Fructose fuels cancer cell growth?

A study showed that treatment of pancreatic cancer cells with fructose increased cell proliferation – uncontrolled proliferation is a hallmark of cancer. This follows on the heels of another study that linked fructose consumption from added sugars to elevated blood pressure. The bad press on fructose is making people question the safety of the ubiquitous commercial sweetener, high fructose corn syrup (HFCS).

Due to the introduction of HFCS, fructose intake has increased dramatically in the U.S. since the 1970s. Between 1970 and 2000, HFCS intake increased by 100-fold, and total fructose intake increased by 30%.1

Fructose makes up half of the sucrose molecule (with glucose), but may also be present in “free” form. Absorption of fructose and glucose, and the differences between fructose in natural foods and fructose in HFCS are explained in this post.

These authors investigated whether cancer cells could use fructose for energy, because they are known to use glucose – cancer cells are known to have a greater number of glucose transporters and metabolize glucose more rapidly than normal cells because their rapid proliferation requires greater amounts of energy.2

Although different transport mechanisms are used to get fructose and glucose into cells, their metabolism is thought to be similar once they enter cells. However, these scientists found that in human pancreatic tumor cells, metabolism of fructose and glucose occurs via different pathways, both leading to cell proliferation. Keep in mind that both sugars led to increased cell proliferation at similar rates – that is, this study did not show that fructose is “worse” than glucose, just that they stimulate proliferation by different mechanisms. Glucose was used by the cancer cells for energy production, whereas fructose was used to generate nucleic acids (DNA and RNA). This study was the first to show that cancer cells could differentiate between fructose and glucose, and that they could use fructose as efficiently as glucose to fuel cell growth.3,4

Sucrose intake, fructose intake, and high glycemic load have all been associated with pancreatic cancer in epidemiological studies, and diabetes also increases risk.5,6  

The message of this study and others on the negative effects of fructose is that added sugars, abundant in the Western diet, are detrimental to health and should be minimized, but sadly this is not the message that is getting through to the public. 

With the media frenzy around HFCS, the conventional wisdom seems to have become that sugar is superior to HFCS because it is more ‘natural’ – prompting many companies to switch from HFCS to sugar for sweetening their products. Meanwhile, the high fructose, low glycemic index sweetener agave nectar, once elevated to health food status, is now being doubted because of the negative press on fructose. 


Comparing sweetener to sweetener is missing the point. All sweeteners have negative health effects, regardless of their relative quantities of fructose, glucose, and sucrose. 

Some sweeteners spike blood glucose, others raise triglycerides and form advanced glycation end products (AGEs), and all provide excess calories and are devoid of nutrients. This is not a question of which sweeteners are healthy and which are unhealthy. None are healthy. All are merely concentrated sugars – contributing to obesity and all its consequences – and therefore should all be minimized or completely avoided in a health-promoting diet.



1. Bray GA, Nielsen SJ, Popkin BM. Consumption of high-fructose corn syrup in beverages may play a role in the epidemic of obesity. Am J Clin Nutr. 2004 Apr;79(4):537-43.

2. Medina RA, Owen GI. Glucose transporters: expression, regulation and cancer. Biol Res. 2002;35(1):9-26.

3. Liu H, Huang D, McArthur DL, et al. Fructose induces transketolase flux to promote pancreatic cancer growth. Cancer Res. 2010 Aug 1;70(15):6368-76.

4. EurekAlert! Pancreatic cancers use fructose, common in the Western diet, to fuel their growth. August 2, 2010

American Institute for Cancer Research Blog. Glucose, Fructose, and the Alarming Pancreatic Cancer News. August 4, 2010.

5. Nöthlings U, Murphy SP, Wilkens LR, et al. Dietary glycemic load, added sugars, and carbohydrates as risk factors for pancreatic cancer: the Multiethnic Cohort Study. Am J Clin Nutr. 2007 Nov;86(5):1495-501.

6. Michaud DS, Liu S, Giovannucci E, et al. Dietary sugar, glycemic load, and pancreatic cancer risk in a prospective study. J Natl Cancer Inst. 2002 Sep 4;94(17):1293-300.

