Nut consumption reduces risk of death

http://news.harvard.edu/gazette/story/2013/11/eating-nuts-reduces-risk-of-death/

by pg • 13 years ago

53 46 13 years ago

news.harvard.edu

mikehotel2• 13 years ago

Thanks for posting! The article from NEJM is at http://www.nejm.org/doi/full/10.1056/NEJMoa1307352#t=article. I didn't see a direct link to it in the Harvard Gazette news story.

jey• 13 years ago

Has a causal relationship been demonstrated from nuts to health, or is this only a correlation? Couldn't it be that health-conscious people are healthier on average, and they usually choose to snack on nuts instead of snacking on something unhealthy?

The line "individuals who ate more nuts were leaner, less likely to smoke, and more likely to exercise, use multivitamin supplements, consume more fruits and vegetables, and drink more alcohol" further reinforces my belief that there's just a confounder here, e.g. maybe being affluent and educated explains all of those. (Yes, including alcohol consumption: http://blogs.discovermagazine.com/gnxp/2010/05/people-of-cla...)

mikehotel2• 13 years ago

Reverse causality is another possible explanation for our findings, because people with chronic disease and poor health might abstain from nut consumption. However, we excluded participants with a history of cancer, heart disease, or stroke at baseline, and we suspended further updating of all dietary variables when participants reported a diagnosis of stroke, heart disease, angina, or cancer. Moreover, the results remained significant when we excluded the first 2 years of follow-up and added a 2-year lag period between nut-intake assessment and each follow-up period.

Indeed, clinical trials have shown that nut consumption has beneficial effects on some intermediate markers of chronic diseases, such as high cholesterol levels,3 oxidation,6,7 endothelial dysfunction,13 hyperglycemia,6,10 and insulin resistance.11,12

The above quotes from the NEJM article imply more than simple correlation, but the conclusion of that article stops short of stating that, specifically, "Nonetheless, epidemiologic observations establish associations, not causality, and not all findings from observational studies have been confirmed in controlled, randomized clinical trials."

Source: http://www.nejm.org/doi/full/10.1056/NEJMoa1307352#t=article

mtdewcmu3• 13 years ago

This study sounds like a waste of time. How you could ever follow up and prove that nuts have all those protective effects is beyond me -- as is why you would even think they do in the first place.

However, we excluded participants with a history of cancer, heart disease, or stroke at baseline...

Sounds like multiple regression, which is used to make insignificant statistics sound more plausible, by reducing the effect of a handful of confounding variables that the researchers happened to think of. That leaves behind any significant correlations plus the infinite number of confounding variables they didn't think of.

tomp• 13 years ago

Well, the correlation at least gives a great probability that nut consumption does not affect the health negatively!

jhuckestein• 13 years ago

In other words, the amount of nuts you eat correlates highly with the number of years you're alive.

recursify2• 13 years ago

"Risk of Death"... pretty sure it's still 100% :)

LearnYouALisp2• 13 years ago

:( I was going to say something like "So if you consume enough nuts, there is a 99% chance of not dying etc.."

mertd• 13 years ago

Instead of being snarky, you could have read the first sentence, which gives the time interval of the mortality risk.

recursify2• 13 years ago

It was a joke. I did read the article.

clumsysmurf• 13 years ago

"Because we lacked data on how nuts were prepared (e.g., salted, spiced, roasted, or raw), we were unable to examine the influence of preparation method on mortality."

Acrylamide forms on almonds when they are roasted ... not sure about other nuts. Its probably a safer bet that raw nuts are healthiest.

smackay• 13 years ago

Maybe, maybe not...

https://en.wikipedia.org/wiki/Aflatoxin

http://www.foodproductiondaily.com/Processing/Extrusion-cook...

The real issue with advice on foods is that it requires a great deal of judgement. Definitive statements that are actionable are relatively rare, and even then with a few years more research the advice can be turned completely on it's head, low-fat diets being the canonical example.

ekianjo• 13 years ago

The title is a joke, again. "Nuts consumption reduces risk of death" hinting at direct causation, and later in the article "The authors noted that this large study cannot definitively prove cause and effect". Can journalists stop linkbait titles ?

jonrimmer• 13 years ago

Maybe some do, but their articles don't get popular on Hacker News and other aggregators, for some reason :-P

adventured• 13 years ago

I always wonder how much substitution benefit plays into studies of this sort. That is, does just not eating really unhealthy foods get you 85% of the way there (with little doubt that the healthy fat in eg almonds, and the protein benefit, add positive value).

dschiptsov2• 13 years ago

My ass, it is nuts we all need, Harvard says so!

