Why does eating pineapple make your mouth tingle? What is bromelain, and what does it do?

Are you afraid of fruit? Some people might find it strange: fruit is sweet and tangy, so what’s there to fear?

For me, the fruit I fear the most is pineapple. This is because when I was a kid, eating pineapple always left my mouth feeling prickly and numb; once, it even made me bleed…

This experience left a significant psychological mark on my young mind.

As I grew up, I learned that this was all due to a substance in pineapples—bromelain.

This "painful" little guy showed up on health supplement shelves one day?! What’s going on here?

What is Bromelain?

Pineapple is a fruit native to South America and is an important part of traditional Hawaiian medicine. It’s one of the richest sources of bromelain in the world.

Bromelain consists of several endopeptidases and compounds, such as phosphatases, glucosidases, peroxidases, cellulases, carboxypeptidases, and protease inhibitors.

Our star today—bromelain—isn’t extracted from the flesh of the pineapple due to its low content but from the stem or core of the pineapple.

In folk medicine, pineapple is widely used to treat various ailments, from indigestion to allergies. It’s rich in bromelain, as well as vitamin C, vitamin B1, potassium, manganese, and phytonutrients.

While pineapple has many benefits, the secret to its magical abilities lies in bromelain.

Bromelain has various immune-regulating and anti-inflammatory mechanisms, affecting cytokines, platelet aggregation, and fibrin formation.

Why Does Your Mouth Tingle?

Some of bromelain's anti-inflammatory effects stem from protein hydrolysis, fibrinolysis, and the activities of gelatinases and collagenases, all of which contribute to its wound healing properties.

If you eat too much pineapple, bromelain can dissolve fibrin and blood clots in tissues, irritating the lips and mouth, causing mouth sores and bleeding.

That’s why when you eat pineapple, it feels like pineapple is “biting” you back.

Bromelain can cause allergic reactions in some people, but soaking peeled and cut pineapple in a light saltwater solution can help.

Not only does this make the pineapple taste sweeter, but the soaking process also disrupts the allergenic structures in bromelain, preventing damage to your lips.

Mechanism of Action for Bromelain

Immune Regulation, Anti-Inflammation, and Pain Relief

Bromelain has many immune-regulating and anti-inflammatory effects, influencing cytokines, platelet aggregation, and fibrin formation.

Some of its anti-inflammatory effects are due to protein hydrolysis, fibrinolysis, and the activities of gelatinases and collagenases, all of which aid in its wound healing capabilities.

Bromelain can accelerate blood perfusion and oxygen partial pressure recovery in wounded tissues; control the expression of tumor necrosis factor-alpha; and enhance the expression of transforming growth factor-beta.

All these mechanisms can improve allergies and systemic inflammation and help alleviate pain.

Animal models of allergic airway diseases show that bromelain significantly reduces bronchial leukocytes and eosinophils and decreases the activation of CD4 and CD8 T cells in the bronchi compared to control groups.

Bromelain also lowers pro-inflammatory cytokines (IL-4, IL-12, and IL-17) and interferon-gamma, contributing to its wide-ranging pain-relieving and anti-inflammatory properties.

Studies from biopsy tissues of ulcerative colitis patients indicate that bromelain can reduce the release of inflammatory cytokines from colonic mucosal cells, including granulocyte colony-stimulating factor, interferon-gamma, and tumor necrosis factor.

Oral bromelain may also reduce the production of pro-inflammatory prostaglandin E2 (PGE2) and substance P, further enhancing its anti-inflammatory and pain-relief mechanisms.

Activating Fibroblasts to Aid Healing

Another focus of bromelain research is the activation of fibroblasts, as all soft tissue healing involves their activation.

In damaged tissues, fibroblasts are recruited to help cells adhere to one another, eventually replacing damaged cells with functional ones, depending on the type of tissue injured.

If cells are too damaged and cannot survive, apoptosis occurs, leading to the recruitment of fibroblasts, which migrate to the injury site and form from precursor cell types.

However, if fibroblasts are overabundant or inappropriately recruited, it can lead to organ fibrosis, loss of vascular elasticity, or excessive scarring on the skin.

These issues can also arise from excessive autoimmune responses, such as in arthritis and connective tissue diseases, leading to fibrosis, loss of function, and pain.

Bromelain can help control excessive fibrosis by promoting cells to remain in a quiescent state, enhancing cellular recovery, lowering elevated IL-6 levels, and reducing apoptosis.

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Effects on White Blood Cell Activity

Bromelain has been found to interfere with P-selectin, a type of endogenous lectin, at the neutrophil binding site. This limits neutrophil attachment to substrates, reducing inflammation and minimizing glycation of cells in diabetes and other inflammatory conditions.

Bromelain may affect various white blood cell surfaces, influencing their activation and migration, neutrophil chemotaxis, and adhesion of white blood cells to blood vessels. These mechanisms contribute to anti-edema, anti-inflammatory, and anti-fibrotic effects, and bromelain also impacts components on cell surfaces, such as L-selectin.

