Biomarkers of dairy fat intake, cardiovascular disease, and all-cause mortality | Hacker News Reader

Biomarkers of dairy fat intake, cardiovascular disease, and all-cause mortality

journals.plos.org

89 pointsKaibeezy56 comments

This aligns with some other stuff I've read. But it's not necessarily the case everywhere - apparently there's a suspicion that the difference between dairy from grass fed and grain fed cows may be a big factor in the differences that different studies report. In Europe, Australia, New Zealand, etc. most dairy is grass-fed, which apparently makes it much higher in fat soluble vitamins (especially K2), Omega-3 fats, Conjugated Linoleic Acid, etc., some or all of which may be more-than cancelling out any negative factors from things like the saturated fat, so most studies with cohorts from these regions show dairy to have some net positive effect to health long term. Whereas the studies that show increased cardiovascular risk tend to be more from places like the US, where dairy cows are apparently more likely to be fed from soy etc. (It may also be a factor that more dairy in the US is probably more sweetened too, like yoghurts etc.?).

Apparently removing fat is also a bad thing if you're starting from good dairy, because you're also taking away a lot of the really good fat-soluble vitamins. But if you're starting from grain-fed dairy that doesn't have much of that to start with, reduced fat dairy is perhaps better.

This article is quite well referenced and mentions these points in a few of the sections: https://www.healthline.com/nutrition/is-dairy-bad-or-good

Thanks for the additional perspective and positive info on Euro dairy. I saw the oversimplified “dairy fat good” analysis on regular media, which made me happy but then instantly realize there’s probably a lot more to it than that.

Yeah, from my research a lot of dietary stuff is like that. I have tried to completely overhaul my diet over the last year or so to be healthier, but there seem to be so many confounding variables that it can be really hard to make firm conclusions for a lot of things.

But yeah, the answer to a lot of things does seem to be "it's complicated". Take the "fat is bad" narrative - was always massive oversimplification, and it really depends on the type of fat - some fats (like monounsaturated and Omega-3 fats) it seems we really should be eating more of, not less!

I suspect a lot of foods that used to be healthy are now unhealthy because they're factory farmed, or have had a lot of nutrition bred out of them due to breeding for looks or high sugar instead.

Even vegetables are bad for you if bred to be high in sugar.

So are cows in Europe, Australia, New Zealand fed 100% grass throughout their life?

In New Zealand, dairy cows, no. Probably 80% - 95%. Many, perhaps most, herds will be 100% pasture fed (grass/clover mix, or just grass.)

There is often supplementary feeding of palm kernel (the solid bits of palm oil seeds left over after the oil is pressed out) maize, and/or lucerne.

Beef cows, these days, yes, almost all. It's part of the branding the country's big meat packers are going for (100% grass fed).

Not 100% but a very large majority of their feed would be fresh grass or silage[1]. If you can't make a profit feeding them grass why are you raising cattle? The economic calculus changes a lot if animal feedstock is highly subsidised like soy or alfalfa in the US but for all its many, many flaws the EU's common agricultural policy is mostly about things people want to eat.

[1] Less confident about this for Australia but I still think that's true.

Frankly, the same is true in Northern California. I see lots of cows out to pasture at all times of year. I'm sure there must be somewhere in the country where it's cheaper to feed grain (or too cold to go outside?), but even with the crazy land prices out here it's cheaper to feed them grass. It's the same price as everything else:

https://cloversonoma.com/

In NorCal there would be more demand for “better” cow products from local grass-fed cows/steers, even if more expensive, right? Some of those West Marin cows have a heck of a nice ocean view while they graze.

This has been going on for a long time. I imagine it’s simply because you can’t really grow crops on the hills but you can use them as pasture.

There are plenty of large concentrated feed lot dairy operations in Northern California as well. Take a look over here, for example, there are several: https://www.google.com/maps/place/36°44'03.7"N+120°14'28.2"W (switch to Satellite view)

Yep, that's Fres(hell)no, the very definition of Central California. Welcome to COVIDlandia! Not much water unless you got rights 100 years ago either. At least they don't grow as much rice in that part of the desert.

