Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
19 Jan

High Fat Diet Linked to Breast Cancer?

One of the great things about our growing community is how people like Denise Minger have emerged from near obscurity to become recognized leaders in certain areas. When it comes to parsing the scientific studies, very few people have the combination of skills, understanding of the scientific method and probability, AND the willingness to dig deep into the minutiae to get to the essence of a study. Denise is one of those rare people. If you haven’t read Denise’s take-down of the China Study, you owe it to yourself to do so.

Lucky for us, Denise has taken the time to dig into the latest research on diet and breast cancer in today’s guest post. (Thank you!) Without further ado, Denise…

If you’ve been scanning the health news lately (or live within earshot of some gloating low-fat adherents), you might’ve noticed a flurry of recent headlines linking fat and cholesterol to breast cancer. In case you haven’t, this should get you up to speed:

Catch the drift?

These doomful blurbs sprang from a mouse study published earlier this month in the American Journal of Pathology, showing that mice fed a higher-fat, cholesterol-enriched diet developed bigger and more aggressive tumors than mice eating their normal “chow” diet. According to the researchers, this suggests that “cholesterol accelerates and enhances tumor formation.” And if the news stories are to be trusted, that means we should curb the fat and toss back some statins with our Healthy Whole Grain dinners.

Even if you’re not a woman, chances are good that you’ve encountered one before, and maybe even spent some time inside one’s womb. And considering about one out of every seven women will face breast cancer in her lifetime, dietary links with this disease tend to be a hot topic for health-minded folks of either gender. So what’s going on with this study? Can it tell us anything important, or is it another one for the lame-research slush pile?

Of Mice and Women

If you don’t want to trudge through the full text of the study linked above, here’s the rundown. The researchers took two groups of mice: one wild, ordinary-mouse-on-the-street strain and one special strain that’s predisposed to developing mammary tumors. For both the wild and the tumor-prone mice groups, half got a standard chow diet and half got a Western diet. These are the only food details offered in the paper:

Female mice hemizygous for the PyMT transgene were given either a Western diet (57BD; LabDiet, Richmond, IN) containing 20.2% fat, 16.8% protein, and 48.0% carbohydrate, or a chow diet (5010; LabDiet) containing 4.5% fat, 23.0% protein, and 50.1% carbohydrate, at age 4 weeks and thereafter ad libitum. Although fat content of the diet was increased, carbohydrate content was not altered. Moreover, energy values of the 2 diets were similar (4.43 kcal/g and 4.14 kcal/g for Western and chow diets, respectively).

Fair enough. From this description, you’d think the main difference between the diets was fat content: 4.5 percent in one and 20.2 percent in the other (with slightly lower protein and carbohydrate levels to compensate). But whenever we hear a diet described only in terms of macronutrient ratios with no assurance that the food variables are controlled, it’s usually a bad sign (and an inevitable slush pile omen). Fortunately, Google exists. Even though the paper’s lips are zipped about the actual ingredients of the diets, the spec sheets for both the chow diet 5010 and “Western diet” 57BD are posted online, so we can figure out exactly what these mice were eating.

Food vs. “Food”

It turns out the chow-diet mice—the ones who got fewer tumors—were feasting on a mix of:

  • Ground corn
  • Dehulled soybean meal
  • Wheat middlings
  • Fish meal
  • Ground wheat
  • Wheat germ
  • Brewers dried yeast
  • Ground oats
  • Dehydrated alfalfa meal
  • Porcine animal fat
  • Ground soybean hulls
  • Soybean oil
  • Dried beet pulp
  • And a bunch of added vitamins and minerals.

Not exactly a five-star cuisine, but most of these ingredients aren’t alien substances to mice. It’s passable fare.

But what about the high fat diet that promoted so much tumor growth? Was it the same as above, just slathered in a few pats of butter? Alas, the “Western diet” mice weren’t even eating food. Along with a small amount of added cholesterol, their diet consisted of:

  • Sucrose (31%)
  • Milk fat (21%)
  • Casein (19 %)
  • Maltodextrin (10%)
  • Powdered Cellulose (5%)
  • Dextrin (5%)
  • And the typical vitamin and mineral array.

