The questionable dark side of fructose

Consumption of fructose, usually in the form of high-fructose corn syrup (HFCS), has been suggested as one of the underestimated causes of the increased incidence of obesity/metabolic syndrome in the U.S.
Given the magnitude of the issue, Medscape covered this report, “Fructose but Not Glucose Consumption Linked to Atherogenic Lipid Profile,” from a presentation at the recent meeting of the American Diabetes Association by Peter J. Havel, DVM, PhD, and colleagues at the University of California at Davis Department of Nutrition.
In this small trial, 23 normal volunteers were first given an energy balanced diet of 30 percent calories from fat and 55 percent complex carbohydrates for 2 weeks. The group was then randomized to receive drinks containing glucose (13 subjects) or fructose (10 subjects) that comprised 25 percent of their daily energy needs for 8 weeks.

Relative to baseline, 24-hour postprandial triglyceride profiles were increased by 212% ± 59% in the fructose-consuming group (P < .0001). In contrast, levels declined by about one third (-30% ± 23%) in the glucose-consuming group. In addition, fasting plasma levels of low-density lipoprotein cholesterol (LDL-C); apolipoprotein B; and small, dense LDL-C, as well as postprandial levels of remnant lipoprotein (RLP)-triglycerides and RLP-cholesterol, were all significantly increased (P < .01) in the fructose group. By comparison, these levels remained unchanged in the glucose group.
Fructose-consuming participants also demonstrated increased plasma concentrations of the atherogenic risk factors oxidized LDL-C (P < .0001) and intracellular adhesion molecule (P < .05), but those consuming glucose did not.
"It is known that fructose, after being metabolized by the liver, is more likely to go into a lipogenic pathway than glucose," Dr. Havel noted. "So these results were not surprising to us, but the magnitude of some of the changes was striking," he added.

Indeed. I was blown away by the tremendous increase in plasma triglycerides with the fructose diet. However, the rest of the article notes that another (uncited) study showed no such changes when fructose comprised 17 percent of total calories. Keep in mind that this report is from a meeting presentation and has not been subjected to stringent peer-review; I’ll be interested to read the discussion of the ultimate full-length manuscript.
Of course, the Corn Refiners Association would refute this study by saying it did not investigate HFCS but rather pure fructose, not a fair comparison since the most commonly used form of HFCS (known as HFCS 55 in the biz) is about 55 percent fructose and 45 percent glucose. They may actually have a point here since regular table sugar, sucrose, is a disaccharide composed of one molecule each of glucose and fructose.
The question that plagues this research area is whether the growing (pun intended) obesity epidemic since the 1970s is due to HFCS or simply our overall increase in consumption of all sweetened beverages. I remember when Coke used to come in 8 oz bottles; now you can buy a 44 oz Big Gulp, or at least an average 20 oz bottle. The HFCS issue is also entangled with public aversion to genetically modified foods, including corn, and the fact that large corn-processing companies benefit from subsidies unavailable to conventional sugar cane producers.
Regardless of whether HFCS is more problematic than glucose or sucrose, the only sure way to reduce one’s risk of weight gain due to HFCS is to replace sweetened beverages with good old water.
(Source: American Diabetes Association 67th Scientific Sessions: Abstract 0062-OR. Presented June 23, 2007.)

13 thoughts on “The questionable dark side of fructose

  1. What I find exasperating about this news is how little traction it gets compared with all of the hand-wringing about detecting benzene in soft drinks. True, it’s not a good practice to continue introducing a carcinogenic contaminant into the food supply (loosely applying the term “food”, with regard to soft drinks). However, there seems to be much less recognition about the larger health hazard, as described in your post. What also might be interesting with regard to this finding is the statistic that sugar-sweetened soft drinks contribute more than 7 percent of Americans’ calories, making them the largest single source of calories in the US diet. (see for more on this).

  2. While I was rooting around for material for a blog post that follows up on this topic, I ran across a citation in PubMed for a animal bioassay of the carcinogenicity from long-term administration of Coca-Cola.
    While you don’t want to place too much weight on a single study, I found it deliciously ironic to see Coke being assessed just like any other toxic substance for adverse health effects.

  3. I went into the doctor a few weeks ago at a time in which I had been working crazy hours and drinking lots of soda. I was about 4200 triglycerides (not a typo) at 165lbs. Previous doctor visit a few years ago had me at 1500 triglycerides at 190lbs. I thought my health was improving!
    My blood visibly separated into components after it had been drawn at 4200 triglycerides. After only three weeks of avoiding soda completely, and lower carbs in general, they were not able to show me this effect when they drew my blood again. Of course, I am type 2 diabetic and on a serious diet/exercise regimen now.

  4. I am all about the water. We drink 100% juices too, but as they are on the expensive side, the five year old gets most of that. On the rare occasions when we get a soda treat, we drink Hansen’s. While it still contains the fructose, it has a much lower sugar content overall.
    I am not a big soda fan, Coke (and many other sodas, Coke just seems to work the best) makes great and I mean great, paint stripper. I have actually used it on jobs, for customers with chemical sensitivities. Works as well as a heat gun or most solvents, excepting those with ketones in, doesn’t release a lot of fumes into the air.

  5. Too bad we can’t just put fructose in our gas tanks instead of gasoline or ethanol. Even the farmers might be happy. Healthy nutrition and sports nutrition research though is critical to improve our quality of life.

  6. I used to drink a lot of HFCS and fruit juice. When I gave it up during the run-up to being considered for obesity surgery, I lost 30 pounds in two months. No lie. I shocked myself.

  7. Perhaps I’m being naieve here, but surely is you are overweight, then switching to diet soft drinks (which are pretty much zero-calorie) is about the easiest step you can possibly take?
    (Certainly if you are getting to the stage of considering surgery..)

  8. Regarding the comment that “large corn-processing companies benefit from subsidies unavailable to conventional sugar cane producers.”
    The U.S. government provides support to a number of farm commodities, including sugar cane producers, in order to ensure a stable farm economy and a reliable food supply during periods of market volatility and adverse weather. These payments are paid directly to farmers as a “safety net.” Manufacturers of corn sweeteners and other food ingredients do not receive such payments.

  9. I used to drink a ton of it throughout school, especially in college and just after. The friends and I would have weekend gaming sessions where we’d consume upwards of a six-pack in a day. I’ve always been fairly thin, but when I moved to Japan, where cold teas are more prevalent than soda, I dropped 15 pounds (180->165) very rapidly. Course, the added walking and exercise might account for it.
    Anymore, I’ve lost the taste for soda, even Coke. It just tastes bad to me. I definitely would like to see more studies done on HFCS.

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