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

I believe it is always cheaper to feed cows grass. The grain is more expensive, but fattens the cow up and produces better marbling, and most would say better taste. That is why it is done.

How can this work, then?

https://www.kerrygoldusa.com/irishgrassfed/

What is confusing you? If you explain what you find puzzling i can try and answer.

Uhm. IIRC the statement that the economies of scale, and subsidies make it economically infeasible (the grass feeding, mostly), and then a company advertising irish dairy products shipped over the ocean (guess they don't do air freight).

I said that a very large majority of at least West European and Kiwi cows' feed is grass so we're in vigourous agreement on the economic viability of grass fed cattle agriculture. If other people think that can't work you provided a good existence disproof.

Oh!

I am skeptical of this idea of "good dairy" and "bad diary". Especially the corn fed/grass fed distinction. It would be nice if you had some studies to back up the claim that corn versus grass fed dairy makes a difference in long term health outcomes rather than just pointing out that there is small difference in omega-3 levels in corn-fed versus grass fed beef. To the best of my knowledge, the science on this is very mixed at best.

Dairy is bad in general. It is proven to increase biomarkers of oxidation and inflammation.

It's the most common food allergen by far, but mostly causes very mild symptoms. a bit of stuffy nose, a bit of reflux, things like that.

Consumption of dairy in general is correlated with osteoporosis. Some hypothesize this effect is mediated by the osteolytic effects of chronic allergic inflammation.

BMJ study from 2014: https://www.bmj.com/content/349/bmj.g6015

Diary is inflammatory: "In subsamples of two additional cohorts, one in males and one in females, a positive association was seen between milk intake and both urine 8-iso-PGF2α (a biomarker of oxidative stress) and serum interleukin 6 (a main inflammatory biomarker)."

"High milk intake was associated with higher mortality in one cohort of women and in another cohort of men, and with higher fracture incidence in women."

8-iso-PGF2α is produced by inflammatory cells (mast cells, etc). You do not need to have clinically significant allergy to suffer from chronic inflammation.

> Consumption of dairy in general is correlated with osteoporosis.

Have some research that supports this?

Consuming dairy (for those who aren't allergic or sensitive) is one of the best ways to get keep calcium and vitamin D intake high, which is pretty important for _preventing_ osteoporosis (see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7353177/ as one example, I'm sure there are many other studies on this).

A quick search turns up contradictory results. I imagine it would depend on factors a lot of studies would not cover. As one semi related example, when I was extremely ill I found grass-fed organic meats less acidic and more tolerable than other meats.

I imagine the devil is in the details and this is likely part of why there end up being strong opinions on both sides where people with opposing views feel vehemently that both studies and firsthand experience agree.

People concentrate too much on mineral density and calcium/VitD when it comes to diary.

Chronic inflammation is the actual reason for negative effects of diary, but it is an fairly inexpensive energy-dense non-perishable food that sells great and most can live with chronic inflammation for decades right up until they need a knee replacement.

The "contradictory" results are simply an effect of a well funded industry.

Got milk?

The "contradictory" results are simply an effect of a well funded industry.

I've spent a lot of time in alternative med circles and spent a lot of years pursuing alternative remedies for my deadly inflammatory condition (many of them dietary in nature). I don't think it's that simple.

I think it makes a big difference how the cows are raised, treated, fed, etc. I've known people who swore by, for example, unpasteurized milk.

We do a lot of things to our food these days that mean that not all milk is chemically equivalent. That's my point.

You don't have to agree, of course. But don't pretend I didn't already say exactly that earlier.

you find some types of milk products help your condition?

I eat a lot of cheese. That's a milk product.

I also use a lot of butter. When I was sicker, I tried to stick to organic and even sometimes clarified it. It made a difference when I was really, really sick.

