Monday, February 25, 2013

Ketogenic Diet And Prostate Cancer In Mice

It's always nice to find research the confirms ones' prejudices. I've thought a bit about the causes of prostate cancer, and came to the conclusion that it's probably sugar. My doctor has (happily) observed that I have the prostate of a teenager. (Given the nature of the prostate exam, this is not a time for idle chatter...)

I've speculated that the incidence of prostate cancer might be the result of linoleic acid, or wheat (my two favorite dietary bogey-men), but I have been unable to find any evidence to support those suppositions. So I was left with sugar. I substantially cut back on my sugar intake in my late teens, having had countless cavities (I literally cannot recall how many) and eight teeth pulled. I was done with dentists. 20 years passed, I had zero cavities, and my prostate was, according to my Doc, unchanged.

Along comes this: Carbohydrate restriction, prostate cancer growth, and the insulin-like growth factor axis:
"In this xenograft model, despite consuming more calories, [No Carb. Ketogenic Diet]-fed mice had significantly reduced tumor growth and prolonged survival relative to Western mice and was associated with favorable changes in serum insulin and IGF axis hormones relative to low-fat or Western diet."
Interesting. That's mice, and mice ain't people; but there is absolutely no downside that I'm aware of in cutting out sugar and reducing your carbohydrate intake.

And note the following about the ketogenic mice:
"Despite consuming equal calories, NCKD-fed mice lost weight (up to 15% body weight) relative to low-fat and Western diet-fed mice and required additional kcal to equalize body weight."
Nothing wrong with that...

Tuesday, February 19, 2013

"No Change In AHA Recommendations On Saturated Or Poly-unsaturated Fat"

P.P.S (I usually put post-scripts at the end of the post, but this one so fundamentally changes the nature of the AHA's press release, you need to see it first.)

The lead researcher on the study below was one Christopher E. Ramsden. Turns out he and the AHA have a history, the AHA posted this letter from him in 2009 concerning the Sydney Diet-Heart Study:
"Regrettably, the recent AHA Advisory [1] relied heavily upon a one-line meta-analysis cited in a non peer-reviewed book chapter [2] to support its position that high intakes of omega- 6 fatty acids reduce CHD. Unfortunately, the credibility of this advisory is undermined by four additional critical errors.

1) The AHA Advisory mistakenly cited the Sydney Diet-Heart Study [3] when referring to Gordon’s meta-analysis [2] and its ascribed conclusion that “PUFA lowered the risk of CHD events by 24%” [1]. The Sydney study did not report CHD events and was not included in Gordon’s analysis of CHD events. Importantly, the study did report that 39 of 221 (18%) high omega-6 [Linoleic Acid] dieters died within 5 years versus only 28 of 237 (12%) of controls, and that 63 of 67 (94%) of these deaths were due to CV disease [3]. This 49% increased death rate in the high-LA group warrants attention and discussion in any balanced review of published evidence....
This casts a new light on the AHA's dismissal of this new research. Circle the wagons, indeed.

End of post-script.


It's no surprise that the American Heart Association doesn't want to admit error. But the way they do it is most instructive:
"A recent study published in the British Medical Journal analyzed data from the late 60’s and early 70’s and concluded that substituting polyunsaturated fats (PUFAs), rich in Omega-6 linoleic acid, for saturated fats did not result in cardiovascular benefits among a group of men who had experienced a heart attack or other cardiac event...."
"Did not result in ... benefits".

What the study said was:
"...The results show that the omega-6 linoleic acid group had a higher risk of death from all causes, as well as from cardiovascular disease and coronary heart disease, compared with the control group...."
No benefit, indeed! "Penny Kris-Etherton, Ph.D., R.D., American Heart Association spokesperson and distinguished professor of nutrition at Pennsylvania State University" (argument from authority, anyone?) goes on:
"...However, the researchers admitted their analysis was limited by the fact that they did not have access to the original study protocol, so they could not fully appraise its accuracy.

