Alzheimer's-Like Disease Reversed by Dietary Compounds - In Mice
New research shows that a diet containing compounds found in green tea and carrots reverses Alzheimer's-like symptoms in mice genetically programmed to develop the disease.
In a recent study published in the Journal of Biological Chemistry, researchers analysed two compounds: epigallocatechin-3-gallate (EGCG), a key ingredient in green tea, and ferulic acid (FA), which is found in carrots, tomatoes, brown rice, wheat, oats, and pineapple.
The researcher used transgenic mice expressing mutant human amyloid βprotein precursor and presenilin 1 (APP/PS1) to model cerebral amyloid plague, which in humans appears to be linked to Alzheimer disease. These mice with Alzheimer's-like pathology and symptoms were randomized to one of four groups with an equal number of males and females. For comparison, each group also contained an equal number of healthy mice. For three months, the mice consumed a combination of EGCG and FA, or EGCG or FA only, or a placebo. The dosage was 30 mg per kilogram of body weight - a dose level which is well-tolerated by humans and easily consumed as part of a healthy, plant-based diet or in the form of supplements.
Before and after the three-month special diet, the mice were put through a battery of neuropsychological tests that are roughly analogous to the thinking and memory tests that assess dementia in humans. Of particular note was a maze in the shape of a Y, which tests a mouse's spatial working memory - a skill that humans use to find their way out of a building for example.
Healthy mice instinctively explore each arm of the Y maze, looking for food or a route to escape and entering the three arms in sequence more often than by chance alone. Impaired mice do not accomplish this as well as their mentally healthy counterparts.
The results: after three months, the combination treatment with EGCG/FA completely restored working memory and learning impairment, with the Alzheimer's mice performing just as well as the healthy comparison mice.
The researchers believe that one mechanism for this improvement appeared to be the ability of EGCG/FA to prevent amyloid precursor proteins from breaking up into the smaller proteins called amyloid beta that accumulate and damage Alzheimer patients' brains. The study demonstrated that the treatment with EGCG/FA significantly reduced β-amyloid burden. In addition, the compounds appeared to reduce inflammation and oxidative stress in the brain - key aspects of Alzheimer's pathology in humans.
The study supports the idea that combination therapy, rather than a single “magic bullet”, may offer a better approach to treating the 5.7 million Americans currently living with Alzheimer's. Combination treatment is already the standard of care for diseases such as cancer, HIV infection and rheumatoid arthritis.
It is important to note that this study was in mice, and many mouse discoveries do not fully translate into human treatments. Nevertheless, the findings lend credence to the idea that certain readily available, plant-based supplements might offer protection against dementia in humans.