> "If someone asked me to put together a presentation on the value of drinking milk, I could put together a 1-hour presentation that would knock your socks off. You'd think, 'Whoa, everybody should be drinking more milk.' If someone said do the opposite, I could also do that.
Pretty much sums up the state of nutrition science.
I wonder if the scientist in question doesn't know of the possibility of confounders, didn't mention them to the reporter, or the reporter just didn't think that was exciting enough to include in the article. It seems just possible that there is something about 1% fat milk drinkers that is different from 2% fat milk drinkers, which causes them to drink 1% fat milk and which also causes them to have longer telomeres. Unfortunately, there is no link to the study, so we can't see what was controlled for. But if I were a betting man I'd bet that most of the difference is caused by other causes than the difference in milk drinking.
I think this is correct. The non-milk-drinkers had telomere lengths between those of the reduced-fat and the full-fat groups, which leads me to conclude that among milk-drinkers, those who go for the reduced-fat milk tend to live a healthier overall lifestyle. Those who go for the full-fat milk tend to live a less healthy lifestyle. The non-milk-drinker category is a mixed bag, since the preferred-fat-percent variable is lost.
Alternative hypothesis: People who choose to trade flavour for lower milk fat tend to also be more risk-aware, prefer a healthier lifestyle (don't smoke, work out) which contribute to slower telomere shortening.
People who chose flavour over lower milk fat would probably self-describe as "living the moment", likely tend to favour short-time gratification more, and do more activities that lead to faster telomere shortening.
Obviously this is an anecdote, but what's ironic is that in my life, the "generally healthier" people all opt for either whole-milk or alternative kinds of milk (almond, oat, etc.), whereas the overweight people I know almost always opt for skim milk.
I am a pretty active person and health-conscious, and in my group, we all typically agree that we aren't fond of the substitutes made in skim milk.
No doubt. If I could get a diet burger and diet fries, same quantity, about the same taste, sure I would. Diet soda seems just as good from what I can tell. A veggie burger is nowhere near as good as a fat greasy hamburger.
That's why it's so hard to figure out the long term effects of a lot of foods. People who do/don't eat X, tend to make other choices as well, which can easily have a bigger impact than X itself. Plus people are notoriously unreliable in accurately reporting what they eat and do.
We'd need to have long term randomized controlled trials where the only difference between groups is the one variable. Which there's no ethical way to accomplish.
So unless we figure out some other method, I suspect we'll never really know about many things in nutrition until we have fully accurate human simulations...
Serious question - would it make these studies more accurate if in addition, the scientists were also able to control for differences in dna? ie, maybe protein absorption is not as good in a significant amount of the tested population for this study.
Much of food science and the media reporting about it is thoroughly co-opted by the foods industry. See also the stories about pushing fat rather than sugar as the cause of obesity in the US.
I have a friend with a Phd in food science who went to work for General Mills. He quit 6 months later because all the projects he was given were essentially "Figure out how to make product X with cheaper materials J,K, and L and have it taste the same."
The 6 or so existing conglomerates/holding companies that own the food products industry are all about their own profits, not about health or telling the truth, and they'll do whatever is necessary to keep those profits intact.
True, and my frustration probably shows. I shouldn't rant.
Maybe the finding is drink whole milk until 18 to lower risk of obesity then switch to 1% to slow effects of aging.
What I'd like to see is a reliable source that synthesizes recent, reproducible research into cogent diet recommendations. Anyone aware of such a source?
In the meantime, I'd prefer not to be pestered by narrow tree-instead-of-the-forest articles that seem to be published every week with hyperspecific diet research. Up to me to ignore them I guess instead of ranting.
Still I thought this was an especially poignant example of research popularized just a few weeks apart that could understandably leave many people wondering what action to take or reducing confidence in diet research in general.
There's a study I want to see. Mortality rate broken down by cause compared to health enthusiasm rated by sect.
Or even simpler, compared to book ownership. Pick a few hundred of the most popular health books and track a population of owners and their cause of death or significant health events.
Just opened the study and read a bit about the methods and I wonder why they didn't include people that do not drink milk so the telomere lengths could be compared.
We cannot know if milk (in general or 1%) is causing aging or protecting against it, cases which point for very different conclusions.
