Sugar intolerance is a digestive condition resulting from the body’s inability to properly break down certain carbohydrate molecules due to a deficiency in specific digestive enzymes. When undigested sugars travel to the colon, they are fermented by bacteria, causing symptoms like gas, bloating, abdominal pain, and diarrhea. The most common forms involve lactose (milk sugar), fructose (fruit sugar), and sucrose (table sugar), each linked to a lack of a corresponding enzyme, such as lactase or sucrase-isomaltase.
Pinpointing the Type of Sugar Intolerance
Effective management relies on accurately identifying the specific sugar that the body cannot process. Consulting a medical professional is the first step to determine the cause of digestive distress and rule out other conditions like Irritable Bowel Syndrome (IBS) or Celiac disease. The primary diagnostic method used for lactose and fructose intolerance is the hydrogen breath test (HBT), a non-invasive and reliable procedure.
During an HBT, a patient ingests the suspect sugar, and the amount of hydrogen and methane gas in the exhaled breath is measured over several hours. If the sugar is not absorbed in the small intestine, gut bacteria ferment it in the colon, producing these gases, which are then exhaled. A rise in breath hydrogen above 20 ppm indicates malabsorption. Alternatively, a blood glucose test may be used; a lack of a rise in blood sugar after ingestion suggests malabsorption because the sugar was not properly broken down.
Implementing Dietary Restriction and Substitution
Once the specific sugar is identified, the primary treatment involves controlling its intake through dietary restriction and substitution. Unlike in a true food allergy, complete elimination is often unnecessary, as most individuals with an intolerance can tolerate a certain amount, known as their personal threshold. For example, many people with lactose intolerance can comfortably ingest up to 12 grams of lactose at one time, which is roughly the amount found in one cup of milk.
Determining this individual tolerance level involves a temporary elimination diet followed by a gradual, monitored reintroduction of the sugar. Consuming the offending sugar alongside other foods, or distributing the intake throughout the day, can improve tolerance by slowing down the digestive process. Reading food labels is important for successful management, as many processed foods contain hidden sources of the problematic sugar, such as high-fructose corn syrup or lactose used as a filler in certain medications.
For those managing lactose intolerance, widely available lactose-reduced or lactose-free dairy products are simple substitutions that allow continued consumption of dairy nutrients. Hard cheeses and yogurt with live cultures often contain naturally lower amounts of lactose due to the fermentation process, making them better tolerated. When managing fructose intolerance, the strategy shifts to focusing on foods where the fructose is naturally balanced with glucose, which aids absorption.
Specific substitutions for high-fructose foods include opting for low-fructose fruits like berries, clementines, kiwi, or pineapple, while limiting high-fructose choices such as apples, pears, and mangoes. It is recommended to limit total fruit intake to one or two servings per day to maintain control over the fructose load. When eating socially or dining out, individuals should communicate their dietary needs clearly and focus on whole, unprocessed foods that have fewer hidden ingredients, prioritizing options like plain meats, eggs, and vegetables.
Utilizing Enzyme Replacement Therapies
Enzyme replacement therapies offer a non-dietary intervention that directly addresses the underlying enzyme deficiency. These therapies serve as an aid to digestion, rather than a cure for the intolerance, and their effectiveness can vary among individuals. The most common example is the lactase enzyme supplement, which provides the enzyme needed to break down lactose in the small intestine.
These lactase supplements are available over-the-counter and must be taken immediately before consuming any food or drink containing lactose to ensure they are present in the gut when the lactose arrives. For individuals with congenital sucrase-isomaltase deficiency, prescription enzyme replacement is available to help digest sucrose. Another common over-the-counter product contains alpha-galactosidase, an enzyme that assists in breaking down complex carbohydrates found in foods like beans and some root vegetables.
In addition to direct enzyme replacement, supporting the overall gut environment can also be a helpful strategy. Probiotics and prebiotics are being studied for their potential to help manage sugar intolerance symptoms. Probiotic strains, particularly those containing Lactobacillus and Bifidobacterium, may improve lactose tolerance by providing bacteria that convert lactose into less symptom-provoking substances.
Maintaining Nutritional Health Long-Term
Long-term management requires careful attention to nutritional balance to prevent deficiencies associated with restricted diets. Dairy products are a primary source of nutrients, and their avoidance puts individuals at risk for insufficient intake of:
- Calcium
- Vitamin D
- Vitamin B12
- Riboflavin
- Phosphorus
Calcium is concerning, as inadequate intake can compromise bone health over time, potentially leading to conditions like osteopenia.
To mitigate these risks, alternative sources of these nutrients must be incorporated into the daily diet. Fortified non-dairy alternatives, such as almond or soy milk, can provide calcium and Vitamin D, though their overall nutritional profile must be compared to cow’s milk. Calcium intake should be maintained within the recommended range, between 1,200 and 1,500 milligrams per day for adults, and targeted supplementation may be necessary to meet these needs.
Regular follow-up with a medical professional or a registered dietitian is highly recommended to monitor nutritional status and ensure the management plan is sustainable. A dietitian can help identify nutrient gaps, plan a balanced diet using alternative food sources, and determine if specific vitamin or mineral supplements are necessary to support continued health. The goal is to successfully manage the intolerance without inadvertently creating new health problems from nutrient deprivation.