In recent years, many diseases have become the talk of the town, and seem to be spreading throughout the population. Such is the case with Crohn's disease. But what is it?

What is Crohn's disease?

Crohn's disease is a chronic inflammatory disease of the digestive tract that causes thickening of the lining, as well as ulcers and, occasionally, fissures and perforations. These lesions can affect the entire digestive tract, from the esophagus to the rectum. Non-contagious and evolving in flare-ups, Crohn's disease can cause stomach pains and diarrhea that can persist for several weeks. Over time, these flare-ups can lead to fatigue, anemia, malnutrition and weight loss.

Episodes vary in duration and frequency.

Symptoms are only observed during inflammatory flare-ups (crisis period); during periods of remission, patients may show no symptoms at all.
In a third of cases, Crohn's disease, also known as Terminal Crohn's Ileitis, affects only the small intestine (especially the terminal part, the ileum), and only the colon in another third of cases. The remaining third involves both ileum and colon.

In addition to daily discomfort, patients may also complain of fatigue, sometimes associated with fever or anemia. When flare-ups last several weeks, the patient may lose weight and show signs of malnutrition.

In some cases, digestive symptoms may be associated with other manifestations, such as rheumatoid arthritis in the limbs or spine (spondylitis), uveitis, or skin problems (erythema nodosum, small, firm, red nodules in the thickness of the skin).

These non-intestinal symptoms reflect a state of general inflammation, with a tendency for the immune system to attack various organs.

Crohn's disease, a growing disease?

In France, Crohn's disease affects around one person in a thousand. Just under four thousand new cases are diagnosed each year. Crohn's disease has become more frequent since the 1950s. There are major variations in its frequency from one country to another: it is more common in northern European countries than in southern ones.
Crohn's disease is most often diagnosed in young adults (aged between 20 and 30), but is sometimes seen in children and adolescents, or in elderly subjects. Women are slightly more often affected than men.

What causes it?

The causes of Crohn's disease are poorly identified. Today, it is thought that Crohn's disease develops through genetic factors (a familial predisposition), as some thirty genes have been identified as favoring the development of the disease. In particular, the NOD2/CARD12 gene encodes proteins involved in the functioning of the immune system.

Similarly, the quality of the intestinal microbiota is thought to be involved (the latter being initially transmitted during childbirth and also dependent on genetic factors). Indeed, intestinal dysbiosis associated with unidentified environmental factors (lifestyle) is predisposing to the development of chronic inflammatory diseases such as Crohn's disease.
However, Crohn's is not a purely genetic disease, and the presence of other, as yet unknown, factors is essential for its onset.

Is Crohn's disease an autoimmune disease?

The interaction of genetic and environmental factors causes the patient's immune system to attack the cells lining the digestive tract. This suggests that Crohn's is an "autoimmune" disease, like psoriasis, rheumatoid arthritis, spondyloarthritis or multiple sclerosis. This hypothesis is reinforced by the nature of Crohn's disease non-intestinal symptoms, such as uveitis and rheumatism, and by the effectiveness of treatments aimed at reducing immune system activity.

Can the disease be prevented?

At present, there are no preventive measures that can reduce the risk of suffering from Crohn's disease. Relapse prevention relies on maintenance treatment.

However, as the disease depends on the integrity of the microbiota, it is advisable to maintain it by avoiding a diet too rich in carbohydrates and by taking regular probiotic cures.

Smoking increases the severity and frequency of Crohn's disease flare-ups, as well as the need for surgery. Smokers with Crohn's disease are advised to quit smoking completely as soon as the disease is diagnosed. Similarly, children with Crohn's disease should, if possible, live in a non-smoking environment.

During flare-ups, diet can influence the severity of symptoms. In general, doctors recommend excluding fruit and vegetables during flare-ups. Other foods can aggravate symptoms, but their nature depends on the individual patient. So, during flare-ups, it's a good idea to keep a food diary to identify these "aggravating" foods (red meat, certain cereals and dairy products are often cited). Excluding a "suspect" food from your diet for two or three weeks will give you a better idea of whether your suspicions are well-founded.

Spices and drinks containing caffeine can also aggravate the symptoms of Crohn's disease flare-ups.

Are there any treatments available?

Crohn's disease is treated with drugs designed to reduce the activity of the immune system: anti-inflammatories and immunosuppressants. Taking a maintenance treatment when the disease is not flaring up helps to control the disease and avoid possible complications. Crohn's disease treatment may also involve surgical measures to remove the part of the intestine causing complications, treat abscesses or remove fistulas.

The undesirable effects of oral corticosteroids appear when the treatment is continued for several weeks: swelling (edema), diabetes, osteoporosis, muscle wasting and abnormally thin skin, cataracts, glaucoma, etc. People taking long-term corticosteroids should undergo regular check-ups to detect these possible side effects.

More natural anti-inflammatory treatments are prophylactic. Research continues into the role of microbiota quality in chronic inflammatory diseases, but there is every reason to believe that it is involved. Maintaining the microbiota is highly recommended, and requires a low-glycemic index diet, i.e. limiting refined sugars and flours. Choose wholemeal flours and sugars such as xylitol or erythritol, which don't raise blood sugar levels and have a very interesting sweetening power, not to mention being low in calories!