Excessive intake from processed foods and drinks raises concerns; fructose from whole foods appears safe
By Craig Weatherby
According to the U.S. Department of Agriculture, the average American downs more than 65 pounds of high fructose corn syrup (HFCS) per year.
And the most recent official U.S. diet-health survey found that more than 10 percent of the average American’s daily calories come from fructose … with sweetened drinks being the single biggest source.
Some critiques of HFCS – versus the fructose found in plant foods and cane sugar – appear scientifically sound.
For example, see “Corn-Sweetened Sodas High in Pro-Aging Agent”.
But most attacks on HFCS cite evils that apply equally to cane sugar … which contains even more fructose: see “Fructose Called Most Dangerous Sugar”, “Fructose May Promote Obesity & Inflammation”, “Corn Syrup vs. Sugar in Weight Control”, and “High-Fructose Corn Syrup Declared Unnatural”.
Earlier this month, scientists from the University of Maryland, Baltimore and Boston University Medical Center published a review of the evidence, which affirmed prior evidence that fructose promotes cancer.
As they wrote, “Fructose intake is associated with increased risk of pancreatic and small intestinal cancers, and possibly others … [it] is associated with more aggressive cancer behavior and may promote metastasis.” (Port AM et al. 2012)
And as they noted, this fact has worrying public health implications: “Fructose has become ubiquitous in our food supply, with the highest consumers being teens and young adults … understanding the potential health consequences of fructose and its role in chronic disease development is of critical importance.”
Fructose may fuel cancer
It’s well known that excessive intake of sugar – and refined starches like white flour, which the body converts into glucose almost instantly – promotes cancer growth.
But “sugar” is an inexact term that covers diverse chemical compounds.
Sugars include single molecules like glucose and fructose, and combinations like sucrose and high-fructose corn syrup (HFCS).
Cane sugar consists entirely of sucrose, which is also the dominant sugar in fruits and vegetables.
Sucrose is a 50/50 combination of glucose and fructose, which the body splits apart almost instantly.
HFCS actually contains a bit less fructose than sucrose does, featuring ratios of fructose to glucose that range narrowly from 42/55 (soft drinks) or 42/53 (processed foods, cereals, and baked goods).
Some claim that HFCS is worse because its glucose and fructose are not chemically bound to each other, while they are bound together in cane sugar.
But the body immediately cleaves apart the glucose and fructose in cane sugar, making this a distinction without a metabolic difference.
Dig deeper, however, and we find that excessive intake of fructose – regardless of the source – promotes cancer.
What makes fructose cancer-friendly?
Why would fructose be worse than glucose in this regard?
As the Baltimore-Boston team wrote, “Whereas glucose favors overall growth kinetics, fructose enhances protein synthesis and appears to promote a more aggressive cancer phenotype.” (Port AM et al. 2012)
The body prefers fructose over glucose as a raw material from which to make nucleic acids … compounds essential to growth of tissues … especially tumors.
Fructose also promotes cancer growth in other ways, including altered cellular metabolism, increased generation of free radicals, DNA damage, and inflammation.
Worse, epidemiological studies have linked high intake of fructose (and other sugars) to pancreatic cancer, and to type 2 diabetes and obesity … which are risk factors for pancreatic cancer.
However, the problem is not fructose per se, but excessive intake of this single-molecule sugar.
Despite the fact that the fructose in plant foods is identical to the fructose in HFCS, people who report high intakes of fruits and vegetables show a reduced risk of pancreatic cancer.
How can we explain this difference?
Compared with fruits and vegetables, processed foods and drinks sweetened with HFCS contain large amounts of fructose.
And fruits and vegetables abound in compounds (fiber, flavonoids, and carotenoids) linked to reduced risk of pancreatic cancer and other cancers.
Does Fructose Fuel Cancer?