Does Boiling Soup Destroy Vitamins? A Comprehensive Guide to Nutrient Retention

November 14, 2025 •

4 min read

Studies have shown that boiling vegetables can significantly reduce their vitamin C content by 50% or more, depending on the time and temperature. So, does boiling soup destroy vitamins in the same way, or is there a way to preserve them? The answer is nuanced, depending on the type of vitamin and how the soup is prepared.

Quick Summary

Boiling soup can degrade heat-sensitive, water-soluble vitamins, but consuming the liquid prevents loss. Factors like cooking time and temperature, as well as the type of vitamin, determine nutrient impact. The overall nutritional value remains high.

Key Points

Water-Soluble Vitamins Can Leach: Heat-sensitive nutrients like Vitamin C and most B vitamins can dissolve into the cooking water.
Consume the Broth to Retain Nutrients: In soup, drinking the cooking liquid ensures you ingest the water-soluble vitamins that have leached from the vegetables.
Fat-Soluble Vitamins are Stable: Vitamins A, D, E, and K are more resilient to heat and are not lost during boiling.
Boiling Can Increase Bioavailability: For some nutrients, such as lycopene and beta-carotene, cooking breaks down cell walls, making them easier to absorb.
Shorter Cook Times are Better: To minimize nutrient loss, add more delicate ingredients closer to the end of the cooking process.
Beware of Reheating: Repeatedly heating soup can cause a progressive loss of the remaining heat-sensitive vitamins.

The Science Behind Vitamin Loss in Boiling Soup

To understand what happens to vitamins in soup, it is essential to distinguish between water-soluble and fat-soluble vitamins. Water-soluble vitamins, such as vitamin C and the B-complex vitamins (including thiamine, folate, and riboflavin), dissolve in water and are highly sensitive to heat. When vegetables containing these nutrients are boiled, a significant portion of them leaches into the cooking liquid. If this water is drained, the vitamins are lost. However, in the case of soup, where the liquid is consumed, these leached vitamins are largely retained within the dish, offering the full nutritional benefit.

Conversely, fat-soluble vitamins like vitamins A, D, E, and K are generally much more stable when exposed to heat and are not dissolved in the cooking water. In fact, cooking some vegetables can break down tough cell walls, making fat-soluble vitamins and other compounds, like beta-carotene in carrots and lycopene in tomatoes, more readily available for the body to absorb. This means while a long simmer may reduce the potency of some water-soluble vitamins, it can actually enhance the bioavailability of others.

Water-Soluble vs. Fat-Soluble Vitamins

Water-Soluble Vitamins (Vulnerable): These include Vitamin C and the B vitamins. They are susceptible to being destroyed by both heat and water. Longer cooking times and higher temperatures increase the risk of degradation. However, consuming the liquid in a soup mitigates the loss from leaching.
Fat-Soluble Vitamins (Resilient): These include Vitamins A, D, E, and K. They are more stable under heat. Cooking can sometimes increase their bioavailability by breaking down plant cell structures.

Factors Influencing Vitamin Retention in Soup

Several factors play a critical role in how many vitamins survive the cooking process. Controlling these elements can help you create a more nutrient-dense soup without sacrificing flavor.

Minimize Cooking Time

Just as boiling vegetables for a short time preserves more nutrients, cooking your soup for a shorter duration can prevent the degradation of heat-sensitive vitamins. This can be achieved by adding delicate vegetables toward the end of the cooking process or by using a pressure cooker, which speeds up cooking time while trapping nutrients.

Use Minimal Water

Using just enough liquid to cook your ingredients is another strategy. This concentrates the leached vitamins and minerals in a smaller volume, ensuring you consume a higher dose of nutrients with each spoonful.

Prepare Ingredients Correctly

Cut food larger: Cutting vegetables into smaller pieces increases their surface area, exposing more nutrients to heat and water. Keeping ingredients in larger chunks can help protect the nutrients inside.
Leave the skin on: Many nutrients are concentrated in or just below the skin of vegetables. Leaving the skin on where possible, such as with carrots and potatoes, can increase the fiber and nutrient content.

Comparison of Cooking Methods for Nutrient Retention


Cooking Method	Effect on Water-Soluble Vitamins (C, B)	Effect on Fat-Soluble Vitamins (A, E, K)	Why?
Boiling (Soup)	Leaching occurs, but nutrients are largely retained since the broth is consumed.	Largely stable, with some becoming more bioavailable.	Water-soluble vitamins move from solids to liquid; fat-soluble vitamins are heat-stable.
Steaming	Minimal leaching; retains most water-soluble vitamins.	Stable, but absorption is improved by adding a healthy fat afterward.	No direct contact with water; quick cooking time.
Microwaving	Quick cooking time and minimal water use lead to good retention.	Retained effectively due to short cooking times.	Minimal heat and water exposure due to fast cooking.
Sautéing / Stir-Frying	Fair retention due to minimal water, but high heat can degrade vitamins.	Excellent absorption when cooked with a healthy fat.	Short cooking time, but heat sensitivity still a factor.
Reheating Soup	Reheating can cause additional loss of sensitive vitamins.	Stable upon reheating.	Repeated heat exposure degrades remaining heat-sensitive vitamins.

Is Your Soup Still Healthy? The Conclusion

Does boiling soup destroy vitamins? The answer is both yes and no, but leaning towards no, especially if you consume the broth. While the heating process does cause some degradation and leaching of water-soluble vitamins like C and B, the very nature of soup—where the cooking liquid is retained—means those nutrients are not lost down the drain. Furthermore, boiling can improve the digestibility and bioavailability of certain other nutrients, such as fat-soluble vitamins and antioxidants. By incorporating techniques like adding fresh ingredients at the end of cooking and using a variety of vegetables, you can create a delicious and nutrient-rich meal. The ultimate takeaway is that homemade soup, even after boiling, remains a healthy and satisfying meal. You can find more comprehensive advice on healthful cooking at sites like AdventHealth.

Link: AdventHealth - What Makes a Soup Healthy?

Frequently Asked Questions

Yes, B vitamins are water-soluble and heat-sensitive, meaning they can leach from the solid ingredients into the broth during cooking. However, since you consume the broth in a soup, you still get most of these leached nutrients.

To preserve the most vitamins, use minimal water, keep cooking times short, and add delicate, leafy greens and other heat-sensitive vegetables toward the end of the cooking process.

Yes, reheating soup can cause a further loss of heat-sensitive vitamins like C. Each cycle of reheating exposes the soup to more heat, degrading the remaining vitamins.

Canned soups can be a decent option, but they often contain high levels of sodium. Choosing low-sodium varieties and adding your own fresh vegetables can significantly boost their nutritional value.

Yes, simmering (cooking at a lower, non-boiling temperature) is less destructive to vitamins than a full boil, especially over shorter periods. However, both methods can cause leaching of water-soluble vitamins over time.

A great tip is to add a squeeze of lemon or lime juice just before serving. This boosts the vitamin C content without it being subjected to prolonged heat that would cause degradation.

Bone broth is rich in protein, collagen, and minerals extracted during a long simmer. While some water-soluble vitamins in added vegetables are still affected by heat, the broth base itself is nutrient-dense, and you still consume all the liquid.