Bon appétit.

It’s a marvel the Western diet got labeled “high fat and cholesterol” when it’s only 21 percent fat and nearly a third pure table sugar. It’s also a marvel that the researchers pegged the tumor-enhancing effects of the Western diet on its cholesterol content rather than on any of the other differences it had with the chow diet (for example: everything). In fact, the protein source alone might play a role in spurring the big, speedy tumors found in the Western diet rats, since so much of their diet was casein. Dare I reference my old pal T. Colin Campbell, whose research showed isolated casein tends to boost tumor growth in rodents when it exceeds 5 percent of their diet? I dare. There may be something uniquely cancer-promoting about isolated complete proteins (like casein) in a purified diet, probably due to the fact that they promote growth in general but lack the matrix of protective substances found in whole foods.

But the most interesting thing here is that hefty dose of sucrose in the Western mouse diet. Even back in the 80s, researchers were noting an association between sugar consumption and breast cancer, speculating that:

A possible connecting link between sugar consumption and breast cancer is insulin. This is an absolute requirement for the proliferation of normal mammary tissue and experimental mammary tumours may regress in its absence. Insulin secretion occurs in response to blood glucose level and could be excessive if the regulatory mechanism is overtaxed by large sugar intake.

There’s a growing body of research addressing the insulin-breast cancer link, and unlike with fat, the findings are more consistent. High insulin is associated with a greater risk of death from breast cancer, may lead to a greater risk of breast cancer in postmenopausal women, and may be a risk factor for breast cancer independent of estrogen. Although insulin responses to sugar vary between mouse strains, there’s some evidence that mice fed sucrose as their primary carbohydrate (opposed to other foods like cornstarch) have higher levels of insulin and insulin-like growth factor 1. Both insulin and IGF-1 can potentially stimulate the growth of breast cancer cells and hike up testosterone levels (which also has some compelling links with breast cancer). And one study examining the effects of different sources of protein, fat, and carbohydrate on mammary tumors in mice showed that the sucrose-eating mice had 100 percent tumor incidence by the end of the study.

Since the researchers were mostly concerned with fat and cholesterol in this study, they didn’t examine potential pathways between tumor growth and insulin, or consider whether the high sugar and casein content of the Western diet had anything to do with cancer promotion. I’ve got a hunch there are some untapped clues there, but from this study, we’ll never know for sure.

The Cholesterol Connection

Although most of the media outlets pounced on the “high fat” part of this study, the researchers themselves were more intrigued by the effects of cholesterol. Interestingly, the mice exhibited lower cholesterol as their tumors grew—suggesting that the tumors seemed to guzzle cholesterol and use it for cell proliferation, causing a drop in serum levels. (This jibes with a trend we’ve seen in humans, where certain cancer patients have significantly lower cholesterol than the rest of the population.) The researchers speculate that lowering blood cholesterol could help limit tumor growth in humans, and they conclude: “Drugs that target cholesterol metabolism could be used in addition to drugs that may facilitate the elimination of breast cancer cells.” (Did you hear that? Could it be the joyous clinking of the statin companies’ wine glasses?)

Even if tumors (breast or otherwise) do hoard cholesterol, there’s no way to tell from this study whether cholesterol actually promotes their growth, and if deliberately lowering your levels would do a darn thing for cancer prevention. In fact, the researchers note that “it is not unreasonable to assume that liver function may be affected in this disease” and that “plasma lipoprotein levels could be influenced by reduced hepatic lipoprotein secretion”—in which case the breast tumors might not be reducing cholesterol by using it for their own growth, but the body is simply producing less of it.

So What Do We Take Away From It All?

This study might’ve uncovered an interesting role of cholesterol in tumor growth, but it’s hard to tell what the significance would be even if that’s the case. Given the total lack of a control diet and the sketchy assembly of ingredients in the Western cuisine, we can’t glean much of anything about the role of fat or cholesterol in human breast cancer. The only things saving this study from that slush pile are the three nuggets of wisdom it confers: Don’t be born a tumor-prone mouse, don’t eat a foodless diet based on table sugar and casein, and read the full text of studies before letting news headlines make you nervous.

