But it’s gained fame – and infamy – as a component of manmade high-fructose corn syrup or HFCS.
The use of HFCS in sweet drinks and many process foods has been blamed for America’s epidemic of obesity and diabetes … or “diabesity”.
Cane sugar and HFCS are about equally abundant in fructose, with each sweetener being half glucose and half fructose (HFCS ranges from 45 to 55 percent fructose).
So there's no reason to believe that HFCS would be worse for you metabolic health, compared with white or brown cane sugar.
In fact, there are problems with claims that HFCS is a unique factor in obesity or metabolic syndrome:
- Obesity is also rising in countries where cane sugar still dominates.
- The rise in America’s obesity rates also parallels the rise in consumption of soybeans and soy oil high in omega-6 fatty acids, which promote inflammation and other obesity-fueling effects.
- Most studies of the effects of fructose have been in rodents, and those in humans have produced mixed results with regard to insulin resistance: a key pre-diabetic, obesity-promoting condition.
Rather than a rise in fructose consumption, the worldwide rise in diabesity is more likely a result of diets increasingly loaded with processed, refined foods.
Processed foods are high in sugars (of all kinds), white starch, and omega-6 fatty acids, but low in healthful fibers, micronutrients, and phytochemicals, including antioxidants.
When it's consumed in excess as a refined sugar (rather than in whole fruits) fructose may exert unique adverse effects … see “Does Fructose Fuel Cancer?” and “Fructose May Promote Obesity & Inflammation”.
And there are concerns about adverse effects unique to HFCS, due to the chemical processes by which is made … see “Corn-Sweetened Sodas High in Pro-Aging Agent”.
But as far as the biological effects of sugars go, there's also evidence that fructose may offer some advantages over glucose: see “Can Fructose Aid Blood-Sugar Control?”.
Excess intake of either of the world's major refined sweeteners – cane sugar or HFCS – is likely to promote obesity, inflammation, diabetes, and more … see “Corn Syrup vs. Sugar in Weight Control”, “The Weight Gain Blame-Game”, and “Sugar Takes Another Heart-Health Hit”.
Assigning special blame to fructose or high-fructose corn syrup (HFCS) can be a deceptive distraction from the evils of any and all sugars, whether HFCS, cane sugar, or their constituent sugars: fructose and glucose.
That idea is borne out by recent research that seems to rebut the blame assigned to HFCS or other sources of fructose as uniquely powerful drivers of the diabesity epidemic.
Evidence review found no weight-gain gap between fructose and glucose
Two years back, Canadian researchers reviewed more than 40 published studies that asked whether fructose is a uniquely powerful driver of weight gain.
As part of this review, scientists from St. Michael’s Hospital in Toronto analyzed 31 “isocaloric” clinical trials (Ha V et al. 2012).
These were studies in which participants in two or more test groups consumes similar numbers of calories but ate diets that differed in some other way.
In the 31 trials reviewed by the Toronto team, one group ate pure fructose and the other ate non-fructose carbohydrates.
And in these trials, the fructose groups did not gain more weight than the non-fructose groups.
They also reviewed 10 “hyper-caloric” trials, in which one group consumed their usual diet and the other added excess calories in the form of pure fructose to their usual diet or a control diet.
Unsurprisingly, those who consumed extra calories (from fructose) gained weight, compared with the control group.
However, it was entirely predictable that a group assigned to eat extra calories – no matter the source – would gain more weight.
None of the studies the Canadian team reviewed studied the effects of HFCS, which is about 55 per cent fructose and 45 percent glucose.
The majority of the studies available to examine were small, of short-duration, and of poor quality, so there is a need for larger, longer and better quality studies.
For overall health, fructose found no worse than other sugars
Earlier this year, the same St. Michael’s Hospital team reported that they found no health benefits from replacing fructose with glucose in commercially prepared foods.
The findings show that when portion sizes and calories are the same, fructose does not cause any more harm than glucose (Sievenpiper JL et al. 2014).
“Despite concerns about fructose’s link to obesity, there is no justification to replace fructose with glucose because there is no evidence of net harm,” said Dr. Sievenpiper.
Sievenpiper and his team analyzed data from clinical trials that compared the effects of fructose and glucose on several health risk factors.
They concluded that – as shown in other studies – fructose-heavy diets may raise total cholesterol and triglycerides more than glucose does.
However, fructose did not appear to affect insulin production, other fat levels in the blood, or markers of fatty liver disease any more than glucose did.
In fact, fructose showed potential advantages over glucose in some key risk factor categories.
“Some health care analysts have thought fructose to be the cause of obesity because it’s metabolized differently than glucose,” said Sievenpiper.
“In calorie-matched conditions, we found that fructose may actually be better at promoting healthy body weight, blood pressure and glycemic [blood sugar] control than glucose.”
Dr. Sievenpiper suggested that over-consumption of calories – rather than one type of sugar – is the more probable cause of obesity.
“Overall, it’s not about swapping fructose with glucose,” said Dr. Sievenpiper. “Overeating, portion size, and calories are what we should be refocusing on – they’re our biggest problems.”
We would add that America’s “omega imbalance” – which began to emerge about the same time as HFCS – may drive weight gain, inflammation, diabetes, and other problems as much or more than excess sugar intake.
- Ha V, Sievenpiper JL, de Souza RJ, Chiavaroli L, Wang DD, Cozma AI, Mirrahimi A, Yu ME, Carleton AJ, Dibuono M, Jenkins AL, Leiter LA, Wolever TM, Beyene J, Kendall CW, Jenkins DJ. Effect of fructose on blood pressure: a systematic review and meta-analysis of controlled feeding trials. Hypertension. 2012 Apr;59(4):787-95. doi: 10.1161/HYPERTENSIONAHA.111.182311. Epub 2012 Feb 13. Review.
- Sievenpiper JL, de Souza RJ, Cozma AI, Chiavaroli L, Ha V, Mirrahimi A. Fructose vs. glucose and metabolism: do the metabolic differences matter? Curr Opin Lipidol. 2014 Feb;25(1):8-19. doi: 10.1097/MOL.0000000000000042.