I'm not a big milk drinker.

According to your source, milk and other dairy foods are poor sources of Vitamin D. Its only after fortification with added Vitamin D that they become good sources. So, I dont see any reason to choose dairy over any other source of supplementary Vitamin D (yes, dairy has calcium, but so do many other foods).

Linked below are a couple from the well-referenced article I linked above. The differences in fatty acids, vitamins etc. is significant (e.g. 500% increase in CLA in grass fed).

The Vitamin K2 I think is very significant, because of the potential positive effects against inflammation etc. [3] - it comes from bacteria in the cow’s stomach breaking down nutrients in grass.

1. https://pubmed.ncbi.nlm.nih.gov/7905466/

2. https://pubmed.ncbi.nlm.nih.gov/10531600/

3. https://pubmed.ncbi.nlm.nih.gov/15514282/

None of these studies show any difference in health outcomes as a result of consuming diary from corn-fed versus grain-fat cows, which is what I asked for.

I am not ready to jump from observing in differences in chemistry of the milk to a difference in health outcomes without some data showing different outcomes as a result of consuming the different types of milk. There are just too many variables in play to make this conclusion. And if the data is so convincing, this should be easy to produce, no?

Studies on farmed vs wild caught fish and the impact diet has on end product of nutritional value are a good start

https://www.health.harvard.edu/blog/finding-omega-3-fats-in-...

Yes, those studies exist for farmed salmon. But here, we are talking about milk, not salmon.

Dairy cattle around me are primarily fed alfalfa. Would that be considered “grass fed”?

I also wondered about that... Isn't most "corn" fed to cattle actually silage which is fermented field corn, i.e. the WHOLE plant, not just the grain portion? And corn is actually grass...

Actually I did some reading and while silage is used, actual grain is used as well, look up cattle feed concentrate.

We gave your food the option to eat a salad — to wash down all of the sugar (grains).

Dairy is just bad in general, it's just that some people can tolerate it better than others. It's an inflammatory food.

BMJ study from 2014: https://www.bmj.com/content/349/bmj.g6015

"In subsamples of two additional cohorts, one in males and one in females, a positive association was seen between milk intake and both urine 8-iso-PGF2α (a biomarker of oxidative stress) and serum interleukin 6 (a main inflammatory biomarker)."

"High milk intake was associated with higher mortality in one cohort of women and in another cohort of men, and with higher fracture incidence in women."

8-iso-PGF2α is produced by inflammatory cells (mast cells, etc). You do not need to have clinically significant allergy or sensitivity to suffer from chronic inflammation, which can be silent.

Dairy is inflammatory: https://www.arthritis.org/health-wellness/healthy-living/nut...

As you can see, the Arthritis Foundation does not give blanket recommendation to eat diary "because cal/vitD". Instead they urge caution and even try diary elimination.

Another study, 2015: https://pubmed.ncbi.nlm.nih.gov/26674761/ "Directly Associated with Dairy Food Consumption and Low-Grade Inflammation in a German Adult Population"

Another one, 1994. “Consumption of dairy products, particularly at age 20 years, was associated with an increased risk of hip fracture in old age. (“Case-Control Study of Risk Factors for Hip Fractures in the Elderly”. American Journal of Epidemiology. Vol. 139, No. 5, 1994).

One more, from 1997. “Data does not support the hypothesis that higher consumption of milk or other food sources of calcium by adult women protects against hip or forearm fractures.” (Source: Feskanich D, Willett WC, Stampfer MJ, Colditz GA. Milk, dietary calcium, and bone fractures in women: a 12-year prospective study. American Journal of Public Health. 1997).

12 year long Harvard Nurses’ Health Study found that those who consumed the most calcium from dairy foods broke more bones than those who rarely drank milk. This is a broad study based on 77,761 women aged between 34 and 59 years of age.

25 years of results that point to no benefits at best, and corroborate association of diary intake and chronic inflammation at worst. Got milk?

