What are some natural MAO inhibitors?

According to extensive literature, a wide variety of medicinal plants and food products contain compounds with potential monoamine oxidase (MAO) inhibiting properties. But what are some natural MAO inhibitors and how should they be approached with caution and awareness?

Quick Summary

This article explores various plant-derived compounds and foods that can naturally inhibit monoamine oxidase (MAO), highlighting potential benefits and significant health risks associated with their use. It covers important dietary and medication considerations to ensure safety.

Key Points

• MAO Functions: MAO enzymes break down neurotransmitters, while MAO inhibitors prevent this action, increasing levels of serotonin, dopamine, and norepinephrine.

• Sources of Natural MAOIs: Many plants, such as Syrian rue, St. John's Wort, and passionflower, contain compounds that act as natural MAO inhibitors.

• Tyramine Risk: Combining MAOIs (natural or synthetic) with tyramine-rich foods like aged cheese and cured meats can cause a dangerous spike in blood pressure.

• Serotonin Syndrome: Serious, potentially fatal reactions can occur when natural MAOIs are mixed with other antidepressants or supplements, increasing serotonin to unsafe levels.

• Medical Caution: The potency and safety of natural MAO inhibitors are highly variable, making medical supervision essential to avoid dangerous interactions and unpredictable side effects.

• Diverse Compounds: Natural MAO inhibition comes from a variety of phytochemicals, including beta-carboline alkaloids in ayahuasca ingredients and flavonoids in St. John's Wort.

Understanding MAO and Its Inhibitors

Monoamine oxidases (MAOs) are a family of enzymes found throughout the body, including the brain, liver, and gut. Their primary role is to break down monoamine neurotransmitters like serotonin, norepinephrine, and dopamine, which are crucial for mood regulation. Monoamine oxidase inhibitors (MAOIs) are substances that block the action of these enzymes, preventing the breakdown of neurotransmitters and increasing their levels. This can influence mood, anxiety, and other neurological functions. While synthetic MAOIs are prescribed for certain mental health disorders, natural versions exist in many plants and foods, presenting unique benefits and serious risks.

There are two primary types of MAO, known as MAO-A and MAO-B, which differ in their specific roles and what they metabolize. MAO-A predominantly breaks down serotonin and norepinephrine, while MAO-B prefers substrates like phenylethylamine. Tyramine and dopamine can be metabolized by both enzyme types. The distinction is important, as some natural and pharmaceutical inhibitors are selective for one type or the other, influencing their effects and safety profile.

Plant-Based Sources of Natural MAO Inhibitors

Many plants contain compounds, primarily alkaloids and flavonoids, that exhibit MAO-inhibiting activity. These are often used in traditional medicine but require extreme caution due to their potency and potential for severe side effects.

Key Herbs and Botanicals

• Syrian Rue (Peganum harmala): This plant is a powerful source of beta-carboline alkaloids such as harmine and harmaline, which are potent reversible inhibitors of MAO-A. Historically used in traditional Amazonian practices, its MAOI effects are significant and can interact dangerously with other substances.
• St. John's Wort (Hypericum perforatum): A popular herbal supplement for mild to moderate depression, St. John's Wort contains several compounds with MAO-inhibiting properties, including flavonoids like quercetin. While its effect is less potent than synthetic MAOIs, it can still lead to serious interactions with other antidepressants.
• Passionflower (Passiflora incarnata): Traditionally used for its calming effects, passionflower contains beta-carboline alkaloids with MAOI activity. Harman is a key MAO-inhibiting beta-carboline found in this plant.
• Banisteriopsis caapi: This vine is another significant source of harmala alkaloids, including harmine and harmaline, making it a powerful MAO inhibitor. It is the basis for the psychedelic brew known as ayahuasca.
• Turmeric (Curcuma longa): Curcumin, the active compound in turmeric, has been shown to inhibit both MAO-A and MAO-B in animal studies, contributing to its potential mood-enhancing properties.
• Nutmeg (Myristica fragrans): This common spice contains a compound called myristicin, which is a weak inhibitor of monoamine oxidase. Consumption of high doses can be toxic.

Dietary and Food-Based MAO Inhibitors

In addition to concentrated herbal sources, some common foods contain mild MAO-inhibiting properties, primarily from natural alkaloids and flavonoids. While the effect is typically very weak in normal dietary amounts, it becomes a crucial safety consideration for those on prescribed MAOI medications.

Common Foods with MAO-Inhibiting Activity

• Chocolate/Cocoa: Theobroma cacao contains beta-carbolines that can inhibit MAO.
• Coffee: The caffeine and other compounds in coffee have been noted to have mild MAO-inhibiting effects.
• Tobacco: Contains significant levels of beta-carbolines, which are believed to contribute to its psychoactive effects and dependence potential.