This table also has something interesting that corroborates with this idea:
Note how the ones that rarely drink any milk have the same telomere lengths, same as the ones that drink full fat or 2% milk. SE is also so big for 1% and non-fat on the "rarely" row that telomere lengths can be considered to be the same for all the columns (on this row).
It makes me wonder if it's the milk or if there is any other covariable that is playing a role here. In fact, they themselves cite this in the study ("Discussion" section):
"However, it is possible that other dietary differences account for some of the biological aging differences among the milk fat categories."
Therefore, I'd take this study with a grain of salt. If anything can be concluded by these numbers is that 1% milk may be protective, not that full-fat milk promotes aging.
I hate food science, Just few weeks back had switched from 1% milk to full fat milk by reading one another article which states opposite. That sugar lobby has demonised fat and actually consuming non skimmed milk reduces craving. So you do less beinge eating. Now this is opposite!!
I know everyone's reaction (mine included) was: "No shit, people who drink low-fat milk probably live healthier lives in general"... But it looks like they really did account for other variables and found that milk-fat percentage was the only strong factor in play:
> "High-fat milk consumers may have lifestyles that are less healthy than low-fat milk drinkers. Since this possibility was recognized before the onset of the investigation, statistical adjustments were made for a dozen potential confounders. Statistical analyses determined that these variables had little influence on the milk fat and telomere relationship. Nevertheless, other variables could explain some of the relationship between milk fat intake and telomere length identified in the present investigation."
Okay, but let's stop and think about it for ten seconds: Of course drinking a slightly different brand of milk doesn't make you live 4.5 years longer; the headline claim is obvious nonsense. (And as I understand it, it's now thought that to the extent there is any difference, it's in favor of the high-fat milk.)
So then the conclusion seems to be that confounding factors have an extremely strong effect on the conclusion, even when the investigators have tried hard to screen them out.
Why? What went wrong with the attempts to screen out the confounding factors?
To be fair, it's a pretty large claim to just assume that something "went wrong with the attempts to screen out the confounding factors" and that the conclusion must be false.
It's a shocking conclusion, I'll give you that. And to be honest, I'm not convinced either. You might very well be right. But it's a strong claim to make agains a peer-reviewed journal publication.
> But it's a strong claim to make against a peer-reviewed journal publication.
Remember that peer-review only means that two or three persons had read the manuscript and found no obvious error and think it's inteligible and interesting. It doesn't mean that the reviewers had reproducer and checked all the details.
It is more trustworthy that a webpage in all-caps with white text over a black background, but it depends a lot of the journal. There are serious journals, and there are crappy journal that publish any rubbish if you pay them.
This is not may area, so I'm not sure. I looked at the other articles published in the journal and they look fine, but this is not my area. (Crackpot articles tend to aggregate, so looking at the other articles is sometimes useful.)
It's is very strange that an article about 5834 persons has only one author. Again, this is not may area, but I'd expect 5 or 6 authors. (The other articles in the journal have multiple authors.) It's not a smoking gun, but it's very strange.
In the article, the more interesting part is table 4 https://new.hindawi.com/journals/omcl/2019/1574021/tab4/ It looks fine. I didn't redo all the calculations, but it looks fine. (It may be a professional defect I have, but for me most articles are "Bla bla, bla bla, important table, bla bla.".) The table looks nice.
Also, they are measuring telomere length, not a self reported coefficient. I never trust self reported data. (Some of the covariant they use are difficult to measure like "percentage of total energy derived from saturated fat". How did they measure that? Anyway, I don't expect that to be a problem.)
It's important to wait until the study has been reproduced. (Exact reproductions are difficult to finance and publish, but you can make a twist. For example comparing the four combinations of normal vs cocoa milk and 1% vs 2% milk.)
@GP: Note that the (research) article does not claim that you live 4.5 years longer. They claim that the telomeres are reduced approximately 145 bases, that is somehow equivalent to 4.5 years of aging. Probably having 145 less bases in the telomeres increase some illness, but I doubt it affect too much the accident death rate.
I am inclined to think genetic signature matters. Is the lengthening of telemores a genetic thing? I am not sure if that’s even a right question to ask.
Isn't milk such a small part of most people's diets that it couldn't possibly have much of an effect? Especially for adults. Most people I know just put a bit in coffee and that's about it. I can't remember the last time I drank a glass of milk.
