There’s scant evidence that healthy foods prevent cancer or fatty foods cause it

http://www.startribune.com/lifestyle/health/256766501.html

by tokenadult • 12 years ago

76 60 12 years ago

epistasis2• 12 years ago

This shouldn't surprise anyone...

People need to realize that research publications are not textbooks. They are communications to other researchers about the way that the evidence is pointing, that helps them design new experiments, that justifies expensive and spendy clinical trials, which eventually find conclusive evidence.

The idea that one can open a science journal and find interpretable truth revealed is a pernicious one. Trust that the data is true, but do not trust the models or the conclusions. Everything is in flux, and it's science because we likely don't know what the real world is like yet.

History will go back and pick out the key experiments and construct a path of discovery, but in real time almost nobody knows what the most important experiments truly are.

This makes for difficult journalism, but one should remain true to the physical world rather than the narratives that are easy to squeeze into 500 word news blurbs.

001sky• 12 years ago

This is all true, but the atricle says something quite different than what you are commenting on. The "original findings" which are being reversed were based on 4,000 pieces of peer-reviewed research.

After reviewing more than 4,000 studies, the [1997] authors were persuaded that green vegetables helped ward off lung and stomach cancer.

It's easy to dismiss a single instance as an arbitrary data point. When you can dismiss a large portfolio of such points--you have another problem. That problem is a core-weakness in methodology/approach/and institutional incentives. That seems to be the larger issue highlighted here.

epistasis2• 12 years ago

Well, the sentence immediately preceding that one gets it right:

The situation seemed very different in 1997, when the World Cancer Research Fund and the American Institute for Cancer Research published a report, thick as a phone book, concluding that diets loaded with fruits and vegetables might reduce the overall incidence of cancer by more than 20 percent.

With "might" being the most important word there. These 4,000 studies were all retrospective analyses, and retrospective analyses only find conclusions of the "might" sort, which is well understood by the scientists, but not so well communicated by journalists.

Still, a 20% "might" is a an absolutely enormous amount of potential upside in cancer prevention, even a "maybe" of this magnitude justifies great excitement. Which is why they embarked on the prospective study, which is the real story here.

It is absolutely ridiculous to conclude that there are methodology or misaligned institutional incentives based on this case, it's exactly how things should work. It's just another example of scientists being blamed by bad reporting that they have no control over.

That said, there are many other cases where methodology is wrong or institutional incentives are wrong.

frozenport• 12 years ago

You need to weight them by quality, from experience in my field of E&M the papers with 2k citations are correct and the ones with 4 citations aren't.

Also 4k papers is too much to go through by hand, so something else was done.

tachyonbeam• 12 years ago

It's not just that. There's a huge problem with selective bias here. People think that "healthy foods" automatically means good health, and bad health is automatically a result of processed foods, "bad health habits", etc. Bad health is your own damn fault for profoundly insulting mother nature by feeding your body Kraft Diner a few too many times.

News at 11: cancer is a natural occurrence. You could exclusively eat prime quality fish, raw organic fruits and veggies and still get a heart attack at 52 and cancer at 58. In other news, I seriously question the idea that paleolithic humans had incredible food wisdom and perfect health. They probably ate whatever the hell they could find at a given time of the year in their immediate environment, and that was probably hugely lacking in nutritional value when it's the winter, all the plants are dead and most animals hibernating.

I agree that making an effort to eat well is a good idea, but it doesn't make you immune to diseases, and diseases are not necessarily a result of bad habits. There is also a huge amount of conflicting information as to what is healthy food.

yaketysax4• 12 years ago

"News at 11: cancer is a natural occurrence."

So what? Something being "natural" has no bearing on whether it is favorable or preventable.

"You could exclusively eat prime quality fish, raw organic fruits and veggies and still get a heart attack at 52 and cancer at 58."

Of course it's possible. But if you had any amount of sense, you wouldn't be making conclusions from a single case.

"In other news, I seriously question the idea that paleolithic humans had incredible food wisdom and perfect health."

Who's making that claim? The claim most paleo advocates seem to be making is that you should eat food that the body is adapted to eating.

return0• 12 years ago

There's a great TEDx talk debunking the myths of paleo diets: https://www.youtube.com/watch?v=BMOjVYgYaG8

vacri• 12 years ago

Your comment suffers from the affliction that "if it doesn't completely eradicate -foo-, then there's no point at all". If there was a magic food that cut your chance of getting any sort of cancer by a factor of 1000, your statement of 'you could still get heart attack/cancer in your 50s' would still be true.

