Sickly Sweet: The Development of a Standardized Method Testing for Lactose and Fructose Intolerance and Malabsorption Taylor Lawless East Carolina University Faculty Mentor: Kimberly B. Myers East Carolina University ABSTRACT Lactose intolerance has been a known cause of gastrointestinal distress for many years. Recently, scientists have discovered that fructose intolerance elicits many of the same symp- toms as lactose intolerance. The consumption of fructose has more than doubled in the past twenty years; similarly, the instances of fructose intolerance have also increased. Fructose and lactose intolerance are measured using similar methods. While there are common prac- tices and guidelines used when testing for fructose and lactose intolerance and malabsorptive issues, there is no official standard method including precise practices for before, during, and after the test. Therefore, in the present study a standardized form and set of recommendations were suggested by comparing methods used in previous studies. If used on a wide scale, the standard system would enable researchers to compare results of different studies. Ultimately, this would help researchers gain a better understanding of lactose and fructose intolerance and malabsorptive issues and to measure the frequency of diagnoses for each condition in order to develop improved treatments and potential cures. actose intolerance has been a popular are not completely understood, there is re- Ltopic in the study of nutrition for many search being conducted on the different types years. Many people suffer from irritable of sugar malabsorption and intolerance. bowel syndrome (IBS) due to the sugar lac- Malabsorption refers to sugar not being prop- tose found in dairy1. Interestingly, as fructose erly broken down in the gastrointestinal tract4 has become more prevalent in the human di- and intolerance implies that the body is inca- ets, people have begun suffering similar mal- pable of breaking down the sugar5. Thus, re- absorpitve effects. searchers are interested in questions regard- Lactose intolerance can cause an array ing the relation between the type of sugars of painful and irritating symptoms such as individuals are consuming and the way the gas, bloating, diarrhea, vomiting and nau- sugars are absorbed and metabolized. sea2. These same symptoms have been ob- Fructose consumption has more than served in those with fructose intolerance3. doubled in the past 20 years due to the use Because the causes of sugar malabsorption of the inexpensive sweetener high fructose 92 Taylor Lawless corn syrup3. Fructose is naturally found in ambiguity of varied extant testing systems. fruits and some vegetables. It is also part The research questions for the present of the simple sugar sucrose, which is a di- study were 1) what are the common charac- saccharide commonly known as table sugar. teristics of the methods and results published Sucrose is comprised of glucose and fructose in the current literature, and 2) could the molecules, which are both monosaccharides. common features of testing be combined to High fructose corn syrup contains a higher create a standard method for testing? A lit- percentage of fructose than glucose. Its use erature review on fructose and lactose malab- is controversial as it is added to many foods sorption studies was conducted. The review as a sweetener because it is less expensive, was conducted after analyzing published arti- but not necessarily healthier, than table sugar. cles about fructose and lactose malabsorption It has been said that the increase in instances and intolerance in order to build a knowledge of intolerance is because it fructose is now in foundation about common practices. The pri- more foods6. mary focus of the review was on the methods While the full effect of this increase of used for diagnosis, and the results obtained fructose in foods is not yet known, more in- in the treatment studies. The methods used stances of fructose malabsorption are being for diagnosis often affected the conclusions diagnosed. Some attribute this malabsorp- about the results, thus, we reviewed methods tion to the metabolic pathway of fructose, and results together. speculating that fructose is absorbed by fa- cilitated diffusion or that fructose can only be Literature Review absorbed with glucose5. While the absorp- tion of fructose is still being studied, it is One of the most referenced studies was known that the enzyme lactase breaks lactose one by Choi et al. 3. The objective of this into the simple sugars galactose and glucose study was to determine how common fruc- in the human body7. tose intolerance was in the sample popula- Fructose and lactose malabsorption and in- tion and to see if lifestyle changes regarding tolerance can impact the life of an individual fructose intake would have an effect on IBS tremendously, and misdiagnosis of these con- experienced by the patients. The research- ditions can also have negative implications. ers questioned how effective