Polyphenol and PUFA Rich Diet Could Delay Onset of Alzheimer’s Disease

Researchers have confirmed that a diet rich in polyphenols and polyunsaturated fatty acids (PUFAs) helps boost the production of the brain’s stem cells (neurogenesis) and strengthens their differentiation in different types of neuron cells.

The study revealed that mice fed a polyphenol and PUFA rich diet, when compared to those fed a control diet, have more cell proliferation in the two areas of the brain where neurogenesis is produced, the olfactory bulb and the hippocampus, both of which are greatly damaged in Alzheimer’s disease patients. These results give support to the hypothesis that a diet made up of foods rich in these antioxidant substances could delay the onset of Alzheimer’s disease or even slow down its evolution.

Previous studies have verified the effects of polyphenols and PUFAs on regulating cholesterol levels and hypertension, two risk factors commonly associated with heart disease and Alzheimer’s disease.

During the development of the brain, stem cells generate different neural cells (neurons, astrocytes and oligodendrocytes) which end up forming the adult brain. Until the 1960s it was thought that the amount of neurons in adult mammals decreased with age and that the body was not able to renew these cells. Now it is known that new neurons are formed in the adult brain. This generative capacity of the cells however is limited to two areas of the brain: the olfactory bulb and the hippocampus (area related to the memory and to cognitive processes). Although the rhythm of cell proliferation decreases with age and with neurodegenerative diseases such as Alzheimer’s, it is known that exercise and personal well being can combat this process.

The main objective of this research was to study the effect of a polyphenol and PUFA cream-enriched diet on the neurogenesis of the brain of an adult mouse. Scientists used two groups of mice for the study. One group was given a normal diet and the other was given the same diet enriched with a cream composed of a mixture of natural products: dried fruits and nuts, coconut, vegetable oils rich in polyunsaturated fat and flour rich in soluble fiber. Both groups were fed during 40 days (approximately five years in humans). The analyses carried out in different brain regions demonstrated that those fed with the cream had a significantly higher amount of stem cells, as well as new differentiated cells, in the olfactory bulb and hippocampus.

The second objective was to verify if the cream could prevent damage caused by oxidation or neural death in cell cultures. Cultures of the hippocampal and cortical cells were pretreated with the cream. After causing oxidative damage with hydrogen peroxide, which killed 40% of the cells, scientists observed that a pretreatment with the cream was capable of diminishing, and in some cases completely preventing, oxidative damage. The hippocampal and cortical cells were also damaged using amyloid beta (anomalous deposits of this protein are related to Alzheimer’s disease). The results obtained were similar to those obtained using hydrogen peroxide.

These results demonstrate that a polyphenol and PUFA diet is capable of inducing the generation of new cells in the adult brain, and of strengthening the neural networks which become affected with age and in neurogenerative processes such as Alzheimer’s disease, as well as protecting neurons from oxidative and neural damage, two phenomena which occur at the origin of many diseases affecting the central nervous system.

In this study researchers have used different biochemical and molecular analysis techniques, with the help of specific antibodies, to detect different neuronal markers implied in the process of differentiation.

The researchers have spent years studying the effects oxidases have on oxidative stress as a factor implied in neurodegenerative disorders such as Parkinson and Alzheimer’s disease, and the effects of different natural products with anti-inflammatory and antioxidant properties in different experimental models of Alzheimer’s disease.

References:
1. Valente, et al. A diet enriched in polyphenols and polyunsaturated fatty acids, LMN diet, induces neurogenesis in the subventricular zone and hippocampus of adults mouse brain”. Journal of Alzheimer’s Disease, 2009 Volume 18:4.