For More Insightful Research Analysis Visit Denise’s Blog, Raw Food SOS

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. Thank you for providing your analysis for this study, Denise. As a woman who is scared silly by the “1 in 7 women will get breast cancer” statistic, I’m relieved not to have to give up my primal diet and go back to a low-fat diet to try to avoid breast cancer.

    Clarissa wrote on January 19th, 2011
    • You ought not be “scared silly” by the one in seven statistic until you sort out where you fit in the demographics.

      kem wrote on January 19th, 2011
      • Are you trying to inject rational thought into an irrational fear?

        Clarissa wrote on January 20th, 2011
    • A good book on false positive medical tests is Calculated Risks by Gerd Gigerenzer. He uses breast cancer specifically as an example. Many of the positive tests are false positives, and some of the tumors are so slow-growing that one might even consider leaving them alone.

      Lori wrote on January 20th, 2011
      • Thank you for the book recommendation. I’ve got it in order.

        Clarissa wrote on January 20th, 2011
  2. Hey do you guys eat Greens + on Paleo. Its got wheat grass? Wheat grass no go?

    jason j wrote on January 19th, 2011
  3. Denise, I await your first book. Your writing is truly engaging… not what one would expect from a critical analysis of a mouse study.

    Mice in my woolshed tend to primarily food on barely or wheat through the tiny holes they make in the bottom of the sack. That is, until they encounter the cat…

    kem wrote on January 19th, 2011
  4. I would like to point out also that yes high fat is bad when it is coming from these highly processed oils plus carbs and factory farm meats and dairy. These high fat diets should contain natural occuring oils, grassfed meats, and raw dairy or at least as close to it as you can find. I sometimes wonder if everyone understands this point.

    Dave Parker wrote on January 19th, 2011
  5. My 15 year old read the article and said,”they’re missing half of their experiement because they didn’t have proper control by changing the ingredients…and they seem to be calling sugar, hi-fat. Every H.S. student knows this from Middle School science class.”

    Rose Adams wrote on January 19th, 2011
  6. My vague understanding is that cancer is the unnaturally rapid growth of mutated cells. Isn’t cholesterol necessary in cell construction? Could the cholesterol be being sucked up to grow these cancerous cells?

    Pat wrote on January 19th, 2011
    • A rapidly growing cell will need more cholesterol, but in comparison to the grams of this nutrient that your body makes every day, the amount in your diet is not very significant. Your body makes about 70% of the cholesterol you need, with only 30% coming from your diet.

      Therefore it is unlikely that you could have any effect on the growth rate of a cancer cell by changing your diet.

      Tim wrote on January 20th, 2011
  7. Another fantastic “take down” of a study that essential proves NOTHING.

    Simply brilliant.

    Primal Toad wrote on January 19th, 2011
  8. Denise Minger, you may be my new hero. I only just heard of you for the first time a few days ago. Read your articles on the China Study. Amazing work, greatly appreciated. Please continue shedding light on studies like this one that become summarized headlines fed to the general public. I have a feeling you’ve found your calling, or it found you. You seem to have the ability to expose the truth (humorously, at that) in the studies that others want to twist to their agenda. Thanks.

    Carol wrote on January 19th, 2011
  9. Great post, too bad we can’t get this reported as widely and publicaly as the psuedo scientists did

    art wrote on January 19th, 2011
  10. Don’t listen to this Denise person!

    Fat and cholesterol makes you get cancer!!

    Go get on statins ASAP!! It’s your only chance!

    Rat Study Author wrote on January 19th, 2011
  11. Thanks Denise.

    Sue wrote on January 19th, 2011
  12. For those promoting a low fat, low or no meat diet to prevent breast cancer, I have two words:

    Linda McCartney.

    Alec wrote on January 19th, 2011
  13. Thank you so much Denise. As an everyday housewife, without a lot of higher education, I really appreciate how skillfully you break these bogus studies down so that people like myself can understand them. It really helps that you have a wonderfully engaging writing style.


