In a study in Nature in June 2000, researchers Eberhardt, Lee & Liu showed that 100g of whole apple has the antioxidant activity equivalent to 1500mg of vitamin C - and this despite the fact that there is only about 10mg of vitamin C in that amount of apple. This really highlights the dangers of reductionist thinking - if we just looked at the amount of vitamin C in the apple we might think that we still needed to take more vitamin C to get our RDA.
The researchers also showed that whole apple extracts inhibit the growth of colon and liver cancer cells in vitro (in a test tube) in a dose dependent manner. This means, the more apple the greater the effect agains the cancer cells.
Apple intake has been shown to be protective against lung cancer, even at two apples per week. In a study of 1600 adults in Australia, apple and pear consumption was associated with a decreased risk of asthma and a decrease in bronchial hypersensitivity. In a study of over 13 000 adults in the Netherlands, apple and pear intake was associated with improved lung function and less chronic obstructive pulmonary disease. This was also shown in a study of middle aged Welsh men.
Whole apples have so many beneficial compounds. Polyphenols are substances in apples (and other plants) that include flavonoids, catechins, anthocyanin (in red skins only) and dozens of others. These phytonutrients help to regulate blood sugar in many different ways. Flavonoids such as quecertin in apples can inhibit enzymes that break down complex carbohydrates into simple sugars, thus lowering the load of sugar in our blood stream.
The polyphenols also decrease the absorption of glucose from our digestive tract, once again keeping simple sugar out of the bloodstream. They stimulate the beta cells of the pancreas to release insulin which helps remove sugar from our blood.
Another advantage of eating apples is that this can lower bad cholesterol and triglycerides in the blood and increase good cholesterol.The soluble fibre content, pectin, although only present in a modest amount in the apple, plus the polyphenols, combine to do this in an interaction that supports the benefits of eating the whole fruits as opposed to taking dietary supplements.
A bonus for people watching their weight or trying to lose weight, is that eating whole apples reduces hunger and improves the level of satisfaction with food far more than after consuming the same amount of calories from apple sauce or apple juice. One study showed that eating an apple fifteen minutes before a meal decreased the amount of calories that participants ate in that meal by 15%. So for an average (North American) evening meal of 1200 calories, that would be a reduction of 180 calories. Over a year that would equate to over 65 000 calories or 18 pounds of fat saved!!
SO maybe there is more than a grain of truth in the old saying “an apple a day keeps the doctor away”!