Spicy Foods, Digestive Health, & Sports

November 18, 2022

Nowadays, spicy ingredients have become almost indispensable in our cuisine. Apart from enhancing the flavor of our dishes, did you know that it can be really beneficial to health?


Let's start by talking about the active compounds in spicy (pungent) foods. Among the most commonly used worldwide, we will highlight pepper, which contains piperine, and chili peppers, as well as certain varieties of peppers (paprika), which contain capsaicin.

Capsaicin is much more potent in its effects than piperine.

These compounds belong to the alkaloid family (just like caffeine, nicotine, and morphine). They are the end product of the metabolism of certain plant amino acids as a protection against herbivores. Curiously, birds do not have receptors for spiciness, so they can disperse the seeds of plants containing capsaicin. 

How to Measure Spiciness? The Scoville Scale


Capsaicin concentration depends on the plant's genetic structure and the conditions in which it grows (heat and drought increase the concentration in its fruits), as well as the degree of maturity of these, achieving maximum spiciness at the moment when the green fruit begins to change color. In 1912, Wilbur Scoville developed a sensory method to classify the intensity of peppers or hot peppers called the Scoville Scale.

Other spicy foods present in our diet are garlic and onion, which are spicy when consumed raw or semi-raw. This is due to allicin, which is different from alkaloids: it is a sulfur compound, produced by these vegetables also as protection against the attack of certain herbivores. 

The effects of allicin are lost when they are cooked at high temperatures and when left for some time in the ambient air. 

Other less popular spicy ingredients are mustard, wasabi, and radishes, which contain allyl isothiocyanate, another type of spiciness different from capsaicin. 

The concentration of piperine is higher in black pepper than in white pepper due to the time and process of harvesting the plant.

Nutritional Properties of Piperine and Capsaicin

The nutritional properties of pepper and hot peppers are interesting because they offer a considerable amount of vitamins and minerals, but it must be taken into account that to benefit from optimal doses of these nutrients, would mean consuming enormous quantities of black pepper and chili peppers.

For example, the richness in potassium of the pepper is about 1,326 mg per 100 g and if we compare it with the banana which offers us about 368 mg per 100 g, it is much higher, right? 

But let's say that to obtain the same amount that the banana offers (if we consume them of a considerable size that already weighs more than 100 g), you would have to consume at least 50 g of pepper (6-8 teaspoons a day) or 300 chilies a day, which would be unthinkable. 


These spicy substances have multiple benefits, such as:

  • Stimulants and antidepressants (by an increase in the brain neurotransmitters activity such as noradrenaline, serotonin, and dopamine)

  • Analgesics due to their action at the level of nociceptors (pain receptors)

  • They facilitate weight loss because they activate metabolism and lipolysis.

  • They are antioxidants

  • Cardiovascular protectors due to their vasodilatation effects

  • Antineoplastic: immune system stimulants

  • They improve rhinitis problems due to their decongestant effect.

  • They have gastrointestinal effects.

How Hot Spices Act at the Gastrointestinal Level

  • They increase the secretion of digestive juices

Digestion begins in the mouth. Spiciness stimulates multiple sensory receptors (especially nociceptors: pain receptors) in the tongue and oral cavity: the taste buds (enhancing the perception of taste), as well as the vagus nerve, which increases the activation of the glands involved in digestion (salivary, gastric, biliary, pancreatic, intestinal), improving digestion, reducing flatulence and neutralizing certain microorganisms.

  • They amplify the absorption of multiple nutrients

This is due to an increase in intestinal permeability (which in excess is what we call the "Leaky gut syndrome") and could lead one to think that the greater the intestinal permeability, the greater the assimilation of nutrients. But this is not entirely true.

The intestinal mucosa constitutes a sophisticated barrier that allows a careful selection of substances absorbed into the organism. 

At the same time, it prevents certain harmful substances such as pathogens, toxins, or allergens from entering the bloodstream. 

Regarding microorganisms and their toxins, although gastric acids attack them, they may not be completely destroyed ( some will be resistant), which means that even if fragments of them reach the bloodstream, the immune system would detect them as if they were a real infection with the consequent immunological reaction that can vary from one individual to another. And if they arrive alive, they will cause an infection in the blood (septicemia). 

There are many allusions to spiciness and the eradication of microorganisms (it is suggested that it is secondary to the increase of hydrochloric acid) but the reality is that no conclusive study has been found. Allicin, on the other hand, is an exception because it acts differently by directly inhibiting the pathogenic mechanisms of microorganisms.

