Irritable bowel syndrome (IBS) is a chronic functional condition affecting the gastrointestinal tract, characterized by recurrent abdominal pain, discomfort, and changes in bowel habits, such as diarrhea, constipation, or a mixed pattern. IBS is estimated to affect 10% to 20% of the world's population and is more common in women and young individuals. Nutritional management is important in treating this condition, helping to alleviate symptoms and improve patients' quality of life.

The relationship between diet and irritable bowel syndrome

Many IBS patients report that certain foods worsen symptoms. This occurs due to visceral hypersensitivity and altered intestinal motility, which make the digestive tract more sensitive to certain nutrients. Studies suggest that foods rich in short-chain fermentable carbohydrates, known as FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols), are particularly problematic for this group of patients.

The low FODMAP diet has been extensively studied as an effective intervention for managing symptoms. However, this approach must be conducted by qualified professionals to avoid nutritional deficiencies and ensure that the patient's dietary needs are met.

Diagnosis and evaluation of patients with IBS

Before implementing any nutritional intervention, it is essential to confirm the diagnosis of IBS based on the Rome IV Criteria. In addition, dietary history, reported symptoms and possible individual triggers must be evaluated.

During the consultation, ask the patient about:

• Frequency and duration of symptoms;

• Association of symptoms with the consumption of specific foods;

• Presence of stress factors or psychological disorders;

• Bowel habits and relationship with lifestyle.

Laboratory and imaging tests may also be ordered to rule out other conditions, such as celiac disease, lactose intolerance, or inflammatory bowel disease.

Main nutritional approaches in the treatment of IBS

1. Low FODMAP Diet

The low-FODMAP diet is one of the most effective strategies for alleviating IBS symptoms. It consists of three main phases:

• Restriction phase: temporary elimination of foods rich in FODMAPs, such as dairy products, onions, garlic, wheat, legumes, and certain fruits;

• Reintroduction phase: phased introduction of food to identify individual triggers;

• Customization phase: creation of a dietary plan adapted to the patient's tolerance.

Studies show that around 75% of patients report significant improvement in symptoms after adopting this diet.

2. Control of fat consumption

Fat-rich foods may exacerbate symptoms in individuals with IBS due to the slowdown of gastric emptying and increased intestinal motility. It is recommended to choose healthy fat sources, such as olive oil, avocado and fish rich in omega-3, and avoid ultra-processed foods and fried foods.

3. Increased fiber consumption

The role of fibers in IBS is complex, as the type of fiber ingested influences symptoms. Soluble fibers, found in foods such as oats, carrots, and unpeeled fruits, can help with intestinal regulation. On the other hand, insoluble fibers, present in wheat bran, may worsen symptoms in some patients.

It is important to introduce fibers gradually and in conjunction with adequate hydration.

4. Modulation of the intestinal microbiota

The alteration in the intestinal microbiota is a key factor in the physiopathology of IBS. Probiotics can be used as an adjunct intervention to improve microbial diversity and reduce symptoms such as abdominal pain and bloating.

5. Stress Management and Attention to Lifestyle

Psychological factors, such as anxiety and depression, are strongly associated with IBS. Interventions that combine dietary modifications with stress management techniques, such as mindfulness, yoga, or cognitive behavioral therapy, have proven effective.

Considerations about nutritional supplementation

Supplementation can be a useful tool in managing IBS, especially in cases where there are nutritional deficiencies or the need for additional support. Some options include:

• Soluble fibers: may help regulate bowel movements, such as psyllium;

• Probiotics: Indicated to improve the balance of the intestinal microbiota;

• Vitamin D: Deficiencies are associated with a greater severity of IBS symptoms;

• Peppermint oil: Studies suggest that it may help alleviate intestinal spasms.

It is important that supplementation is personalized and based on the patient's individual needs.

Conclusion

The nutritional management of irritable bowel syndrome is a challenge that requires a multidisciplinary and personalized approach. Understanding the interactions between food, gut microbiota, and psychological factors is fundamental to successful treatment.

Health professionals must be aware of the latest evidence and trained to apply effective strategies, such as the low FODMAP diet, the modulation of the intestinal microbiota, and adequate nutritional supplementation.

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