Dr. Bray Links

Friday, April 17, 2015

Time To Take Milk Off The Menu?

"A new study conducted by scientists at Kaiser Permanente, the large U.S. health insurer, and published in the Journal of the National Cancer Institute (link is external) found that breast cancer survivors consuming high-fat cows’ milk foods had a higher risk of dying from breast cancer than women eating little to no high-fat dairy.


What links dairy fat to breast cancer is likely to be the hormone estrogen. Much of the cow’s milk we drink today is produced from pregnant cows (link is external), whose estrogen and progesterone levels are markedly elevated. When humans consume milk from these cows, this can increase their own estrogen levels (link is external), creating an environment that is conducive to breast cancer but has also been linked to prostate, endometrial and ovarian cancers.


So what’s a dairy eater to do?

Moreover, plant milks are almost always sold in cartons lined with plastic containing estrogen-like compounds that are thought to leach into the milk we drink. Lastly, they often contain an additive called carageenan, a seaweed extract that is thought to cause gastrointestinal inflammation and higher rates of intestinal lesions, ulcerations, and even malignant tumors (link is external). So unless you make your own plant milk from scratch, you’re probably best advised to minimize their intake.

Does this mean we should swear off milk altogether? Not necessarily. This brings me – like a broken record – back to the traditional Mediterranean Diet.

For millennia, dairy around the Mediterranean basin was consumed sparingly and almost always in the form of fermented milk curds – such as yogurt, kefir, labneh – and fresh goat’s and sheeps’ cheeses such as feta cheese, halloumi, ricotta and fresh chèvre (log-shaped goat’s cheese). Cow’s milk was rare as the terrain generally did not lend itself to such large, thirsty animals; instead, goats and sheep were better adapted to the rocky, arid landscapes that line the Mediterranean shores and prized not only for their milk but also their meat and – in the sheeps’ case – wool.

Interestingly, in a recent study (link is external) the levels of estrone and 17β-estradiol in goat's milk were found to be significantly lower than in any of the cow's milk products tested – including organic cow's milk. (I have not been able to find similar data on sheep's milk.) Thus, the occasional goat's milk yogurt or small piece of goat’s cheese are acceptable, but until there is more research, don’t go overboard on these either.

Finally, if you choose not to eat any dairy at all, this should pose no health risk at all. After all, we are the only mammals that continue to consume milk long after we’re weaned – and another species’ milk at that! Indeed, in many of us, the ability to digest lactose (the sugar in milk) begins to decline from the age of two, the age at which, in nature, we might begin transitioning from mothers' milk to solid foods. Might this be Nature’s way of telling us to lay off milk after infancy?"

Many people eat dairy foods because they think they need them to maintain bone strength; but rest assured: in many parts of the world – much of Africa and Asia, for instance – milk is not consumed at all and people’s bones do not crumble! Green leafy vegetables, legumes and seeds, bone-in fish (e.g. canned salmon or sardines) and chicken, beef or fish broth are excellent sources of calcium.

So once again, Mediterranean wisdom prevails: if you eat dairy foods, do so sparingly, choose minimally processed ones made from the milk of pasture-fed, organically-reared animals that did not receive hormone treatments, opt for fermented milk wherever possible, and vary your milk source, rotating goat's, sheep's and occasional cow's milk products.


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