    Susan wrote on January 19th, 2011
  14. Being fat is linked to cancer but eating too much fat isn’t linked to cancer if you are at an ideal weight in regards to your BMI. But if you eat a lot of fat, you probably eat a lot of everything and eat too much in general, so then you are fat and then you are more likely to have cancer. Correlation does not equal causation. I talk about this a lot on my blog…

    Mike @ Papa Star Health wrote on January 19th, 2011
    • If you eat a lot of clean animal fat, you will likely *not* eat a lot of everything else, because you’ll be sated, with stable blood-sugar.

      Welcome, and I hope you stick around to read about the necessity of clean animal fats in the human diet. :)

      imogen wrote on January 20th, 2011
  15. Denise, you rock!
    Why is there still no donate button on your blog?
    And please do alert your loyal readers to this post. Not everyone hanging on your every word also hangs out over here.

    Birgit wrote on January 20th, 2011
  16. Nice takedown. Almost every “study” is absolutely flawed.

    The best studies these days are the ones you do on yourself. If it works, keep it. If it doesn’t, drop it and find something that does!

    Oh, and sugar isn’t an option. =)

    George wrote on January 20th, 2011
  17. Thanks for such a detailed analysis, Denise and Mark. As Daniela Huppe wrote in the comments above, once I saw the composition of the two feeds that were being compared I stopped reading. Neither the rest of the study design nor the results matter when there is such a big design flaw. Good job looking up the chow components, Denise.

    As a molecular biologist, who has actually worked in a lab studying obesity in a rodent model (rats) and seen this very thing happening – labs ordering chow from a catalogue without looking at the composition of the foods, this doesn’t surprise me at all. I tried once to put forth the idea to my then boss that perhaps fats have been wrongly demonised, and that several different academic organisations are now saying that a higher protein diet may be beneficial compared to a higher carb diet. None of it mattered to my boss who was convinced that eating too much protein would ‘screw up your kidneys’ and fats are obviously the problem and ‘complex carbs’ are the best thing since sliced bread (pun intended!). I gave up arguing eventually, also because the main focus of their work was not diet composition per se, but was looking at maternal weight gain during pregnancy and how this affects the child’s appetite and chances of getting diabetes later in life (affects both badly). Unfortunately, other than the small but emerging group of scientists who conduct studies and publish results comparing paleolithic/primal diets with CW diets, the large majority of academics in this field are still firmly stuck in the old way of thinking.

    Anyway, just wanted to point out one more thing that hasn’t been mentioned. The wild-type (WT), aka control mice in the study are not actually ‘ordinary mouse on the street’ strains. No mice reported in any scientific studies are this. Mice used for scientific research are usually from a handful of different strains available world-wide and commonly used for research. In this study, the only different between the WT and the mutant mice is the one gene, the PyMT trans-gene.

    These mouse strains have all be inbred for hundreds of mouse-generations and maintained in a sterile or semi-sterile lab environment. If let out into the real world, these mice would probably die of massive infections as their immune systems have never seen real-world bugs and have not had time to build up immunity – another reason why we should be very careful extrapolating study results between mice and men, especially in diseases where the immune system may have a role – eg inflammation and cancer, as normal, steady-state immune profiles of inbred lab strains of mice are very different from that of a human living out in the real world.

    Sorry for the long comment. I’m a long time reader, very rare commenter, but this one I had to say something for.

    Meg wrote on January 20th, 2011
    • thanks for sharing your experience, Meg. It’s very informative!

      The Tiny Homestead wrote on January 20th, 2011
    • Awesome. Thanks for that! Comment more! 😀

      imogen wrote on January 20th, 2011
  18. The scary thing is most common folk will just read the headline and take it as truth without even bothering to read the rest of the article.
    Cholesterol = Breast Cancer.

    BigD wrote on January 20th, 2011
  19. Denise, you’re my hero :)

    Hanna wrote on January 20th, 2011
    • Hear, hear! It’s great when people like Denise and Gary Taubes absolutely destroy these studies, because all they are is manipulated statistics that prove the author’s pre-conceived notions…and nothing more.

