Jalapeños are spicy chili peppers from the hot pepper family.

They are small, green or red in color and moderately spicy.

Jalapeños are commonly used in Mexican cuisine but popular worldwide.

They're also packed with nutrients and have many health benefits.

This article reviews the benefits of eating jalapeños, discusses their possible side effects and suggests ways to add them to your diet.

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Jalapeños are low in calories and full of vitamins, minerals, fiber and antioxidants.

One raw jalapeño contains the following (1):

  • Calories: 4
  • Fiber: 0.4 grams
  • Vitamin C: 10% of the RDI
  • Vitamin B6: 4% of the RDI
  • Vitamin A: 2% of the RDI
  • Vitamin K: 2% of the RDI
  • Folate: 2% of the RDI
  • Manganese: 2% of the RDI

Like most fruits and vegetables, jalapeño peppers are a good source of fiber. One pepper provides 2% of the RDI for a person consuming 2,000 calories per day.

Jalapeños also contain lots of vitamin C and vitamin B6.

Vitamin C is an antioxidant that fights free radical damage and keeps your skin healthy and firm, while vitamin B6 is an essential nutrient involved in over 140 bodily reactions (2, 3, 4, 5).

One of the most unique compounds in jalapeños is capsaicin, an alkaloid that gives peppers their characteristic spicy quality and is responsible for many of their health benefits.

Summary Jalapeños are low in calories and a good source of fiber, vitamin C and vitamin B6. They also contain a compound called capsaicin, which gives them their spice.

Jalapeños may help you lose weight by boosting your metabolism, increasing fat burn and reducing your appetite (6).

Several studies have found that capsaicin and other similar compounds called capsaicinoids can boost metabolism by 4–5% per day, potentially making it easier to lose weight (7, 8).

In addition to boosting metabolism, capsaicinoid supplements have been shown to reduce abdominal fat and appetite so that people eat 50–75 fewer calories per day (6, 9, 10).

All of these factors help explain why regularly consuming chili peppers is associated with a significantly reduced risk of becoming overweight or obese over time (11).

While this research is promising, it is important to note that many of these studies investigated the effects of capsaicin or chili peppers in general, not just jalapeños.

Summary Research suggests that jalapeños and other spicy peppers may promote weight loss by boosting metabolism, increasing fat burn and reducing appetite.

Lab studies have shown that capsaicin has strong anti-cancer properties and is capable of killing over 40 types of cancer cells without harming normal cells (12, 13, 14).

Capsaicin fights cancer by (15, 16, 17, 18):

  • Stopping the growth and division of cancer cells
  • Slowing the formation of new blood vessels around cancer tumors
  • Preventing cancer from spreading to other areas of the body

However, human studies have not replicated the anti-cancer benefits found in lab studies.

In fact, several human studies have found that regularly eating chili peppers is linked to a higher risk of cancer. However, not all studies have shown this connection (19, 20, 21, 22).

It also appears that dosage matters. While high doses of capsaicin appear to slow the spread of cancer, low doses may encourage spreading (23).

More studies are needed to determine how capsaicin and chili peppers influence the risk of cancer in humans.

Summary Preliminary studies suggest that capsaicin may help fight cancer in high doses, but more research is needed to determine whether this holds true in humans.

Capsaicin is an effective pain reliever when used externally (24).

It soothes pain by temporarily blocking pain receptors in the area where it is applied. At first, a burning sensation may be felt, followed by numbness and an absence of pain (25).

Capsaicin lotions and patches are frequently used to relieve pain caused by the shingles virus, diabetic nerve pain and chronic muscle and joint pain (26, 27, 28, 29).

In one study, older adults with rheumatoid arthritis experienced a 57% reduction in pain after applying a capsaicin cream to their joints. This was significantly more effective than the placebo cream (29).

In addition to applying capsaicin to the skin, it can be used as a nasal spray to relieve migraine pain (30, 31).

While capsaicin-containing lotions and sprays may be effective at treating pain, it is unclear whether eating jalapeños or applying them to the skin has the same effect.

Summary Products that contain capsaicin can help relieve pain when used topically, but it is unknown whether jalapeño peppers have similar effects.

Stomach ulcers can be caused by a number of factors, including (32):

  • Growth of H. pylori bacteria within the stomach
  • High levels of stomach acid
  • Low blood flow to the stomach
  • Taking too many NSAID pain relievers
  • Drinking alcohol
  • Smoking
  • Stress

While it is commonly believed that spicy foods like jalapeños can cause or aggravate stomach ulcers, research has shown this to be false (32).

In fact, the capsaicin in chili peppers may protect the stomach from developing ulcers in the first place.

It may have this effect by reducing stomach inflammation in people with H. pylori and even helping kill off the infection. However, it is not clear whether the amount of capsaicin in jalapeños is large enough to have this effect (33, 34, 35).

Chili peppers can also help reduce the stomach damage caused by the overuse of NSAID pain relievers and alcohol, potentially preventing the formation of ulcers from the start (36, 37).

Summary While it is commonly believed that spicy foods can aggravate stomach ulcers, research suggests that capsaicin may protect the stomach from ulcers.