(Note I mean milk the drink, dairy is probably a big part of diets but that's not being studied here)
That was also one of my initial thoughts. But who knows. I'm sure milk consumption varies a lot in different geographies, cultural backgrounds, upbringings, etc...
I personally never drink milk. The only dairy product I regularly consume is butter. But I had a roommate who drank a glass of milk with dinner every day and occasionally had a bowl of cereal in the mornings. So It's at least a spectrum.
Serious question: is 1% milkfat known to be "more healthy" than 2%? The body needs fats, and the USA (most of all) is still recovering from an unhealthy fear of fats instilled by the megacorps the past ~30 years.
[me: grew up drinking 2% until I was fully grown / 18yrs]
>Effect modification testing indicated that the milk fat and cellular aging association may be partly due to saturated fat intake differences across the milk fat groups. When the sample was delimited to adults reporting only high total saturated fat intake (tertile 3), the milk fat and telomere relationship was strong. However, when the sample was restricted to adults reporting only low saturated fat consumption (tertile 1), there was no relationship between milk fat intake and telomere length.
This is consistent with other research that found that vegans live about 10 years longer on average. It seems no-milk is even better for longevity than low-fat milk.
This is probably BS, another example of "correlation is not causation". Vegans most likely live longer because they don't eat horribly unhealthy foods like average people, and are much more conscious about eating healthy foods and having healthy lifestyle habits. They could do the exact same with meat, fish, dairy, etc. and probably get the same result.
The simple fact is that most people have unhealthy eating and lifestyle habits. So if you isolate one group that does much better on these because of their focus on healthiness, then of course they're going to be healthier and live longer on average. It doesn't mean than their particular food choices are optimal or necessary.
To counter your point, just look at Japan. It has the highest average life expectancy IIRC, yet vegetarianism there is pretty much non-existent, to the point where vegetarians (and especially vegans) who try to vacation there have a very difficult time. Meat and especially fish are huge parts of the diet.
The study is not causal, you can't say that no-milk is good for longevity, just that it's associated with it. Switching to no milk or low fat milk won't necessarily help you live longer because it could just as easily be other dietary choices.
These kinds of studies are worse than doing nothing because they lead people to believe that one small change could be the difference in your length of life when all they do is observe correlations. Hell, the guy even said he could easily argue for any conclusion about dairy that was asked of him!
India has the highest percentage of vegetarians of any country (at 38% of the population), yet they rank 128th out of 185 countries in life expectancy. Meanwhile, you look at the top 10 countries for life expectancy, and there's plenty of meat in the diet, including Hong Kong, who eat more fish and beef than Americans do, and Iceland, who consume at least 200 pounds of fish a year:
I am at the point where I don't believe any food or drug research and reporting has practical value outside cases where a linear relation between substance and effect is established and at a high enough dose the effect kills you.
The literature is full of fishing expeditions for premeditated statistically significant results. People seem to choose a belief set which is intuitively appealing to them (bonus points if it can make them feel like they are morally superior) and then write and share volumes which poorly represent weak research as gospel.
This report should say the opposite, more accurate "People with shorter telomeres prefer higher fat milk". There is no evidence presented that would indicate you can influence your telomeres by choosing different milk or that milk choice is actually the culprit.
Biology-substance-effect research and especially reporting is strongly biased towards telling a good story and the motivations driving that bias strongly devalue the results.
> We’ve been brought up to think that drinking milk is good for our bones, but new research suggests that not only is this false, but the sugars in it may actually be accelerating the ageing process.
The large scale China Study had negative finds on human's drinking milk intended as a baby cow growth hormone as well: "Dr. Campbell says that in multiple, peer-reviewed animal studies, researchers discovered that they could actually turn the growth of cancer cells on and off by raising and lowering doses of casein, the main protein found in cow’s milk." Ref: https://www.wellandgood.com/good-food/china-study-cheat-shee...
Dr. Jason Fung often shows a graph from a study showing that Osteoporosis increased in Greece over the years, correlated to the increase in milk consumption.
