Archive for the 'health and diet' Category

Polyphenols and milk

I don’t know how I missed this issue for so long, but I stumbled across it the other day and still can’t decide if it’s something worth worrying about, or if it’s just another chance to overcomplicate things by “sweatin’ the small stuff”.

The short version of this study on polyphenols and milk is that they fed some people blueberries with water and observed the levels of two major polyphenols as well as the “antioxidant capacity” of their blood for five hours. Then they did the same thing except they gave the subjects blueberries and milk. The milk did three things: 1) “flattened” the curve for serum levels of polyphenols, i.e., slowed down the absorption of both polyphenols, 2) non-trivially reduced the area-under-the-curve for serum levels of one of the polyphenols, and 3) completely muted the sharp increase in antioxidant activity that they saw in the blueberry/water group. As a person who consumes blueberries nearly every day because of their superfood status, this worried me because while I don’t consume them with milk, I frequently consume them with either a protein supplement or in greek yogurt, both of which contain healthy doses of casein, which is one of the two kinds of protein in milk and the thing that the researchers hypothesized was the culprit.

To be sure, this looks like a complicated issue. The Wikipedia blurb on this issue reads

A study of Charité Hospital in Berlin by Lorenzo et al., published in The European Heart Journal, showed adding milk to tea causes the casein to bind to the molecules in tea that cause the arteries to relax, especially a catechin molecule called EGCG, although a more recent study by Reddy et al. (2005) suggests the addition of milk to tea does not alter the antioxidant activity in vivo,[32] and the cardiovascular effect remains controversial.[33][34] A study published in the journal Free Radical Biology and Medicine found that consuming 200 mL of whole milk (vs. water control beverage) abolished the 6.1% increase in plasma reducing and chain-breaking antioxidant potential that resulted from consuming 200 g of blueberries, and reduced the peak plasma concentrations of caffeic and ferulic acids, “as well as the overall absorption (AUC) of caffeic acid.”[35] The authors did not specifically associate this with the milk’s casein content, however. Reviewing previous studies on the impact of milk on absorption of polyphenols, the authors say, “It is a matter of fact that the discrepancy of the results in humans is remarkable, with half the reports suggesting a lack of effect and the other half suggesting an inhibitory effect of milk.”[35]

Also, at least one study showed that milk doesn’t blunt at least one of the major benefits of cacao consumption, but I’m not sure if the cholesterol/cardiovascular benefits of tea and cacao are necessarily thought to be mediated through their polyphenols. The second page of this post over at Longecity has a useful discussion.

So, unfortunately, there is just enough information here to be confusing. However, if it’s not too inconvenient for you, perhaps it’s worthwhile to eat your berries either before or well after you eat your dairy or other source of milk proteins.


Paleo diets, crying babies, and dumb chicks with sweet boobs

Sometimes when people observe my eating habits or hear me talking about them, they ask if I’m doing some kind of Paleo Diet. The answer is no. Granted, I’ve spent some time reading Paleo websites, and I even have a link to such a site on the very front page of this blog (Mark’s Daily Apple). I also think that most Paleo adherents have their “heart in the right place” and eat a healthier diet than the average person. However, I’ve always been extremely suspicious of their “methods” and a lot of their conclusions (e.g., legumes are evil). After all, does anyone really know what Paleolithic man’s diet was like? And if so, wouldn’t that person be an expert in a field like, say, anthropology? Why don’t I ever see anthropology PhDs promoting the Paleo diet? It seems that Paleo proponents base their dietary beliefs on a rather arbitrary caricature of ancient man.

So, I was happy when Brad Pilon posted a link to the following video on Facebook the other day. It’s never fair to decide a debate without giving the other side a chance to rebut, but this speaker’s points jibe nicely with my long-held suspicions. If you care, spend twenty minutes watching Debunking the Paleo Diet. I should add that, judging from her comments at the end, she hardly seems to be a member of the Anti-Fat Legion of Carb Fornicators of which Paleo dieters (and many others) are wary.

This what-did-our-ancestors-do-type reasoning pops up in other areas of life. Apparently it’s quite seductive. However, my skeptic alarms go off immediately whenever anybody invokes it. And so should yours. I’m not the first person to draw attention to this. Arguments exhibiting such reasoning are often called just-so stories. However, the fact that these just-so stories keep reappearing and are still often so well received means that more ink (and bytes) should be marshaled against them.

For example, just over a year ago, I had the pleasure of becoming a father. And like a lot of parents, my wife and I have struggled to get our kid to sleep properly. (To all you parents who think this is odd because your little one slept through the night steadily after two months, please go to the kitchen, find the largest, sharpest knife you have, and push it into your ear. That’s right, all the way to the handle. Thank you.) For those who don’t know, perhaps the biggest debate in the world of baby sleep training is over how long you should let your baby cry without comforting or feeding her at bed time. A non-trivial number of people think that you should never or almost never let your baby cry without immediately trying to comfort her. Letting your baby cry at all, they argue, is completely at odds with how humans are wired. After all, prehistoric man couldn’t let the baby cry even a little bit because it would have given away their location to nearby predators that would then come eat them and poop them out.

Again, just-so stories are seductive. They paint a nice picture in our heads, and our brains seem to like nice pictures. If you think about this one for a second, though, it’s flimsy. First, why wouldn’t this argument apply to any noise? Do you think these same parents try to suppress nighttime baby laughter or cooing? Second, it seems highly unlikely that tigers and jaguars have posed an evolutionary-pressure-inducing threat to mankind any time in recent history. Once man’s ancestors became sophisticated enough to make halfway decent tools like spears and social enough to form hunter-gatherer bands (which would’ve been millions of years ago), I think bears would’ve dropped off the radar as a major threat to humanity itself. I mean, the general crappiness of our babies immediately after birth seems to necessitate a rather formidable group of defenders. Our babies can’t even sit up for months, while it takes a baby antelope all of two minutes to learn to sprint across the savanna. (Before anyone cries tu quoque here, I’m not actively arguing that this just-so story is true. I’m simply writing a different one with the opposite conclusion. My point is that real empirical work is required before a belief either way is warranted.)

Finally, this kind of faulty reasoning is most pernicious when it results in racism and sexism. In these instances, I don’t think most people reason so explicitly to their conclusions, but I think that these kinds of arguments are always sort of floating around in the pop culture ether provides somewhat of a safe harbor for discriminatory attitudes. For example, if you ask people whether boys or girls are better at geometry, I think a good majority of people will say that boys are. They’ll probably say this only because they’ve heard other people say it. However, when pressed to provide a justification for that belief, I think a lot of those respondents would latch onto these kinds of pseudo-scientific arguments. They’ll probably tell some story about how throwing a spear requires more geometry than breast feeding or berry picking. And they’ll feel that this is a perfectly acceptable argument because, as we’ve seen, we deploy these kinds of arguments all over the place without much resistance. Now, I’m not saying that there definitely aren’t or can’t be differences between men and women or between races, differences whose origin might well be rooted in circumstances that would make a story as tidy as those above. I’m just saying that the stories alone don’t warrant such beliefs.

So, what’s a good take-home here? How about, if a person can’t immediately name the subepoch during which Sinanthropus pekinensis existed, then he shouldn’t be making evolutionary arguments about diets or anything else. And if he does, then nobody should listen. While not a foolproof criterion, I think observing it would eliminate 90% of just-so BS.


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