SUGARS AND CANCER

A reader asked me for some information on cancer and sugar, so I pulled up some items from my research database.  As long as I had the articles in front of me, I thought I’d share them.

Nothing listed here proves absolutely that sugars drive cancer or that a ketogenic diet will prevent cancer, but taken together, the articles do paint a picture.  Let’s take a look.

Cancer cells slurp up fructose, US study finds

Pancreatic tumor cells use fructose to divide and proliferate, U.S. researchers said on Monday in a study that challenges the common wisdom that all sugars are the same.

Tumor cells fed both glucose and fructose used the two sugars in two different ways, the team at the University of California Los Angeles found.

They said their finding, published in the journal Cancer Research, may help explain other studies that have linked fructose intake with pancreatic cancer, one of the deadliest cancer types.

“These findings show that cancer cells can readily metabolize fructose to increase proliferation,” Dr. Anthony Heaney of UCLA’s Jonsson Cancer Center and colleagues wrote.

“They have major significance for cancer patients given dietary refined fructose consumption, and indicate that efforts to reduce refined fructose intake or inhibit fructose-mediated actions may disrupt cancer growth.”

I found some suggested meal plans on the USDA’s official My Plate site, which I’ll share in another post.  Whole milk isn’t on the meal plan for breakfast, but orange juice and strawberry-flavored (i.e., sugary) skim milk are.  Remind me again … which of those drinks contains fructose and which doesn’t?

Compound That Blocks Sugar Pathway Slows Cancer Cell Growth

Scientists at Johns Hopkins have identified a compound that could be used to starve cancers of their sugar-based building blocks. The compound, called a glutaminase inhibitor, has been tested on laboratory-cultured, sugar-hungry brain cancer cells and, the scientists say, may have the potential to be used for many types of primary brain tumors.

The Johns Hopkins scientists, inventors on patent applications related to the discovery, caution that glutaminase inhibitors have not been tested in animals or humans, but their findings may spark new interest in the glutaminase pathway as a target for new therapies.

Glutaminase is an enzyme that controls how glucose-based nutrients are converted into the carbon skeleton of a cell. Additional enzymes that help construct the so-called “bricks” of the carbon skeleton are controlled by a gene called IDH1. In some brain cancer cells, IDH1 is mutated and the resulting enzyme grinds up the bricks into nutrients that feed cancer cells.

Yes, yes, I know what you’re thinking:  if blocking the glucose pathway slows cancer growth, why not just tell people to stop eating foods that spike glucose?  Well, I’m pretty sure the answer lies in the fact that scientists have applied for patents.  You can’t patent dietary advice, but you can patent a drug.

Diabetes Medication May Get New Life as Cancer Treatment

The drug metformin, a mainstay of diabetes care for 15 years, may have a new life as a cancer treatment, researchers said.

In a study in mice, low doses of the drug, combined with a widely used chemotherapy called doxorubicin, shrank breast-cancer tumors and prevented their recurrence more effectively than chemotherapy alone.

The findings add to a growing body of evidence that metformin, marketed as Glucophage by Bristol-Myers Squibb Co. and available in generic versions, could be a potent antitumor medicine.

In the report, being published in the Oct. 1 edition of Cancer Research, a journal of the American Association for Cancer Research, researchers said the combination of metformin and doxorubicin killed both regular cancer cells and cancer stem cells.

In contrast, doxorubicin alone had limited effect on the stem cells.

Mice that grew tumors generated from human breast-cancer cells have remained tumor-free for nearly three months on the combined treatment, while tumors have recurred in those not given the diabetes remedy.

Researchers said the results have potentially broad implications for cancer treatment.

Hmmm, now why would a drug given to type 2 diabetics be effective against cancer?  You have to read pretty far down the article to find out:

How metformin affects cancer isn’t certain, but one possibility is that it deprives tumor cells of sugar.

“Cancer cells are gluttons for glucose,” said George Prendergast, president and chief executive officer of Lankenau Institute for Medical Research, Wynnewood, Pa. “It is likely that metformin is taking advantage of this gluttony of the cancer cell in order to attack it.”

Cancer cells are gluttons for glucose … I’ll be sure to think about when I’m drinking my USDA-approved skim milk with added sugar.

Dietary glycemic load and colorectal cancer risk

The link above is to an observational study based on food questionnaires, so it doesn’t exactly meet the gold standard for research.  Nonetheless, here’s the conclusion:

The positive associations of glycemic index and load with colorectal cancer suggest a detrimental role of refined carbohydrates in the etiology of the disease.

The next time some vegan zealot trots out an observational study showing a weak association between meat and cancer, you can reply with this one and explain that since glycemic load is strongly associated with colorectal cancer, you’re sticking with a low-glycemic diet – meat included.  If the vegan zealot starts quoting the China Study, you can reply with this (sort of) China study of Chinese Americans:

Carbohydrates and colorectal cancer risk among Chinese in North America

Here’s the conclusion:

These data indicate that increased eCarb (non-fiber carb) and total carbohydrate consumption are both associated with increased risk of colorectal cancer in both sexes, and that among women, relative risk appears greatest for the right colon, whereas among men, relative risk appears greatest for the rectum.

So get T. Colin Campbell’s high-carb diet out of my face.

Effects of a ketogenic diet on tumor metabolism

This one isn’t a study; it’s a case report from 1995 of two pediatric cancer patients put on ketogenic diets.  Here are some quotes from the abstact:

OBJECTIVE: Establish dietary-induced ketosis in pediatric oncology patients to determine if a ketogenic state would decrease glucose availability to certain tumors, thereby potentially impairing tumor metabolism without adversely affecting the patient’s overall nutritional status.

So all the way back in 1995, at least some doctors suspected that depriving cancers of glucose might help.  Sheesh.  Anyway …

RESULTS:  Within 7 days of initiating the ketogenic diet, blood glucose levels declined to low-normal levels and blood ketones were elevated twenty to thirty fold. Results of PET scans indicated a 21.8% average decrease in glucose uptake at the tumor site in both subjects. One patient exhibited significant clinical improvements in mood and new skill development during the study. She continued the ketogenic diet for an additional twelve months, remaining free of disease progression.

Improvements in mood and skill development?  No, no, no … low-carb diets make you depressed and irritable.  I know that’s true, because I read it on Yahoo Health.

Glucose deprivation activates feedback loop that kills cancer cells

Compared to normal cells, cancer cells have a prodigious appetite for glucose, the result of a shift in cell metabolism known as aerobic glycolysis or the “Warburg effect.” Researchers focusing on this effect as a possible target for cancer therapies have examined how biochemical signals present in cancer cells regulate the altered metabolic state.

Now, in a unique study, a UCLA research team led by Thomas Graeber, a professor of molecular and medical pharmacology, has investigated the reverse aspect: how the metabolism of glucose affects the biochemical signals present in cancer cells.

In research published June 26 in the journal Molecular Systems Biology, Graeber and his colleagues demonstrate that glucose starvation — that is, depriving cancer cells of glucose —activates a metabolic and signaling amplification loop that leads to cancer cell death as a result of the toxic accumulation of reactive oxygen species, the cell-damaging molecules and ions targeted by antioxidants like vitamin C.

Hey, I don’t care if it’s an amplification loop that does the job or if the cancer cells just die off from a lack of fuel.  The point is, once again we see that depriving cancer cells of sugars can kill them.

Keep starving those cancer cells, folks.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s