by Marion Nestle
Aug 10 2007

Sugars: Fructose v. Glucose v. Sucrose

Today’s question: “From what I’ve read about high fructose corn syrup, the bad-for-you part about it (in addition to the high quantities people consume at once, like in a 20 oz coke) is the fructose. Is fructose the real evil, and if so, then aren’t foods like fruit juices bad as well?”

Today’s answer: I deal with this vexing question in the Sugar(s) chapter of What to Eat. The problems (and I’m not convinced they are very serious) of fructose depend on what you compare it to. Sucrose, the white stuff in sugar bowls, is a double sugar made of glucose and fructose, 50% each. Corn sweeteners are also glucose (42%) and fructose (55%). I’m not convinced the body can tell them apart. Fruit juices also have glucose and fructose. If you compare the metabolism of fructose to glucose, there are differences, but I think the problems are with quantity, not quality. A little sugar makes foods taste good; a lot adds calories that nobody needs these days. From the standpoint of calories, fruit juice has just as many as soft drinks so a little goes a long way even though it is a healthier alternative.

  • There is pretty unanimous agreement now (despite a few persistent naysayers) that the body does respond differently to fructose sugars, particularly in the way they affect glucose and insulin levels in the body for the first few hours after consumption. This effect is quantified with a scale called the Glycemic Index, which though still controversial, continues to gain significant ground in the research community (e.g. Dr. Walter Willet et. al’s epidemiological work) in respect to linking long-term exposure to high-glycemic load meals to insulin resistance and diabetes.

    But there’s an economic side to the fructose question, and that is in respect to the system involved in the fructose manufacturing (e.g. high-fructose corn syrup). Regardless of health questions, by choosing foods with HCFS one is participating in a system that has impacts individual, community and ecosystem health in so many ways that I couldn’t begin to list them here.

  • Thanks for making these points. Bodies do respond differently to fructose as compared to glucose. But because table sugar (sucrose), corn sweeteners, and fruits almost always contain both fructose and glucose in roughly the same amounts, the body handles the sugars in those foods in pretty much the same way. Your second point is extremely important and worth emphasis. It’s better for the health of people and the planet to eat real foods, not processed miracles of food technology.

  • greg

    isnt the main problem with HCFS is that it is metabolized by your liver and not your pancreas (which usually handles sugar / insulin duties)??

    i thought that andy’s Small Bites blog / newsletter explained sugars pretty well also, esp. HCFS.

    and as phil said, the economic side to HCFS and why its in all of our food is because of the huge subsidies for corn in this country. lets hope that the senate cuts back subsidies for big farms even more than the house proposed in their version of the farm bill.

  • Bix

    I’m in Marion’s corner here. I understand the difference, but I think it’s more a problem of quantity. Where a medium peach has about 1.5g of fructose, a “small” 16 oz. HFCS-sweetened carbonated beverage can have about 25g of fructose!

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  • Label translation, please!

    What are “Fructose Crystals?”

    I discovered this ingredient listed on a bottled white tea beverage. (7 grams sugar total per 8 oz)

  • You’ve seen crystals of table sugar (sucrose, a molecule made of glucose and fructose). These are the same thing, only made of fructose by itself.

  • Jennifer

    According to the Canyon Ranch Cookbook they utilize fructose instead of other sugars because it has a lower glycemic index and you also need to add less quantity as its sweeter. This is a good thing for people controlling carbs for health reasons such as diabetes. What is the difference between HFCS and plain fructose?

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  • levi C.

    Cornstarch is treated with a number of enzymes to eventually produce HFCS. Two of the enzymes used, alpha-amylase and glucose-isomerase, are genetically modified to make them more stable at higher processing temperatures. Consumers trying to avoid genetically modified foods should avoid HFCS. It is almost certainly made from genetically modified corn and then it is processed with genetically modified enzymes.

  • Shari L.

    “Healthy” HFCS Salad dressing.

    Yesterday, I spent the day with some friends who have a 13 year old daughter. We went to a local farm and farmer’s markets. We made an easy beautiful dinner – farm/free range chicken sausages, grilled bella mushrooms; fresh breads; corn on the cob; a big salad.

    The daughter didn’t like the simple oil and vinegar dressing. She went to the fridge and got out wishbone spray. You pump “salad dressing” all over your salad. They told me how great it was, because she uses less dressing. I picked it up and read the ingredients. First item? Of course: HFCS.

    Frankly, to me it was quite a yucky thing to watch.

  • Caroline

    “It’s better for the health of people and the planet to eat real foods, not processed miracles of food technology.”

    I am wondering why exactly? Take a glass of reduced sugar Tang (or some other juice mix), sweetened by sucralose, acesulfame potassium, and Neotame and enhanced by vitamins and minerals. How is it unhealthier for a person than a glass of natural full sugar orange juice, which has more sugar and more calories?

    The carbon-footprint of the Tang might be more immense but with nutrients added to the processed drink, how is it more unhealthy for a person to drink?

  • This one is easy. Orange juice has loads of nutrients and antioxidants along with its sugars. These can’t be replaced artificially.

  • MikeP

    Is natural honey a better substitute for HFCS or the sucrose (white granulated sugar) in my afternoon cup of tea?

  • If you use less honey than you use of the others, it’s a better bet.

  • jnc

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