Thursday, December 1, 2011

More Evidence That The Paleo Diet Can Reduce Cancer Risk

More Evidence That The Paleo Diet Can Reduce Cancer Risk

A very interesting article was recently published on October 26th, 2011 by Nutrition & Metabolism, entitled: “Is there a role for carbohydrate restriction in the treatment and prevention of cancer?”. The article delivers more evidence that the Paleo Diet can reduce cancer risk, and improve heart disease markers. British Dr. John Briffa, a prominent low-carb advocate, posted the following summary of the article on his blog:
The paper starts with reference to hunter-gatherer diets, and their relatively protein-rich, low-carb nature, and remarks that cancer has been found to be rare in societies eating such a diet. It then goes on to postulate several major mechanisms that may account for this association. These include:
1. Cancer cells feed preferentially on sugar (glucose)
Glucose (from sugary and starchy foods) provides the prime fuel for cancer cells, so a diet lower in carbohydrate may therefore reduce tumour development or progression.
Ketones are your friend.
2. Insulin and IGF-1 can stimulate tumour cell growth
High carbohydrate diets increase levels of insulin and what is known as insulin-like growth factor-1 (IGF-1) which stimulate tumour cell growth. A lower carbohydrate diet may reduce tumour proliferation as a result.
3. Ketones suppress cancer
Very low carbohydrate diets can lead to the production of ‘ketones’ (mainly produced from fat) that suppress tumours.
4. Low-carbohydrate and ‘ketogenic’ diets ‘starve’ cancer
Low-carbohydrate diets mimic caloric restriction and ketogenic diets mimic starvation – and caloric restriction/starvation is linked to reduce tumour development and progression.
5. Low carbohydrate diets can reduce inflammation
Inflammation is believed to be a risk factor in the development of cancer, and high-carb diets encourage inflammation. Low-carbohydrate diets have been found to be more effective than low-fat ones in terms of reducing markers of inflammation.
The paper also makes the case that such diets may help better meet the nutritional needs of those with cancer.” – Dr John Briffa
You can find the “provisional” version of the article in PDF form here. In the meantime, this is (in my opinion) one of the most poignant paragraphs from the document:
In this context, it is important to note that a low CHO diet offers further possibilities to target inflammation through omission or inclusion of certain foods. Usually, CHO restriction is not only limited to avoiding sugar and other high-GI foods, but also to a reduced intake of grains. Grains can induce inflammation in susceptible individuals due to their content of omega-6 fatty acids, lectins and gluten [159, 160]. In particular gluten might play a key role in the pathogenesis of auto-immune and inflammatory disorders and some malignant diseases. In the small intestine, gluten triggers the release of zonulin, a protein that regulates the tight junctions between epithelial cells and therefore intestinal, but also blood-brain barrier function. Recent evidence suggests that overstimulation of zonulin in susceptible individuals could dysregulate intercellular communication promoting tumorigenesis at specific organ sites [161].
Paleolithic-type diets, that by definition exclude grain products, have been shown to improve glycemic control and cardiovascular risk factors more effectively than typically recommended low-fat diets rich in whole grains [162]. These diets are not necessarily very low CHO diets, but focus on replacing high-GI modern foods with fruits and vegetables, in this way reducing the total GL. This brings us back to our initial perception of cancer as a disease of civilization that has been rare among hunter-gatherer societies until they adopted the Western lifestyle. Although there are certainly many factors contributing to this phenomenon, the evidence presented in this review suggests that reduction of the high CHO intake that accounts for typically >50 E% in the Western diet may play its own important role in cancer prevention and outcome.” [1]
It’s nice to see further evidence of what the Paleo Community has known to be true for a long time, that a lower-carbohydrate version of the Paleo Diet is one of the best, easiest and yummy ways to secure your health for the future. If you want to live a long healthy life, and stand the best possible chance of avoiding cancer, heart disease, and pretty much any disease of civilization you can think of, the Paleo Lifestyle is the way to do it.

Geoff Roes's Take On Barefoot/Minimalistic Running

Geoff Roes posted this on his blog. Then, he deleted it. But he could not delete it from my feed reader, so I am posting it here:

After yesterday's not so serious post I thought I'd write about something a little more serious today (although only a little more): Shoes. Specifically why I wear the shoes I wear and is there a specific type of shoe that I think works the best for ultrarunning?

People ask me some variation of the following question all the time: "What do I feel like the main difference is between running ultras compared to shorter distance races?" My answer usually goes something to the effect that when you run for 50+ miles it stops being as much about how fast you can go at the fastest points and more about how fast you can go at the slowest points. That is to say, how much you can do to minimize the rate at which you slow down over time.

We can't run forever. There are things which break down as we run that we simply can't rebuild until we stop and tend to these things. No one that I've ever met can process calories as fast as they burn them when they are running, and no one I've ever met can run continually without muscle fatigue catching up to them at some point. In running shorter distance races (probably anything up to 3 or 4 hours) we can get by more efficiently with stored energy than with energy we take in on the run. This is to say that calories we get from eating a gel doesn't offset the time we spend fumbling to open, eat, and digest the gel. Same can be said of water, although the time before we hit this tipping point is much shorter with water (depending on the temperature somewhere in the 30-90 minute range). In ultrarunning though, not only is it more efficient to take in lots of calories/water while we run, it's pretty much necessary.

