Dairy wars: Of fats, phobias and froth

Little Miss Muffet, clearly, was arachnophobic. Just as clearly, she was dauntless in the face of dairy products. You can still find people like that, of course. But these days, you’re just as likely to find those with opposing attributes: They are good with spiders, but flee from dairy in dread or disgust.

If one can manage to wade through the whey, and climb past the curds, there proves to be armaments for all sides in the dairy wars. And in the end, a one-size-fits-all answer is about as clear as your average milkshake. I will do my best here to skim the cream.

There is a case that adult mammals have no business consuming dairy, period. We speak about “lactose intolerance” as if it were an abnormality, but the opposite is true. Lactose

tolerance is the aberration

.

A gene is responsible for generating the enzyme, lactase, needed to cleave the compound sugar in milk, lactose. That gene is active in all newborn mammals, allowing them to digest their mother’s milk. But the gene turns off in early childhood in tandem with weaning, the enzyme disappears and lactose “intolerance” ensues. Of course, lactose intolerance is irrelevant — because once weaned, mammals never again encounter milk.

[Read: Non-Dairy ‘Milks:’ Once the Solution, Now Part of the Problem .]

Unless those mammals happen to be us. And in our case, a funny thing happened on the way to the forum of globe-spanning human civilization. Facing stunningly diverse environments in the great diaspora of our kind, we, too, diversified. Lactose tolerance is a fascinating example of that, and an illustration of natural selection in fast-forward. So, too, is white skin, for related reasons — but that’s another story.

In some harsh environments, such as Northern Europe and Iceland, recourse to dairy may have been a crucial defense against incipient starvation. Under such circumstances, those who digested the available food well did a lot better than those who did not. In extreme conditions, doing better meant surviving.

Survivors are far better at passing on genes than non-survivors; people who don’t live long enough to make babies, make really crummy ancestors. So it is that in populations that (a) were challenged by harsh conditions and the threat of starvation, and (b) had recourse to milk-producing, domestic animals- lactose tolerance developed. A mutation in the lactase gene that kept it stuck in the “on” position was favored, and proliferated.

The result is that today, some human populations are all but universally lactose tolerant, while those without a long tradition of dairying remain lactose intolerant, like all other mammals.

[Read: 5 Non-Dairy Foods With Calcium .]

What, then, of the health effects of dairy among those favorably disposed to digest it? There is evidence to satisfy every taste (1).

The literature suggesting health benefits from dairy is expansive. Benefits demonstrated relate to weight control and body composition, cardiometabolic parameters and bone health.

Inevitably, though, such benefits show up in comparison to an often dubious baseline. So, for instance, higher dairy intake in children in the U.S. is associated with weight and health benefits. But while that could be due to direct benefits of dairy, it might also be much about the alternative choices. Kids who don’t drink much dairy are often drinking soda. The principal benefit of higher dairy intake could be mostly about what people are avoiding.

If the benefit of dairy were directly due to what it was adding to the diet, that benefit should be seen even against the backdrop of an already optimal diet. That is by no means clear. Health outcomes are outstanding in Mediterranean populations with traditional diets that include some, albeit modest amounts, of dairy, but are apparently just as outstanding in Asian and North American populations with plant-based diets that exclude dairy.

The closest thing to date to a study of what dairy does or doesn’t add to the benefits of a plant-based diet is probably the DASH studies. For blood pressure reduction, there was added benefit with added dairy — notably low-fat and non-fat dairy, in this case. But then again, a meta-analysis of vegetarian diets shows they, too, are effective for blood pressure reduction, no dairy required.

How to sum all this up? Pretty hard to do, given the extent and diversity of the relevant evidence, but I’ll give it a shot.

Adding dairy to the generally rather junky diets that prevail in developed countries is apt to confer benefit, particularly if the dairy products displace less nutritious foods, especially soda. There is no reliable evidence that adding dairy to any variant on the theme of ” optimal diets,” comprised of wholesome foods mostly direct from nature in sensible combinations, confers consistent benefit. Based on the information we have to date, a diet can be optimal with or without dairy — and the net effect depends substantially on the routinely neglected question: “Dairy, in lieu of what?”

Moving on, then, to the New-Age question: What of dairy fat, per se?

Here, again, a simple, summative answer is precluded by the quality, quantity and diversity of available evidence (2). Recent studies suggest lack of harm from the saturated fat in dairy, but that in turn begs the question: Lack of harm, relative to what? The most notorious, recent study on the topic actually showed no change in heart disease rates in the U.S. as saturated fat intake (presumably from dairy and meat) declined over time, and intake of refined starch, added sugar and total calories increased.