Isn’t there a confusion between milk and all other dairy products? I know plenty of people (me included) that never consume milk but eat cheese and butter. Unfermented milk high in lactose seems to have a very different nutritional profile.

I heard it’s the same for eggs, their omega-3 to omega-6 ratio can completely change depending on how the chicken are fed, even maybe their activity.

It's important to point out that this isn't dairy as a whole, or on its own, that the researchers were looking at here. This is strictly about dairy fat.

Keep in mind that there is a mechanism of action that explains why the consumption of mammalian food products (including dairy) significantly increases risk of chronic inflammation, heart disease, diabetes, and cancer in humans: the autoimmune response of dietary N-Glycolylneuraminic acid (Neu5Gc) uptake in human cells.[1]

Neu5Gc is a sialic acid which tend to exist on the ends of proteins.

1. MedCram's video which explains the biochem and physiology that describe this mechanism of action and how it relates to the 4 conditions mentioned above: https://www.youtube.com/watch?v=xRkRilP1OTU

> Keep in mind that there is a mechanism of action that explains why the consumption of mammalian food products (including dairy) significantly increases risk of chronic inflammation, heart disease, diabetes, and cancer in humans: the autoimmune response of dietary N-Glycolylneuraminic acid (Neu5Gc) uptake in human cells.

That's interesting but wouldn't the consumption of dairy fat be very strongly correlated with the consumption of dairy? And these folks had lower bouts of heart disease, not higher. Do you know how much this autoimmune response is associated with red meat as opposed to dairy?

Quite literally nobody in the entire world knows that exactly. This is as close to bleeding edge as you can get, it's an ongoing area of research.

"detailed underpinning immunological mechanisms were not fully known"

https://www.frontiersin.org/articles/10.3389/fimmu.2019.0162...

If I die earlier due to my love of dairy, well that's a price I'm willing to pay.

I think you misread the study. It’s claiming the opposite:

> In a meta-analysis of 18 observational studies including our new cohort study, higher levels of 15:0 and 17:0 were associated with lower CVD risk.

Give it 5 years. They'll be saying the opposite. And in 10 they'll be back to what they're saying today.

There is no "they" here, it's a meta analysis involving many scientists in different countries.

There is absolutely a they. There are many, many plausibly neutral choices involved in choosing how to collect and analyse data. There's no view from nowhere. Science is a process more than a result.

Lower CVD risk, but higher all-cause mortality than those who had lower levels (closer to median).

If I die earlier due to my love of methamphetamines, well that’s a price I’m willing to pay. /s

In all honesty people cannot perform a cost/benefit analysis without accurate cost data.

There are a variety of unique constituents of dairy fat not found in most other saturated fats, including most meats and seeds. The odd-chain fatty acids are one example. Short-chain fatty acids are another. Conjugated linoleic acid and vaccenic acid are technically trans fats, but they're polyunsaturated, and studies in animal models suggest beneficial effects — the main post-hydrogenation trans fat eliadic acid is monounsaturated and linked to heart problems. SCFAs may increase fat metabolism (this is dubious).

So it's plausible that dairy fat may have effects different from saturated fat on the whole.

Take anything in PLOS Medicine with a large dose of NaCl...

I did some poking around on this and found that while PLOS is different than something like JAMA or The Lancet, I didn’t see where it was dubious to the point of being non-credible. Can you point to any sort of ranking or index where it’s clearly below a reasonable standard?

From the paper: "...fermented dairy products, such as cheese and yoghurt, may be more protective than milk and butter..."

It's now possible to supplement C15:0 directly: https://fatty15.com/

Not C17:0 yet, however.

tl;dr: The findings from our study using fatty acid biomarkers suggest that higher intake of dairy fat were associated with lower CVD risk in diverse populations including Sweden (a country with high dairy intake), though more trials are needed to understand if and how dairy foods protect cardiovascular health.

need a eli5 version of this tl;dr

Milk does a body good.

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