Tibetans who never saw a tree in a whole life must be died away long ago without a proper nut supply.)

Yet another example of a meme-based science.

dschiptsov2• 13 years ago

OK, ok, a non-falsifiable claim (which cannot be tested) of a assumed correlation (probably due to statistical error) instead of causation, without a proper cross-cultural validation.

tarekmoz• 13 years ago

This is nuts!

LearnYouALisp2• 13 years ago

Studies show that consumption of air prevents death. As long as you are consuming air, you will be alive.

mtdewcmu3• 13 years ago

Maybe they're comparing eating nuts with eating nothing. I would not doubt that nuts reduce risk of death under those circumstances.

leeoniya• 13 years ago

Tomorrow: "Nut consumption linked to obesity and depression"

Please, just let me live and die without reading another <some food> linked to <some health or disease> article. I don't mind stuff like "tuna shows elevated and unsafe mercury levels", but this constant stream of weakly correlated, never conclusive, always contradictory shit is mind numbing.

I don't understand why this is on HN front page...and getting upvotes!

[EDIT] ah, pg posted this.

TeMPOraL• 13 years ago

If you pick a small enough sample from a large enough population, you can link anything to anything. I'm pretty sure I could find that eating veggie foods is linked with mass shootings if I try hard enough.

Riseed• 13 years ago

According to data from five western countries, increased consumption of linoleic acid from vegetable oils is correlated with increased violence.[0] That's a great first step in proving that too many veggies are linked to mass shootings. I think you're likely correct that a carefully crafted study can find any link it seeks.

[0]http://www.ncbi.nlm.nih.gov/pubmed/15736917

kalleboo• 13 years ago

I think it was when I read that eggs will both kill you and prolong your life in the same day in two different newspapers that I stopped reading any "food health" articles. You can find contradictory articles for each and every claim, often based upon the same study!

pantalaimon• 13 years ago

But did you not take into account that they might prolong your life and then kill you?

capnrefsmmat2• 13 years ago

I bet you'd like this, then:

"Is everything we eat associated with cancer? A systematic cookbook review"

Most ingredients they studied had studies saying they increased the risk of cancer, along with other studies saying they decreased the risk of cancer. Combining studies, the overall evidence was basically zero.

http://ajcn.nutrition.org/content/97/1/127.abstract

code_duck• 13 years ago

Mmm... Haha. Not for me. I'm allergic to all the tree nuts they list.

wjnc• 13 years ago

Socio-economic status was not used as a covariate in this study. They report that this issue is smaller than in other studies because only health-professionals were in the study. Well at least for the economic part, there are pretty huge disparities within healthcare.

And then my other remark. In the appendix. Table S4: most of the confidence intervals overlap all the way from the 'no nuts'-group to the 'daily nuts'-group. I know you shouldn't focus overly on those intervals. But those splines don't look that convincing to me.

So considering you have a measured effect that is not that clear, where you really expect the "true" effect to be orders smaller than the reported 20% reduction in mortality, without proper controls in the studies for one of the largest effects (higher income >> longer life) and with lots of overlapping confidence intervals, I wouldn't bet my nuts on this study.

stonemetal• 13 years ago

Given all that I don't find: The researchers also accepted a grant from the International Tree Nut Council Nutrition Research and Education Foundation to cover the cost of analyzing the data. to be a surprise either.

http://www.npr.org/blogs/thesalt/2013/11/21/246549388/nuts-f...

spodek• 13 years ago

As much as I love the findings since I replaced nearly all my junk food with eating nuts I get at the bulk food store near me, you don't have to look into any detail to challenge the report. The funding would seem to indicate bias. From the article: "The study was supported by National Institutes of Health and a research grant from the International Tree Nut Council Nutrition Research & Education Foundation."

