You may have seen ads for “fat trappers” containing chitosan. Do they really work for weight loss
It is claimed that chitosan can bind to fat in the intestine so that they are not readily absorbed by the body. This means fewer calories and fat absorbed to, theoretically, lead to weight loss. It is also claimed that chitosan can reduce cholesterol levels by the same mechanism.
Although several small studies showed that chitosan reduced body fat and reduced cholesterol and triglyceride levels in overweight subjects, the studies were not well controlled. A larger, better controlled human study showed no benefit at all in terms of fat loss, weight loss, or cholesterol. Some animal studies have shown that chitosan reduces fat absorption and promotes weight loss, although this is not yet proven in humans.
There is some concern that if chitosan works, it can bind to vitamins and minerals causing reduced absorption which can lead to vitamin and mineral deficiencies. It has been shown that Orlistat, a legitimate fat blocking drug, reduces absorption of fat soluble vitamins A, D, E and K. If chitosan really fat binding properties, it can also block the absorption of these vitamins. Few other serious side effects have been seen. Some chitosan users have experienced problems with mild diarrhea or constipation, and there have been reports of palpitations from people taking it, but it is not clear whether these were directly linked to chitosan. Since chitosan comes from exoskeleton of crabs and shrimp, there is the possibility of allergic reactions in those with shellfish allergies.
Currently there have been no well-controlled, large studies showing that chitosan is beneficial for weight loss in humans. Unfortunately, there is no free ride when it comes to weight loss. The best plan is to continue to eat a healthy diet and exercising regularly.