Irritable bowel syndrome (IBS) is a functional bowel disease characterized by abdominal pain or abdominal discomfort with altered bowel habits, with examination to exclude organic diseases that could cause these symptoms. The current global prevalence of IBS is 11.2%, while the prevalence in Europe is 4.7%-25% and slightly lower in Asia, with 4.6%-5.67% in China. The incidence of IBS is significantly higher in women than in men, and studies have found that serum testosterone levels are negatively correlated with the severity of IBS symptoms, and that differences in sex hormone levels can lead to greater sensitivity to visceral pain in women. The etiology and pathogenesis of this disease are still unclear. It is currently believed that it may be related to abnormal intestinal dynamics, abnormal visceral sensation, psychological factors, infection, food intolerance, intestinal flora dysbiosis, disturbance of brain-gut axis regulation, altered intestinal mucosal permeability, genetic and environmental factors and cholecystokinin. Because of the high prevalence of IBS and the lack of effective drug treatment, which seriously affects the quality of life of patients and increases the huge medical costs, it is especially important to seek more effective and economical treatment methods.
More than half of the patients with IBS believe that they have uncomfortable symptoms after consuming certain foods. Common IBS symptoms related to diet include postprandial epigastric pain, feeling of fullness or flatulence, and postprandial diarrheal episodes. Therefore, it is necessary to treat them with a proper diet. One study showed that most IBS patients believe that certain foods can trigger GI symptoms, especially foods rich in carbohydrates and fats or foods that can cause histamine release. Another study showed that 62% of IBS patients adopted food restriction or reduction to relieve their symptoms. Through relevant statistics, Wang Weida et al. found that the common foods that can trigger or aggravate IBS symptoms are cold foods, spicy foods and greasy foods in order, suggesting that different foods may cause neuroendocrine and/or gastrointestinal physiological changes through multiple pathways, thus triggering IBS. The study found that spicy food, fried food, alcohol abuse, fatigue, chronic anxiety, sensitive personality, family history of diarrhea and gastrointestinal tract infection were all independent risk factors for IBS, suggesting that the development of IBS is influenced by various factors, among which chronic fatigue and anxiety can easily lead to mental stress, which leads to digestive system dysfunction. prevention. To sum up, IBS patients should pay attention to avoid cold, spicy and greasy food in their diet, and should also avoid excessive alcohol consumption.
Most patients with IBS have diarrhea and/or increased bowel movements after ingesting cold foods or having a cold abdomen, and their symptoms are relieved by avoiding cold foods, applying heat to the abdomen, and drinking hot water. It was found that raw and cold food can stimulate the activation of epithelial cells in the stomach wall to synthesize and release 5-hydroxytryptamine, which can act on adjacent endocrine cells and the enteric nervous system to release a series of neuropeptides such as substance P and calcitonin gene-related peptide, which has a strong pro-digestive smooth muscle contraction and stimulates the secretion of water and electrolytes from the small intestine and colon mucosa. In addition, pathogenic bacteria carried by raw foods can increase the probability of intestinal infections, and some studies have shown that 3% to 36% of intestinal infections can lead to persistent IBS symptoms after the infection has healed, called post-infectious IBS. Up to half of IBS patients develop GI symptoms such as abdominal pain, diarrhea, and increased frequency of bowel movements after ingesting spicy foods (commonly including chili peppers, pepper, onion, ginger, and garlic). It is now believed that transient receptor potential vanilloid subtype 1 (TRPV1) plays an important role and that TRPV1 mediates the onset of abdominal pain, gastrointestinal cramps, increased abdominal pressure and burning sensation. Studies have shown that women who consume spicy foods with high frequency (>10 times per week) have a 2-fold higher risk of IBS than women who do not consume spicy foods. Such patients who abstain from spicy foods can experience significant improvement in their symptoms.
Nearly half of patients with IBS experience diarrhea and bloating after consuming fatty foods. A high-fat diet stimulates the secretion of cholecystokinin and glucagon-like peptide-1, leading to increased intestinal peristalsis and increased secretion of intestinal fluid.
Ethanol is a gastrointestinal agonist, and some studies have confirmed that diarrheal IBS has the highest ethanol intake compared to other subtypes and healthy controls, and that ethanol is significantly and positively associated with the severity of symptoms in patients with diarrheal IBS. Hey et al. noted that ethanol may cause osmotic diarrhea due to its high sugar content.
The study of food intolerance is currently a research hotspot in European countries, and its application is rapidly gaining popularity worldwide. One of the more widely accepted theories in this field is the principle of the development of food intolerance as described by German scientist Dr. Fooke, who believes that many foods are not fully digested by the body because they lack the appropriate enzymes and are recognized by the body as foreign substances, leading to an immune response and the production of food-specific IgG antibodies. There are currently 14 food intolerances tested, including beef, milk, chicken, pork, cod, rice, corn, shrimp, crab, soy, egg whites/yolk, tomatoes, mushrooms, and wheat. Several clinical randomized controlled trials have shown that dietary interventions result in good improvements in all aspects of abdominal pain severity and frequency, bloating, quality of life, and anxiety/depression in patients with IBS. Other studies have indicated that a dietary elimination approach based on food-specific IgG antibodies is superior to patient self-exclusion diets in improving quality of life and health.
The relationship between food and IBS is receiving increasing attention and dietary restrictions are becoming more common in IBS patients, but most are not directed by a health care practitioner. In clinical practice, patients should be encouraged to have a balanced diet to avoid possible malnutrition. Low-carbohydrate dietary regimens have been shown to alleviate symptoms in patients with IBS, but must be modified to ensure nutritional adequacy; therefore, it is important to develop an effective, rational, and individualized dietary regimen. The basic dietary adjustment includes regular diet, three meals a day should be regular and quantitative, not overly hungry, not overeating, which is conducive to the balance of intestinal digestion and absorption, and avoid intestinal dysfunction caused by uncontrolled diet. Avoid eating cold and spicy foods, consume less high-fat diet, and avoid excessive alcohol consumption. Because food intolerances are mostly caused by the usual daily food, and the onset of the disease is delayed, it is difficult to detect the cause and make self-diagnosis in time. Through food intolerance testing, we can promptly identify unsuitable foods in the daily diet, adjust the diet, and adopt methods such as rotation and avoidance of food to avoid the adverse effects of intolerant foods on the human body, thus reducing the psychological and economic burdens of patients and significantly improving their quality of life. It is recommended that basic dietary adjustment combined with dietary adjustment based on food-specific IgG antibodies can not only effectively reduce the gastrointestinal symptoms of IBS patients, but also urge patients to abandon poor dietary habits while ensuring a balanced diet, thus improving the quality of life.