That said, if you eat chips, pretzels, candy and such and want to cut down, nuts work great. You can get them bulk online if no stores near you have them. At first they don't have the intense flavors and crunch of typical junk, but the more you eat them the more you find the subtleties in their flavors and textures, much richer and complex than chips and candy. http://joshuaspodek.com/variety-choice-manufactured-illusion

This fall I noticed the nuts I normally got tasted a lot more flavorful. I checked and it turns out nuts are seasonal, so they'll taste different at different times of the year, depending on where you source them. I should have known that, but I enjoyed learning it by noticing the taste. I wouldn't have noticed such subtlety without stopping eating junk food and I find catching those subtle complexities more pleasing than the intensities of junk food.

I throw a bunch on my oatmeal with chopped fruit and chia seeds for a great breakfast that takes less than a minute to prepare. http://joshuaspodek.com/fitness-beliefs-habits-part-2

The mix I get has cashews, almonds, hazelnuts, brazil nuts, and pecans. So much better than pretzels, chips, or candy.

The pecans I don't put in the cereal or eat with the rest. They taste so much better to me. I eat them one at a time so I can savor them specially.

capnrefsmmat2• 13 years ago

Testing whether confidence intervals overlap is a poor test for statistical significance -- confidence intervals can overlap and still represent a statistically significant difference between groups.

http://www.refsmmat.com/statistics/significant-differences.h...

Skimming through the paper, it appears they did not correct for making multiple comparisons. That will raise their false positive rate. Oh well...

thepoet• 13 years ago

Although this study was done on US population, nuts are costly here in India so a large section of population cannot afford to eat it on a regular basis. Could it be remotely possible that poverty lead to diseases, improper or no treatments, more accidents etc. lower life expectancy rather than "not eating enough nuts".

Mr. Gates would surely start a Nuts for India campaign to increase life expectancy.

johnpowell• 13 years ago

Nuts are expensive in the USA too. The same goes for anything grown here that isn't frozen.

I can get a big pizza from the freezer for six bucks. It is double that for individual ingredients to make a salad. And we wonder why healthcare costs are absurd.

_delirium• 13 years ago

Peanuts are dirt-cheap in the U.S., one of the cheapest sources of calories and protein (they're not a proper nut, but included in this study anyway).

vixen99• 13 years ago

Are nuts (about 40% protein) expensive? Compared to what? I don't know about prices in the US but in Europe I would say they're a cheaper source of protein than meat (turkey breast around 30% protein, for example).

Google Scholar lists numerous published papers indicate benefits from eating nuts though there doesn't seem to be a coherent story as to why this should be so - yet - though I may have missed it.

aestra• 13 years ago

Calorie wise nuts are not that expensive. A handful of almonds is 200 calories and only costs less than a dollar.

jbert• 13 years ago

It's interesting that the population seems to be very critical of any food-health articles, presumably from over-saturation of poor science reporting. (Best example of this I know of - http://kill-or-cure.herokuapp.com/ - a study of things the UK's "Daily Mail" "newspaper" has claimed cause or cure cancer, many are in both categories).

But it is also clear that what and how we eat has a significant effect on our health, which is interesting and relevant to us.

How to sort the wheat from the chaff?

A "truth database" or factchecking site might be pretty useful. Or would it just boil down to "eat your vegetables and do a bit of exercise"?

eurg• 13 years ago

Don't forget: Eat not too much, and not too little. Sulfuric acid is not healthy.

Yes, it's mostly that. When I started reading around in preparation of living vegan, I was slightly surprised how well people can live from different diets. From almost pure meat-based, to pure plant-based, much fat, little fat, one meal a day, five meals a day, much carbs, few carbs...

It seems that the modern US-European food-style is one of the few diets which mixed and matched together stuff in a really bad way.

ck2• 13 years ago

correlation != causation

http://en.wikipedia.org/wiki/Correlation_does_not_imply_caus...

bobowzki• 13 years ago

Risk of death still 100%

jgeerts• 13 years ago

I'm allergic to nuts, either way I'm screwed.

pawelkomarnicki• 13 years ago

Eating nuts people have no time to do stupid things, simple ;)

Nut consumption reduces risk of death

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