on their compounds and cancer-preventive properties, the National Institutes of Health provides a comprehensive review of Allium vegetables: PMC4366009.


Feature	Onion	Garlic
Nutrient Density	Lower per gram	Higher per gram
Key Antioxidant	Quercetin, Anthocyanins	Allicin, Organosulfur Compounds
Primary Health Focus	Anti-inflammatory, Gut Health	Cardiovascular, Immunity, Cholesterol
Culinary Flavor	Sweet, Depth (cooked); Sharp (raw)	Pungent, Kick (raw); Nutty (cooked)
Cooking Time	Longer to caramelize	Shorter, burns easily
Folate Content	Higher	Lower
Vitamin B6/C	Lower	Significantly Higher
Minerals	Lower (except calcium)	Higher
Prebiotic Fiber	Significant Source	Good Source

Frequently Asked Questions

Both are excellent for heart health, but through different mechanisms. Garlic is well-known for its ability to lower cholesterol and blood pressure, while onions are rich in quercetin, which helps combat high blood pressure and improves blood flow.

Raw garlic retains a higher concentration of allicin, its most active and potent compound, which is known for its immune-boosting benefits. Raw onions offer a higher dose of vitamin C. However, some beneficial compounds are better absorbed when cooked.

Garlic is typically added after onions because it cooks much faster and can burn easily, turning bitter. By sautéing onions first, they have time to soften and sweeten before the more delicate garlic is introduced.

While from the same family, their flavors are distinct. Onion adds a sweet, fundamental depth to dishes, while garlic provides a pungent, sharp kick. They are not directly interchangeable, and many dishes use both for a balanced flavor profile.

Yes, both are beneficial. Garlic's compound allicin has potent antimicrobial and antiviral properties, while onions provide antioxidants like quercetin that help fight oxidative stress and inflammation, supporting overall immune function.

Both contain prebiotic fibers that feed beneficial gut bacteria. However, onions are generally a richer source of these prebiotics, making them a particularly good choice for supporting gut health.

Some individuals with sensitive stomachs or IBS may experience gas, bloating, or other digestive issues from both onion and garlic, as they contain high levels of FODMAPs. In such cases, using infused oils or cooking thoroughly may help, but it's best to consult a dietitian.

For hair growth, some remedies suggest garlic due to its higher mineral content (zinc, selenium) and stronger antimicrobial properties, which can improve scalp health. However, both contain sulfur compounds that support healthy hair.