[Read: Raw Milk Is Gaining Fans, but the Science Says It’s Dangerous .]

This is hardly the ringing endorsement of dairy fat it has been made out to be. Viewed in one direction, this study did show that our heart disease rates were not higher when our intake of dairy fat was higher. Viewed the other way, however, it also showed that our rates of heart disease did not go up as we swapped out dairy fat for sugar — seeming to suggest that each may be as bad, or good, as the other.

Arguing against that are some studies looking more directly at the saturated fatty acids in dairy, and noting a relative lack of harmful effects. But since when is “lack of harm” an acceptable standard for good nutrition? Cardboard would presumably clear that bar.

Despite the current clamor, what we really don’t have is evidence suggesting that a shift to higher intake of dairy fat offers any health benefit. We do have evidence of just the opposite.

Perhaps the best example is the Lyon Diet-Heart Study, a multinational, randomized clinical intervention trial. Adults with coronary disease were randomly assigned to a conventional, Northern European diet, relatively high in saturated fat from meat and dairy; or to a Mediterranean diet, with a comparable amount of total fat, but predominately unsaturated. The Mediterranean diet, over a span of years, reduced the rate of cardiac events by approximately 70 percent.

Lastly, there is a batch of important considerations having little to do with dairy nutrition, per se.

Dairy cows on large factory farms may be subject to cruel abuses. If we are decent, the ethical implications of our food choices should matter to us. It is not trivial that the heir to the Baskin-Robbins fortune renounced the fortune and the venture, and became a crusader for kinder, gentler treatment of our fellow species. John Robbins did so based on what he observed first hand.

A University of Michigan study, hot off the presses, highlights the environmental impact of our food choices – – singularly indicting dairy intake as a source of greenhouse gases. We cannot ignore the environmental implications of our food choices, because there simply are no good food choices, raw or cooked, for a population whose planet is cooked.

Finally, dairy needs to be judged partly by the company it all-too-often keeps. Much of the prevailing dairy supply is a delivery vehicle for antibiotics,

used rather wantonly in densely packed populations of bovines. It may deliver hormones, particularly bovine growth hormone, implicated in the early onset of menarche, and perhaps obesity.

And so it is that much of the frothing about dairy — for or against — is based on preconceived convictions, and a selective rendering of the vast, diverse evidence that pertains.

I cannot offer a decisive, one-size-fits-all answer, but I can tell you what I do.

I do include dairy in my diet, but not a lot. I have a plant-predominant, Mediterranean-style diet, because it is the variant on the theme of “best diets” my family favors.

The dairy I consume is preferentially organic, sparing me exposure to hormones and antibiotics, and preferentially sourced locally, sparing the cows abuse.

[Read: Is Dairy Healthy or Not? ]

I avoid all dairy products with added sugar. As Robert Lustig notes, many commercial yogurts deliver sugar as efficiently as sodas. I avoid sweeteners of all kinds, having no love for artificial sweeteners.

I prefer my dairy fat-free. This is not because I am dietary fat-phobic. My dietary fat intake is moderate. But as noted, the evidence is that a balanced array of polyunsaturated fats with an emphasis on omega-3s and monounsaturated fats actually promotes health. I have reviewed the evidence extensively, and see nothing to suggest any benefit in switching from a balanced portfolio of unsaturated fats to more saturated fats. Since I get plenty of fat from nuts, seeds, olives, avocados, fish, seafood, cooking oils and such, I see no reason to go out of my way to get more from dairy. Besides — and yes, this matters — I simply prefer the taste of fat-free dairy.

Beyond the diatribes, there are sound arguments for and against dairy. Whether or not dairy or dairy fat is “good” for us depends substantially on what dairy, in place of what else, in the context of what overall diet. It also depends on whether “good” includes environmental stewardship, sustainability and the avoidance of cruelty to animals.

If we can get past the fads, the phobias and the frothing at the mouth, we can find our way to sensible, individualized choices. We can love food that loves us back. We can have our cake, in other words, and eat it, too — with or without a glass of milk to wash it down (3).

Footnotes:

1) A Pubmed search on 9/7/14 limited to human research, using the terms “dairy AND health,” and limited to articles featuring both words in title or abstract retrieved 1,827 citations.

2) A Pubmed search on 9/7/14 finds the terms “dairy AND fat” in the titles or abstracts of more than 5,000 articles; and the term “dairy fat” in those of 126.

3) Should we eat cake? Topic for another day. But in the interim, I recommend this one!

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Dairy Wars: Of Fats, Phobias and Froth originally appeared on usnews.com

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