Understanding Why There is no Pepper on AIP

January 11, 2026 •

4 min read

An estimated 50 million Americans are living with an autoimmune disease, which is why protocols like AIP are so important. So, why is there no pepper on AIP? The answer is more complex than it first appears, involving two distinct types of 'pepper' and their different inflammatory mechanisms.

Quick Summary

Pepper is excluded from the AIP diet due to two different reasons: black pepper is a seed spice, and nightshade peppers contain inflammatory compounds. The protocol eliminates both to minimize potential triggers for autoimmune reactions and support gut healing.

Key Points

Black Pepper is a Seed Spice: The AIP diet eliminates all seeds, including black peppercorns, during the elimination phase to reduce potential gut irritants and inflammatory triggers.
Nightshades are Excluded: Peppers like cayenne, paprika, and bell peppers are nightshades, containing compounds like alkaloids and capsaicin that can worsen inflammation for those with autoimmune diseases.
Focus on Gut Healing: By removing both types of pepper, the AIP diet minimizes gut irritation and reduces intestinal permeability, or 'leaky gut', which is central to its healing philosophy.
Piperine's Complex Role: While some studies show anti-inflammatory properties of piperine (in black pepper), it can also be a gut irritant for sensitive individuals, justifying its removal during the initial healing phase.
AIP-Compliant Alternatives Exist: You can use a variety of compliant herbs and spices, such as ginger, turmeric, garlic powder, and oregano, to add flavor without using pepper.
Prioritizing Safety over Complexity: The strict removal of both black pepper and nightshade peppers is a core principle of the AIP's cautious, systematic approach to identifying food sensitivities and promoting immune regulation.

Why Are Seeds Excluded on the AIP Diet?

First, it's important to clarify the different types of "pepper" commonly found in kitchens. Black pepper comes from the dried berries of the Piper nigrum plant and is technically a seed spice, unrelated to chili peppers. On the other hand, nightshade peppers, which include bell peppers, cayenne, chili, and paprika, belong to the Capsicum genus and the nightshade family. Both are eliminated on the Autoimmune Protocol (AIP) but for different reasons.

The AIP is a healing diet designed to reduce inflammation and symptoms associated with autoimmune diseases by removing potential food triggers during an elimination phase. Nuts and seeds are among the key food groups eliminated in this phase. Seeds are often excluded because they contain proteins and other compounds, such as lectins, that can be difficult to digest and may contribute to intestinal permeability, also known as 'leaky gut'. In individuals with compromised gut health or autoimmune conditions, these compounds can potentially pass through the gut lining and trigger an exaggerated immune response. This is the primary reason why black peppercorns, which are the seeds of the pepper plant, are restricted during the AIP elimination phase.

The Role of Piperine and Gut Health

Black pepper's active compound, piperine, has been shown to have complex effects on the body. Some studies suggest it has anti-inflammatory and immunomodulatory properties, which might seem contradictory to its exclusion on AIP. However, the AIP's core principle is to remove all potential irritants during the healing phase. While piperine may have beneficial effects for some, it can also have an irritant effect on the intestinal lining for those with a hypersensitive gut. The AIP's cautious approach prioritizes minimizing any potential irritants to allow the gut to heal fully before gradually reintroducing certain foods.

The Problem with Nightshade Peppers

Nightshade peppers, which belong to the Solanaceae plant family, are another story entirely. This family also includes tomatoes, potatoes, and eggplant. Nightshades are eliminated on the AIP because they contain alkaloids and other compounds that can be inflammatory for some individuals, particularly those with autoimmune diseases. These compounds have been shown to increase intestinal permeability and trigger a negative immune response.

The Impact of Capsaicin

The compound capsaicin, which gives hot peppers like cayenne and paprika their heat, is a known irritant to mucous membranes. For a person with an autoimmune disease and an already overactive immune system, introducing an immune stimulant like capsaicin can exacerbate symptoms and cause flare-ups. By removing all nightshades, the AIP diet helps to reduce this potential irritation and give the body a chance to calm its immune response and heal the gut lining.

Comparison: Black Pepper vs. Nightshade Peppers on AIP

To further clarify, here's a comparison of why each type of pepper is excluded from the AIP diet during the elimination phase.


