Eat fruits, not antibiotics

Good bacteria in the colon produce an enzyme that releases glucose found in plant cell walls.

Now, you have another reason to go on an all-fruit diet!

Biochemist Dr. Vadivel Ganapathy has observed that a transporter in the colon called SLC5A8 plays an important role in enabling the colon to get the last bit of good out of food before the unusable is flushed away.

The research published online as an accelerated communication in the 'Journal of Biological Chemistry' notes that good bacteria in the colon produce an enzyme that releases glucose found in plant cell walls, the leftovers of broccoli and other vegetables, fruits and cereals, which cannot be digested in the small intestine.

In the oxygen-less environment of the bacteria-packed colon, bacteria ferment this glucose to use for energy which also results in the production of short-chain fatty acids, the preferred nutrients for colon cells.

Researchers at the Medical College of Georgia have found in animal and human cells that SLC5A8 is a final piece of the model, a transporter expressed by colonic cells to absorb the just-produced, energy-packed short-chain fatty acids.

"We used to teach that bacteria produced short-chain fatty acids which are used by colonic cells but it was not known that these cells possessed an efficient active transport system to absorb these fatty acids," Dr. Vadivel Ganapathy, biochemist, said.

The finding helps explain why fruits and vegetables are good for the body and not antibiotics, which wipe out good bacteria along with bad, should only be taken when absolutely necessary.

"We do not make the enzyme to digest cellulose; bacteria make the enzyme in the colon. Therefore, you need to eat dietary fiber to provide the food for bacteria. Otherwise, they are not going to survive there. Antibiotics can wipe out good bacteria as well, leaving a void where disease-causing bacteria can grow." Dr. Ganapathy, said.

The colon's main function is to collect waste from the diet and store it until it can be eliminated.

Cancer researchers at Case Western Reserve University in Ohio reported in 2003 in the 'Proceedings of the National Academy of Sciences' that they had cloned the SLC5A8 transporter from the human colon.

Dr. Ganapathy's lab actually cloned SLC5A8 from a mouse kidney three years earlier. Since his initial attempts to identify the transport function of SLC5A8 failed, he used Northern blot to investigate the tissue expression pattern of this transporter, hoping that the expression pattern would lead him to the identity of its transport function. .