Vaccine that may lead to a Treatment for Human Obesity

04/08/06 Imagine a vaccine which allows you to eat as much as you like and slows down your weight gain. Scientists from the Scripps Research Institute gave 17 rats a series of injections and found the over-eaters put on weight at a significantly reduced rate.

Researchers believe this vaccine may well lead to an effective treatment for human obesity.

In this new study, the vaccine tricked the bodies of the 17 rats into neutralising the effects of a protein, ghrelin, closely linked to weight gain. The human body has the same protein, which is also closely linked to weight gain.

You can read about this study in the Proceedings of the National Academy of Sciences.

One of the scientists, Kim Janda, said the vaccine looks like a serious workable solution to the growing problem of human obesity.

In the developed world, and much of the developing world, obesity and overweight have become a serious public health problem. In the USA 31% of all adults are obese and 65% are overweight.

The rats in this study were divided into two groups. One group received a placebo while the other received the vaccine containing the active ingredient. Both groups were then allowed to eat as much as they wanted. The rats on the placebo gained 1.6 grams per day, while the ones on the active ingredient gained 0.8 grams per day.

Further studies showed the vaccine is most effective when rats are on a low-fat, low-energy diet. As most western-diets are not low-fat and low energy, it remains to be seen how effective it may be on humans from developed countries. Most people who become obese have not done so because of a low-fat, low-energy diet.

Scientist believe that the protein ghrelin was developed during our evolution as a way of storing energy in response to erratic food supplies. When humans' access to food was erratic, it was necessary for the body to store as much as possible when supplies were good - to put on weight fast. The problem is we still have ghrelin in our bodies. If we overeat regularly our bodies will do the same as thousands of years ago - store as much energy as possible to prepare for lean times. In developed countries and many parts of developing countries food supplies are plentiful. Ghrelin, instead of being an asset for survival, may now have become a liability.

Ghrelin was discovered seven years ago.

Any vaccine which stops what ghrelin makes our bodies do could have a significant impact on obesity rates.

The scientists say the vaccine, if research progresses well, will most likely be more effective in preventing obesity rather than making obese people slim again.

As research on this vaccine progresses we will be able to answer more questions, such as:

-- How effective is it for humans?

-- Can it completely prevent human obesity or will it just slow down the rate at which an overeater puts on weight?

-- Are there any side-effects?

-- Will humans have to change their diets when taking the vaccine?

-- Who would receive the vaccine? If it probably won't reverse obesity, but prevent it - who gets it?