Quick notes for mid November 2014

Updated 11.19.2014; reformatted 9.7.2015
Here are some brief comments on recent items.

• Milk is not manna.
• To lower IGF-1, go vegan.
• Are we staying too warm?
• Go ahead and eat before cardio.

Milk is not Manna

A recent Upshot at the New York Times (NYT) discusses human milk consumption. Conventional wisdom (and followers of the Weston A Price Foundation or WAPF) hold that cow's milk is healthy for humans to drink, conveying great benefits on those who drink it. Indeed the WAPF followers often insist milks consumption is necessary for health. The review at The NYT's Upshot suggests otherwise.

I have a distinct bias here as someone who is lactose intolerant. I have nothing against dairy, and still find that I can eat most cheeses. However, I chafe at the insistence that milk is some kind of "manna from heaven" for human health. Dairy consumption is not required for good health, and the evidence that too much dairy may adversely affect health is compelling to me. But again— I note my bias.

Milk consumption is touted for bone health, but when milk consuming humans were followed across their lifespans, consumption of cow's milk made no difference in terms of bone breakage. In fact, in a Swedish study, milk consumption increased the number of broken bones. The Upshot also notes that the health effects of vitamin D have likely been overstated.

Bottom line: If you enjoy drinking milk do so, but doing so does not endow you with some special health benefit.

Calorie Restriction and IGF-1

Restricting calories isn't enough to lower IGF-1, you have to avoid animal products. The link is to Dr. Michael Gregor's video presentation comparing the study results on IGF-1 levels in vegans, calorie restriction and fit athletes. The good doctor is a vegan himself, so almost every question he asks is answered with the advice to "eat more plants." He does stick to the science, however.

Higher IGF-1 levels are associated with higher incidence of cancer, and it turns out that fat cells produce IGF-1. This likely explains why obesity correlates with the incidence of certain cancers. Breast cancer is one type with an association with obesity, as are stomach and esophogeal cancers. Oh, but Health at Every Size... right?

Season Affective Disorder? Too little sun or not enough cold?

Ray Cronise hypothesizes that obesity and seasonal affective disorder might be the result of staying too warm during the cold season. Note: I'm not sure if that link will remain live. To see his archives you have to register at the site.

Cronise's hypothesis is that moderate cold stress (not extreme cold) can be beneficial to the metabolism, though it's not plain that all the evidence he includes in this post supports that. He goes out of his way to emphasize that he's not talking about taking ice baths or walking exposed in freezing temperatures. Cronise does advocate keeping the extremities warm (hands, nose, feet) and then layering the core for warmth only as necessary. Don't pack on layers and then remove them as you overheat.

I have been trying this on a casual basis. Since entering the post-menopause stage of life, my body temperature regulation has mostly returned to its pre-menopause state. Which to say that my hands, feet and nose are very often colder than the rest of me. I have always tended to dress in layers, but during menopause doing so was essential. I needed to be able to shed a layer to help mitigate the effects of a hot flash. But more recently the flashes are rare and rather than go back to wearing a lot of layers I've tried What Cronise suggests. I focus on the extremities, and only further cover up if I'm uncomfortable. My personal experience is that there's something to it. Cronise continues to research his idea, and raises money to do so through his site.

The rest of the article is coverage of his current experiment on himself, where he is trying to lose 30 pounds in six weeks without supplements or exercising. In essence, he's fasting and measuring the changes in his own metabolic biomarkers. Not sure what relevance his data (he's 50) will have for a post-menopausal woman... but it's worth a read.

Go ahead and eat before doing cardio

There are many myths in fitness, one of which is that exercising in a fasted state burns more fat than if you eat first. The Suppversity blog reports on a recent study that busts this myth. The differences in fat mass, weight lost, etc. were not statistically significant. And even if you decide the loss in fat mass (which was higher in the fasted state) would be worth it, you need to recognize that the lean mass loss was greater too.

So don't punish yourself by running before eating. Go ahead and eat then get to exercising.

Disclaimer