Spices and herbs have long been used in cooking to help prevent spoilage and food poisoning (38).

Compounds found in spicy chili peppers are especially powerful at slowing the growth of common foodborne bacteria and yeasts (39, 40, 41).

Chili extracts can even stop cholera bacteria from producing toxins, potentially reducing the impact of this deadly foodborne disease (42).

Beyond food poisoning, new research suggests that capsaicin can help prevent other types of infections, such as strep throat, bacterial tooth decay and chlamydia (43, 44, 45, 46).

However, it is important to note that all of these studies used chili extracts, not whole chilis, and were conducted in test tubes, not humans.

These early studies suggest that chili peppers may have strong antimicrobial properties, and future research is underway to determine if they may be used as natural preservatives or medicines.

Summary Jalapeños and other spicy chilis contain compounds that can prevent the growth of harmful bacteria and yeasts that cause infectious diseases.

Some of the biggest risk factors for heart disease include diabetes, high cholesterol and high blood pressure.

Capsaicin can help reduce the impact of these factors and may help keep your heart healthy (47, 48).

Eating 5 grams of chili peppers before a high-carb meal has been shown to help stabilize blood sugars and prevent the large spikes that occur after meals (49, 50).

Capsaicin has also been shown to lower cholesterol and lipid levels in animals, but no studies have been conducted in humans (51, 52).

Animal studies also suggest that capsaicin can help lower blood pressure by relaxing blood vessels, but there is no research to show whether this is true in humans (53).

Overall, preliminary research suggests that capsaicin and chili peppers may be beneficial for heart health, but more human studies are needed.

Summary Capsaicin and chili peppers have been found to have beneficial effects on blood sugars, cholesterol and blood pressure, but more human research is needed.

While eating jalapeños is associated with many promising health benefits, there are also some potential side effects.

The most common side effect is a temporary burning sensation of the mouth after eating. Depending on the spiciness of the chili, this reaction can range from mild to severe.

For people with a low tolerance to spicy foods, there are a few precautions that can reduce reactions to jalapeños (54, 55, 56):

  • Avoid scarring: Look for smooth jalapeño peppers without small brown lines, as scars indicate a spicier pepper.
  • Use gloves: Wearing gloves when handling peppers can prevent transferring the spicy compounds to other sensitive areas of your body like your eyes.
  • Remove membranes: Remove the white membranes inside the jalapeño before cooking with them, since the membranes have the highest concentration of capsaicin.
  • Drink milk: If the burning sensation becomes too strong, drinking full-fat cow’s milk can help temporarily reduce the pain.

At least one study has found that capsaicin can worsen heartburn, so those with reflux may want to avoid jalapeños if they trigger symptoms (57).

People with irritable bowel syndrome may also experience unpleasant symptoms after eating spicy chilis, especially if they are not a regular part of their diet. Common side effects include abdominal pain, burning, cramping and diarrhea (58, 59, 60).

Additionally, dried peppers and spices can be contaminated with aflatoxin, a type of mold that grows on certain foods in certain conditions. Selecting irradiated spices may help reduce your exposure (61, 62).

Summary The most common side effect of eating jalapeños is a temporary burning sensation of the mouth, but simple steps can be taken to reduce it. Those with heartburn, IBS or aflatoxin sensitivity may want to avoid chili peppers to avoid symptoms.

Jalapeños can be eaten raw, cooked, smoked (also known as chipotle peppers), dried and even powdered.

Research shows that there is little to no loss of capsaicinoids during the drying process and only a moderate reduction from smoking or pickling, so it can be beneficial to consume jalapeños in all of their forms (63, 64).

Jalapeños can be enjoyed:

  • Raw in salads, salsas, chutneys or guacamoles
  • Infused in spicy chili oils
  • Cooked in main dishes
  • Pickled, as a condiment
  • Smoked, as chipotle peppers
  • Blended into smoothies
  • Baked into cornbread or egg dishes
  • Stuffed with meat, cheese or pilafs

According to estimates, the average person living in the United States or Europe consumes roughly 1.5 mg of capsaicinoids per day.

Capsaicinoid consumption is much higher (between 25–200 mg per day) in countries like India, Thailand and Mexico, where cooking with chilis is more common (65).

Research shows that people who regularly eat chili peppers have a 12% reduced risk of death from any cause, even when controlling for other factors, so it may be beneficial for people to add more spicy peppers to their diets (66).

Generally, the spicier the pepper, the more health-promoting capsaicin it contains, but newer research also indicates a health benefit for non-spicy capsaicinoid compounds (67).

Summary Jalapeños can be eaten in a variety of ways, including raw, cooked, smoked (also known as chipotle peppers), dried and even powdered.

Jalapeños are a versatile and nutritious fruit that can be enjoyed in a variety of ways.

They contain capsaicin, a compound that likely accounts for many of their health benefits, including weight loss, pain relief, improved heart health and lower ulcer risk.

While safe for most, they can cause a temporary burning sensation of the mouth and uncomfortable intestinal side effects in some.

If you enjoy spicy food and do not experience any side effects, jalapeños can be a healthy addition to your diet.