“The British Medical Journal study is interesting, but not conclusive. It is offset by a large body of scientific evidence that continues to show cardiovascular benefits associated with eating mono- and poly-unsaturated fat, rich in Omega-6 linoleic acids, in place of saturated fats...”
Again, from the study:
"Without access to the original study protocol, we cannot fully appraise the accuracy of outcome ascertainment and other quality aspects of the SDHS. Another potential limitation was incomplete data recovery, owing to our inability to identify some of the study variables recorded on punch cards. However, we were able to identify, confirm, and verify each of the key variables for the dietary, laboratory, and coded mortality outcomes that were required to interpret the main study findings (web appendix, part 1)."
The professor doesn't address the part after the "however", nor does she address this:
"An updated meta-analysis of LA intervention trials showed no evidence of cardiovascular benefit."
She merely reasserts:
"“The British Medical Journal study is interesting, but not conclusive. It is offset by a large body of scientific evidence that continues to show cardiovascular benefits associated with eating mono- and poly-unsaturated fat, rich in Omega-6 linoleic acids, in place of saturated fats,”"
So there either is or is not evidence. But the BMJ study at least presents some, the AHA merely asserts its authority and dismisses the study, ignoring the bulk of it, and finding fault with a technical aspect.

Of course the AHA led with their strongest salvo:
"The association bases its recommendations on a robust body of scientific studies that demonstrate a strong association between eating a diet high in saturated fat and the development of atherosclerosis, which clogs arteries and causes heart disease."
Even though Dr. Krauss has found that:
"A meta-analysis of prospective epidemiologic studies showed that there is no significant evidence for concluding that dietary saturated fat is associated with an increased risk of CHD or CVD."
Who's Dr. Krauss?
"...founder and past Chair of the [American Heart Assocation] Council on Nutrition, Physical Activity, and Metabolism, and a National Spokesperson for the AHA."
Circle the wagons, AHA.

Tuesday, February 12, 2013

Clueless Experts on the Evolution of Human Nutrition

This is an interesting post in many respects: "Experts on the evolution of human nutrition", but it also displays the utter cluelessness of academics when it comes to applying what should be useful knowledge to a real-world problem.
"Want to eat a diet that mimics that of our Paleolithic ancestors? It might be a little more complicated than what the popular books say. "The fact is, there was never one Paleo Diet; it's more likely there were hundreds of them and that they were continually changing and broadening over evolutionary time.

"That was the overarching takeaway message of an impressive lineup of experts on ancient human diets at a symposium entitled "The Evolution of Human Nutrition" organized by the Center of Academic Research and Training in Anthropogeny (CARTA) at UC San Diego on December 7, 2012...."
That's not particularly useful as a takeaway message, although I guess it's useful to an academic's career: "Things are complicated, they need more study, which I'd be happy to do..."
"...President of the Wenner-Gren Foundation for Anthropological Research Leslie Aiello, who chaired the symposium, expressed some amusement over folks who aspire to the great lengths of trying to live like cavemen in the big city.

"However flawed their premise, she noted, the gaining interest into the diet of our ancestors was one to be welcomed. After all, it could lend clues into current causes of epidemics of obesity, type-2 diabetes, and cardiovascular disease...."
The mind reels. Clearly the Chair of this symposium doesn't know enough about the "Paleo Diet" to know that it not only will "lend clues" about the "epidemics of obesity, type-2 diabetes, and cardiovascular disease", but it often resolves them. And there's not only countless anecdotes to that effect, but actual research studies. Guess she doesn't read those journals. But maybe I'm unfair, I mean, not everyone can be an expert on the Paleo Diet... Oh wait. She is supposedly an expert on the Paleo Diet. Time to do some homework, professor.

Moreover, she points to the old NY Times article featuring John Durant and Melissa McEwen. John cured his obesity with the Paleo Diet, and Melissa cured a chronic digestive condition that had a huge impact on her life. How is that "flawed"?

John describes the Paleo Diet thus:
"Followers of the paleo lifestyle argue that the agricultural revolution led to a marked decline in health, in part due to less diverse sources of nutrients. “Our diet became very narrow, very quickly. We went from eating a wide variety of animal foods and plant foods driven by seasonal eating, to a very narrow set of foods.”"
So is this in marked contrast to what these "experts" have to say?
"...By 15 to 10,000 years ago, modern humans had taken over the landscape and were already shifting from foraging to farming, which represented a major transition in the human diet, Schoeninger said.

