Monday, September 6, 2010

Milk: Thumbs Up or Down?

As you know, I'm a convert to the caveman diet -- but unlike hardcore paleo eaters, I still eat foods derived from cow juice. I just love the taste of dairy products. And since "Good Calories, Bad Calories" helped me unlearn the conventional wisdom about the dangers of dietary fat, I've been guiltlessly enjoying the pleasures of butter, cream, and whole milk Greek yogurt.

Strict paleo eaters must have a reason for avoiding dairy, though, and I think it's about time I looked into them. Here's what I found:

The case against milk isn't being made only by paleo enthusiasts and vegans. In this month's issue of "Men's Journal," Ben Hewitt writes (in an article that doesn't appear to be online) that "an increasing chorus of doctors, armed with some compelling new research, are claiming that dairy may not be fit for human consumption after all."
"We're not calves, and we're not evolved to drink cow's milk," says Dr. Alexa Fleckenstein, a board-certified internist in Boston. "That's why milk is such a highly inflammatory food for humans: It's unnatural." While acute dairy allergies are relatively rare among healthy adults (only about 2.5 percent of children are allergic to dairy, and they typically outgrow it), an estimated 60 percent of the world population is lactose intolerant.
Fleckenstein points out that of all the world's animals, "humans are the only ones that drink the milk of other animals -- and that may be why consuming dairy makes so many people sick."

What's more, "[a]ccording to a study from the Department of Human Nutrition in Denmark, drinking lactose leads to a high insulin response that mimics the metabolic reaction to cane sugar. That can make us sluggish and bloated and puts us at greater risk for diseases like diabetes down the road." Researchers have also found evidence that links dairy to "autoimmune disorders such as Crohn's disease and rheumatoid arthritis."

The "Men's Health" article also quotes Pedro Bastos, a Portuguese scientist and dairy expert, who argues that calcium -- the primary nutrient in milk that "does a body good" -- is actually absorbed better "from vegetables in the Brassica family -- broccoli and cabbage, to name a few."

That's not all that Bastos had to say. When Hewitt was researching his article, Bastos sent him an email that elaborated on the problems associated with dairy intake:
Ten thousand years ago, humans didn't drink non-human milk. Thus, cow milk consumption is relatively new to human evolutionary and dietary history -- and since "milk is species specific, we would expect this new habit to have unintended consequences," including the following: 
  • Dairy produces a "very high insulin response" -- and we know that repeated surges in insulin can "downregulate the insulin receptor, and hence lead to insulin resistance," which drives metabolic syndrome and obsesity.  
  • "[D]airy intake is strongly associated with a higher incidence of acne and moderately associated with prostate cancer," along with various autoimmune diseases," including rheumatoid arthritis, Type 1 diabetes, Crohn's disease, and Celiac disease.  
  • Milk contains "various growth-stimulating steroid and peptide hormone and also catalysts, transporters and stabilizers that ensure their maximum bioactivity," including bovine insulin, estrogen metabolites, and other steroids.
Not everyone should avoid milk. According to Bastos, if you're not eating good, whole/real foods, not getting enough protein, fat and Vitamin D, and generally overdosing on the sugary, over-processed staples of the Standard American Diet (S.A.D.), dairy remains preferable to the other crap you're eating.

If your diet's already clean, "milk is not necessary" -- but it's damn tasty. I'll probably reduce my intake of cow's milk somewhat, but my gut tells me that the struggle to eliminate dairy altogether would be so un-fun that it'd end up backfiring on me.