The World’s Healthiest Foods – Apples!

Cortland apple

Today is the first installment in a series called "The world's healthiest foods". In it, I will choose one example and examine the many health benefits of that food, beginning with the common apple.

Apples are high in fibre, including the soluble fibre pectin, and vitamin C. Apples contain polyphenols, a relatively new category of micronutrient, that are a category of antioxidants with numerous health benefits to humans. These polyphenols include quercetin, catechins, and anthocyanins (if the apples are red-skinned). 

The phytonutrients in apples can help regulate blood sugar. Apple polyphenols can help prevent spikes in blood sugar through a variety of mechanisms. Flavonoids like quercetin found in apples can inhibit enzymes like alpha-amylase and alpha-glucosidase. Since these enzymes are involved in the breakdown of complex carbohydrates into simple sugars, your blood sugar has fewer simple sugars to deal with when these enzymes are inhibited. In addition, the polyphenols in apples lessen absorption of glucose from the digestive tract, stimulate the beta cells of the pancreas to secrete insulin, and increase uptake of glucose from the blood via stimulation of insulin receptors. All of these mechanisms triggered by apple polyphenols make it easier to regulate blood sugar levels.

The fiber found in apples may combine with other apple nutrients to provide you with the kind of health benefits you would normally only associate with much higher amounts of dietary fiber. These health benefits are particularly important in prevention of heart disease through healthy regulation of blood fat levels. It's not fiber alone that explains the cardiovascular benefits of apple, but the interaction of fiber with other phytonutrients in this fruit. To get the full cardiovascular benefits of apples, consume whole apples for their unique fiber-plus-phytonutrient combinations.

Whole apples are also important if you want full satisfaction from eating them. You will feel less hunger (and better satiety) after eating whole apples than after eating applesauce or drinking apple juice. If you are looking to lose weight, try eating an apple approximately 15 minutes before a meal.

Scientists have recently shown that important health benefits of apples may stem from their impact on bacteria in the digestive tract. In studies on laboratory animals, intake of apples is now known to significantly alter amounts of two bacteria (Clostridialesand Bacteriodes) in the large intestine. As a result of these bacterial changes, metabolism in the large intestine is also changed, and many of these changes appear to provide health benefits. For example, due to bacterial changes in the large intestine, there appears to be more fuel available to the large intestine cells (in the form of butyric acid) after apple is consumed. If this extends to humans the potential health benefits of apple will be extended to its impact on bacterial balance in our digestive tract.

The colour of the apple is also an indication of the nutrients it contains. In terms of flavonols, quercetin is the primary phytonutrient found in apples, and it's far more concentrated in the skin than in the pulp. If apples are red, it's because of their anthocyanins, which are largely concentrated in the skin. When an apple is more uniformly red in color, or darker red, it's because there are more anthocyanins. In terms of catechin polyphenols, epicatechin is the primary nutrient found in apples. The flavonoid phloridzin accounts for 98% of the flavonoids found in the apple seeds. This would mean that juicing whole apples nets you more nutrients because you are consuming the seeds as well.

Why are anthocyanins important? The amazing array of polyphenols found in apples is the mechanism used by apples to protect themselves from UV-B radiation. Cells in the skin of apple that conduct photosynthesis are especially sensitive to UV-B light from the sun. Many of the polyphenols in the skin of apples can actually absorb UV-B light, and thereby prevent UV-B from damaging the photosynthetic cells in the apple skin. Polyphenols, then, are like the apple's natural sunscreen. What works for the apple, works similarly for the person ingesting the apple. The same is true for other dark red or purple skinned fruits.

Most of the polyphenols in apples function as antioxidants. Particularly strong is the ability of apples to decrease oxidation of cell membrane fats. This benefit is especially important in our cardiovascular system since oxidation of fat in the membranes of cells that line our blood vessels is a primary risk factor for clogging of the arteries (atherosclerosis) and other cardiovascular problems. Apples' strong antioxidant benefits are also related to their ability to lower risk of asthma in numerous studies, and their ability to lower risk of lung cancer. In addition to their unusual polyphenol composition, apples also provide us with about 8 milligrams of vitamin C. While that amount is not a lot, it's still important, especially since the recycling of vitamin C in our body depends on the presence of flavonoids and apples do an amazing job of providing us with those flavonoids.

Enjoy an apple on a regular basis and get all these amazing benefits!