The fruit sugar fructose provides energy for cellular activity, but its consumption is not without controversy. For most people, the fructose content in fruit is only one factor used to determine how healthy a given fruit is. Understanding how the fructose in fruit affects the body and how the other components in fruit affect how the body utilizes it can help you make wise choices about which and how much fruit to eat.
The Basics
The simple sugar fructose provides fuel for the body's cellular activity. Fruit is the main dietary source of fructose, and most fruits contain high levels of this carbohydrate. In the body, fructose is taken up by the liver and digested by an enzyme called aldolase B. Some people inherit a defect in this enzyme and cannot properly digest fructose.
Fruit and Fructose
Most fruits are high in fructose, although they also typically contain sucrose or glucose as well. The fructose content of dried fruits tends to be highest, so prunes, raisins and dates contain some of the highest levels. Apricots, nectarines, cantaloupe and peaches tend to have lower levels of fructose than many other fruits.
Significance
The fructose in fruit is not isolated, but instead occurs in conjunction with other components of the fruit, such as fiber and nutrients. Unlike added sugars, including sucrose -- or table sugar -- and high fructose corn syrup, the fructose in fruit tends to have a mild impact on blood glucose levels because the water and fiber content of fruit tempers any rise in blood sugar that fructose causes. The fructose in fruit might also boost the antioxidant activity of fruit by raising uric acid levels in the bloodstream.
Other Sources
Fruit isn't the only source of dietary fructose, but it is one of the healthiest. Some vegetables, such as carrots, sweet potatoes, beets and tomatoes, also have high fructose levels as well as fiber, vitamins, minerals and phytochemicals. Honey and maple syrup also contain fructose, along with nutrients and phytochemicals, but they don't have the healthy fiber found in fruit. Foods with added high fructose corn syrup or isolated granular fructose do not offer the same benefits as consuming whole fruits containing fructose. Instead, these foods have been linked to high blood pressure, high cholesterol and type 2 diabetes.
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