Growing up I figured anything from fresh fruits was good for my health - including fresh fruit juice. While fruit is indeed very good for you - full of fiber and micro nutrients - when the sugar in fruit is concentrated in juice, the sugar levels can become surprisingly high and potentially unhealthy.
I think many of us tend to ascribe a certain sanctity to fruit juice. I was very skeptical when a friend of mine brought the topic up for discussion. I thought to myself, aren't there enough problems with what people eat without having to worry about drinking some fresh fruit juice? However, after some investigation, it turns out that fruit juice has just about as much sugar as a soft drink, and the fact that the sugar comes from fruits doesn't make it any better for you!
Table sugar consists of a substance called sucrose, and it's actually two simpler sugars linked together. Each sucrose molecule consists of one glucose molecule linked to a fructose molecule.
Fruits consist of fructose and glucose individually. Since sucrose is split up into glucose and fructose almost instantly in the stomach, there's really no fundamental difference. It comes down to how much glucose and fructose there is. Some fruits have more fructose than glucose - hence the name! Is that a good thing? It turns out that fructose is in some ways a naughtier form of sugar than glucose. Fructose can only be digested in the liver while glucose is distributed into the blood and can be processed by any cell in the body. In fact fructose appears to be responsible for many of the nastier health side-effects from sugar: Liver disease, weight gain, and heart disease. Below is a great video about fructose - but be warned, it's a bit long. You may want to come back to it later!
Some people have especially serious problems digesting fructose. 30-40% of people in Western Europe have a digestive disorder called Fructose Malabsorbtion. Hereditary Fructose Intolerance is much less common - in the neighbourhood 1 in 10,000. Both conditions seem to have links to things like IBS (irritable bowel syndrome) and celiac disease.
Foods with more fructose than glucose (apples, pears, watermelon, honey, foods with high fructose corn syrup) may be be more of a problem than foods with less fructose than glucose like berries, bananas, and oranges.
How much sugar is there in juice? Well, the Sugar Stacks site, says that an 8oz glass of orange juice has 24g of sugar, which is about half the sugar - by weight - in a 12oz can of coke (which has about 40g of sugar)! Since oranges have about the same amount of fructose as sucrose, the sugar content can be deemed to be equivalent. Apple juice is about the same at 26g, but since it has more fructose than glucose, it may have more potential health risks.
I've looked for information on what amount of sugar one should consume in a day, but it seems there are no explicit guidelines. Many sources indicate that one should not add more than 30g of extra sugar a day to one's diet - that's *not* counting the sugar in fruits and dairy. The truth is, unless you're a high performance athlete, there is probably no reason to add extra simple sugars to your diet at all beyond what you'd get eating a recommended allowance of fresh fruit and milk.
http://recipes.howstuffworks.com/usda-nutrition-guidelines-ga9.htm
http://health.yahoo.com/experts/joybauernutrition/40/sugar-how-much-should-we-eat/
Keep in mind, just because the sugar you consume comes from fruits, it doesn't mean the effects on your health are any less significant. In fact, when you concentrate the natural sugar found in some fruits and remove the fiber (all the meaty pulpy parts of the fruit) which slows down its processing by the body, you end up with a supercharged sugar that, if anything, may be even worse for you than regular sugar!
If you have digestive problems or diabetes, then consider discussing your sugar consumption with your doctor, and particularly consider what kinds of fruits and fruit juices you're consuming. Something you think is healthy may be part of the problem.
By and large, the sugar we get from fresh fruits and milk should be enough. When you eat one orange or one apple, you're not likely to overdose on sugar. There's not that much in the first place, plus there's a great deal of fiber which helps to slow down the absorbtion of the sugar.
When sugar from fruit is concentrated into juice, it can rival the amount of sugar in sugary snacks and soft drinks, and that can lead to problems. Now, fruit juice isn't responsible for the enormous dietary problems we have in Western society. It's the excessive sugar we get from snacks, junk food, and candy that is responsible - along with too much fat and salt - for a lot of the problems people have these days.
Before we vilify juice, keep in mind that all these other sources of excess sugar are mostly to blame for many of the diet-related health problems people have these days. However, it appears to be true that our old fashioned ideas aren't necessarily true: Drinking tonnes of fruit juice is not the road to good health. You're better off eating fruit whole, and if you have kids, it's probably a good idea to replace most juice with whole fresh fruit instead. Many of the nutrients in fruit are close to the peel. Also, you get the full benefit of the fiber in the juice. Finally you won't get addicted to the extra-sweet taste of juice - fructose also tastes 73% sweeter than sucrose!.
Balance is important. Follow the guidelines for a healthy diet. and enjoy food. For most people, a sweet snack every so often isn't the end of the world, whether it's a sinful chocolate truffle, an ice cream cone, or indeed, a glass of juice! However, overdoing sugar leads to long term health problems.
Thanks for reading! Please write to admin@wellbook.org with questions or comments!
Here are some links explaining the differences in the way glucose and fructose are processed by your body:
http://en.wikipedia.org/wiki/Fructose#Health_effects
http://ca.askmen.com/sports/foodcourt_150/182_eating_well.html
http://wholehealthsource.blogspot.com/2009/04/fructose-vs-glucose-showdown.html