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Comments (22) Read through and enter the discussion with the form at the end
Christe - August 20, 2010 2:53 PM

What is your opinion, then, on eating fruit (at E2L levels or slightly higher)?

Benjamin - August 20, 2010 3:02 PM

Thank you Dr. Furhman. The media stories DID make it sound as if fructose was worse than sucrose. You did a sweet job (pun and horribly dry humor intended), on explaining this.

I suppose that is what happens when the lay public skim and report study findings.

Dan - August 20, 2010 3:48 PM

I'm assuming here that fructose in fruit does not cause this prolific "cancer feeding" and it's only the refined sugar we are referring to.

Helen Parkinson - August 20, 2010 4:33 PM

What about honey? I know with a true vegan diet that honey is out but where does honey stand in this sweetener debate considering all the other enzyme and antibacterial qualities that honey and manuka honey in particular are supposed to have.

Laura Ross - August 20, 2010 6:34 PM

Fructose caused the cancer to grow, but I understand it was in vitro. Does that indicate real-life cancer growth, and would it be ethical to experiment with humans or non-humans?

Matt Stone - August 21, 2010 7:08 AM

Perfect post. I also think one important connection that few have made with refined sweeteners as well is that despite being "fine in moderation," they trigger a response in the human brain that tends to trigger larger calorie consumption in susceptible individuals. This appears to be even more true of saccharin, aspartame, and sucralose. Of course, these are all chemically different, but all trigger overeating. It is, in part, the concentrated sweetness that is the greatest problem and more strong support for a whole foods diet, which brings appetite and metabolism into balance.

diana - August 21, 2010 8:27 AM

I understand that it is OK to eat dried fruits/fruits as they are not is sugar. Fruits come with fiber and micronutrients so I assume that the glycemic load is less, and, they would be part of a high nutrient density meal ...not on their own. Still, I confess, that at times, I will come home from a long 12 hour day and have a sorbet!

carfree - August 21, 2010 11:29 AM

Apparently you missed the link provided in the article by Dr. Fuhrman where he explained the difference between eating whole fruit and using concentrated sweetners. It's in the first or second paragraph above and highlighted at the words "this post". In other words, Dr. Fuhrman has explained this all in detail.

kels - August 21, 2010 11:35 AM

So, should I completely eliminate all fruit from my eating? I am confused?

Deana Ferreri, Ph.D. - August 21, 2010 6:54 PM

This post was about using concentrated sweeteners (including honey) not about fruit. Dr. Fuhrman (who is away on vacation) does not place fruit in this same category, nevertheless he recommends a vegetable-based diet, not a fruit-based one, and has been critical in the past of diets that have too much sweet fruit and not enough vegetables.

For an explanation of the differences between the sugars in concentrated sweeteners and those in fruit, read this previous post (which was linked to in the current post):

Lisa - August 21, 2010 10:14 PM

what about agave nectar?

Javier - August 22, 2010 9:38 AM

I would really like to know the answer to this question.

Deana Ferreri, Ph.D
Are these sugar effects for sedentary people who don't workout hard? or for everyone no matter what they eat. Lets say if your a endurance athlete or working out hard. You take fructose 30 minutes before workout. Since active workouts can lower blood sugar spikes is it not really just for sedentary individuals the notion that cancer can build.

Sheila - August 22, 2010 11:36 AM

I havent heard anyone mention dates. Dates are a whole, sweet food. There couldnt possibly be an argument against a whole food sweetener!!

Jean - August 22, 2010 8:36 PM

Deana Ferreri, PHD

Whereas I agree the tone of Dan's post was rather harsh
I do understand his frustration. However, there was nothing disrespectful about his question:

"Your book Eat to Live says to eat four servings of fruit a day. Yes or No?" Could you just answer the question? Yes or No?

You all never really answer this question. You spin all around the question. Yes or No?

StephenMarkTurner - August 23, 2010 9:32 PM

It sounds like Mercola is well intentioned, trying to do something along the lines of Dr Fuhrman, but I think Dr F gets to the point more directly with the health equation "Nutrition /Cals".

Plus, once you know (for example) strawberries are good, you file that in the memory bank and you don't have to keep weighing them over and over.