The main article does this a little as well; there's something of a tone that says 'healthy food has all these other benefits, but since it doesn't stop cancer, it's probably not worth it'. It's weird, because I've never heard of anyone specifically choosing foods because of their reduction in cancer rates - people tend to choose foods that affect their current wellbeing, not future 'maybes'.

stephengillie• 12 years ago

I think what caused such robust health among paleolithic humans is they didn't drive. They had to walk everywhere. Literally miles to find food.

justsomeguynpdx2• 12 years ago

Well, there's this: http://www.clinicalepigeneticsjournal.com/content/3/1/3#B1

commentzorro• 12 years ago

Off to the right there's a picture of a bathroom scale. When you click on it it opens up to ... a larger picture of a bathroom scale. I don't know why I found that so funny but I laughed for a good solid minute.

EGreg2• 12 years ago

Cancer is like a random process. When enough mutated cells gets into a certain neighborhood of events which lead to cancer, that's how it starts.

When I went to Aruba with my friend, a sailor there told us that most sailors eventually got melanoma from being out allthe time. That's what made me realize this.

hamai• 12 years ago

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2515569/

revelation• 12 years ago

Only 5–10% of all cancers are due to an inherited gene defect. Various cancers that have been linked to genetic defects are shown in Fig. 2. Although all cancers are a result of multiple mutations (9, 10), these mutations are due to interaction with the environment (11, 12).

That 5% figure is much less interesting when you realize they mean _inherited_ genetic defects.

EGreg2• 12 years ago

Doesn't this contradict the original article?

wdewind• 12 years ago

Cancer is like a random process.
most sailors eventually got melanoma from being out allthe time

These two statements seem in conflict to me.

gohrt• 12 years ago

Why?

It's lke saying "Craps is a random. If you roll the dice at Vegas all the time, eventually you will lose your bankroll."

bluedino• 12 years ago

I thought it was sugar that makes your body acidic and that causes cancer...

yaketysax4• 12 years ago

I don't understand what's being reported on here.

"The reason for the change was more thorough epidemiology. The earlier studies tended to be "retrospective," relying on people to remember dietary details from the distant past."

So what? Which are the studies that are invalid? If none of them are invalid, then why disregard any information they might give us? 4000 studies with similar observations is not "scant evidence", unless you can rule out every single one. And are these 4000 the only studies which have similar conclusions? Probably not.

"These results were often upended by "prospective" protocols, in which the health of large populations was followed in real time."

I don't know what this means.

glenra• 12 years ago

In a "retrospective" study, you look at the past - for instance, you interview people and ask them what they recall eating over the last year, and see how that tracks with their current health condition. But memories are faulty and selective and easily influenced, so you might be operating from bad data. And the associations you find could be spurious for other reasons. So you can quickly reach some conclusions with this type of study, but they might just reinforce what people already believed rather than tell you what is actually true.

In a "prospective" study, you look at the present - for instance, you could ask a group of people to keep a food journal, measure their health at regular intervals, encourage some of them to make some changes, and see if the advice ends up making them healthier. The advantage is that you have MUCH more accurate data. The disadvantage is: (a) you have to wait many years before you can reach any conclusions, (b) most of the time the conclusion you discover is that the advice didn't help.

Retrospective studies can generate hypotheses but you have to TEST those hypotheses with prospective studies.

yaketysax4• 12 years ago

Ah ok. Had no idea how far back people were expected to remember. A few days might be fine. A year seems crazy.

Also I don't know why the author put prospective and retrospective in quotes. "Prospective study" and "retrospective study" are terms.

joshpadnick2• 12 years ago

The primary thrust of the article seems to be that because (1) the American Association for Cancer Research conference had a very small number of sessions on diet and cancer, and (2) a single follow-up study in 2007 concluded there was little link between diet and cancer that it must be true.

This is only one view and hardly comprehensive. If you read http://www.drfuhrman.com/library/vegetables_cancer.aspx by Joel Fuhrman, MD, you'll get a perspective on why the devil is in the details with many of these studies and why broad sweeping headlines like this one are often inaccurate.

Based on everything I've read on this subject -- The China Study, Eat to Live, and a few others -- I side with the Fuhrman article over the one published in the Star Tribune, a statewide newspaper for Minnesota.

joshpadnick2• 12 years ago

So, interesting follow-up as I researched this further. First, this article was just published last week in the New York Times (http://www.nytimes.com/2014/04/22/science/an-apple-a-day-and...). The Star Tribune was merely syndicating it.

Second, it looks like the Joel Fuhrman, MD wrote a direct response to this article: http://eathealthyandthrive.wordpress.com/2014/04/26/the-nutr...

