New Evidence of Why Excess Fructose is Bad

It has long been known that excess calories, beyond what is consumed by ones basal metabolic rate coupled with their level of physical activity, will lead to the synthesis and storage of fat. This is regardless of whether the calories consumed are from carbohydrate, fat, or protein.

The global rate of overweight and obese individuals has skyrocketed over the past 25 years and a huge amount of the blame lies squarely on the Western (meaning USA) diet. One component of the Western diet that has exploded in use is prepackaged meals and sweetened beverages. The most common additive to enhance the sweetness of foods, and thus ones increased desire to consume them, has been high fructose corn syrup, HFCS. HFCS is generated by chemically converted some of the glucose that is corn sugar (amylose and amylopectin) into fructose.

However, to demonize HFCS is, at best, naive given that natural sugar, that derived from sugar cane and sugar beets, is sucrose. Sucrose is a disaccharide composed of one molecule of glucose and one molecule of fructose. Thus, sucrose is 50% fructose. The highest concentration of fructose in HFCS is around 55%. Therefore, the issue is definitely not just that so many foods and drinks are sweetened with HFCS, especially since so many food manufacturers are now touting the fact that their products contain natural sugar and not HFCS, but that people just consume too many calories from prepackaged and sweetened foods and beverages.

Indeed, it has been long established that high fructose feeding, and its metabolism, is a critical inducer of insulin resistance, the hallmark of type 2 diabetes.

New evidence has discovered that a major contributor to diseases, such as obesity and diabetes, resulting from the over consumption of HFCS and sucrose, is that when the small intestine metabolizes some of the fructose one byproduct is glycerate:

Glycerate from intestinal fructose metabolism induces islet cell damage and glucose intolerance

Under normal dietary circumstance, when fructose is not in excess, the small intestine will metabolize nearly all of the fructose for its own energy needs. However, within the context of the typical Western diet, high in carbohydrates and fats, the intestine will increase the metabolism of fructose to glycerate which is then released to the portal circulation.

One of the negative consequences of the increased fructose-derived glycerate is that it induces pancreatic islet β-cell apoptosis (programmed cell death) which is a key contributor to diabetes.

So what is the Take Home message from this study?

It is never a healthy way to live when one consumes too many total calories but even more so deadly when those calories come from prepackaged sweetened foods and sweetened beverages, especially when the combination is loaded with fructose (either in the form of HFCS or sucrose) and fat.