SHEILA - I have seen date sugar mentioned many times in Dr F's stuff, it is still on the ok list as far as I know.

Cheers, Steve

Deana Ferreri, Ph.D. - August 24, 2010 10:29 AM

We have answered the question. In my comment above, I provided a link to a previous post in which I explain why the fructose in fruit (a reasonable amount of course - around 4-5 servings per day) is not troublesome. In short, much of the fructose in fruit is bound up with glucose as sucrose, not to mention the fiber content of fruit. The sugars in sweeteners enter the bloodstream much more rapidly, raising blood concentrations to higher levels.

Gerald Fiore - August 26, 2010 7:01 AM

In my opinion sugar is sugar, basically if we listen to our tongues (if that makes sense) anything sweet has some form of ose, fructose, sucrose etc some form of sugar, Bananas make you feel good they are full of sugar, so is honey, dates, jams, how about carrots and pumpkins? Sweet aren't they, if you go by what your mouth or tongue is telling you, i.e it's yummy/sweet then there is a sweet substance in what you are eating or drinking, sweet corn? All sweet, Stevia may be okay and sweetcorn are supposed to have lower hyperglycemic level than potatoes, that's strange cause they taste sweeter than potatoes, maybe my source was wrong.

Think about it, it is not natural to eat a few bananas, plums, apples, berries or whatever portions the government or authority say is healthy per day in their current flavour of the month scientific study, if one had to go out and collect these friuts it would be almost impossible to eat this amount of friuts and vegetables in a day, let's say 5 portions each.

There are lies, Damned Lies, and Scientific studies - Gerald Fiore.

Studies do not show the whole pictures, what works on a mouse may not work in humans or may do, in vitro is different to human organism, study suggests X friut, vitamin, supplement, behaviour promotes prostate cancer - Suggests means there is a probability, but they are not sure, medicine old and new are not exact science and one last thing, think of who is paying for a particular study in order to show that X is bad or good for you, we are being influenced for $$$, I beleive that in this world many create fear/need/demand and then create products/services to fill those needs.


Victoria - September 5, 2010 2:29 AM

I am interested in how Dr Fuhrman's recommendations differ from Dr Steven Gundry's, who is a leading cardiologist who recommends a natural food diet low in fruit to promote cardiovascular health. He maintains that eating fruit stimulates a genetic program for storage of fat in preparation for winter, and that we can't lose weight while eating a diet rich in fruit. Both of these doctors recommend very similar diets, but I would love to be sure which is correct when it comes to fruit.

Michael - September 7, 2010 10:02 AM

Hi Victoria,

As an Engineer, I like to look at numbers and definitive, concrete evidence if possible. The problem I see with the hypothesis that fruit promotes storage of fat boils down to primarily caloric density. Next to non-starchy vegetables, fresh fruit (not juice or dried) has the lowest amount of calories of any food. Use a calorie tracking website like to actually measure where you're getting your calories from. Fruit is a low-calorie, nutritious food that we would readily eat in nature. I don't see how it could possibly be harmful unless you're eating a fruitariam diet or some other extreme diet.

Sally - October 26, 2010 12:39 PM

I have been eating 4 fruits a day while on Dr. Fuhrman's Eat To Live plan and have continued to lose weight.

emily - November 5, 2010 8:21 AM

so glad to see a respected expert in the field of dietary health stating that all added sweeteners are bad for us, period. agave, honey, maple syrup are not magic, and are put in processed "natural" treats as if they are healthy.

Victoria- i haven't read the exact article you refer to, but my understanding is that sweet food in general, and sugar of any/all kinds, does promote fat storage for the reasons you refer to.

i love dates, but am not sure they are so much better for us then sugar. dried fruit is very high in natural sugars, i ate a lot of dried fruit and juice as a child because we thought it was healthy and "natural" but i had some health problems because of this.

anonymous - November 18, 2010 11:35 PM

Obviously, too much sugar is bad. However, virtually all fruits and vegetables contain sugar. So adding sugar to food doesn't seem bad, as long as the total daily intake is at the desired level. Wouldn't adding sugar to complex carbs essentially "transform" the high-glycemic sugar into a moderate glycemic food?

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