"The shift was was one from a varied, broad diet that changed with seasons to be replaced with one that included specific plant foods such as cereal grains as a dietary staple, according to anthropologist Clark Spencer Larsen.

"This reliance on single foods such as grains as staples with characteristically low nutritional quality, along with more availability of food and more sedentary lifestyle, he said, was the start of health decline as evidenced by study of bones and teeth of the era...."
So, the obvious conclusion, to me and to John, is to eat like the healthy folks. That's the "Paleo Diet".
"...Barry Bogin, a biological anthropologist of Loughborough University, UK, has witnessed this sort of population health decline first-hand while studying the Maya who in recent years have made the switch from their traditional varied diets to ones that are more modern and containing a great deal more animal products, cereal grains, and added sugars...."
Yes, OK, we get it. Clearly we should eat like the healthy people, right?
"...But when asked about dietary advice (including what food groups to be consumed and to not be consumed) that can be gathered from an extensive knowledge of evolution of the human diet, Ungar simply shrugs and responds, "I tell people to go see a nutritionist.'..."
The nutritionists will tell you to eat the food pyramid, which reliably causes "obesity, type-2 diabetes, and cardiovascular disease." That's not very good advice, but it is the advice that has led to 60% of Americans being overweight.

I get the feeling that some of these folks are a bit peeved that they didn't draw the conclusion that was so obvious to Dr. Eades and the other innovators in the Paleo Diet. Some, like Ungar, just don't know what they're talking about. They're criticizing the Paleo Diet community without having any idea what members of that community are actually saying, and without any idea of the health benefits that have already been demonstrated in those who follow the Paleo Diet.

That's just clueless. But again, it's an interesting post, and there are some videos of the talks at the original link.

Monday, February 11, 2013

"Judge Andrew Napolitano Loses 60 Pounds Just By Dropping Wheat (Just Like Dr. William Davis Said)"

"...Finally, back to Napolitano's nice weight loss, shame on all the pettifogging purists who made a big deal over certain inaccuracies in: Wheat Belly: Lose the Wheat, Lose the Weight, and Find Your Path Back to Health, or who've slammed the heroic Dr. William Davis. While he's out saving lives and helping people to improve their health in the tens of thousands in a very PGP (Pretty Good Paleo) way, useless pettifoggers did squat. Oh, that the world could be as pure lilly white as the driven snow, and nobody ever got any good help but from Snow White."
Amen to that. I think Dr. Davis' book is a bit hyperbolic, and I mention that qualification to people as I am recommending it. That doesn't mean it's worthless, just as a diamond with a few flaws is not worthless.

Tuesday, February 5, 2013

Linoleic Acid, Heart Disease, And "Experts"

British Medical Journal: "Study raises questions about dietary fats and heart disease guidance." Indeed it does:
Death rates continue to diverge with time!

"Dietary advice about fats and the risk of heart disease is called into question on bmj.com today as a clinical trial shows that replacing saturated animal fats with omega-6 polyunsaturated vegetable fats is linked to an increased risk of death among patients with heart disease...."

"...Advice to substitute vegetable oils rich in polyunsaturated fatty acids (PUFAs) for animal fats rich in saturated fats to help reduce the risk of heart disease has been a cornerstone of dietary guidelines for the past half century. The most common dietary PUFA in Western diets is omega-6 linoleic acid (n-6 LA for short)...."

"...An in-depth analysis of the effects of linoleic acid on deaths from coronary heart disease and cardiovascular disease has not previously been possible because data from the Sydney Diet Heart Study - a randomised controlled trial conducted from 1966 to 1973 - was missing.

"But now, a team of researchers from the US and Australia have recovered and analysed the original data from this trial, using modern statistical methods to compare death rates from all causes, cardiovascular, and coronary heart disease.

"...The results show that the omega-6 linoleic acid group had a higher risk of death from all causes, as well as from cardiovascular disease and coronary heart disease, compared with the control group....

