Digestive distress after eating certain meals is a common problem, and Mexican food is a frequent trigger for many people. This reaction often manifests as diarrhea, defined as an increased frequency and wateriness of stools. The body’s response is not a sign of poor food quality, but rather a complex physiological reaction to specific compounds and a heavy load of certain nutrients. The reasons are multifaceted, involving chemical compounds in chili peppers and the way the body processes fats and complex carbohydrates.
Capsaicin and Accelerated Motility
The burning sensation associated with spicy Mexican dishes comes from capsaicin, the active chemical compound found in chili peppers. Capsaicin interacts with a pain receptor called Transient Receptor Potential Vanilloid 1 (TRPV1). This receptor is located throughout the entire gastrointestinal tract, from the stomach to the colon.
When capsaicin binds to the TRPV1 receptors in the intestine, it triggers a response the body interprets as irritation or heat. This irritation stimulates the intestinal lining and sensory nerves, causing the digestive tract to react defensively. The primary reaction is an acceleration of peristalsis, the muscular contractions that move food through the intestines.
This rapid increase in motility shortens the overall transit time of digestive waste. When contents move too quickly through the large intestine, there is insufficient time for the body to reabsorb water from the stool. This results in the characteristic loose, watery stool, or diarrhea, sometimes accompanied by a burning sensation as the capsaicin-laden contents exit the body.
High Fat Content and Digestive Load
Many traditional Mexican preparations, such as deep-fried items, refried beans, and dishes heavy with lard or rich sauces, contain a high concentration of fats. The digestive system must manage this significant fat load, which primarily falls to the small intestine. Fat digestion requires the release of bile acids, produced by the liver, to emulsify the lipids.
If the amount of fat consumed is too high, or if the body is unable to reabsorb bile acids efficiently, the excess bile acids spill over into the large intestine. These unabsorbed bile acids act as irritants in the colon.
In the colon, the excess bile acids stimulate the secretion of fluid, overwhelming the colon’s ability to absorb water. This process, known as bile acid diarrhea, causes a rush of water into the bowel lumen. A similar effect occurs when unabsorbed dietary fat reaches the colon, drawing water in via an osmotic effect, leading to the rapid onset of watery stools.
Common Undigested Triggers (Lactose and Complex Carbohydrates)
Beyond spice and fat, two other common components of Mexican cuisine often lead to digestive issues because they frequently escape full digestion in the small intestine.
Lactose
The first is lactose, the sugar found in dairy products like sour cream, crema, and soft cheeses. Lactose intolerance is caused by a deficiency in the enzyme lactase, which is required to break down lactose into absorbable simple sugars. When lactose remains undigested, it passes into the large intestine, where it acts as an osmotically active substance. This means the undigested sugar draws water from the body’s tissues into the intestinal lumen, increasing the volume of fluid in the colon. Bacteria in the colon then ferment the lactose, producing gas, bloating, and contributing to the fluid retention that results in diarrhea.
Complex Carbohydrates (FODMAPs)
The second set of triggers are complex carbohydrates found in legumes and flavor bases, specifically the fermentable sugars in beans, onions, and garlic. Beans contain oligosaccharides, a carbohydrate type many people lack the necessary enzymes to fully break down. Onions and garlic contain fructans, another type of fermentable carbohydrate. These poorly absorbed carbohydrates, known collectively as FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols), travel to the large intestine where gut bacteria rapidly ferment them, producing large amounts of gas. The presence of these osmotically active, undigested compounds accelerates transit time, pushing the intestinal contents out quickly.
Strategies for Prevention
Minimizing digestive distress from Mexican food involves making conscious adjustments to your meal selection. Since capsaicin is a major trigger, request dishes prepared with a mild heat level. Asking for sauces and salsas on the side allows you to control the exact amount of capsaicin consumed.
To reduce the digestive load from high fat content, opt for preparations that rely on grilling or baking rather than deep-frying. Choosing chicken fajitas or grilled fish tacos instead of deep-fried items significantly lowers fat intake. This helps prevent the overflow of unabsorbed fat and bile acids into the colon.
If lactose is a trigger, request that dairy toppings like sour cream, crema, or shredded cheese be omitted. Hard cheeses are naturally lower in lactose and may be tolerated. For complex carbohydrates, consuming beans in moderation or choosing well-prepared options can help, as soaking and draining beans during preparation reduces their fermentable sugar content. Addressing one or two of these triggers can often provide noticeable relief.