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If fructose is a villain, what about juice?

April 22, 2009 |  5:47 pm

Juice All this endless chatter about high-fructose corn syrup, to the point where regular old sugar -- once reviled as unhealthful -- is even making a comeback.

Why so much focus on high-fructose corn syrup in particular? I can see that the way we shove sugar into pretty much everything is bad news, but the focus on this sweetener confuses me a little.

Perhaps there's good reason to focus on fructose. A new study in the Journal of Clinical Investigation suggests that fructose may exert different physiological effects on the body from another small sugar, glucose -- and not good-sounding ones.

In the 10-week study, 32 overweight people were assigned to one of two groups -- one receiving a glucose-sweetened drink to consume, the other a fructose-sweetened drink. The drink constituted about 25% of the calories the people needed.

At the end of the 10-week period, both groups had gained weight, but those who'd drunk the fructose drink had gained more visceral fat -- fat tucked around internal organs. They also had decreased insulin-sensitivity, higher fasting blood glucose and blood insulin levels -- and other changes in blood fats.

The bottom line was that fructose, more than glucose, seemed to promote a set of unhealthful bodily changes correlated with a higher risk for diabetes and heart disease.

This may seem to point a damning finger at high fructose corn syrup. But doesn't it, more logically, point a finger at juice, and at fruit? (A disclaimer: I like fruit.)

Sucrose -- regular sugar from cane or beets -- is 50% fructose and 50% glucose when it's broken down into its two building blocks. Plenty of fructose there -- not much more, in fact, than what's present in high-fructose corn syrup, which contains about 55%, already as free fructose. So unless there's something physiological that happens before the sucrose is broken down -- which could be so -- it doesn't seem there would be much difference. (Though as we all know, 5% more of something can sometimes make a difference if it's 5% more consistently, day in and day out.)

Maybe what's more important is the increasing presence of sweeteners added to processed foods of all kinds, and not the precise sweetener that's used.

And somehow, amid all this talk of devil sodas, juices -- which some people chug like crazy, because after all, they're healthful -- get a relative pass. Isn't juice loaded with fructose? What part does it play in our diabetes rates?

-- Rosie Mestel 

Photo Credit: LAT / Eric Boyd

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Comments (11)

The fiber in the fruit seems to provide what is necessary for the body to efficiently

digest the fructose that is contained in the juice. Blend the whole fruit, smoothie,

and the inherent problems from drinking just the juice should be avoided.

Fructose is found not only in the proven villain, high fructose corn syrup, but as pointed out in white sugar, soft drinks, fruit juices, and yes, even honey. All these sweeteners or simple carbohydrates are essentially empty calories and should be minimized in any weight loss diet. Instead drink low sodium veggie juices and eat fruits like apples or oranges that also contain these sugars but also fiber and antioxidants. There is really no need for eating simple carbohydrates which rapidly raise insulin. Instead complex carbohydrates from starches slowly release the essential simple carbohydrates needed for metabolism, just like a fire place log creates long lasting heat whereas paper an instant and dangerous flash fire.

instead of rehashing one study, why not do some actual journalism and investigate the effects of juice? does the 'blog' tag mean you don't have to run this past an editor?

Yes!. Fruit juice is a villain. Regular fruit is your friend.

Why? Because juice is easily overconsumed. Regular fruit, rarely. While fruit juice is "healthy", it's too easy to consume too much (with too many calories involved). Regular fruit on the other hand adds fiber with the calories and takes longer to consume.

Try diluting the fruit juice in half with water. Works best with grape juices. Apple juice takes less diluting, since there are fewer calories in it.

You're on to something here. Sugar of all sorts, including juices, is really really bad for you. In fact, carbohydrates of all sorts, including things we are told are "healthy" like breads and fruits, can be really really bad for you.

Google for "gary taubes berkeley" for an hour and a half lecture that will expose the past 30 years of dietary advice as both harmful and misguided.

Insightful post. I see this focus on HFCS as nutritional scapegoating. Fructose may indeed be worse than glucose, but that makes no difference when replacing HFCS with sugar in our diets because, as you've said, both contain the same amounts of fructose. There's no way around this. We just need to consume less sugar in our diet rather than finding excuses like HFCS so that we can still consume the same amounts of sugar, or having our cake and eating it too.

high-fructose corn syrup are really bad

Instead of writing a commentary on what questions to ask, why not do some real reporting. Get on the phone and ask the people that wrote the paper in the JCI! This is exactly the reason people stop paying for the newspaper - this piece has no more useful information than baby puke.

Many people are under the impression that because it's "juice," then it's good for you. The food companies take full advantage of this and have been very successful in their marketing as a result.

sucrose, like other more complex carbs (or in this case a disaccharide), requires more processing in the GI tract to be broken down into absorbable simple sugars. sucrose is healthier than consuming the equivalent of fructose+glucose for the same reason that whole wheat bread is healthier than the equivalent-calorie white bread: it takes longer to break it down in the GI tract (in part due to fiber, in part due to the time it takes to mobilize the relevant enzymes that break down complex carbs; in the case of fruit juices, we are losing some fiber, but the second effect is still present). This provides a longer time period for the fructose and/or glucose to enter the blood stream. This, in turn, dampens the spike in blood sugar - spikes which many in the medical community believe ultimately lead to insulin insensitivity and later diabetes.

One...High Fructose Corn Syrup may contain the same amounts of fructose and glucose, but what no one is mentioning is that it started out as corn and has gone through a multistep process, being broken down and altered and in fact when it reaches the grocery shelves is in no way "natural" or in resemblance of the original product grown in nature. It IS in fact a preservative, despite some claims to the contrary and in no way comparable to fructose in its original form.

Two...Fructose is much lower on the glycemic index than other forms of sugar making it a "healthier" option in moderation and only becomes a problem when consumed in large amounts regularly.

Which brings me to number three...go out and get a juicer and a bag of apples and make yourself a glass of juice equal to what you would typically poor from a bottle of fruit juice. Now, tell me how many apples are left in that bag. BINGO...fruit juices are either 1) "cocktails" or "beverages" made with very little actual fruit or 2)made from extremely large amounts of fruit producing excessive amounts of fructose well beyond what you would consume in an apple or two and minus the fiber and most of the nutritional value. THUS, the reason that fruit juice is not a healthy choice.

If you check out the labels on a basic fruit juice that does not claim to be 100% natural or have "No added sugar" and then on one that does, you will see much higher amounts of sugar in the "no sugar added" one than the one with sugar as the first or second ingredient. That is because one is made from a bag of apples per glass and the other has little actual fruit, but added sugar and other ingredients. Either way...the health benefits are far outweighed by the negative effects and you should stick to a glass of water and an apple.


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