A. Why we should pay attention to the diet and nutrition of inflammatory bowel disease
Patients with inflammatory bowel disease often suffer from malnutrition, underweight, and even cachexia. According to statistics, 56% to 75% of patients with inflammatory bowel disease (especially Crohn’s disease) have underweight, and 60% to 80% have anemia. They are deficient in basic nutrients such as amino acids (basic components of protein), glucose (carbohydrates), minerals and trace elements, vitamins and water, but the most important is protein deficiency. The most direct causes of malnutrition are inadequate intake, excessive loss and impaired absorption of dietary nutrients.
The relationship between inflammatory bowel disease and dietary factors is still controversial. It has been suspected that certain foods or the dietary intake of certain harmful components, such as macromolecular compounds, bacteria or other pathogenic organisms and their antigenic components, trigger an abnormal response of the intestinal immune mechanism, causing immune damage to the gastrointestinal mucosa that is difficult to abort. Animal studies have confirmed that inflammatory bowel disease does not develop even when the genetic background for its development is clearly present, as long as the gastrointestinal diet is not followed. There is a popular saying that “if you don’t eat, you don’t have inflammatory bowel disease”. However, without eating, there is no nutritional intake and no recovery for the patient. Many patients are often afraid to “eat” because they have abdominal pain, diarrhea, blood in the stool, etc. after eating because of strictures, obstructions, ulcers and bleeding in the digestive tract. They think that “it is better to eat less or not to eat rather than to eat harmful”. In some cases, due to surgery, removal of part of the intestine, or fistula, the amount and speed of diet is limited, and the food eaten is not completely digested and absorbed. On the other hand, during the acute activity of inflammatory bowel disease or in patients with more than moderate activity of the disease, in addition to the reduction of the absorption area due to the extent of the lesion, which affects the absorption of nutrients and vitamins and minerals, there is a constant loss of blood and tissue fluid components due to exudation and bleeding at the site of the lesion. This is significantly exacerbated during active disease in Crohn’s disease patients. Moreover, the acute activity of the disease brings about stress in organ functions and a significant increase in nutritional depletion, which, together with the effects of long-term medications such as corticosteroids and aminosalicylates, makes nutritional deficiencies increasingly problematic. In addition to protein and fat, vitamin A, folic acid, zinc, calcium, potassium and magnesium deficiencies are present to varying degrees. Patients show signs of weakness, weight loss, reduced immune function, and difficulty in wound healing. In turn, malnutrition directly affects the repair of damaged areas of the intestine. Once trapped in this vicious cycle, the patient’s condition rapidly worsens and systemic failure occurs.
The similarities and differences in the dietary and nutritional management of Crohn’s disease and ulcerative colitis
Crohn’s disease may affect all parts of the digestive tract, mainly the small intestine, but most often the distal part of the small intestine, the terminal ileum, followed by the large intestine immediately adjacent to the terminal ileum. Ulcerative colitis, on the other hand, invades essentially only the colon. Also in Crohn’s disease or ulcerative colitis, the extent of the lesion varies, as does the size of the invasion and the impact on the patient’s nutritional metabolism. In mild cases, the difference may be less than normal, while in severe cases the patient’s life may be at risk. Both Crohn’s disease and ulcerative colitis can present with impaired absorption and excessive loss of nutrients, but because small bowel lesions are seen primarily in the former, malabsorption is significantly more severe in patients with Crohn’s disease than in the latter.
The small intestine is the main site of nutrient absorption. Enzymes secreted by the mucosa of the small intestine mainly break down carbohydrates, such as lactose into galactose and glucose, which are then absorbed into the bloodstream to be used by tissues and organs such as the liver. Protein is mostly digested and broken down into amino acids in the small intestine, while fat becomes fatty acids, triglycerides and cholesterol. The small intestine also secretes some proteases and lipases to break down the corresponding nutrients. All these small molecules are absorbed in the small intestine and transported to the body. Iron is absorbed mainly in the upper part of the small intestine. The final small intestine is responsible for the absorption of vitamin B12, folic acid and other important hematopoietic factors. In contrast, the large intestine has a relatively simple function, absorbing water that has not been absorbed by the small intestine. Therefore, it is not difficult to understand that in inflammatory bowel disease, especially in those with lesions in the small intestine, the digestion and absorption of the above-mentioned nutrients can be severe. Moreover, Crohn’s disease affects nutrient metabolism differently in different areas. Zinc deficiency can occur in both ulcerative colitis and Crohn’s disease, but is more severe in Crohn’s disease, and zinc deficiency causes a much more severe decrease in immune function. The same type of Crohn’s disease anemia can also be different. In Crohn’s disease with a predominantly terminal ileal lesion, megaloblastic anemia can occur in the absence of vitamin B12 and folic acid. In the case of ulcerative colitis, the impact on the digestion and absorption of nutrients in the small intestine is smaller because only the large intestine area is diseased. Therefore, the impact on nutrient metabolism is also less than in Crohn’s disease. Because of this, there are relatively few patients with ulcerative colitis who suffer from severe malnutrition, mainly due to recurrent mucus and blood stools and the development of iron deficiency anemia. We are also talking about the dietary management and nutritional support of Crohn’s disease.