the fructose If a person is incorrectly diagnosed with an restricted diets would be for limiting IBS. intolerance, the individual may eliminate the Those with positive hydrogen breath test re- sugar from the diet unnecessarily2,8. That is sults were deemed fructose intolerant. The particularly concerning with lactose because patients who produced a positive breath test restriction of lactose can lead to calcium de- were then given a kit that contained informa- ficiencies9. A diagnosis implying the person tion regarding a fructose restricted diet and is not intolerant when the person is can be were asked to implement the diet. After one dangerous as well since the person will con- year, patients were asked to return and repeat tinue to consume the sugar and experience the same tests and surveys. In addition, the discomfort1. patients answered questions regarding how Hydrogen breath tests are the primary tool strictly the diet was followed according to used to measure fructose and lactose malab- the guidelines and how much time was spent sorption and intolerances. The inconsisten- following the guidelines3. cies associated with conducting such tests The results showed that of the 80 partici- have raised questions regarding the validity pants, 31 had a positive fructose breath test. of the results1. Testing differences also makes Greater than 90% of those with a positive test it difficult for scientists to compare results. claimed that the test caused the usual gastro- For these reasons, we recommend a stan- intestinal discomfort symptoms, which have dard system of measurement to alleviate the been attributed to fructose intolerance. The 93 Explorations |Natural Science and Engineering patients reported that the lifestyle changes Review of best practices: Comparison and had a mild to moderate effect on their life- analysis style (a rating of 2.93 on a 5-point scale). The researcher concluded that there was a corre- Best practices from several reviewed lation between the lifestyle changes and the studies were used to create a “standardized symptoms of those in the positive test group3. method and tool.” Inclusion criterion for the Da Silva Mederios, et al. 2 reported on a studies were 1) publication dates between pediatric population. In the pretest proce- 2008 and 2012 and 2) the use of a hydrogen dure, the children’s height and weight were breath test and the measurement of the sugars measured and parents were asked to fill out fructose, lactose or lactulose. Representative a symptom form for their children2. This is studies reviewed are included in Table 1. a potential source of bias as the parents can- The six variables noted for each study were not feel exactly what their children do. The Primary Researcher; Publication; Year; Sugar children were given a hydrogen breath test Tested; Subjects; Pre-Test; During Test; and which was used to determine whether or not Results. “Primary researcher and publication they were an absorber of lactose or malab- year” were used to identify the study. The sorber. The night before, they were asked to “sugar tested” variable noted whether the eat white rice with chicken and not to eat af- study examined fructose, lactose, lactulose ter the meal2. or a combination of the three. The “subjects” Calcium deficiencies were examined in this variable identified the age group, gender, and study. While most of the studies on calcium general information about the participants in absorption focus on adult populations, this the study. The “pre-test” variable described study is one of the few that has examined a the practices and procedures before the test. younger population. Other studies found that The “during test” variable detailed how the the calcium intake was much lower among test was conducted. The “results” variable the lactose intolerant; however, this study did was used to list the findings of each study. not support that theory; there was no statis- The results of the compilation can be found tical difference in bone density between the in Table 1. Common trends were observed two groups (absorbers and malabsorbers)2. and the most effective methods were deter- The lives of individuals could be improved mined by the researchers. We determined by the results of the studies about fructose the most consistent methods according to the and lactose. For example, researchers sug- table. Then the best practices were selected gest that by limiting lactose in the diet, the to be compiled for the creation of a standard- pain suffered by afflicted children could be ized tool. reduced10. Other researchers4 determined that The standardized tool can be seen in Figure fructose and lactose malabsorption can be the 1. The standardized tool is a form with proce- cause of recurrent abdominal pain and that re- dures that are to be followed and is to be com- moving the malabsorbed sugar from the diet pleted by the physician or researcher. Each of the patient can help alleviate the symp- step of the tool was added to ensure each test toms4.