Alleviating Damage from Intense Exercise

Moderate exercise has positive effects on the immune system, but intense exercise can actually harm it. For example, marathon running can increase inflammation and is associated with a higher incidence of upper respiratory infections; it may also cause muscle trauma and promote a pro-thrombotic state.

Studies on marathon runners have shown that bromelain exerts anti-inflammatory and fibrinolytic effects, normalizing levels of interleukins and immunoglobulin A, thereby helping to normalize exercise-induced inflammation. Another study indicated that bromelain can alleviate skeletal muscle damage caused by unfamiliar exercise.

Bromelain has also been shown to reduce fatigue and tends to maintain serum testosterone levels in endurance athletes.

Potential Uses of Bromelain

Possible Cancer Prevention

Research has found that bromelain possesses natural anti-cancer properties, including promoting apoptosis in cancer cells and preventing tumor growth. Animal studies suggest it can induce the production of various cytokines with anti-metastatic effects and inhibit cancer cell metastasis by reducing platelet aggregation.

Helping with Digestive Disorders

Bromelain is particularly effective in digesting proteins and has been found to aid the body in absorbing nutrients and even medications more efficiently. Studies indicate it can reduce colonic inflammation and the secretion of pro-inflammatory cytokines damaging to the intestinal lining, making it beneficial for individuals with gastrointestinal issues such as:

• Inflammatory bowel disease
• Ulcerative colitis
• Indigestion or peptic ulcers caused by H. pylori infection
• Colon cancer
• Constipation
• Crohn's disease
• Heartburn
• Diarrhea

Promoting Faster Recovery from Surgery or Wounds

The anti-inflammatory properties of bromelain make it an excellent natural alternative to pain medications like aspirin. One study evaluated bromelain's ability to aid recovery in patients who had wisdom teeth extracted, finding it promoted wound healing and helped reduce post-surgery pain and swelling.

Most wisdom teeth extraction patients experience noticeable symptoms afterward; unfortunately, antibiotics and painkillers don't always effectively prevent infection or other discomforts during recovery. Among the 80 participants in the study, those taking bromelain reported significantly lower post-operative pain, swelling, and even redness compared to those prescribed standard painkillers.

Combating Allergies and Asthma

A study investigated how bromelain affects mice with asthma and found that bromelain can reduce allergic sensitization and inhibit the development of other inflammatory responses affecting the airways. These findings suggest that this enzyme helps regulate the entire immune system, potentially preventing allergies and an over-sensitive immune response by addressing root causes.

The study observed that levels of CD11c(+) dendritic cells and DC44 antigen-presenting cells did not increase after bromelain supplementation, which could explain its effectiveness against asthma and allergies.

Helping to Prevent or Treat Sinusitis

Researchers at the University of Cologne in Germany studied 12 patients who had undergone sinus surgery, treating them for three months. They found the following benefits of bromelain: improvement in overall symptom scores, better nasal endoscopy scores, enhanced quality of life, and no reported adverse effects. Since surgery is often ineffective for treating sinusitis, this study offers significant hope for those with chronic sinus issues.

Easing Joint Pain

Thanks to its powerful anti-inflammatory and pain-relieving properties, bromelain is excellent for alleviating both acute and chronic joint pain. A study published in the journal Health and Alternative Medicine evaluated 42 patients suffering from degenerative spinal or painful joint conditions. Participants received 650 mg of bromelain capsules 2-3 times a day on an empty stomach. Researchers found that pain was reduced by 60% in those with acute pain and by over 50% in participants with chronic conditions.

Possible Aid in Weight Loss

While the effects of bromelain on weight management and fat cells are still being studied, there is reason to believe that its anti-inflammatory effects, pain relief, and ability to improve digestion may aid in weight loss. According to a 2017 article published in PLOS One, bromelain has been explored as an alternative anti-obesity treatment. The study found that bromelain helps downregulate fatty acid binding protein, fatty acid synthase, and lipoprotein lipase in fat cells. It can also inhibit lipogenesis and reduce triglyceride accumulation.

The Surprising Power of Bromelain

Who knew this little fruit, loved by some and disliked by others, had such impressive components? This enzyme, found only in pineapples, boasts anti-inflammatory and anti-allergic properties, pain relief, and digestive support. Beyond its medical value, it can also be used as a meat tenderizer in the kitchen.

However, I wouldn’t recommend relying on eating pineapple for bromelain since it has a high sugar content, and the downsides of excessive fructose intake are well-known. Plus, this enzyme is mainly concentrated in the stem and core of the pineapple, with very little in the flesh, making it not very cost-effective to get enough through eating the fruit alone.

If you're looking to improve digestion, consider taking bromelain supplements with meals. For other health concerns, it's best to take them on an empty stomach.