Fructose Toxicity

Fruits used to be the main source of fructose in the human diet until the introduction of sugar and sweets. The fructose consumption of Americans has significantly increased in the last decades, not because they eat more fruits, but because they eat more sugar, according to Dr. Robert H. Lustig, Professor of Pediatrics in the Division of Endocrinology of the University of California, San Francisco. Table sugar, honey, molasses, maple syrup and high-fructose corn syrup are roughly half fructose. The wide use of these sweeteners in desserts, candies, baked goods and other processed foods may cause fructose toxicity.

Fatty Liver

Fatty liver disease used to be the result of alcohol consumption, but the prevalence of the non-alcoholic form, also called non-alcoholic steatohepatitis or NASH, increased significantly, along with the prevalence of obesity, according to the June 2008 issue of "Journal of Hepatology." The authors of this paper report that patients developing non-alcoholic fatty liver consume two to three times more fructose compared to healthy subjects. According to these results, fructose can be toxic for your liver. This study also indicates that this finding is probably due to the role of fructose in stimulating the production of an enzyme responsible for converting excess fructose into fat, which can then be stored in the liver, interfering with the healthy functioning of this important organ.

Obesity

Fructose is not metabolized the same way as glucose and can only be metabolized by the liver where it is preferentially converted to fat, which is then stored in your fat cells around your waist, hips and thighs. This conversion of extra sugar into fat is more efficient with fructose than it is with glucose, according to a paper published in April 2004 in the "American Journal of Clinical Nutrition." Fructose can also promote obesity because it doesn't trigger the release of leptin after its consumption. Leptin is an important hormone responsible for stopping you from feeling hungry, and if your leptin is not working properly because of the toxic effect of fructose, you are more likely to overeat.

Triglycerides

Fructose is easily and preferentially converted to a type of fat called triglycerides. Your triglycerides levels should ideally stay below 150 mg/dL to prevent heart problems. A high sugar intake is associated with higher triglycerides levels because of the toxic effect of the fructose contained in all types of sugars and sweeteners. For this reason, the American Diabetes Association does not recommend that diabetics use fructose powder to sweeten their foods to avoid a rise in their triglycerides and cardiovascular risk, as described in their guidelines published in "Diabetes Care" in January 2008.

Decrease Your Fructose Intake

The best way to avoid the toxic effects of fructose on your liver, weight and triglycerides is to reduce your overall sugar consumption. Keep your fructose consumption low by including no more than one to two small servings of fruits a day and avoid all foods and beverages containing added sugar, whether present in the form of regular sugar, brown sugar, high-fructose corn syrup, molasses, honey, sucrose or pure fructose. Do not drink soft drinks or fruit punches and stay away from muffins, cookies, granola bars, breakfast cereals, scones and other baked goods that contain a lot of fructose.