According to Professor Thomas Shea of the University of Massachusetts, age related neurodegeneration can be stalled with the help of the fruit bowl (1). Alzheimer’s disease affects 30 million people worldwide, but is the answer lying in our lunch box? Medicine has energetically addressed global malnutrition since vitamins were first discovered in 1913, but these days its over-nutrition which hits the headlines. Obesity, diabetes and heart disease are multi-factorial in origin and require more than a few vitamins or the latest super-food to cure them. Nevertheless, if we could turn back the body clock, what role might our favourite fruit play in the prevention of one of the most prevalent diseases of the elderly?
Focus on the Facts
Patients suffering from Alzheimer’s Disease gradually accumulate a fibrous protein called beta amyloid in their brains (2). The fibrils of this tiny molecule become entangled within the nerve cells of the brain and eventually precipitate neurodegeneration and cognitive dysfunction. Laboratory studies on mice have shown that a diet of apple juice stalls the production of this protein and improves the performance of the mice in maze trials. Extrapolation of these results to humans suggests that the equivalent of at least two apples a day could similarly delay the onset of the disease (3).
Background Biochemistry
Apples contain flavonoids which behave as powerful antioxidants, mopping up highly reactive oxygen molecules or free radicals - the “exhaust fumes” of metabolism. There are over 4000 naturally occurring flavonoids in plants including quercitin in apples, which shows potential in the treatment of a range of inflammatory conditions - and in the prevention of some types of cancer. In common with other antioxidants, its chemical structure allows it to snatch surplus oxygen from body tissues and reduce inflammation otherwise caused by free radicals. Incidentally, our own white blood cells produce "friendly" free radicals to kill invading bacteria in the blood stream (4).
More good news
Pectin is another useful ingredient in apples. It represents one form of soluble fibre found in plant cell walls and has a two-fold effect on the human bowel. As well helping to prevent constipation, it binds to cholesterol and bile salts in the large intestine, removing them from the gut (5). To compensate, more bile is produced from cholesterol within the liver which in turn reduces the level of cholesterol in the blood - providing you don't pour double cream all over that fruit salad....
The Nutritional Value of Apples
- The average fresh (unpeeled) apple contains 85% water and has an energy value of around 80 Calories based on their sugar content (fructose, sucrose and glucose.) Modern varieties of apples such as the Braeburn contain more sugar than older varieties such as Granny Smiths.
- Protein and fat content are both low and vitamin C content is modest compared to citrus fruits. Limited amounts of mineral salts are present, although plenty of potassium – and there are useful amounts of fibre in apples too.
- The taste of a particular variety depends on the combination of sugars, organic acids and esters stored in the sap which changes as the apple ripens.
- External factors such as the soil quality, local climate and harvesting conditions also determine the precise content of a particular apple.
- Food tables (6) give approximate values based on laboratory samples which may vary significantly from the ones you are eating, but don't let that put you off your daily dose - its still an excellent prescription - and it grows on trees!
References
1. Chan A. Shea T. (2009) Journal of Alzheimer's Disease. Vol 16/ 1. P167-171.
2. American Health Assistance Foundation (2009) Plaques and Tangles.
3. Medical News Today (2009) Apple Juice Delays onset of Alzheimers Disease in Mouse Model
4. Webb G. (1995) Nutrition - A Health promotion Approach. Arnold.
5. Bender D. (1997) Introduction to Nutrition and Metabolism. Taylor and Francis.
6. Food Standards Agency (2008) Manual of Nutrition 11th Edition. London TSO.
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