Why Fructose Is Bad For Your Health
From a naive point of view, the simple sugars found in carbohydrates consist of fructose, sucrose, and glucose. Since 1996, food processors have added High-Fructose Corn Syrup (HFCS) to the list of added sugars.
Fructose, or fruit sugar, is a simple monosaccharide. You can think of a monosaccharide as being a single simple sugar.
Sucrose, or table sugar, is a disaccharide or equal parts of two simple sugars: 50% glucose and 50% fructose.
Glucose is a simple monosaccharide, or a single simple sugar.
There is no need to make this subject any more complicated than it actually is. Scientists like to confuse the issue by throwing around a lot of unnecessary jargon. In short, most scientists fail to communicate because they are just as confused as most people are on what really counts when it comes to improving a person’s personal health.
Physiologically, there is no such thing as sucrose since sucrose is metabolically broken down into fructose and glucose by your body.
In other words, from the perspective of your body there are only two simple sugars: fructose and glucose.
"Glucose is the body's preferred carbohydrate substrate for energy metabolism."[1]
Why is Glucose preferred by your body?
Most carbohydrates are easily handled by our bodies. Carbs are converted quickly to glucose, and in turn used for energy by our cells. The process, however, is not so simple when it comes to fructose. Fructose is NOT needed by your body at all.[5] Fructose has to be converted to glycogen through gluconeogenesis in the liver.[6] Unlike glucose, fructose metabolism occurs mostly in the liver, which helps to explain why it is a chronic liver toxin.
The preferred status of glucose ranks it as a starch, rather than just a simple sugar. Good carbohydrates are starches, polysaccharides, that are composed of multiple molecules of glucose. Thus, the best sources of glucose come from starches which are metabolized to release their glucose content. In other words, large amounts of glucose or starch in your diet are acceptable because of the way your liver handles it.
Because Fructose is "metabolized in the liver differently to glucose, and is more akin to that of ethanol," it is considered to be an evil simple sugar by health advocates.
"Fructose is an intermediary in the metabolism of glucose, but there is no biological need for dietary fructose. When ingested by itself, fructose is poorly absorbed from the gastrointestinal tract, and it is almost entirely cleared by the liver ...
Fructose differs in several ways from glucose ... Fructose is absorbed from the gastrointestinal tract by a different mechanism than that for glucose. Glucose stimulates insulin release from the isolated pancreas, but fructose does not. Most cells have only low amounts of the glut-5 transporter, which transports fructose into cells. Fructose cannot enter most cells, because they lack glut-5, whereas glucose is [easily] transported into cells by glut-4, an insulin-dependent transport system."[5]
What High Fructose Corn Syrup Leads To
High-fructose corn syrup (HFCS) is nothing more than a misnomer. It is actually just a mixture of glucose and fructose, which thus should really be called glucose-fructose syrup. On top of that, there is more than one kind of HFCS. However, for simplicity sake HFCS consists of a mixture of 55% fructose and 45% glucose, or is very close to the chemical composition of sucrose or table sugar.
It gets even simpler than this.
All Sugar Is Bad For You
Physiologically there is only one simple sugar: Fructose. Metabolically, glucose is handled so differently from fructose, that it rightfully should be viewed as a starch. Ergo, all sugar is bad for you because metabolically there is only one sugar: Fructose.
Thus, the great evil in natural health nutrition is fructose rather than HFCS. HFCS is NOT pure fructose but rather a mixture of sugar and starch. In other words, the fructose contained in a glass of pure organic orange juice is just as bad for your health as the fructose is in a can of American Pepsi. It is, thus, preferable to eat a whole orange because of its fiber content than to drink pure orange juice due to its steep fructose sugar load, which is metabolically bad for your body. The fact that Pepsi and Coca-Cola contains high-fructose corn syrup in the United States, but sucrose or table sugar in Mexico and in the rest of the world is quite irrelevant. The great evil facing anybody who is drinking this garbage is still the same: The chronic liver toxin fructose.
Why Fructose Is Bad For Your Health
Fructose is bad for your health because it is metabolized in your body differently than the way glucose is.
- Fructose is "metabolized in the liver differently to glucose."[1] In other words, "the liver must handle triple the substrate as it did for glucose alone"[1] (i.e., triple the workload).
- Fructose promotes eight of the same 12 liver toxic effects as ethanol does. Ethanol is regulated by government as an acute liver toxin, whereas fructose is NOT because it is only a chronic liver toxin.[1]
- Fructose affects both leptin and insulin differently from the way glucose does. In short, fructose does NOT satisfy your hunger, or turn off the hunger hormone in your brain the same way glucose does. As a result, most people will end up eating more total calories, thus adding to the obesity epidemic, when they consume excessive amounts of fructose.[3]
- Fructose raises your triglycerides, while lowering your HDL levels.[1]
- Fructose rasies your systolic blood pressure, fasting glucose, HOMA-IR a marker for insulin resistance, and C-reactive protein a marker for infammation.[2]
- Regardless of your caloric need, 30% of fructose calories are directly converted to fat by your body.[1] Much of which, will be deposited directly on your belly as danagerous abdominal fat.[4] In short, fructose sugar is just as bad as fat.
- Fructose is so pervasive to the Western diet, that the total dose of fructose in your diet is what makes it especially unsafe. Since 1900, there has been a 5-fold increase in the annual consumption of fructose in the United States. We have gone from consuming 15 gm/day of fructose to a shocking 113 pounds per year, or one third pound per day of this chronic liver toxin. Such high levels of sugar in your diet is, thus, totally unnatural.[1]
Please read our Medical Advice Disclaimer.
References:
- The Fructose Epidemic
Robert H. Lustig
The Bariatrician, 2009, Volume 24, No. 1, page 10. - An Audio Reading of The Fructose Epidemic
- Greater fructose consumption is associated with cardiometabolic risk markers and visceral adiposity in adolescents.
Pollock NK, Bundy V, Kanto W, ...
J Nutr. 2012 Feb;142(2):251-7. Epub 2011 Dec 21.
PMID: 22190023 - Effect of glucose and fructose on food intake via malonyl-CoA signaling in the brain.
Lane MD, Cha SH.
Biochem Biophys Res Commun. 2009 Apr 24;382(1):1-5. Epub 2009 Mar 3. Review.
PMID: 19265677 - Sucrose-sweetened beverages increase fat storage in the liver, muscle, and visceral fat depot: a 6-mo randomized intervention study.
Maersk M, Belza A, Stødkilde-Jørgensen H, ...
Am J Clin Nutr. 2011 Dec 28. [Epub ahead of print]
PMID: 22205311 - How bad is fructose? [Full Text Online]
Bray GA.
Am J Clin Nutr. 2007 Oct;86(4):895-6.
PMID: 17921361 - Dietary fructose induces a wide range of genes with distinct shift in carbohydrate and lipid metabolism in fed and fasted rat liver.
Koo HY, Wallig MA, Nakamura MT, ...
Biochim Biophys Acta. 2008 May;1782(5):341-8. Epub 2008 Feb 29.
PMID: 18346472