      They want a specific outcome so they use numbesr, smoke, and mirrors to create an unsubstantiated bunch of data to help make their point. The scientific process that I learned about IN 7TH GRADE doesn’t work that way. Great science SHOULD create more questions, and prove you wrong more often than it confirms your own suspicions. That leads to better research in the future. Sadly, this rarely happens in the world of statins and CW. Nowadays, research is done to sell more pills and promote pre-determined agendas. Very sad. Max Planck is rolling over in his grave.

      Jared wrote on January 20th, 2011
      • Interesting that Gary Taubes was debunked by Harriet Hall over at Science Based Medicine a few days ago.

        Denise wrote on January 20th, 2011
        • I stopped reading when she started using thermodynamic. Of which she obviously as absolutely no understanding.

          Don’t get me wrong, thermodynamic works.

          But “calorie in/ calorie out” only work for a closed system WITHOUT any intelligent intervention. The human body is not a closed system and hormones acts as the intelligent intervention, they rule what happen, when and how!

          Uber wrote on January 24th, 2011
        • @Uber: The physics of conservation of energy have definitely not been disproved. The fact of the matter is that we can use the energy we ingest or otherwise take “in to our system” in a whole variety of ways. We can store it in fat, we can build muscle, we can make our hearts beat, we can walk, we can dream, etc.. Really there isn’t anything our body does that isn’t using energy. That being said, to say that ingesting 3500 calories above one’s base metabolism will inevitably lead to gaining a pound of fat would be absurd. Surely the body would use some of that energy for something other than simply storing fat.

          Really the bickering over whether or not the whole energy balance thing makes sense seems to be nothing more than people not understanding one another.

          Marc wrote on August 24th, 2011
  20. “The scary thing is most common folk will just read the headline and take it as truth without even bothering to read the rest of the article.
    Cholesterol = Breast Cancer.”

    Yes, exactly. I am trying to understand why our society is getting more ignorant. It is a growing trend. People read a headline or watch the news and take the lies as gospel. Why does this happen? Also, why are these scientist evil? They are putting peoples lives in danger from BAD science. Thanks to people like Denise and Mark who help us understand the truth hidden in lies!

    Aaron Curl wrote on January 20th, 2011
    • It’s not that they’re individually “evil”. It’s that the modest transgressions that led to each report add up to more than the whole. In order to get grant money to run experiments, they have to produce papers that get accepted for publication, which means they can’t upset anybody with a stake in the status quo getting upset. They have an incentive to sin at all levels, from conception to the press release designed to get them glory and then quickly bury the report.

      Angela Quattrano wrote on January 21st, 2011
  21. Denise–you’ve done it again with your witty writing style and wonderful sense of humor. We need more scientists like you!
    You hear so much about the link between fat and breast cancer. This study and Denise’s analysis really makes you wonder. I know I’ve become much more critical about what I read when it comes to nutritional studies, thanks to Denise!

    Sue wrote on January 20th, 2011
  22. Wow thanks for the link! I agree, but with most food we have that is processed I think that everything we put in our mouth that is not “Organic” to say is harming us in many ways not just cancer But TONS more! So funny how it takes Studies…to realize what God put here for us is the best for us ; ) Love this post!

    Brittany wrote on January 20th, 2011
  23. How do they manage to call that a Western diet with a straight face and no air quotes? As a commenter above said, simply feeding the mice McDonald’s burgers and fries would more closely approximate a Western diet.

    I’m wondering if comparative data exactly like this wasn’t already available from the chow manufacturers, which would mean that there was very little potential to get new information from this study. It would also explain why next to no thought went into the study design.