"...In an accompanying editorial, Professor Philip Calder from the University of Southampton says the new analysis of these old data “provides important information about the impact of high intakes of omega 6 PUFAs, in particular linoleic acid, on cardiovascular mortality at a time when there is considerable debate on this question.”

"Calder says the findings argue against the "saturated fat bad, omega 6 PUFA good" dogma and suggest that the American Heart Association guidelines on omega-6 PUFAs may be misguided. They also "underscore the need to properly align dietary advice and recommendations with the scientific evidence base."

Sounds like a fine idea. This is what the Paleo community has been trying to do for years.

Stephen Guyenet had this covered years ago:
"...But it gets even better. The intervention group reduced their omega-6 linoleic acid intake to 3.6% of calories, below the critical threshold of 4%. As I described in my recent post on eicosanoid signaling, reducing linoleic acid to below 4% of calories inhibits inflammation, while increasing it more after it has already exceeded 4% has very little effect if omega-3 is kept low*. This is a very important point: the intervention group didn't just increase omega-3. They decreased omega-6 to below 4% of calories. That's what sets the Lyon Diet-Heart trial apart from all the other failed diet trials.

After five years on their respective diets, 3.4% of the control (prudent diet) group and 1.3% of the intervention ("Mediterranean") group had died, a 70% reduction in deaths. Cardiovascular deaths were reduced by 76%. Stroke, angina, pulmonary embolism and heart failure were also much lower in the intervention group. A stunning victory for this Mediterranean-inspired diet, and a crushing defeat for the prudent diet!
So just to sum it up: the "experts" have been giving us the wrong advice for decades.

Thanks to Jamie Scott on Twitter.

P.S. Dr. Briffa, a cardiologist, covers this study as well: "New data from old study reveals that reducing saturated fat in favour of ‘vegetable’ oils increases risk of heart attack and can have fatal consequences."

P.P.S. Adele Hite (one of the few Registered Dieticians you should actually be listening to) has a great post:
"Although the switch to safflower oil did lower total cholesterol, these reductions didn’t help those participants live any longer than those who kept eating saturated fat. In fact, as the authors note, “the increased risk of death in the intervention group presented fairly rapidly and persisted throughout the trial.” (Hmm. Maybe this whole “cholesterol lowering” thing isn’t as important as we thought.)"
I came to the conclusion quite a while ago that what caused fatty-liver disease was not alcohol or sugar, but linoleic acid. You liver can tolerate high amounts of alcohol, for instance, if you are eating a high saturated-fat, low linoleic acid diet.

One of the paradoxes of medical science is why populations like the French or the Kitivans can smoke like chimneys and not get heart disease at the same rates that Americans do. This study provides a clue that resolves the paradox:
"Furthermore, the authors go on to point out that the relationship between linoleic acid consumption and increased mortality was particularly robust in smokers and drinkers, “suggesting that diets high in n-6 [linoleic acid] may be particularly detrimental in the context of oxidative stress induced by smoking and alcohol."
The toxin may not be tobacco, but linoleic acid, which seems to impair the body's ability to heal itself. Both the Kitivans and the French traditionally eat low levels of linoleic acid. (I'm not endorsing smoking, btw, but observing a telling correlation.) I suspect this also explains why the Kitivans, but not the Indians, can get away with eating a high-carbohydrate diet without the associated negative side-effects.

Here's the link to the full study.

Monday, February 4, 2013

"Why Science May Not Be Enough"

James Woodward on Why Science May Not Be Enough:
"It is probably not breaking news that people’s eating decisions are not purely based on a careful reading of the scientific evidence. Better science is probably a necessary part of making the case but I do not think it will be sufficient to affect the type of change that many people in the ‘Paleo’ or ‘Ancestral Health’ communities (or whatever other term you prefer) would like to see. As mentioned, most people are averse to the notion that their beliefs are wrong and, in my experience, will try to come up with some reason for why that is not the case, sometimes resorting to questionable sources for support. This is human nature, I think—cognitive dissonance perhaps, to borrow a term from the psychologists. Based on what I can see, most people are not even willing to entertain the idea that there is a controversy or room for debate about these competing paradigms. Especially skinny people."


Indeed.