Not probable and highly likely to be confounded by secular and social cofactors. These dietary models and recommendations in humans are dumb “one size fits all”. We know from extensive animal research that genome-by-environmental effects are pervasive and can be large. For example in a highly diverse family of mice, a very high fat diet—60% calories from lard—is advantageous in terms of longevity in a few family members; although also true that this extreme diet is generally deleterious (see bioRxiv paper by Suheeta Roy and colleagues, GXE BXD study, 2019).
The contrast between whole milk and no-fat milk is a comparatively subtle dietary shift.
Extraordinary claims require extraordinary evidence, especially when they can impact millions of humans.
I hope people will follow the link to the actual research before commenting, because it addresses almost all of the objections that I’m seeing pop up repeatedly here: https://www.hindawi.com/journals/omcl/2019/1574021/
A smallish red flag from a scientist’s perspective is that the article was published by a publisher based out of a developing country. There’s nothing wrong with that per se, but in practice it often reflects a paper that for one reason or another couldn’t get published in more well-known higher impact factor journals
> "there was no relationship between milk fat and telomere length when total saturated fat intake was low, but the association was strong when total saturated fat intake was high."
Consumption of a near 0% fat cheese called Skyr has historically been high since the 11th century in Iceland. I do wonder if that may have had a role to play in our high average age expectancy.
Sadly our traditional food culture of Skyr, lean grass fed sheep and plenty of fish has given way to a more Americanized fast food culture. So it wouldn't surprise me if our averages will start trending downwards in a generation or two.
This is a useless research and doesn't prove anything.
Milk fat sourced from grass fed cows is actually pretty rich in healthy fats like Omega 3, CLA and Butyric acid. In fact many people who can't tolerate milk, can easily digest milk fats like butter and ghee which are devoid of the usual milk allergens (Lactose and Casein)
I kinda wish they'd speculated on a cause and effect chain here, but then we'd have a different group of readers upset.
I might also like to see results with other kinds of fats, to know if it's something about milkfat in particular.
There was a theory a while back that the lipid size in homogenized milk might be problematic for the human digestive and circulatory system, causing them to get into places they shouldn't.
If that were true, I suppose you could explain these results by showing a link between early cardiovascular disease (CVD) and shortening of telomeres. But it looks like we have a bunch of studies showing shorter telomeres leads to CVD, not vice versa (although we've gotten cause and effect backward before so who knows at this point).
Better yet, don't drink milk at all, it's unhealthy in the same ways as soda and fruit juice (milk does have a lot of sugar which I don't think a lot of people think about).
When it comes to studies that involve measuring telomeres as a result, I've always wondered: is telomere length such a foolproof measure that it can be used to make claims like this? Given two people who will live their entire natural lifespan and have no complications, will the one with shorter telomeres necessarily die first? Are there tolerances of some kind?
Does this study take into account other variables? The article also says that people who do not drink milk have shorter telomeres.
Could it be that people who drink 0% and 1% milk also eat fewer foods high in fat and sugar (or are more aware of their diet in other ways) compared to the average (i.e., those who do not drink milk and those who drink the most common milk available)?
I don't know enough about chemistry to say, but does steaming milk (like for a latte) have any effect on its health properties? I ask because for milk based coffee drinks you really want to be using whole milk. There are no taste and texture options that get anywhere near it.
My immediate thought is, those who grab the 1% milk at the grocery store are more likely to make other healthy decisions as well. Can anyone comment on whether the study adjusted for this?
My immediate reaction as well. Seems like the perfect case of confounding. But after reading the paper, I saw this statement:
> "High-fat milk consumers may have lifestyles that are less healthy than low-fat milk drinkers. Since this possibility was recognized before the onset of the investigation, statistical adjustments were made for a dozen potential confounders. Statistical analyses determined that these variables had little influence on the milk fat and telomere relationship. Nevertheless, other variables could explain some of the relationship between milk fat intake and telomere length identified in the present investigation."
They didn't go into great detail as to what those confounders were, but it looks like they took that into account and isolated milk-fat percentage as well as they could. Source: https://new.hindawi.com/journals/omcl/2019/1574021/
Exactly. As I said, they didn't reveal much of the process that "accounted for confounding" but I just wanted to dismiss everyone's initial reaction that this is just an obvious case of confounding.
Perhaps it is. Perhaps it isn't. It just depends on how much you trust their methodology.
I had the same thought. What other foods have an effect on telemores length?
