All children know that in order to get that chocolate cake for dessert, they must first endure their broccoli and peas. That’s because all parents know that a diet rich in fruits and vegetables is absolutely essential for their growing tot. But what is it exactly in these fruits and vegetables that is so good for us?
Free radicals are highly reactive atoms, or groups of atoms, with an odd number of electrons. Scientists have long known that free radicals cause cell damage and are associated with cancer, diabetes and cardiovascular disease. It is also commonly known that antioxidants can neutralize the effects of these free radicals. Fruits and vegetables just so happen to be antioxidant-rich foods.
Neuroscientists have recognized that people with diets rich in fruits and vegetables tend to have healthier brains and are less likely to suffer from neurodegenerative diseases. Logically, these scientists made the leap to assume that the antioxidants in these foods contributed to the overall neurological health of the consumers. However, there is a big wrench in that theory. In controlled studies, the administration of these antioxidants has failed to prevent or ameliorate diseases such as Alzheimer’s.
Neuroscientist Mark P. Mattson proposed that the healthier brains associated with diets rich in fruit and vegetable are attributable to effects beyond those of antioxidants. Rather, he explains, fruits and vegetables come from plants that produce natural pesticides to ward off predators. When consumed in low doses, these pesticides stress our cells, ultimately leading to their increased resilience. Essentially, the mild stress experienced when these foods are consumed better equips our cells to deal with future stress. This process is called hormesis.
Mattson’s proposal was based on a phenomenon he witnessed in rats. When placed on an alternate-day fasting diet, the neurons in the rats’ brains were found to be more resistant against neurotoxins. The stress that fasting induced in the cells led to increased resilience of the neurons.
This development has led scientists to shift their focus from the effects of antioxidants to the effects of hormetic stress on cells. Ongoing studies are examining the effect of this hormetic stress in combating neurological disorders, like Alzheimer’s or stroke damage. If neurons can be made more resilient, they may be less susceptible to damage from these disorders. However, too much cellular stress can cause irreparable neuron damage. Moderate amounts of certain plant toxins can be beneficial, but they are harmful in large doses. Furthermore, cells must be allowed resting periods in between periods of induced stress.
The study of hormesis has not escaped controversy. Many are wary because crossing the line between beneficial and harmful stress may vary according to individual thresholds. However, these challenges should not dissuade further research. It is possible that these plant-based treatments may be able to treat those suffering from all neurological and neurodegenerative disorders, and without the negative side effects often associated with pharmaceutical alternatives. Furthermore, scientists can now explore whether the concept of hormesis can extend to other “poisons” as well. Perhaps moderate amounts of solar radiation can have similar healing effects. Deliberately induced stress could be beginning of a whole realm of scientific research.