Why are avocados high in histamine and what does it mean for your diet?

December 28, 2025 •

3 min read

According to a study published in the Journal of Agricultural and Food Chemistry, avocados have been shown to contain significant levels of biogenic amines, including histamine. This is a critical factor for individuals managing histamine intolerance, as it directly relates to why are avocados high in histamine and can trigger adverse symptoms. The level of histamine is not static but changes depending on the fruit's ripeness and storage.

Quick Summary

This article explores why avocados are high in histamine and other biogenic amines that affect histamine-sensitive individuals. It details how ripeness impacts histamine content and explains the roles of DAO enzyme inhibition and histamine liberators.

Key Points

Ripeness Increases Histamine: As avocados ripen, enzymes convert amino acids into histamine, meaning older, riper fruit has higher levels.
DAO Enzyme Inhibition: Compounds within avocado can inhibit the DAO enzyme, preventing your body from effectively breaking down histamine.
Biogenic Amine Competition: Other biogenic amines in avocado, like putrescine, compete with histamine for the DAO enzyme, hindering its function.
Fresh is Best: To minimize histamine exposure, opt for fresh, firm avocados over softer, older ones with brown spots.
Individual Tolerance Varies: Personal reaction to avocados depends on individual histamine intolerance thresholds and DAO enzyme activity.
May Act as a Liberator: Some evidence suggests avocados could be 'histamine liberators,' triggering the body's own histamine release, though this is debated.
Monitor Your Symptoms: The most reliable way to manage avocado is by observing how your body reacts and adjusting your diet accordingly.

The ripening process and histamine formation

Avocados are known to contain varying levels of histamine, with their ripeness being a key factor. As avocados mature, their chemical composition shifts. An enzyme within the fruit can convert the amino acid histidine into histamine, leading to an accumulation of biogenic amines over time. This process explains why an under-ripe avocado may be tolerated better by sensitive individuals than an overly ripe one with brown spots.

Enzymatic Activity: As the avocado ripens, enzymes become more active, converting amino acids into biogenic amines like histamine.
Ripeness Matters: Unripe, fresh avocados generally have lower histamine levels compared to their riper counterparts.
Proper Storage: Keeping avocados properly stored in cool conditions can slow down the ripening process and minimize histamine production.

The role of DAO enzyme inhibition

Histamine intolerance is often caused by a deficiency in the diamine oxidase (DAO) enzyme, which is responsible for breaking down histamine in the body. Some foods, including avocados, don't just contain histamine; they also contain other compounds that can inhibit the function of the DAO enzyme. This dual effect—adding histamine and hindering its breakdown—can significantly increase the total histamine load in the body and trigger symptoms in susceptible individuals.

Other biogenic amines and enzyme competition

Avocados also contain other biogenic amines, such as putrescine, which can compete with histamine for the DAO enzyme's attention. This competition further reduces the body's ability to process histamine efficiently, leading to an excess buildup that can cause symptoms. For individuals with a pre-existing DAO deficiency, this competition can exacerbate their condition.

Are avocados also histamine liberators?

There is some debate in the scientific community about whether avocados act as true 'histamine liberators' or if their effects are purely related to their biogenic amine content. A histamine liberator is a food that triggers the body's mast cells to release its own stored histamine, independent of the food's histamine content. Some sources suggest that avocados, along with other foods like citrus fruits and strawberries, may trigger this release. However, more recent research questions this theory, suggesting that the issue might be the overall biogenic amine load and its interaction with DAO.

Navigating avocado consumption with histamine intolerance

For those with histamine intolerance, managing avocado consumption requires a personalized approach. The key lies in understanding individual triggers and tolerance levels. While some people can tolerate a fresh, firm avocado in small quantities, others find it best to avoid them entirely.

Comparison of Avocado Ripeness and Histamine Risk


Feature	Ripe Avocado	Unripe Avocado
Histamine Level	Potentially higher due to enzymatic conversion.	Lower, as the conversion of histidine has not progressed significantly.
Other Amines	Increased levels of biogenic amines like putrescine.	Reduced concentration of other biogenic amines.
Enzyme Competition	Higher risk of competitive inhibition of the DAO enzyme.	Lower risk of competitive inhibition due to fewer competing amines.
Sensitivity	Higher potential to trigger symptoms in sensitive individuals.	Less likely to cause a reaction due to lower histamine content.
Appearance	Softer texture, often with brown spots or discoloration.	Firm texture, without discoloration or bruising.

Conclusion: Personalizing your approach

Ultimately, the reason why avocados are high in histamine is multifaceted, involving the fruit's ripening process and its complex profile of biogenic amines. The issue isn't just the histamine itself but also the presence of other compounds that inhibit the DAO enzyme, making histamine harder for the body to break down. For individuals with histamine intolerance, the best strategy is to approach avocado with caution. Start with small amounts of fresh, firm avocados and monitor your body's reaction. By paying close attention to ripeness, portion size, and personal tolerance, you can manage your intake effectively. Always consult with a healthcare professional or a registered dietitian specializing in histamine intolerance to develop a personalized dietary plan that works for you.

Frequently Asked Questions

Yes, ripeness significantly affects histamine content. As an avocado ripens and ages, enzymes convert the amino acid histidine into histamine, leading to higher levels in more mature, softer fruit.

This depends entirely on your individual tolerance. Since avocados contain histamine and can affect the DAO enzyme, they are often on high-histamine food lists. Some people can tolerate a fresh, firm avocado, while others with high sensitivity may need to avoid it.

Diamine oxidase (DAO) is the primary enzyme responsible for breaking down histamine in the digestive tract. Individuals with histamine intolerance often have insufficient DAO activity, meaning they cannot process histamine effectively, leading to a buildup in the body.

Some sources list avocados as 'histamine liberators' that may trigger the body's mast cells to release histamine. However, this theory is controversial, with some experts attributing the reaction to the high biogenic amine content and DAO inhibition instead.

In many cases, yes. The heat-treating process used to produce avocado oil can destroy the allergenic proteins and potentially lower the biogenic amine content. However, individual tolerance varies, and it is best to test small amounts carefully.

Avocados contain other biogenic amines, such as putrescine, which can compete with histamine for the DAO enzyme. They also contain salicylates and other compounds that can trigger histamine-like responses in some sensitive individuals.

After following a low-histamine elimination diet for a few weeks, try reintroducing a very small amount of fresh, firm avocado. Monitor your symptoms closely and gradually increase the amount if no reaction occurs. Always do this under the guidance of a healthcare professional.