    Angela Quattrano wrote on January 20th, 2011
  24. Denises excellent job here highlights a link that i tried to post here yesterday – (hasn’t been approved??) but if you google :

    Why Most Published Research Findings Are False

    you’ll get a peer reviewed medical journal essay on why these studies almost always go awry and are undependable (even the ones we LIKE the results of folks!)…

    DaiaRavi wrote on January 20th, 2011
  25. Most research studies are total BS. Roger Haeske did an interview with Dr. Jennifer Daniels. In the interview she talks about her experiences in medical school when she was asked to falsify research data. When she refused to do so the strangest things started happening. You can listen to the interview here:

    Karmyn wrote on January 20th, 2011
  26. I love this article – it demonstrates how glaringly obvious facts are overlooked as potential causative factors in cancer (i.e. high sugar – high insulin) so that “researchers” can back up conventional beliefs. How useless, misleading and dangerous for those who don’t investigate these studies for themselves.

    Jodi Forsythe wrote on January 20th, 2011
  27. How does this kind of rubbish even get published?

    Thankyou, Denise, for keeping such a keen, sceptical eye on the latest “research.”

    fritzy wrote on January 20th, 2011
  28. Thanks for sharing such a wonderful article

    hispanic booking acts wrote on January 20th, 2011
  29. High fat leads to breast cancer

    Cash for cars san diego wrote on January 20th, 2011
  30. I am amazed from the quality of article

    cart rental baton wrote on January 20th, 2011
  31. this is a highly impressive article.I am very much impressed with it

    mechanical bull rental baton rouge wrote on January 20th, 2011
  32. quiet an impressive articl.Having a depth of knowledge

    hip hop booking acts wrote on January 20th, 2011
  33. Ok, I get your point, AND I agree with it. But “Even though the paper’s lips are zipped about the actual ingredients of the diets” is not the means to start to discredit a paper. I hope you realize space is limited in papers, and the AUTHORS pay to have it published. So the longer it is, the more it costs. So why put in a paper (ex. nutrient breakdown of food) what can easily be found in other papers or *gasp* by searching Google (just like you did!). This isn’t so conspiracy!

    Alissa wrote on January 21st, 2011
    • It is when the *conclusion* doesn’t take into account the design of the study, and most importantly in a nutrient-focused study, the nutrient-make-up of the control group(s).

      Let’s not feign sympathy for poor starving scientists just doing the work for the greater good, unless they actually are. I don’t buy it in this case.

      imogen wrote on January 21st, 2011
  34. Denise, you did an amazin job.
    I have to say, I had a big laugh when I first saw the headline about sat. fats causing tumors, but I’m glad someone actually did the work dissecting this:) Kudos to you.

    chocolatechip69 wrote on January 21st, 2011
  35. Like Yogi Berra said “It’s like deja vu all over again”…just like the Framingham Mass. studies done decades ago…these “scientists” just don’t give up!

    Jon DeVaul wrote on January 21st, 2011
  36. More great work from Denise. I am currently doing a Med Phys master’s degree and have recently posted about cancer, positron emission tomography and the Warburg effect on my new blog… PET gives a much better idea of which food is most associated with tumour growth.

    Amanda wrote on January 22nd, 2011
  37. ‘Bad’ cholesterol saves lives; it does not take lives. LDL allows the blood to flow through injured blood vessels without causing a life-endangering situation.
    I have a feeling that the only reason cholesterol was low in the mice with tumors was because it was sent to the tumors to protect the body.


    sam wrote on January 22nd, 2011
  38. One thing I find interesting when reading about people like Christina Applegate, also a vegetarian and daughter of breast cancer survivor, is how she had regular mammograms starting at age 30 and by 36 had breast cancer. I believe she said she had one a year and then one every 6 months. I have also read about other women that were “at risk” doing this and then getting a fast growing tumor. Many studies done all over the world have shown mammograms increase the cases of breast cancer, not decrease. I fear we are causing cancer with all of this “Prevention” that is making so many people very rich.
    This diet study is another example of telling us to do something that will make us sick.

    “Breast cancer rates increased significantly in four Norwegian counties after women there began getting mammograms every two years. The study concludes that the reason for the sharp spike in cancer rates is that some of the cancers detected by mammography would have spontaneously regressed if they had never been discovered on a mammogram and treated with chemotherapy and radiation. They go on to state that some invasive breast cancers simply go away on their own, healed by the body’s own innate immune system.”

    April wrote on January 23rd, 2011

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