Fructose is a naturally occurring sugar found in many fruits, honey, and some vegetables. It is also a component of table sugar (sucrose) and high-fructose corn syrup (a sweetener commonly used in processed foods and beverages). In moderate amounts, naturally occurring fructose is generally considered safe and part of a balanced diet. But in excess, fructose can have adverse health effects.
In our body, fructose is metabolized in the liver and can be converted to glucose, which cells use for energy. Fructose can also be stored as glycogen in our liver or muscles. However, our bodies can only store glycogen once, and the remainder is converted to fat. Thus, consuming large quantities of fructose leads to the accumulation of fat.
The main concern regarding fructose is its role in weight gain and the development of obesity and other metabolic disorders. In addition, some people cannot correctly digest fructose (fructose malabsorption), which can lead to excessive gas and digestive discomfort.
Studies have shown that a high fructose intake, especially from added sugars, can lead to increased fatty liver disease and adiposity (fat accumulation). It can also contribute to an increase in the levels of triglycerides and uric acid in the blood and cause insulin resistance.
In addition to causing excess fat storage, fructose can impair a person’s immune system and cause chronic inflammation. High-fructose diets have also been linked to non-alcoholic fatty liver disease, a condition that causes scarring and cirrhosis of the liver. Furthermore, a recent study conducted by Pfizer showed that consuming high amounts of fructose caused the liver to become fatty, leading to hepatotoxicity (liver failure).
While it is recommended to limit our intake of added sugars, fructose from whole fruits and vegetables is not considered harmful in moderation. A typical serving of whole fruit contains only 5-7 grams of fructose. It is when consuming fructose from sugary drinks and other processed foods that it becomes a concern. Fructose, particularly in the form of high-fructose corn syrup or other types of added sugars, should be avoided as much as possible to maintain good health and prevent chronic diseases.