Eating fewer calories and decreasing meal frequency delayed the onset of Huntington’s disease-like symptoms in a study of mice. The change in diet also protected nerve cells from genetically induced damage and lengthened the mice’s lives.

Researchers say that if the results can be applied to humans, a change in diet may be able to extend the lives of Huntington’s disease patients.

In the study, mutant huntingtin, the abnormal human gene that causes Huntington's disease (HD), was introduced into mice that were then given an intermittent fasting diet during adulthood.

The fasting mice developed clinical signs of the disease about 12 days later than mice allowed to eat as much as they wanted. The mice on the fasting diet also lived 10 percent to 15 percent longer, were able to better regulate their glucose levels and did not lose body weight as quickly as mice on an unrestricted diet.

There were also differences noted between the brains of the fasting mice and the unrestricted diet mice. The fasting mice had fewer degenerated nerve cells as well as elevated levels of heat-shock protein-70 (HSP-70), which is known to increase cellular resistance to stress. In the unrestricted diet mice, however, levels of HSP-70 levels were decreased. The fasting mice also had higher levels of BDNF (brain-derived neurotrophic factor), a nerve cell growth factor that stimulates the growth and survival of nerve cells.

The elevated levels of BDNF may protect nerve cells from the adverse effects of the Huntington's gene, and researchers are exploring whether increasing levels of BDNF in the brain can prevent the progression of HD without a change in the diet.

Huntington's disease, which affects about one in every 10,000 people in the United States, is passed from parent to child. It results from the genetically programmed degeneration of nerve cells, called neurons, in the brain. When the neurons degenerate, it causes uncontrolled movements, loss of intellectual capabilities and emotional disturbance.

When HD progresses, speech may become slurred and vital functions such as swallowing, eating, speaking and walking become increasingly difficult. Some individuals remain aware of their surroundings and emotions, however others may have difficulty in recognizing family members.

Past studies have found calorie restricted diets increase the lifespan of everything from protozoa to laboratory animals. Calorie-restricted diets have also been found to prevent or delay the development of age-related disorders such as kidney disease, diabetes, tumors and declines in immune function.

Proceedings of the National Academy of Sciences February 10, 2003

Journal Neurochemistry February 2003;84(3):417-31