Feature	Black Pepper (Piper nigrum)	Nightshade Peppers (e.g., Cayenne, Paprika)
Source	Dried berry (a seed spice)	Fruit of a nightshade plant
AIP Reason for Elimination	Considered a seed spice and potential gut irritant	Belongs to the nightshade family; contains inflammatory alkaloids
Active Compound	Piperine	Capsaicin and other alkaloids
Potential Impact on Autoimmunity	Contains lectin-like proteins that may increase gut permeability; can irritate sensitive guts	Capsaicin is a mucous membrane irritant; alkaloids increase gut permeability and exaggerate immune responses
Culinary Effect	Mild, aromatic heat; foundational seasoning	Significant, sometimes intense heat; primarily for adding spiciness

Delicious AIP Alternatives for Seasoning

For those on the AIP diet, giving up pepper doesn't mean giving up flavor. There are many compliant herbs and spices that can be used to add depth and warmth to dishes without triggering inflammation. These alternatives allow you to create flavorful meals while adhering to the elimination phase of the diet.

Here are some excellent AIP-friendly alternatives to pepper:

Herbs: Basil, oregano, thyme, rosemary, cilantro, and parsley add fresh, aromatic flavors.
Root Spices: Ginger and turmeric provide a warm, earthy quality. Ground ginger can offer a similar heat to pepper in certain dishes.
Other options: Gan-thoda powder, also known as long pepper, is a lesser-known but compliant spice that offers a peppery kick. Garlic and onion powder are also great for adding savory flavor.

Creating your own compliant spice blends is a great way to control ingredients and ensure you avoid hidden sources of non-AIP additives that are often found in pre-mixed spice products. By experimenting with these alternatives, you can discover new flavor profiles that make your AIP journey enjoyable and satisfying.

Conclusion: A Precautionary Principle

The core reason why there is no pepper on AIP is rooted in the protocol's precautionary approach to reducing inflammation and promoting healing. By eliminating both black pepper (a seed spice) and nightshade peppers (a nightshade fruit) during the elimination phase, the diet minimizes exposure to potential triggers, such as lectins, alkaloids, and digestive irritants. While some of these compounds might have potential benefits or are tolerated by many, the goal for those with autoimmune conditions is to create the cleanest possible environment for the immune system to reset and the gut to heal. Understanding the distinct reasons for excluding each type of pepper is key to successfully navigating the AIP diet and its focus on anti-inflammatory, nutrient-dense foods. Once a period of healing has occurred, some individuals may be able to reintroduce black pepper under careful observation, as it's often an earlier reintroduction than nightshades. However, the foundational understanding of the exclusion during the initial phase is crucial for success.

For more information on the complex immune effects of piperine, you can consult studies like this one on its impact on T lymphocytes: Piperine from black pepper inhibits activation-induced proliferation and effector function of T lymphocytes

Frequently Asked Questions

Yes, all forms of pepper are excluded during the elimination phase of the AIP diet. This includes black, white, and green peppercorns (seed spices), as well as nightshade peppers like cayenne, bell peppers, and paprika.

Black pepper is a seed spice from the Piper nigrum plant and is removed because of seed compounds. Cayenne pepper is a nightshade vegetable and is removed because nightshades contain inflammatory alkaloids and the irritant capsaicin.

Nightshade vegetables contain compounds like alkaloids and lectins that can increase intestinal permeability (leaky gut) and trigger an immune response, exacerbating autoimmune symptoms.

You can use AIP-compliant spices and herbs such as ginger, turmeric, garlic powder, onion powder, and certain mixes like gan-thoda powder, to add flavor without the risk of irritation.

After the elimination phase, you can attempt to reintroduce black pepper, often considered an early reintroduction, under careful observation. Nightshade peppers are typically reintroduced much later in the process due to their higher potential for provoking a reaction.

While black pepper's active compound, piperine, has been studied for its anti-inflammatory properties, it can also act as a gut irritant in sensitive individuals, which is why it's removed during the AIP elimination phase to ensure a safe healing environment.

Pink peppercorns are not related to black pepper or nightshades and are often tolerated, but due to being a seed, they are typically avoided during the initial elimination phase. Some individuals reintroduce them later to test for tolerance.