Can Pomegranate Consumption Prevent Alzheimer Disease?

Alzheimer disease represents the most prevalent form of dementia, accounting for up to 60% of all cases of dementia. Although there are multifactorial contributions to the development of most types of dememtia, including Alzheimer disease, there is a considerable amount of evidence indicating a strong correlation between inflammatory processes in the brain (termed neuroinflammation) and the progression of Alzheimer disease as well as other neurodegenerative conditions. In the process of neuroinflammation, pro-inflammatory cytokines, reactive oxygen species (ROS) and reactive nitrogen species (RNS), and pro-inflammatory lipids (especially prostaglandin E2 (PGE2), function as key contributors to the development and maintenance of inflammatory responses. Within the brain, neuroinflammatory processes are mediated through the microglia (a type of glial cell) that are the resident immune macrophages in the CNS and are responsible for active immune defense in the brain.

The pomegranate is the fruit of the Punica granatum tree which is a long-living tree cultivated throughout the Mediterranean region, as far north as the Himalayas, in Southeast Asia, and in California and Arizona in the United States. The pomegranate tree, especially its fruit (including the seeds and the rind), has a vast history of uses for the treatment of a variety of medical and health related issues. In the past decade, numerous studies on the antioxidant, anti-carcinogenic, and anti-inflammatory properties of pomegranate constituents have been published, focusing on treatment and prevention of cancer, cardiovascular disease, diabetes, dental conditions, erectile dysfunction, bacterial infections and antibiotic resistance, and ultraviolet radiation-induced skin damage. Other potential applications include infant brain ischemia, male infertility, Alzheimer disease, arthritis, and obesity.

The major bioactive phytochemicals extracted from pomegranate are ellagic acid and punicalagin. For more information on the health benefits of polyphenols and other phytochemicals in pomegranates go to my Supplement Science site.

Numerous studies have reported a strong correlation between the consumption of fruits and vegetables and a reduction in the risk for numerous chronic diseases, such as cardiovascular diseases, cancer and inflammatory disorders. In addition, several studies have correlated diet composition with modification of risk factors for Alzheimer disease. With respect to the pomegranate, the polyphenol, punicalagin, has been shown to exhibit anti-inflammatory activity through its ability to reduce the expression of cyclooxygenase-2 (COX-2) and the activity of the potent immune response amplifying transcription factor, NF-κB. However, all of these studies have involved systemic immune responses, not those occurring within the brain (neuroinflammation).

A recent study published in the journal Molecular Nutrition and Food Research has found that punicalagin is a potent inhibitor of neuroinflammation, a key contributor to the progressive deterioration in neural tissues in disorders such as Alzheimer and Parkinson diseases.

Punicalagin inhibits neuroinflammation in LPS-activated rat primary microglia

The significant findings from this study include the fact that punicalagin did not affect the viability of microglia cells so the suppression of neuroinflammation is not due to loss of the brain resident immune cells. In addition, punicalagin was shown to suppress the production of potent pro-inflammatory cytokines, to suppress the production of PGE2 and COX-2, and to interfere with the pro-inflammatory signaling pathways initiated by NF-κB.

Although the results of this study are highly significant, they still only represent cell and tissue culture (in vitro) experimental results. Further studies will need to be carried out to determine the level of bioavailability of pomegranate-derived punicalagin to the brain and the effects exerted there under conditions of neuroinflammatory stimulation.

Clearly another step in the right direction to solidify the evidence that what one eats can have profound effects on ones health. It is important to point out that punicalagin is found at highest concentration in the rind of the pomegranate fruit, NOT in the tasty pulp surrounding the seeds which is what most people consume. So it is important that if you truly want the benefits of the pomegranate you MUST eat the entire fruit (rind, seeds, and pulp) to attain the truly beneficial health effects.

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