Fructose: Is It Bad For You?

There is a lot of controversy surrounding the use of high-fructose corn syrup as a sweetener in foods nowadays.  I’ve been reading a lot of research about fructose and its effects on the body and thought I’d summarize.

Back in the 1970s researchers found they could make a very cheap sweetening agent from corn.  It really caught on in the USA because we have huge supplies of corn but not a lot of sugarcane.  High-fructose corn syrup became an enormously popular sweetener and today is used in all sorts of foods.  The most widely used area is in soda.

First of all, fructose is a monosaccharide (“one sugar”).  There are three monosaccharides:  fructose, glucose and galactose.  In nature, sugars occur in the form of disaccharides (“two sugars”), which are two monosaccharies joined together.  There are three main disaccharides:  sucrose (table sugar, glucose-fructose), lactose (found in milk, glucose-galactose), and maltose (found in grain and beer, glucose-glucose).  Other carbohydrates are in the form of polysaccharides (“many sugars”), referred to as starches.

It’s important to realize that the ONLY sugar that tastes sweet is fructose.  Fructose is why table sugar is sweet.  The more fructose in a food, the more sweetness it has.  Humans are hard-wired to like sweet-tasting foods.  Newborn babies naturally eat more of foods that taste sweet.  If a food manufacturer puts more fructose in a food, it will have more appeal for consumers.  (Disclaimer:  I know there is more to making food taste good than making it taste sweet, but this is a generalization.)

So is fructose bad?  I wanted to base my opinion on the scientific research, so I went to the PubMed database.  There are over 800 research articles on fructose and obesity.  Lots of research to wade through!  Here’s the Cliffs Notes version:

1.  Fructose is metabolized in the liver as if it were a FAT, not a SUGAR.  It is changed directly to triglycerides, which are stored in fat cells.  High fructose intake increases triglyceride levels in the blood.

2.  Increased triglyceride levels increase insulin resistance.  Insulin resistance makes it much more difficult to lose and maintain weight.  It also interferes with energy metabolism and makes one very tired.

3.  Fructose causes leptin resistance.  Leptin is the current holy grail in obesity research.  It is a hormone produced by fat cells that turns off hunger and craving signals in the brain.  If fat cells make leptin but the brain can’t hear the signal, you will continue to feel hungry and experience cravings.  Fructose makes it more difficult for the brain to hear the “satiety” signal that makes you feel full and satisfied.

4. Fructose intake also increases uric acid levels.  Uric acid is central to the illness called gout (a severely painful and destructive joint disease).  Gout is on my personal top-five list of illnesses I NEVER want to experience personally.

What about fruit?  It tastes sweet.  Is fruit bad?  It seems that if you consume fructose in combination with dietary fiber, it slows the absorption and processing and blunts the effect on triglycerides and leptin.

So what is the take-home lesson about this little dissertation on fructose.  It’s not something most people are going to want to hear.

The bottom line is that if it tastes sweet, it has fructose in it.  (Let’s leave the topic of artificial sweeteners for another day.  I promise it is on the short list of future blog topics.)  If it tastes sweet, it is NOT good for you and should be eaten in very limited amounts.  Fruit is acceptable, but fruit juice doesn’t have the fiber and should be avoided.  (Sorry that’s bad news for the juicing crowd).

If you have a taste for something sweet, try a small bowl of berries or some apple slices.  They should not trigger cravings if eaten in moderation.  I promise you, after a few days of “detox” from sugar you will feel more energy and less aches and pains.

Question (and challenge, LOL!):  Go look at the ingredient list on your favorite snack foods.  Are there any that contain high-fructose corn syrup?  Which ones?

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