[..] Telomere length is positively associated with the consumption of legumes, nuts, seaweed, fruits, and 100% fruit juice, dairy products, and coffee, whereas it is inversely associated with consumption of alcohol, red meat, or processed meat.[..]
If you don't look at the study, how will you know if they accounted for that or not? There are techniques available to control for correlations like that.
> There are techniques available to control for correlations like that.
If we knew all the correlations, we might stand a pretty good chance of controlling for them, but we don't know them. We might hypothesize that drinking 1% milk is associated with higher rates of exercise, and we might go out and measure that against a control group. But what if it's also associated with drinking less alcohol? Or not smoking? Or anything else.
We don't know all of the correlations, because human beings are complex, and we can't hold all other variables static, which is why nutrition science has been so abysmal. Only if we first hypothesize the correlation, or collect the data necessary to make the connection, can we even attempt to control for it.
That's not really the point. They attempted to control for demographics, and for dietary covariates like protein, total dietary fat, fiber, and saturated fat. But that is a tiny sliver of the possibly correlated factors.
Did they control for the possibility that 1% milk drinkers learned to drink 1% milk at a young age, and that population happens to live in areas further away from sources of pollution, even in comparison with other households in the same income quintile? Did they control for blood lead levels in childhood?
The point is that we don't know what the covariates are. We have no way to even approach the problem.
I'm with GP. I'd read the study if they did an experiment - randomly assigned milk to people and watched the impact - but there's too little value in these purely observational studies from nutritionists. The field hasn't grown up yet.
> There were a dozen covariates controlled in the present study (age, gender, race, household size, smoking, body mass index, MET-minutes of total physical activity, alcohol use, grams of protein consumed per kilogram of body weight, percentage of energy derived from dietary fat, grams of dietary fiber consumed per 1000 kilocalories, and percentage of total energy derived from saturated fat.
How would one handle that many factors? I am very curious what the techniques for doing so would be.
I'm no expert but my initial reaction would be that you need more than 5834 adults in a study that controls for all of those factors. We don't really know how household size, for example, would affect the results, so wouldn't you need a bunch of test data to analyze all of the combinations? Or did they only study people who are the same in most of them? (i.e. 45, male, with a household size of 4, nonsmoking, etc...)
Would love to hear from someone more informed on this than myself.
It depends on the effect sizes, but in most contexts 5k participants is considered a very sufficient sample. You don’t need millions of participants to study things like this.
The actual paper seems inconsistent and contradictory. For example, from Section 4:
> Fourth, adjusting for differences in demographic, lifestyle, and dietary covariates has little influence on the relationship between milk fat intake and biological aging. Fifth, there is no relationship between milk fat intake and telomere length among adults who consumed low levels of total saturated fat (tertile 1), but it is strong among adults who consumed moderate or high levels of total saturated fat.
There are of course other confounding variables that this study likely does not take into account (whether because they can’t measure it, or they chose not to include it)
True, the article at least doesn't mention if milk fat consumption correlated with other health factors. It mentions that the study considered frequency of consumption, but doesn't say if that affected results. Like much science reporting, it makes more questions than it answers.
In my opinion, drinking nonfat milk is a strong indicator that you're willing to follow dietary advice even if it's unpleasant. I can't stand the stuff.
Same here. Low-fat/nonfat milk tastes of nothing. I'd rather drink water. I found it works best to hydrate with actual water (ie. drink enough water to never feel thirst) and then if I want the taste, I'll just have a glass of full fat milk.
As soon as any behavior is widely reported as healthy health conscious people will start doing it and if there wasn't a correlation before there will be now.
If you're exercising so you can make big concessions in your daily diet, you're delusional. Take a look at the calories you burn doing high intensity exercise vs. those in your preferred dessert.
Not saying it's a good or bad decision, just that it's what motivates a lot of people. Who otherwise probably wouldn't exercise as much or at all. And that to presume a (near) universal correlation between eating healthy and proper exercise is wrong.
Drinking no milk at all is best! Reducing dairy intake reduces Parkinson's disease rate[0], reduces hip fracture rate[1], reduces twinning offspring rate in women[2], and may even reduce Prostate Cancer[3]. You really don't miss it after a while, and the most annoying thing is modifying your restaurant orders to remove all the cheese :/
Pretty much sums up the state of nutrition science.