Ok, by now you're probably wondering what the hell this has to do with shoes. Don't worry, you're not the only one confused. I've kind of gotten myself off topic such that I can't remember what the point was about shoes. Oh, wait, I've got it: I think the same idea applies to shoes. When you think of why we wear shoes: cushioning, stability, protection - these are all things which we can get by without much of for some period of time, but if you go long enough you will hit that tipping point when the extra weight you are carrying around on your feet in the form of extra cushioning, stability, and/or protection begins to be offset by the time you are gaining from having less muscle fatigue and less damage to your feet. To some degree, the longer we run the more shoe we need to find this right balance.

In terms of what the "right' shoe is for a 50 or 100 mile race I think this varies a fair amount from person to person. For me the Montrail Mountain Masochist has been the "right" shoe for almost 3 years now. I have run almost every single step in these shoes since March of 2009. I think this shoe is nearly perfect in terms of it's balance between being lightweight but still enough shoe to help the body hold up after 50 or more miles. Any shoe I've worn that is much lighter (and thus has less cushioning) feels great for a couple hours, but then usually pretty horrible if I go much beyond that.

It's no secret that the basic trend in running shoes over the past few years has been minimal, minimal, and more minimal. In my mind many people are taking the minimal thing way too far. I think extremely minimal footwear makes a decent amount of sense for shorter distance running/racing, but for ultrarunning I think in many cases it's just not enough shoe for the amount of abuse that you're putting your body through running 100 miles on rugged trail. The trend that I see that I think is the most wreck less is that many runners seem to train in one shoe and then race in significantly lighter shoes. Again, in shorter distance races this makes perfect sense, as we all did this in track and cross country back in high school. But in my mind doing this in ultras is similar to trying to eat as few calories as possible during a 50 or 100 miler. I haven't yet seen a "low calorie" gel. Essentially that's what you're getting when you try to run 100 miles in super minimal shoes. It might be the perfect shoe for a half marathon trail race, but the point I'm trying to make is that the perfect shoe for a 100 mile race and a 13 mile race are not the same shoe.

Before I go any further I must say, Yes, I have read the book, and I think it's an entertaining read, and I think there are some benefits to some of the thoughts involving barefoot running. I like that the "craze" has turned so many new folks on to running. In terms of ironic fads I think running around town in foot gloves is way more beneficial than say, trucker's caps. But I'm not talking about a cute fad. The argument that prehistoric man ran barefoot so it makes the most sense for us to tap into this lineage of experience as barefoot runners sounds really great in theory, but it doesn't work in the reality of trying to run 50 or 100 miles on rugged trail as fast as possible. Instead this argument is akin to saying that at one time man didn't have clothing so we should roam around naked to give our bodies an opportunity to adapt to be able to better protect us from the elements. I guess this makes sense if you're hoping to be the last one in the nudist colony who's able to stay outside when the sun dips below the horizon on a winter afternoon. But no matter how much you get your body to adapt you're not going to be as warm as the dude next door who has on a pair of down pants and a down jacket. In this same way I can see the point that incorporating barefoot running into our training forces our bodies to adapt in ways that will make us much stronger barefoot runners, but I'm not, in this conversation, interested in that. I'm interested in what we can wear on our feet to be the fastest and most efficient we can be at the 99.9% of trail ultramarathons in which shoes are allowed.

One more rant about the barefoot thing: Think about it this way: when we run an ultramarathon we pick our feet up and place them down, over and over, hour after hour, hundreds of thousands of times. I don't give a shit what cavemen did when they ran. What I care about are the options available to me. I can either put my feet down on a couple centimeter thick piece of foam that has been engineered and re-engineered by thousands of shoe developers for the exact purpose of absorbing the impact of these hundreds of thousands of footsteps, or I can put my foot (or my foot wrapped in a foot glove) down directly on roots, rocks, pavement, gravel, or whatever else I encounter over the course of 50 or 100 miles. Any guesses as to which one I'm going to choose? I'll give you a hint: It's the same choice that every other runner I've ever met who is trying to turn themselves into the fastest ultramarathon runner possible has also chosen.

I do think it's important to think a bit about the bio-mechanics of barefoot running when choosing shoes, but in terms of the larger point I'm making here I think that is where the barefoot conversation ends. I just thought I should address the barefoot thing so as to avoid having dozens of responses wondering how I could ignore such an important part of the running footwear conversation.

Ok, so back to the larger point. How do we know then what is the right amount of shoe for us? In my mind there's no better method than good old trial and error. When you have the right shoe you'll know it. What you'll know even more is when you have the wrong shoe. If you're looking for somewhere to start I would say try to find the happy medium somewhere between what was popular 10 years ago and what is popular now. Somewhere in there for about 5 minutes the typical "popular" trail shoe made sense for racing ultras. The pendulum seemed to swing so quickly from over built "tanks" suited more for backpacking or thousand mile adventures to uber minimal flats that would be great if we were all back in high school trying to run 3.1 miles over grassy hills as fast as we can. My guess is that at some point the pendulum will swing back and you'll actually be able to go into any store and find yourself a nice solidly built pair of shoes, but not over built, weighing in somewhere in the 9-11 ounce range. I would even imagine that we'll start to see companies make shoes that are specifically intended for running ultras. I guess if I've made one point in this way too long post it's that I think the right shoe for ultras is quite different than the right shoe for shorter races. One could argue that Hoka has started the trend of making shoes that make sense specifically as ultrarunning shoes. Too bad they're so stiff that they're less comfortable than running in a pair of clogs. For now I would recommend just trying a pair of Mountain Masochist and then go up or down from there.

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