Important Safety Concerns and Dietary Interactions

Using natural MAO inhibitors carries significant health risks, especially for individuals with underlying health conditions or those taking other medications. The most critical concern is the risk of a hypertensive crisis, a dangerous spike in blood pressure, from consuming tyramine-rich foods. Tyramine is an amino acid normally metabolized by the MAO-A enzyme. When this enzyme is blocked, tyramine levels can rise rapidly and cause a severe, potentially life-threatening reaction.

Foods to avoid with MAOIs

For individuals on MAOI medications, strict adherence to a low-tyramine diet is necessary. Foods to avoid include:

• Aged cheeses (e.g., cheddar, Swiss, blue cheese)
• Cured and fermented meats (e.g., sausage, salami, pepperoni)
• Fermented cabbage (e.g., sauerkraut, kimchi)
• Soy products (e.g., soy sauce, tofu, miso)
• Certain beans (e.g., fava beans, broad bean pods)
• Overripe fruits and vegetables
• Tap and draft beers, red wine

Another severe risk is serotonin syndrome, which can occur when MAOIs are combined with other drugs that increase serotonin levels, such as SSRI antidepressants, certain pain medications, and St. John's Wort. Symptoms include agitation, confusion, rapid heart rate, and high fever.

Natural vs. Synthetic MAOIs: A Comparison

Feature	Natural MAO Inhibitors	Synthetic MAO Inhibitors (e.g., Moclobemide)
Source	Plants, herbs, and certain foods	Pharmaceutical drugs
Potency	Highly variable; can range from weak (nutmeg) to very potent (Peganum harmala)	Standardized and typically potent
Selectivity	Can be selective (e.g., some beta-carbolines for MAO-A) or non-selective depending on the source	Can be selective for MAO-A (RIMA) or MAO-B
Form	Raw plants, supplements, teas, dietary ingredients	Pills, capsules, or skin patches
Regulation	Varies widely; often not subject to the same regulatory standards as drugs	Strictly regulated by health authorities (e.g., FDA)
Safety Profile	Less understood, high risk of interactions with other substances and tyramine-rich foods	Well-researched, but still carries risk of hypertensive crisis and drug interactions

The Need for Medical Supervision

Given the potential for severe side effects and drug interactions, using natural MAO inhibitors for therapeutic purposes without medical supervision is extremely dangerous. The concentration of active compounds in natural sources is unpredictable, making dosages unreliable and risky. For individuals with conditions like depression or Parkinson's disease, MAOI therapy should only be undertaken with professional medical guidance, utilizing regulated pharmaceutical options. Discuss any herbal supplements with a healthcare provider to understand potential risks.

Conclusion

While many plants and foods do contain natural compounds that inhibit MAO, their use is fraught with risks. The allure of a 'natural' solution can be misleading when it comes to potent pharmacological effects. The potential for dangerous interactions with medications and common foods, including a hypertensive crisis and serotonin syndrome, necessitates extreme caution. Consulting a healthcare professional before considering any form of MAO-inhibiting substance, natural or otherwise, is the only safe approach to protecting one's health. The therapeutic use of MAO inhibitors, due to the complexity of the MAO enzyme system and its interactions, requires a carefully monitored clinical setting.

For more in-depth information on the mechanisms and discovery of plant-based MAO inhibitors, the NIH publication titled "Natural Products Inhibitors of Monoamine Oxidases: Potential for the Therapy of Neurological Disorders" is an excellent resource.

Frequently Asked Questions

What is the difference between MAO-A and MAO-B inhibition?

MAO-A preferentially breaks down serotonin and norepinephrine, while MAO-B primarily metabolizes phenylethylamine. Both types metabolize tyramine and dopamine, so inhibiting either can increase levels of these neurotransmitters.

Which natural MAO inhibitors are considered the most potent?

Plants containing beta-carboline alkaloids, such as Syrian rue (Peganum harmala) and the Banisteriopsis caapi vine, are known to contain potent reversible MAO-A inhibitors, like harmine and harmaline.

Is it safe to take natural MAO inhibitors like St. John's Wort with antidepressants?

No, it is extremely dangerous and can lead to serotonin syndrome. You should never combine MAOIs, natural or synthetic, with other antidepressants without strict medical guidance and a washout period.

What is a hypertensive crisis and how is it related to MAO inhibitors?

A hypertensive crisis is a sudden, dangerous increase in blood pressure. It can be triggered by eating tyramine-rich foods while taking an MAOI, because the enzyme that breaks down tyramine is inhibited.

What kinds of foods should be avoided when using MAOIs?

Aged, fermented, cured, pickled, or spoiled foods and drinks should be avoided. Examples include aged cheeses, cured meats, sauerkraut, and draft beer.

Are MAO-inhibiting effects in foods like cocoa and coffee a serious concern?

While these foods contain compounds with MAOI properties, the effect is typically very mild and not a concern for most people. However, it is a risk for individuals taking synthetic MAOI medications, who must adhere to strict dietary guidelines.

Why is it important to consult a doctor before using natural MAO inhibitors?

A doctor's consultation is crucial because natural MAO inhibitors can have potent and unpredictable effects. They pose significant risks of severe drug-drug and drug-food interactions, which can be life-threatening.