Dietary management and nutritional support for patients with different conditions
In order to ensure the nutrition of patients with inflammatory bowel disease and to avoid overloading the gastrointestinal tract with digestion and absorption and exacerbating inflammation, various dietary formulas and nutritional support treatments have been designed. For patients with extensive lesions, severe disease, and complications that cannot be addressed by the gastrointestinal diet, special diets or total parenteral nutrition are required. The latter is a nutritional support treatment that does not go through the gastrointestinal tract at all and relies only on intravenous input.
1. Diet and nutrition for patients in remission or mild disease
Patients who are in remission or mildly ill are those who do not have fever, have diarrhea three times a day or less, have no or little blood in their stools, and have normal blood counts, hematocrit, sedimentation, and C-reflective protein. Nevertheless, their dietary management should be taken very seriously. It is important to have adequate nutritional intake to ensure the repair of intestinal lesions, but also to avoid inappropriate diet that could promote disease activity. Patients should communicate frequently with their physicians and dietitians for dietary and nutritional guidance and should not assume that they have recovered and can eat without concern.
In addition to caloric intake (about 1200 calories a day for those without physical activity), protein intake must be emphasized in order to ensure the repair of intestinal lesions. Other nutrients should not be neglected either. These patients should also pay attention to supplementation with foods rich in folic acid, zinc, calcium and other nutrients. In a sense, most of the foods available to normal people are basically not contraindicated for patients with inflammatory bowel disease. Meat, fish, poultry and eggs, milk and dairy products provide essential proteins and other nutrients and are also suitable for them. The emphasis of the diet is not on which foods can be eaten to prevent relapse, but rather on how they are selected, prepared, and eaten.
In patients with inflammatory bowel disease, the digestive and absorption area of the intestine has been reduced. The limited area for nutrient absorption must be used to achieve the absorption of more nutrients. This places different demands on food processing and cooking. In order to break down the ingested food, meat or vegetables into large molecules and then degrade them into small molecules for absorption, the food must be cooked thoroughly, cooked well, and cooked simply, using less or no coloring, spices and seasonings that are not nutritious or even harmful and irritating. Do not add sugar, especially refined sugar, as epidemiological studies have shown that refined sugar is associated with the onset and activity of Crohn’s disease. Cooking Good food should be predominantly semi-liquid and liquid in nature, and food or dishes should not be cooked very hard or half-cooked. Stir-fry dishes are mostly unsuitable for patients with inflammatory bowel disease. Raw, semi-raw, pickled, brewed, coarse, spicy, fried, greasy, and unfresh foods and dishes need to be avoided.
The diversity of disease types and the degree of intestinal involvement in patients with inflammatory bowel disease, as well as individual differences, mean that it is not possible to develop a fixed diet plan that will work for all patients. Moreover, the disease itself is constantly changing, and dietary patterns must change with it. Therefore, dietary and nutritional management must have both overarching principles and must be implemented on an individualized basis. The overall principle is to achieve a balanced diet, also known as a healthy diet. It must cover the patient’s daily nutritional quota and satisfy all the nutritional components required by the body. Since most of these patients are deficient in many nutrients such as folic acid, vitamins A and D, calcium, and iron, foods rich in these nutrients should be selected. The patient’s diet should provide adequate amounts of calories and high quality proteins and related nutrients mentioned above. Recipes should include a variety of foods: meat, fish, poultry, dairy products (if tolerated), grains, fruits and vegetables. For example, by eating less and more meals every 3-4 hours, 5 meals per day can be arranged, with each meal being a little less than the usual 3 meals per day and each meal lasting longer. This will help the gastrointestinal tract to adapt to the food and fully digest and absorb it. If there is lactose intolerance, the intake of milk and dairy products should be reduced. High-fiber foods such as nuts, corn, and some vegetables should be appropriately limited. A low-fiber, less residue diet should be the mainstay. If the lesion is extensive and the symptoms of activity are obvious, the restriction should be more strict. High-fiber foods promote intestinal motility and can lead to diarrhea if they are not fully digested in the small intestine. However, some patients may experience post-feeding abdominal discomfort and intestinal cramps even after following the above dietary recommendations. For these patients, medication can be helpful. Antispasmodics and antidiarrheal medications taken 15-20 minutes before eating will relieve symptoms.
