What is Chitosan?

• Chitosan is made from chitin, a substance derived from the exoskeletons of crustaceans--shrimp, lobster, crabs and crayfish. Chitin is a substance that already has various other uses: wound healing or for water purification because of its ability to absorb impurities in the water.
  
  It's these absorption capacities that the makers of chitosan claim works for weight loss.
  
  

How Does Chitosan Work?

• First, a brief explanation of how the body absorbs fat. When you eat, the food needs to be broken down into ever-smaller particles in order to be absorbed into the body. The break down is accomplished by stomach acids and enzymes while the absorption happens mainly in the small intestine through villi, which are tiny projections on the intestinal wall. After fat is absorbed through the villi, it's taken though the bloodstream to storage places in your body.
  
  What fat blockers do is to prevent the absorption of fat through the villi, generally by keeping it from becoming small enough to be absorbed. Thus, food passes through the small intestine undigested and is eliminated without being used.
  
  In the case of chitosan, the supplement absorbs and binds the fat in such a way that it can't be broken down enough to be taken up by the villi, and thus the fat calories consumed don't wind up being stored. Ideally, chitosan is taken just before mealtimes, so the supplement is there to receive the fat that is being ingested.
  
  

How Effective is Chitosan?

• The makers of chitosan claim that their product aids weight loss by trapping fat, but according to Memorial Sloan-Kettering Cancer Center, "several clinical trials found no increase in fecal excretion of fat or weight loss as compared to placebo." Such a study appeared in the June 2001 issue of Obesity Research. Other studies claim a little fat absorption, but not enough to be substantial. Meanwhile, the Federal Trade Commission in 2002 filed a contempt action against the Enforma Natural Products Inc. for "unsubstantiated claims" involving its chitosan-containing products.
  
  

Side Effects of Chitosan

• Compared to other weight-loss supplements, the side effects of chitosan are generally minor, such as constipation. However, those with seafood allergies should not take chitosan to avoid allergic reactions. Also, the absorption of fat-soluble vitamins like A, E or D might be inhibited by chitosan.
  
  

Some Brand Names of Supplements Containing Chitosan

• Among brand names for chitosan are Fat Trapper, Fat Trapper Plus, Fat Absorb, Fat Blocker, Eclipse Sport Supplements Chitosan, Stacker 3 Metabolizing Fat Burner with Chitosan, NaturalMax and Super Chitosan.