The increase in intestinal permeability occurs at the expense of an inflammation of the enterocytes (cells that line the wall of the digestive tract), causing a greater separation between them, and disturbing the local production of a part of the enzymes that help the completion of digestion. 

Thus, an imbalance of the intestinal flora can occur, with a dominant production of pathogenic microorganisms, which could lead to a local infection that can become serious. 

Here we could briefly mention zonulin, a protein produced locally by enterocytes, which is also involved in intestinal permeability regulation (the higher the production of zonulin, the higher the intestinal permeability). 

The production of this protein is regulated by the presence of certain intestinal bacteria and gluten. 

So, let's say that an athlete whose diet is mainly based on pasta and bread, which contain varying amounts of gluten, is associated with an abusive consumption of spicy food, and the excess of carbohydrates that would enhance the overproduction of pathogenic bacteria and produce intestinal alterations.

The arrival of poorly digested food molecules into the bloodstream can cause a disturbance in the immune system, which would recognize them as foreign, leading to trigger intolerances and food allergies (or aggravating them) as well as autoimmune reactions. 

In addition, if there is a massive entry of molecules in this state, it would have secondary repercussions in an overload of work at the hepatic level to try to reduce this "toxic" state.

If consumed in excess, it could cause gastroesophageal reflux (or aggravation of the same) or gastrointestinal ulcers due to increased production of hydrochloric acid, which could trigger a neoplastic process secondary to a higher acid exposure to which the digestive cells are used of. 

The excess hydrochloric acid can also cause hypokalemia and higher risks of muscle cramps and cardiac arrhythmias, among others. And as we have previously explained, it is impossible to compensate for this potassium deficit with the simple intake of a few grams of piperine. 

Interesting Aspects Concerning Piperine and Consumption Precautions

The spicy compounds are fat-soluble (they dissolve better in fats), so their effect is enhanced when associated with a fatty ingredient such as olive oil or avocado. 

Likewise, if you want to quickly relieve your mouth from the spicy effect, it is better to consume milk, butter, or ice cream, instead of water.

Black Pepper and Turmeric

As we have said, excess piperine increases inflammation and intestinal permeability. Some studies show that the bioavailability of turmeric (turmeric polyphenol, its active compound and very beneficial for health) is quite low when associated with piperine than if we associate it with ginger and/or cloves (which have less aggressive pungent active ingredients and at the same time a good amount of polyphenols in addition to those of turmeric). This way you will give an exotic touch to your dishes. And always remember to associate it with a fatty ingredient for better absorption (since they are all liposoluble). 

Regarding Drugs

The higher the intestinal permeability, the higher the bioavailability and, therefore higher the blood concentration. 

This could lead to greater side effects. Here we can refer to non-steroidal anti-inflammatory drugs (NSAIDs) such as Ibuprofen, consumed by a considerable part of athletes, and their consequent increased risk of a gastrointestinal ulcer when associated with spicy foods.

Also, people taking anticoagulants with high consumption of black pepper can increase the risk of bleeding.

Since we have already mentioned turmeric and garlic: we must be cautious and also advise against the consumption of these ingredients in people taking coumarin anticoagulants because of the added blood-thinning effect of curcuminoids and garlic allicin, which would also lead to an increased bleeding risk.

What is the Recommended Daily Dose?

There is not too much reliable data on what is the recommended amount of capsaicin, but we recommend favoring the consumption of nutritional doses (and through food) rather than pharmacological doses (capsules) so that there will be much less incidence of its deleterious effects.

We can recommend the following guidelines based on certain studies, to obtain a balanced benefit/risk effect

  • Piperine - 2 mg to 8 mg (maximum a teaspoon of black pepper)

  • Capsaicin - it's difficult to calculate with each food since the amount is very variable depending on the characteristics and weight of the pepper. It can vary between 35 mg/g and 53 mg/g, but it would be advisable not to consume it daily.

  • The consumption of garlic and onion - better fermented or marinated (which maintains all its properties, being less aggressive, at the same time slightly removes the taste so peculiar and sometimes annoying). No maximum daily doses have been found, in any case, the consumption of these foods are much more beneficial overall than the rest of the spicy foods. 

Final Word

A touch of spiciness can be beneficial, but in excess and predisposed people, especially before intense training or competition (even after), it could lead to harmful gastrointestinal effects. 

Adding the stress of physical and psychological effort on top would further disrupt the proper functioning of the gastrointestinal tract. 

Therefore, you should be more selective and moderate in your hot spices selection and consumption, especially avoiding them before intense training and competitions.