Is fructose really a healthy sugar? Since it is found in nature fructose is frequently touted as a healthy sugar. But, growing evidence suggests otherwise. If you have high blood pressure, abnormal cholesterol, have too much body fat, are pre-diabetic or diabetic, and have silent inflammation then you might be suffering from fructose poisoning, or excess fructose consumption. Collectively all of these conditions make up metabolic syndrome.
Fructose is naturally found in fruits and vegetables. But, where it is found in nature it is also found in association with fiber. Fiber limits the potential harm of fructose by delaying the absorption of the fructose enabling the liver to metabolize it more safely. It’s the fructose, and especially high-fructose corn syrup, that is added to many foods that is the problem as those foods are typically low in fiber.
Fructose and Health Concerns
The rise in obesity in the United States over the last 40 years parallels very nicely the increase in consumption of high fructose corn syrup. Consumption of high fructose corn syrup has increased 1,000 fold between 1970 and 1990 alone.
In more specific terms, excessive fructose consumption increases the risk of abdominal obesity in males by 39%, the risk of insulin resistance by 9% and the risk of high blood pressure in men by 11%.
Why is that?
Fructose acts like a toxin to the liver where it is metabolized in four ways. It is metabolized in the liver much like alcohol leading to production of unhealthy end-products. This includes undesirable lipids (fats) and uric acid. Fructose also causes glycation that damages tissues and accelerates the aging process. And finally, fructose does not suppress appetite like glucose contributing to overeating.
Adverse Effects of Fructose on the Body?
Fructose triggers something called the JNK pathway that activates inflammation. The production of uric acid causes elevation in blood pressure. Fructose alters the metabolism of the liver leading to increased production of unhealthy lipids like triglycerides and a lowering of the HDL or good cholesterol. In addition, like alcohol, fructose causes fatty liver disease.
Fructose alters control of the appetite center in the brain that also helps regulate glucose metabolism – one indirect effect is decreased ability of the muscles to use glucose leading to elevated blood sugar and insulin levels.
Fructose now accounts for 10 to 15% of the calories consumed in the US and adolescents obtain up to 30% of their calories from fructose. And, we wonder why we have an obesity epidemic.
What to Do?
Table sugar is 50% glucose and 50% fructose. High-fructose corn syrup is 55% fructose and 45% glucose. To avoid developing the conditions related to metabolic syndrome limit your intake of fructose to no more than 25 grams a day.