Choosing Your Foods

Dietary treatment for Congenital Sucrase-Isomaltase Deficiency (CSID) is based on restricting the consumption of sucrose, isomaltose, and maltose. The degree of restriction required to relieve gastrointestinal symptoms is specific to the individual. If you have CSID, you should plan your diet in conjunction with your physician and registered dietitian. Every individual’s case of CSID is unique, so beneficial diets can vary considerably.

When you are figuring out a CSID diet, it’s imperative to keep a food log or food diary. Every item you eat or drink should be recorded, along with the time of ingestion. Recording serving size or weight can also be helpful. Also write down the timing of any gastrointestinal symptoms you experience, such as bloating, gas, diarrhea, or abdominal pain. This detailed food record helps the registered dietitian tailor your diet more effectively.

To first determine your sucrose tolerance levels, it may be necessary to remove all sucrose-containing carbohydrates from your diet. Sucrose, a carbohydrate, is typically table sugar or white sugar, which can be an additive in many prepared foods. There are additional forms of sucrose, and sucrose also occurs naturally in some foods. Sucrose digestion is a problem for most individuals with CSID. Sucrose tolerance levels may be determined by introducing increasing amounts of sugar-containing foods slowly, combined with Sucraid® (sacrosidase) Oral Solution to help limit gastrointestinal symptoms.

In addition to sugars and fibers, starch is a component of some carbohydrates. Starches are typically found in grains such as wheat, potatoes, corn, and rice. In the typical American diet, approximately 60% of the total calories consumed each day are due to dietary carbohydrates.1 The disaccharidase (enzyme) sucrase-isomaltase is responsible for approximately 60% to 80% of maltase digestion of starches in the small intestine.1 The remainder of the maltase activity is contributed by maltase-glucoamylase.2

Individuals with CSID have varying amounts of these enzymes, affecting their ability to tolerate starch in their diet. It is important to determine starch tolerance by introducing starch-containing foods gradually. Some individuals with CSID are able to tolerate normal amounts of dietary starch, some can eat limited amounts of starch, and some cannot tolerate any dietary starch.

You should consult with your physician and registered dietitian to discuss how much starch you can tolerate. If you know your disaccharidase assay results, the finding may be used as an initial indication of starch-digestion capacity, based on your level of maltase-glucoamylase activity. There are no FDA-approved supplemental enzymes available that facilitate starch digestion.

Once it is determined how much dietary sucrose you can tolerate, with and without Sucraid®, starches can be added to the diet slowly, watching carefully for gastrointestinal symptoms. In this way, these dietary starch challenges help determine your starch digestion capacity. When introducing new food items, it is recommended that you wait at least three days before introducing an additional food item.

Your physician and registered dietitian can use the food composition tables on this website to begin to build an appropriate CSID diet for you. In determining your capacity to digest various fruits and vegetables, they can consult the food composition tables to determine acceptable food items within your sucrose and starch dietary limits. Below are some general dietary guidelines to discuss with your physician or registered dietitian.

When beginning a diet, you could start with the food items that most individuals with CSID can tolerate and then add other food items over time, as tolerated. A registered dietitian can assist you in using a food log and determining food tolerances.




Fruits Tolerated by
Most CSID Patients
Fruits Tolerated by
Some CSID Patients
Fruits Tolerated by
Few CSID Patients
boysenberrieswatermeloncantaloupe (rockmelon)
cranberries, freshgrapefruit
figs, rawhoneydew melon
lemonspassion fruit
pearsmandarin oranges



Vegetables & Legumes Tolerated by
Most CSID Patients
Vegetables & Legumes Tolerated by
Some CSID Patients
Vegetables & Legumes Tolerated by
Few CSID Patients
alfafa sproutsedamame soybeansbeets
artichoke, globe*jicamablack beans
arugulaleekblackeyed peas (cowpeas)
asparagus*okrabutternut/buttercup squash
bamboo shootspumpkincarrots
bok choysnow peascassava (yuca)
broccoli*tempehchickpeas (garbanzo beans)
brussels sprouts*tofucorn
cabbage*yellow wax beansgarlic
cauliflower*green peas
celerykidney beans
chicorylima beans
chivesnavy beans
collard greensonions
cucumberpinto beans
green beanssplit peas
kalesweet potatoes
mung bean sprouts
mustard greens
peppers (red, yellow, green)
spaghetti squash
yellow squash
zucchini (courgette)

*Artichokes, asparagus, broccoli, brussels sprouts, cabbage, and cauliflower can cause gastrointestinal gas in all individuals, not just individuals with CSID. For this reason, it is recommended that you monitor consumption of these vegetables closely.




Grain-Based Starches

When starting a CSID-friendly diet, it is recommended that you consume no grain-based starches at all. This restriction is necessary to determine your sucrose tolerance levels before introducing dietary starches. Once sucrose tolerance levels have been established, you may begin to slowly introduce foods containing starches.

Well-known starchy fruits and vegetables include bananas, corn, carrots, legumes (beans), and potatoes. The starch content of fruits and vegetables is an important variable to consider when introducing dietary starches. You can use the food composition tables on this website to determine the starch levels in food items. Once sucrose tolerance and non-grain starch tolerance levels have been established, grain-based starches may be introduced to your diet.

Some individuals find that slowly-digestible carbohydrates, such as whole grains, are easier to tolerate. Some starches are digested more slowly in the small intestine and will slow gastric emptying, the rate at which food moves from the stomach into the small intestine and the rest of the digestive tract. Because the small intestine and large intestine are getting smaller amounts of starch at any given time, you may be better able to tolerate the dietary starch.

