Wednesday, February 25, 2009

Polyunsaturated fat and cancer

I've had posts before about the way in which a low carb diet seems to be effective in treating cancer. Cancer cells need sugar to survive so starving them of glucose starves them. Richard has had good posts on the same lines too.

Anyway I spotted this story today:

New findings measure precise impact of fat on cancer spread

Researchers at Purdue University have precisely measured the impact of a high-fat diet on the spread of cancer, finding that excessive dietary fat caused a 300 percent increase in metastasizing tumor cells in laboratory animals. might put you off eating fat! BUT when you read on a bit beyond the headline you find out that it is not all fat that is the is polyunsaturated fat! That is supposed to be the healthy fat.

The researches used the imaging and cell-counting tools to document that linoleic acid, which is predominant in polyunsaturated fats, caused increasing membrane phase separation, whereas oleic acid, found in monounsaturated fats, did not. Increased membrane phase separation could improve the opportunity of circulating tumor cells to adhere to blood vessel walls and escape to organs far from the original tumor site. The new findings support earlier evidence from other research that consuming high amounts of polyunsaturated fat may increase the risk of cancer spreading.

So all these people getting rid of butter and scoffing their "healthy" margarine do not know what they are risking.

As usual of course Barry Groves is ahead of the pack on this one: Polyunsaturated Oils Increase Cancer Risk



Matt said...

I pulled the study, and what they actually fed the mice was mostly lard with some soybean oil. For a given pellet, it had 25gm soybean oil and 245gm lard.

The stuff about PUFA mentioned in the article seems to refer to a separate part of the paper (e.g., Fig. 6) where the researchers pre-treated cancer cells with various lipids. There, they also pegged saturated fat as bad (but I don't think they were feeding it to the mice--just using it on cancer cells in a dish).

I'm still scratching my head over saturated fats, so this just leaves me puzzled.

Study here:

Mice's food datasheet here:

Chris said...

Thanks for the links matt.

Arlo said...

I was actually just thinking about carbs and cancer, as I discovered that my co-workers family seems (...) predisposed to cancer, especially at a young age.

You said, "Cancer cells need sugar to survive so starving them of glucose starves them."

So what fuels our regular cells when we restrict carbohydrates? How is the metabolism in a cancer cell different than in any other cell?

She'll probably never go low carb, low fat is incredibly ingrained in her thinking, but it's nice to have some evidence to back up the idea. :)


Chris said...


Didyou check the post I linked to? The basic argument is that unlike healthy cells, which generate energy by metabolizing sugar in their mitochondria, cancer cells appeared to fuel themselves exclusively through glycolysis, a less-efficient means of creating energy through the fermentation of sugar in the cytoplasm. The theory is simple: If most aggressive cancers rely on the fermentation of sugar for growing and dividing, then take away the sugar and they should stop spreading. Meanwhile, normal body and brain cells should be able to handle the sugar starvation; they can switch to generating energy from fatty molecules called ketone bodies — the body's main source of energy on a fat-rich diet — an ability that some or most fast-growing and invasive cancers seem to lack.

Look through all the posts on this blog tagged as cancer here and there are several about treating cancer with a ketogenic diet.

Chris said...


there is a huge amount of maltodextrose and sucrose in that diet. High Fat ketogenic diets have been provided to be successful in fighting cancer. e.g. here or here or the other posts I've tagged cancer.

The sugar they gave these rats will keep the cancer going and growing.....

Anonymous said...

The article below seems to offer a different take on PUF's vs MUF's (oils). Hmmm.....

Anonymous said...

Sorry, try this complete link.

Matt said...


Good point about the sugar. Interestingly, the carbs for the "lean diet" came from corn, wheat, barley, and oats:

It's disappointing to me that the researchers didn't use the same ingredients in the mice chow and just alter the macronutrient ratios.