Thursday, October 8, 2009

Some Notes on Fructose

You've probably read that high-fructose corn syrup is supposedly not healthy. I just learned that some people can't handle regular fructose either. In the book, Why Doesn't My Doctor Know This? David Dahlman writes that for some of us, fructose contributes to irritable bowel syndrome.

I'm going to stay off fructose for a week or so to see if that helps. I looked up fructose in Wikipedia to get more information. Here are my notes from that detailed article and from a linked page on Fructose Malabsorption.
  • The primary food sources of fructose are fruits, vegetables, and honey.
  • Apple and pear juices [have] the high concentrations of free fructose, and these juices can cause diarrhea in children.
  • Studies indicate that fructose is not completely absorbed in the small intestine... it is transported into the large intestine, where it is fermented by the colonic flora... The presence of gases and organic acids in the large intestine causes gastrointestinal symptoms such as bloating, diarrhea, flatulence, and gastrointestial pain. Exercise can exacerbate these symptoms by decreasing transit time in the small intestine, resulting in a greater amount of fructose being emptied into the large intestine.
  • It is suspected that eating large amounts of fructose increases the likelihood of weight gain.
  • Excessive fructose consumption is also believed to contribute to the development of non-alcoholic fatty liver disease.
  • Even in healthy people, only about 25-50 g of fructose per sitting can be absorbed.
  • Foods with a high glucose content actually help sufferers absorb fructose.
  • Fructose malabsorption is common in patients with symptoms of Irritable Bowel Syndrome. A small proportion of patients with both fructose malabsorption and lactose intolerance also suffer from celiac disease.
  • Patients with fructose malabsorption may need to avoid inulin, FOS, sorbitol, and xylitol.