Good choices of these types of dietary starch are whole grain breads or those made with stone-ground flour instead of processed and refined white breads. Breakfast cereals or grains that contain whole oats, barley, or bran are better options than more-processed, refined cereals. Whole-wheat pasta, quinoa, lentils, brown rice, or wild rice are better options than more processed grains such as white rice. You need to read labels carefully because some whole grain products contain added sugars, including sucrose.

In summary, most food items made with refined and processed flour may be difficult for you to consume without developing gastrointestinal symptoms. Over time, these food items may be added to the diet once sucrose and starch levels have been established and you are free of gastrointestinal symptoms. It has been noted that some individuals with CSID are able to increase their starch tolerance as they age and their digestive tract grows longer.



Meats and Other Sources of Protein

In general, most individuals with CSID can eat plain sources of protein, including beef, pork, lamb, fish, turkey, chicken, and eggs. Plain protein means foods that have been prepared with no sauce or seasonings. However, protein sources such as meats may be cooked with butter, oils, salt, and pepper without triggering CSID-like symptoms. Until your starch tolerance levels have been established, it is suggested that you avoid breaded meats.

You should also avoid processed meats such as bacon, sausage, luncheon meat, deli meat, liverwurst, and pâté since many of these food items are cured with sucrose or have starch fillers. These food items may be added at a later date, once appropriate sucrose and starch tolerance levels have been established through food diaries or logs.

Most individuals with CSID can tolerate eggs. Nuts and nut butters can be a great source of calories for you. However, it is recommended that these be avoided until sucrose and starch levels have been established with food diaries or logs. Starch and sugar components for different varieties of nuts can be found in the food composition tables on this website. Legumes and beans can be added to your diet once sucrose and starch levels have been established. Most legumes and beans are starchy, so this content should be taken into consideration. Most individuals with CSID can tolerate tofu.




Most individuals with CSID can eat dairy products such as cow’s milk, ricotta cheese, plain cottage cheese, sour cream, butter, cream, whipping cream, and hard cheeses like cheddar, Colby, mozzarella, Swiss, Parmesan, and provolone. In addition, most individuals can tolerate plain, unsweetened yogurt and yogurt sweetened with dextrose or fructose. Many individuals eat full-fat dairy products to ensure they are eating sufficient calories. Over time, you may be able to tolerate more dairy products than those listed above. Once sucrose and starch tolerance levels have been established, you may introduce additional dairy items to determine your tolerance of dairy products.

A minority of individuals with CSID also have lactose intolerance. Consult a physician and registered dietitian to see if test results indicate you are expected to tolerate milk products. It is recommended that you avoid processed cheeses or cheese products since many of these food items contain sucrose or starch fillers. Processed cheeses and processed cheese products are made from normal cheese, but may include other unfermented dairy ingredients, emulsifiers, extra salt, food colorings, or whey. American cheese slices and Velveeta® cheese products are examples of processed cheese products.





In general, you can consume most fats and oils, such as butter, margarine, olive oil, and vegetable oil, without restriction. In the case of margarines, it is always a good idea to read labels carefully for potential starch or sucrose content.





In general, individuals with CSID can tolerate milk, water, diet soda, and homemade limeade or lemonade made with fresh juice and sweetened with fructose or dextrose. Some can tolerate regular, non-diet sodas that are sweetened with high fructose corn syrup. Sweetened sodas should only be tried under the advice of a registered dietitian or physician.





In general, most individuals with CSID tolerate salt. Some tolerate pepper and others do not since black pepper does have a small amount of sucrose and some starch. When starting a diet, it is recommended that you use few other spices or seasonings in order to more clearly determine your tolerance levels since many spices contain sugar or starch fillers. Other spices may be added later, once sucrose and starch tolerance levels have been established through food diaries or logs.


Other Tips

Parents and caregivers have noticed a few trends that have helped raise tolerance levels when adding starch to a CSID diet.

First, chew foods containing starch for a long period of time. For example, it is suggested that you chew a bite of the food item 30 times before swallowing. Salivary amylase, the first enzyme in the process of starch digestion, is released in the mouth. The levels of salivary amylase are not affected by CSID. Starchy foods break down more easily if exposed to salivary amylase in the mouth for an extended period. Thus, the more a starchy food item is chewed, the greater the exposure the starchy food has to this necessary digestive enzyme.

Second, combine a high-starch food with a fatty food at the time of ingestion. High-fat foods slow the rate food moves through the small intestine. The more time ingested food remains in the small intestine, the greater your ability to digest the starchy food. Thus, combining a high-fat food with a starch increases the time the foods remain in the small intestine and allow the starch to have more exposure to pancreatic amylase, isomaltase, and maltase in the small intestine. An example of this combination is a fatty cheese dip with a starchy vegetable.

Working with a registered dietitian is crucial to dietary success. Even though it might be difficult to find registered dietitians who have experience with CSID, they will be able to demonstrate how to effectively write and manage a food log or diary and how to add foods by trial to the diet. They will also be able to network with other registered dietitians who have experience with a CSID diet. When looking at the list above, it may appear to be a very short list of foods someone with CSID can eat. Be assured that over time and by paying close attention to specific foods and related symptoms, the list of acceptable foods grows substantially.


  1. Treem WR. Clinical aspects and treatment of congenital sucrase-isomaltase deficiency. J Pediatr Gastroenterol Nutr. 2012;55(suppl 2):S7-13. doi:10.1097/01.mpg.0000421401.57633.90
  2. Quezada-Calvillo R, Robayo-Torres CC, Ao Z, et al. Luminal substrate “brake” on mucosal maltase-glucoamylase activity regulates total rate of starch digestion to glucose. J Pediatr Gastroenterol Nutr. 2007;45(1):32-43. doi10.1097/MPG.0b013e31804216fc