It's on a random Wordpress blog here, but this was sent out to his eNewsletter earlier this week (though not posted on his website).

fthssht• 12 years ago

Certain kinds of fat are likely healthy. Certain population s of indigenous people thrived on high fat diets.

relampago5• 12 years ago

No mention of the demonization of fat and promotion of artificial sweeteners and additives promoted and used to "fix" the fat problem.

paul_f• 12 years ago

The title of the article really annoys me. Not all fat is unhealthy. What is especially bothersome is that food companies are creating "low fat" foods by replacing fat with sugar, making them much less healthy than the original yogurt or sour cream or whatever.

teichman• 12 years ago

This newspaper article states "In 2007, a major follow-up [to the 1997 AICR report] all but reversed the findings." They don't cite the study or provide a link, but it's almost certainly the 2007 AICR report.

Fortunately you can take a look for yourself [0]. The published research findings are pretty much the opposite of the Star Tribune's claims that eating healthy has no effect on cancer.

These are the AICR recommendations:

    Be as lean as possible without becoming underweight.
    Be physically active for at least 30 minutes every day.
    Avoid sugary drinks. Limit consumption of energy-dense foods.
    Eat more of a variety of vegetables, fruits, whole grains and legumes such as beans.
    Limit consumption of red meats (such as beef, pork and lamb) and avoid processed meats.
    If consumed at all, limit alcoholic drinks to 2 for men and 1 for women a day.
    Limit consumption of salty foods and foods processed with salt (sodium).
    Don't use supplements to protect against cancer.

[0] http://www.aicr.org/research/research_science_expert_report....

Edit: formatting.

DenisM• 12 years ago

That's odd. The same article was in New York Times, do you know how did they manage to get the opposite conclusions? Maybe it's a different study after all?

websitescenes• 12 years ago

No evidence, sources or credibility. Sorry but this article is just silly. This is an old world corporate fed point of view that is obviously incorrect.

atmosx• 12 years ago

I get the same feeling.

relampago5• 12 years ago

What's with a news source promoting misinformation?

Malarkey73• 12 years ago

This article (and some people here) seem to be mixing up the conclusion that particular so-called "super foods" are viewed with skepticism by oncologists. And a poor high fat high sugar diet is very clearly associated with cancer, diabetes and heart disease. In between these is a grey area of whether a slightly more healthy than merely adequate balanced diet is good.

Its pretty clear though that poor diet is associated with cancer.

relampago5• 12 years ago

complete bunk

relampago5• 12 years ago

A sensationalist title with no links to any studies cited.

Why the misinformation? Are we, the readers, expected to be so ignorant to think that foods grown in our gardens are equal (in health) to those found at our local fast food restaurant?

No mention of the relationship between genetically modified foods, artificial sweeteners, organic food, oxygen, etc to disease.

Another failure of the fourth-estate to inform the public.

#FAIL

ribs• 12 years ago

I find the evidence for your claims to be lacking. GM foods? Are you kidding me? There's no evidence that GM foods are bad for your health. Perhaps some evidence will turn up. (It's possible; I doubt it will happen.) But there is none. And organic foods? Come on, you're thinking like some ancient Greek who took Aristotelean "essential natures" seriously. Like you're going to paste bird feathers on your flying machine because birds fly so surely the feathers will help.

justsomeguynpdx2• 12 years ago

There's quite a bit of evidence that organic foods have higher levels of antioxidants. (This is not a first source, but it references quite a few) http://www.altmedrev.com/publications/15/1/4.pdf

"Organic strawberries had significantly higher total antioxidant activity (8.5% more), ascorbic acid (9.7% more), and total phenolics (10.5% more) than conventional berries (Table 2), but significantly less phosphorus (13.6% less) and potassium (9.1% less) (Table 1)." Organically managed surface soils also supported significantly greater microbial biomass (159.4% more), microbial carbon as a percent of total carbon (66.2% greater), readily mineralizable carbon (25.5% more), and microbial carbon to mineralizable carbon ratio (86.0% greater) (Table 6). These indicate larger pools of total, labile, and microbial biomass C and a higher proportion of soil total and labile C as microbial biomass. All measures of microbial activity were significantly greater in the organically farmed soils, including microbial respiration (33.3% more), dehydrogenase (112.3% more), acid phosphatase (98.9% more), and alkaline phosphatase (121.5% more). The organically farmed soils had a significantly lower qCO2 metabolic quotient, indicating that the microbial biomass in the organically farmed soils was 94.7% more efficient or under less stress than in the conventionally farmed soils [40]. These same differences, except for qCO2, alkaline phosphatase, iron, boron, and sodium, were also observed in soils from the bottom of the mounds (20–30 cm depth). http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjourna...

