Posted by Linda Bonvie
February 6, 2014
BY BILL BONVIE
Ever get the feeling that there’s no real coordination between the scientists and researchers who are dealing with the same basic issues? Or that they somehow fail to take each other’s work into account?
A case in point is the latest research that’s received considerable coverage in the print media. Being called “the biggest study of its kind,” it was performed by a team from the Centers for Disease Control and Prevention (CDC), and purports to show that too much sugar in our diet raises our risk of heart disease.
The only problem with this study is that it apparently makes no differentiation between “sugar” (as in sucrose, or common table sugar) and high fructose corn syrup (HFCS), which is mainly what the researchers involved are talking about when they use the word “sugar.”
In fact, nowhere in the rather extensive Associated Press account of the study does one find even any reference to HFCS — but that’s probably because the study itself doesn’t make such a distinction. (One paper’s website even accompanies the story with a depiction of sugar crystals.) Nor is it mentioned in the press release from JAMA (The Journal of the American Medical Association), which published the study.
And while the coverage quotes a number of experts on the subject in regard to the study’s conclusions, it fails to acknowledge that other research done at prestigious institutions has specifically linked HFCS consumption to potential heart problems, along with obesity, diabetes, fatty liver disease, and other health issues.
So to try to obtain some clarification, I attempted to contact some of the people mentioned or quoted in the story.
One was the lead author, a Ph.D. at the CDC named Quanhe Yang, who I was unable to call directly .In fielding my request, however, Karen Hunter, an representative of the press office, told me that my questions were “way beyond the scope of CDC’s study, which looked at data from the National Health and Nutrition Examination Survey (NHANES) re sugar consumption (NHANES does not have detailed data related to different forms of added sugar) and NCHS mortality data. But CDC does not conduct clinical research and thus cannot answer your questions related to HFCS and heart disease. “
Hunter suggested, however, that I “might want to contact the American Heart Association to find out if they are aware of any research along these lines.”
So I did – or to be more specific, I got in touch with Rachel Johnson, a University of Vermont professor and head of the American Heart Association’s nutrition committee, and who was quoted in the article. Her suggestion was that I “ask the authors of the recent paper linking high intakes of added sugars with death from coronary heart disease why they did not separate out high fructose corn syrup.”
“As you likely know,” she added, “the authors did look at sugar-sweetened beverages (SSBs) separately.” (Ah, there it is again – those “sugar-sweetened beverages” that are actually almost all sweetened with HFCS, which I asked a researcher about for another recent blog, only to be told that particular terminology was used “in the literature.”)
Soft drinks: hard on the liver
If all of this seems to be going around in circles, I should note that after starting this blog, I was provided with some clarification by Laura Schmidt, a health policy specialist at the University of California, San Francisco, who wrote an editorial accompanying the study that appeared in Monday’s JAMA Internal Medicine.
As Schmidt explained it, NHANES wouldn’t allow the distinction between sugar and HFCS to be made because it’s “already challenging enough to get consumers to provide good data” on their dietary habits without further complicating the matter by asking them specifically about HFCS.
She did acknowledge, however, that HFCS probably comprises most of what’s being referred to as “sugar,” but is actually “sugars” in FDA terminology. A more accurate description, she noted, might be “added caloric sweeteners,” the consumption of which has greatly increased since HFCS became an intrinsic part of the American diet, while that of actual sugar itself has remained flat.
She further pointed out that fructose has been “singled out for a lot of aggressive research” because of the way its metabolized in the liver, driving high amounts of triglyceriardes into the bloodstream, and eventually resulting in fatty liver disease and damage to the organ that can resemble that caused by alcohol.
By contrast, Schmidt noted, the fructose in fruit itself doesn’t seem to cause any such problems, probably because it’s bound into the fiber that comes with it – although the jury is still out on whether the fructose content of fruit juice might also help bring about the kind of “metabolic syndrome” that can lead to all sorts of health issues.
Many of those concerns, in fact, have been linked to HFCS and high fructose consumption by those other studies I mentioned, including:
- A University of California at Davis study of adults between the ages of 18 and 40 that found that those who consumed high fructose corn syrup for two weeks as 25 percent of their daily calorie requirement had increased blood levels of cholesterol and triglycerides, which have been shown to be indicators of increased risk for heart disease.
- A Georgia Health Sciences University study of 559 adolescents aged 14-18, who consume more fructose than any other age group, that linked such consumption with “multiple markers of cardiometabolic risk.”
- A University of Florida study that determined non-alcoholic fatty liver disease (NAFLD) may be associated with excessive dietary fructose consumption, and a Duke University Medical Center study that found HFCS consumption correlated with increased fibrosis severity in people with NAFLD.
- Another University of Florida study that concluded high fructose consumption can result in leptin resistance, a condition associated with weight gain and obesity.
- A University of Southern California study that showed countries using high-fructose corn syrup to have 20 percent higher diabetes rates than countries that didn’t add the sweetener to foods.
- A study by UCLA cancer researchers that found fructose can help promote the growth of pancreatic cancer.
And while none of these findings are reflected in the latest study from the CDC, as Schmidt observes, “What we do know is that the increase in the consumption of added sugars (as opposed to ‘sugar’) has been from high fructose corn syrup.”