Fruits are the main source of vitamins and other nutrients. People usually eat fruits raw. For people with inflammatory bowel disease, it needs to be treated differently whether they can eat them raw or cooked before consumption. It is a requirement of the dietary management of Crohn’s disease that fruit be cooked and then consumed. However, this also needs to be treated flexibly. We do not force all patients to cook the fruit before consumption. If the patient has obvious signs of activity, such as increased diarrhea and significant blood in the stool, then cooking must be emphasized; for those with stable disease and no basis for activity, eating fresh fruit is not strictly contraindicated. However, attention should be paid to the amount and speed of consumption, which should be less rather than more, and slower rather than faster.
Another issue is how to accurately treat the issue of dietary fiber. Dietary fiber is not only important for normal people to promote intestinal motility, accelerate the excretion of harmful bacteria, waste and toxins, and maintain intestinal microecological balance and immune function, but also for patients with inflammatory bowel disease. In the past, there was a one-sided emphasis on avoiding dietary fiber in these patients, but in fact, this view is wrong. Patients with inflammatory bowel disease also need food to provide the necessary fiber content. The current view is that, in addition to active severe inflammatory bowel disease, patients in remission or mild disease should be encouraged to eat appropriate amounts of fiber-containing foods and vegetables.
2. Nutrition in the acute active phase
Special attention should be paid to reducing the load on the intestinal tract, such as abdominal pain, diarrhea, blood in the stool and fever and other manifestations are more serious, patients should fast. At this time, if the patient’s diet remains the same and does not reduce the load on the diseased intestine, then no therapeutic measures will be effective. If necessary, oral medications should be discontinued or given by injection. At this time, the only way to supply nutrition may be total parenteral nutrition, which can replenish the basic nutrients required by the patient daily, or special nutrition in the form of liquid nutrition by placing a nutrition tube or taking it orally, which is also known as “space diet”. Industrialized liquid food”. These are liquid mixtures of different formulations of various nutrients. Depending on the ancestry, they are also called low-molecule diets, high-molecule diets, or elemental diets. NASA developed the space diet to ensure adequate nutrition for astronauts in the limited space of spacecraft. The diet is as free of “crude impurities” as possible. The nutrients in this type of diet are small molecules that do not contain dietary fiber and are quickly and completely absorbed by the upper part of the human digestive tract, leaving no residue to enter the large intestine, where they need to be eliminated. This means that the lower part of the digestive tract, the small and large intestine, can be completely rested, which is the key to successful liquid nutrition or tube nutrition therapy. Traditional space diets are not reproducible because they contain only amino acids, have an unpleasant odor and poor taste. Current liquid nutrition contains oligopeptides as a low molecular nutrient, and also incorporates fats and flavoring substances, which are pleasant to the palate and have a wide variety of flavors that are suitable for patients with different conditions.
Liquid nutrition can be divided into high molecular liquid diet and low molecular liquid diet. The former has been modified to include a high fiber diet, a high molecular diet or a high molecular diet with MCT (medium chain fatty acids). The nutrients in the low-molecular diet have been broken down into simple molecules and are therefore more easily and completely absorbed into the gastrointestinal tract. It is also a balanced diet, which also covers the patient’s daily nutritional quota and is free of fiber. Normally, the liquid diet is delivered via the nasogastric (intestinal) tube into the duodenum and requires a controlled, continuous infusion using a pressure pump. Some low-molecular liquid diets can also be given directly by mouth.
For patients who are able to take it orally, they should be encouraged to take it orally to meet the basic nutritional intake, and gradually achieve a full nutritional supply from small to large amounts. Different flavors of liquid nutrition should be provided to suit the requirements of different patients. In addition, patients should be ensured to have adequate daily fluid (water) intake. The amount and rate of nutritional fluid intake and changes in abdominal symptoms and urine output should be monitored and recorded in detail. It is also important to choose a liquid diet with a limited amount of fat for a certain period of time, depending on the patient’s condition, and then gradually add medium-chain fat. For those who cannot tolerate a high molecular fluid diet, a low molecular fluid diet should be substituted.