Glyphosate, used with GM soy, adversely affects good gut bacteria in poultry at levels of 5ppm while bad bacteria are highly resistant to it. http://www.netwerkvlv.nl/downloads/2012-Krueger,%20M-glyphos...

relampago5• 12 years ago

I'm just pointing out that none of these topics can be or were addressed head on by the author. He instead chose to infer by generalization that food is food, with no supporting documentation just a tactically written "scientific" opinion piece.

For evidence look into the work of Jeffrey Smith. Here's just a 2min clip of some of what you seek, http://www.youtube.com/watch?v=TvopGRiPHdE. Also check out Joel Salatin. Best of luck on your journey.

Cowicide• 12 years ago

Eating less and exercising more has worked pretty well for me, but that's not for everyone. I've also learned to see which foods give me more, sustained energy over time and which ones don't or even drain me. But, once again, I doubt that will work for everyone.

I'm also very skeptical of a lot of studies that discount things that are clearly working for me. For example, a lot of studies that discount fish oil tend to not take an enteric coating and proper absorption into account. Actually, after many years, I'm still waiting for those studies. In the meantime, I've seen the positive effects myself and will continue to use enteric coated fish oil as a supplement.

I've also watched countless friends, family and acquaintances try the Atkins diet only to yo-yo and see later problems develop. So, I'm not going to consume buckets of lard to lose weight. But, if the Atkins thing works for you, more power to you!

My conclusion is what works for me may or may not work for anyone else and vice versa. But, that said, I still look at some studies over time and try to glean some slight insight into what works and doesn't work for others and experiment here and there.

dj-wonk• 12 years ago

Unless an article compares various studies using a meta-analysis methodology (see https://en.wikipedia.org/wiki/Meta-analysis), I'm probably not going to give it much attention.

To summarize one key problem: journalists (and even some scientists) are prone to say two studies "disagree" if one demonstrates an effect and another does not. This is a problematic style of argument, because this kind of "disagreement" may be caused by random variation in sample sizes and/or differences in thresholds. You have to dig in to make an honest comparison and synthesis. This requires some basic statistical understanding, which apparently is lacking in many educational programs (but that is another thing!).

Please, if you do this kind of work or care about interpreting a set of studies collectively, go read the first few chapters from "Introduction to Meta-Analysis" by Borenstein, Hedges, Higgins, and Rothstein.

jpatokal• 12 years ago

Now this is what I call dogfooding your own recommendations:

That evening at a reception hosted by the M.D. Anderson Cancer Center, guests partook of a sumptuous buffet that included thick slabs of roast beef, a variety of rich cheeses and generous servings of wine. Afterward came the cancer research association’s grand celebration known for its dessert buffet.

charlieflowers• 12 years ago

Yeah, it had been 10 years since the first convention which got all preachy about healthy diets. So these folks had all that pent up diet-rebellion, and then the convention says, "Nevermind." They promptly went and pigged out.

nl3• 12 years ago

I don't think any credible health organisation or government body has ever claimed that what you eat has a serious effect on cancer incidence. I'm sure there are plenty of random books written by self-appointed experts who claim that though. They probably recommend coffee enemas for cancer treatment, too.

OTOH, heart disease has long been thought to be associated with eating high levels of saturated fat. Recent evidence is beginning to challenge that though[1].

[1] http://www.nhs.uk/news/2014/03March/Pages/Saturated-fats-and...

encoderer• 12 years ago

"Cures Cancer" is a high bar for anything.

Eat healthy food because you'll have a better life if you do.

Hell, just try it for a month. Don't eliminate carbs, reduce them. Don't skip meals, shrink portion sizes. Add veg that you've never used before. Instead of mashed potatoes, go for mashed cauliflower or (even better imo) celery root puree. Toss veggies in EVOO, salt, pepper and roast on a baking sheet at 425* until tender. Get high quality proteins and cook in a little fat with simple seasonings. Eat less than you do now. Just because you're not full doesn't mean you're hungry. I found that last lesson hard to learn.

aaron695• 12 years ago

If you read the actual title which seems much less misleading than the subtitle it tells a different story.

Foods aren't 'good' for you.

But it seems to fail to mention is the important bit. Some foods aren't bad and some food help stop you eating as much bad foods.

brc• 12 years ago

Diets are easy.

Don't eat anything that is advertised on TV. If an actor in a televised 30 second play convinced you to eat it, you probably shouldn't.

Apart from that, invest in good quality scales. When the numbers go up, change your behaviour until the numbers go back down again.

Oh, and quit making endless excuses in your head. They are just lies you tell yourself. If you really want to be healthier, than just go ahead and do it.

There’s scant evidence that healthy foods prevent cancer or fatty foods cause it

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