Investigation of Dietary Absorptive Capacity of Fructans in Healthy Subjects - A Dose Response Study
Condition: Healthy Volunteers
Study type: Interventional

Summary: 
      Fructan is a carbohydrate polymer that is composed of fructose and a terminal glucose moiety
      . Fructans are naturally found in artichokes (6.1 grams/serving), leeks (5.9 grams/serving),
      onion bulbs (1.01 grams/serving), flour (4.0 grams/serving), garlic (.52 grams/serving),
      watermelon (.92 grams/serving), nectarines (.27 grams/serving) and white peaches (.50
      grams/serving). Because fructans are present in many common foods, people typically ingest
      high levels of fructan. The most common structural forms of fructan are inulin, levanare and
      geraminan . The human body absorbs only 5% of fructan, however it is estimated that the daily
      intake in the USA may vary between 1-20 grams, and possibly higher due to the recently
      discovered benefits of inulins . Dietary trends indicate that high levels of fructans are
      common in the European and American diet, as more wheat based products such as breakfast
      cereal, pasta, and bread are consumed.

      Fructans may not be well tolerated by some subjects and its malabsorption may result in
      gastrointestinal (GI) symptoms such as heartburn, belching, abdominal pain, diarrhea, gas,
      and bloating; and this is especially true when higher doses are ingested. Unlike glucose,
      fructans are not efficiently digested or absorbed by the small intestine. The mechanism for
      malabsorption is related to the inability to hydrolyze glycosidic linkages in the complex
      polysaccharide, resulting in the delivery of malabsorbed fructans to the large bowel1. In the
      colon, the malabsorbed fructans are rapidly fermented, and byproducts of this fermentation
      include H2, CH4, and other gases that may contribute to bowel symptoms. Furthermore, the
      small molecular nature of fructans results in an osmotic effect which draws more water into
      the small intestine and causes bloating and diarrhea.

      Ingestion of high doses of fructans can cause symptoms in healthy adults, but may cause more
      bothersome symptoms in subjects with Irritable Bowel Syndrome (IBS). Earlier studies have
      identified that IBS affects between 10 and 15% of the population in the United States.
      Ingestion of 10-20 grams of fructan daily may cause symptoms of IBS, and restricting fructan
      intake in a diet may reduce symptoms in a variety of gastrointestinal disorders. One study
      recently published found that dietary restriction of fructan and fructose was responsible for
      symptomatic improvement in patients with IBS.

      Hypothesis:

      The investigators hypothesize that healthy individuals will absorb fructan 7.5 gram and 10
      gram doses, and will experience malabsorption at the 12.5 gram fructan dose.
    


Intervention name(s): Fructan - 7.5; Fructan - 10; Fructan - 12.5; Fructan -- 5 grams
Intervention type(s): Dietary Supplement; Dietary Supplement; Dietary Supplement; Dietary Supplement
Intervention description(s): Subjects will consume 7.5 grams of fructan; Subjects will consume 10 grams of fructan; Subjects will consume 12.5 grams of fructan; Subjects will consume 5 grams fructan.
Other intervention name(s): 7.5 grams of Inulin; 10 grams of Inulin; 12.5 grams of Inulin; 5 grams of Inulin
Intervention MeSH terms: Levan
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Triple (Participant, Care Provider, Investigator)
Primary purpose: Treatment