For those who need long-term liquid nutrition, transnasal gastrointestinal tube is usually used. Before implementation, patients can discuss with their physician whether they need oral nutrition at home or a gastrointestinal nutrition tube. The greatest advantage of liquid nutrition, whether administered orally or by tube, is that it prevents atrophy of the microvilli of the small intestine and a decrease in intestinal immune function. It is recommended to start slowly and control the amount of nutrition by tube, 300-500ml on the first day, and then gradually increase. With liquid nutrition preparations, it is possible to change the diet from regular to liquid nutrition without hospitalization, even if the patient is found to be deteriorating. It is important to note that liquid nutrition is not easily prevented at room temperature for too long to avoid deterioration.
Both low-molecular liquid diets and high-molecular liquid diets have been shown to have good therapeutic effects on inflammatory bowel disease. During an acute attack of ulcerative colitis, an oral liquid diet is usually sufficient and total parenteral nutrition (TPN) is not required. If diarrhea and blood in stool are very serious, or if symptoms worsen after oral liquid nutrition, total parenteral nutrition must be implemented.
②Total parenteral nutrition is usually used for the failure of oral or transoral tube nutrition infusion, lesions in the upper gastrointestinal tract, especially in the upper small intestine, small intestine obstruction, scar formation or leaky tube affecting nutrition infusion (such as rectovaginal fistula), and the short bowel syndrome due to excessive small intestine surgical resection.
Total gastroenteric parenteral nutrition is administered through central venous cannula (CVC), where nutrients and active ingredients are fed directly into the bloodstream as a liquid. Thus, the body’s stomach and intestines are completely rested. However, there are advantages and disadvantages to this type of nutrition supply. On the one hand, the patient’s gastrointestinal tract is completely rested for a short period of time, and inflammation and its associated symptoms recover quickly. On the other hand, the gastrointestinal tract becomes “lazy”, i.e., the gastrointestinal mucosa is disused and undergoes morphological and functional atrophy. In this case, the original digestive and absorption functions can be restored only after a certain period of time. The timing of total parenteral nutrition or enteral nutrition should be determined according to the patient’s condition. As long as the subjective symptoms of intestinal inflammation, such as diarrhea, remain abnormal, total parenteral or enteral nutrition should be continued. However, total parenteral nutrition should be stopped as soon as possible, and oral nutrition should be gradually resumed. This process can be started by crossover for a few days, i.e., decreasing intravenous nutrition and starting oral low or high molecular nutrition solutions. The duration of total parenteral or special enteral nutrition should be at least 2 to 4 weeks. If the patient’s symptoms do not resolve, the patient should continue to avoid food.
③How to transition to a normal diet after the acute active phase
Once the patient’s general condition improves, a gradual transition to a normal diet should be considered. Initially, the patient may eat some beverages, cereal and a small amount of bread. If the patient can tolerate it, further cooked fruits and vegetables, potatoes, rice or pasta paste, low-fat cheese, lunch and lean meats, poultry or fish are given. Finally, more fat, cheese or meat is added. At this point, the patient is ready for a normal diet.
A light normal diet (LND) can also be given during hospitalization, depending on the condition of the patient and his or her body. When configuring a light diet, foods and cooking processes that are not tolerated by the patient should not be chosen. It may not be necessary to continue the light diet after discharge from the hospital. Patients should also avoid foods and cooking methods that are not tolerated at home. During the first few days, do not expect to give the patient enough energy right away. Do not rush to withdraw parenteral or enteral nutrition; it can be combined or crossed over to avoid weight loss. When transitioning to a normal diet, pay attention to the time rhythm and do not rush the process. The fiber component should be increased only after the disease has improved.
The transition to a normal diet should be planned in close cooperation between the patient, the physician, the dietitian and the hospital nutrition department. Patients should be in constant contact with their physicians and dietitians to receive information at all times. Frequent attention should be paid to the patient’s heart, liver and kidney function, as these organs are related to the nutritional elements of the diet. When consulting and discussing nutrition with the physician, consider vitamin, mineral, and micronutrient supplementation. Patients should also have the opportunity to discuss with their physician and dietitian to develop a diet that is appropriate for them.
V. Several things that patients need to do
1. Keep a diary of the course of the disease and a dietary diary
Managing inflammatory bowel disease requires long-term collaboration between the patient, physician, and dietitian. Since most patients are not in the hospital or have occasional hospital visits for flare-ups. Therefore, it is important for patients and their families to monitor their condition during their time away from the hospital and to have a record that truly reflects objective changes in their condition. Only when this is done can the physician fully grasp the changes in the patient’s condition and propose appropriate individualized treatment for the patient’s illness.
