Apples contain the three "F's" -- fiber, flavonoids and fructose. All three have their benefits, but when it comes to fructose, it is possible to have too much of a good thing. According to Harvard School of Public Health, eating no more than 2 cups of raw apples per day will keep your fructose intake in check.
What Is Fructose?
Also known as a fruit sugar, fructose is the sweetest of all natural sugars. Despite the sweet factor, fructose has a low glycemic index. Naturally found in fruit along with glucose and sucrose, fructose is also naturally occurring in honey and some vegetables, according to the University of Florida IFAS Extension. Fructose is also a component in high-fructose corn syrups commonly used to sweeten beverages and processed foods such as breakfast cereals and condiments.
Fructose in Apples
The amount of fructose in an apple depends on its size. A single, medium-sized, raw apple -- approximately 3 inches in diameter -- contains approximately 11 grams of fructose. A small apple, at 2 and three-quarter inches in diameter, contains 9 grams of fructose, while a large apple -- 3 and one-quarter inches in diameter -- contains 13 grams.
Compared to candy or a can of soda, a fructose-filled apple seems like the better choice. But the University of Florida News explains that fructose is fructose no matter what the source. Fructose is a monosaccharide, or simple sugar, usually broken down and absorbed quickly by the body. Fiber in the apple helps slow down the fructose absorption -- to an extent. While eating one apple may not be a problem, eating several apples at a time may cause a sudden spike in blood sugar levels.
When you eat an apple, most of the fructose that you consume enters the liver where liver enzymes carry out metabolization, according to the Harvard Medical School Family Health Guide. The body does not use fructose as a source of energy, so any apple fructose metabolized by the liver immediately turns to unhealthy body fats such as triglycerides and fatty acids. Excess amounts of body fat can lead to serious heart-related conditions.
The health benefits of apples may far outweigh negative fructose concerns. Silvina Lotito, Ph.D., of Oregon State University’s Linus Pauling Institute explains that apples contain flavonoids that may reduce the risk of acquiring certain cancers and chronic diseases. In addition, ingesting apple fructose increases plasma uric acid levels in the body. This increase in uric acid shares a common link to rises in plasma antioxidant capacity. High levels of uric acid can aid in the battle against inflammatory conditions.
- Harvard School of Public Health: The Nutrition Source: Vegetables and Fruits: Get Plenty Every Day
- University of Florida News; Too Much Fructose Could Leave Dieters Sugar Shocked; April Frawley Birdwell; December 2007
- Harvard Medical School Family Health Guide; Added Sweeteners; December 2006
- Oregon State University’s Linus Pauling Institute; Why Apples Are Healthful; Silvina Lotito, Ph.D.; November 2004
- USDA National Nutrient Database: Apples, Raw, With Skin