The contents of the diary should reflect the changes in the patient’s condition and nutritional status. Therefore, the most important part of the diary is the record of symptoms and signs related to the patient’s condition and the record of medications, and the other part is the record of diet and nutrition. The diary should include: ①Two temperature measurements per day, one hour before breakfast and one hour after lunch. The abdominal pain, distension, abdominal distension and bowel sounds and their relationship to diet. This is used to reflect the activity of the disease, the presence of intestinal strictures and obstruction, and the tolerance of the gastrointestinal tract to the food eaten. (3) The number, nature and amount of stools, and the relationship between stools and diet. (3) The frequency, nature and amount of stool, and the relationship between stool and diet, etc. Be specific about what kind of food is eaten at each meal, whether it is meat, eggs, fruits, beverages or vegetables. Specific cooking methods should be included. If blood in the stool is present, describe the color, amount, and odor. ④ The weight should be measured once a day. The time to do this is in the morning after waking up (6 to 7 o’clock), urinating once (no bowel movements), not eating anything, and wearing the same clothes (weight). A diet diary can help you accurately measure your intake of calories, protein, and vitamins and other nutritional elements.
2. The meaning and method of accurate weight measurement
Weight is an important indicator of nutritional status and development. Patients in good nutritional status are more able to tolerate the damage caused to the body by disease and inflammation. If they are underweight, they will lose more weight during acute relapses, making the lesions more difficult to repair. Therefore, patients with inflammatory bowel disease should maintain a normal or near-normal weight (calculated as the ratio of height to weight) as much as possible, and not less than 20% of the standard weight. Some patients may exceed the normal weight limit. If they are mildly overweight (e.g., 10%), they do not need to lose weight through a restrictive diet. These patients are fortunate enough to have more energy stores for repair or to cope with increased exertion.
Normal weight is usually calculated using Broca’s index, i.e. height in cm – 100 = kg of body weight. The reduced value should not exceed 20% of normal. This formula is applicable to a height of 160-190 cm, and the calculated value (theoretical value) may be high if it is above or below these two upper and lower limits. When applied in practice, slight changes should be made. Another weight calculation method is body-mass index (BMI). The formula is: BMI = weight (kg)/height (m).2 The upper and lower limits of normal values are 18 and 25, respectively.
3.Find the cause and solve the problem of food intolerance
Improper diet can promote or exacerbate inflammatory bowel disease. The problem is that it is not possible to identify and tell which food or its preparation is intolerant to a particular patient and which food causes symptoms of discomfort such as abdominal pain, bloating and diarrhea. Some articles list a number of possible intolerances such as: legumes, raw vegetables, juices (especially lemon juice), citrus juices (oranges, grapes, oranges, lemons, etc.), saueraut, onions, fatty foods, acidic foods, milk (lactose intolerant), and dairy products. Each patient reacts differently to food, but it is important not to fear and resist certain foods without reason. This is not conducive to nutritional intake. Therefore, the solution is for the patient to be observant and to look for and identify the foods that he or she cannot tolerate.
We strongly encourage patients to keep a diary of their own food intake to address food intolerances. The diary should be maintained over time. It should include the time of all meals (eaten or drunk), the type of food or drink, subjective feelings and symptoms after eating, especially symptoms of discomfort such as abdominal pain and diarrhea. The number and nature of daily stools and their color should be recorded in detail. As long as the patient does this, you will soon find out what foods are intolerable after a few weeks. This way, you can remove such foods from your diet and avoid triggering disease activity. Of course, you can also try these foods again after a few weeks, especially after your condition has improved significantly. Some foods can be changed from intolerable to tolerable when the disease improves.
After an acute attack, it is important to start with foods that were tolerated when the patient resumes eating. Well-cooked meat, fish, rice or pasta paste, cooked fruits and vegetables should all be tolerated. The diet should be varied, covering bread, omelets, butter, jam, honey, meat, poultry, fish, and cheese. If there is no discomfort after a few days, new foods can be added. Add a variety every 2 to 3 days. If there is still no problem, indicating that it is tolerated, you can continue adding more new varieties. It is important to note that one or more discomforts may occur with reduced doses of corticosteroids. At this point, do not mistake it for food intolerance.
4. Be proactive in keeping in touch with your physician and dietitian
Patients with inflammatory bowel disease have different conditions. Even for a specific patient, the condition changes from period to period. This requires continuous adjustment of the patient’s medication and dietary management. Patients and physicians (including dietitians) should have open and frequent contact with each other to exchange information in a timely manner. Patients should report their condition and dietary management to their physicians accurately and promptly, and monitor relevant indicators regularly or irregularly, without fear of inconvenience.