Welcome to EAD’s first nutrition workshop guest column. Today’s post is from Jessica Kuzma who helps guide clients through the transition to a Paleo lifestyle. Jess enjoys helping people reach their health and fitness goals by tailoring plans to individual needs. In her post, Jess advises that if you include dairy in your, or your child’s, diet be sure to seek out full-fat, grass-fed products whenever possible.
There are conflicting views in the Paleo community regarding milk, cheese, and other dairy products and whether they should be strictly excluded from the diet. We need to use caution when labeling foods ‘good’ or ‘bad’ based simply on whether or not they were part of our hunter/gatherer ancestors’ diet, as this should serve only as a template for further investigation.
Milk is an inexpensive source of highly bio-available protein and is packed with antibodies, immune factors, and growth promoters. Intuitively, this makes sense—cow’s milk is naturally intended for calves which have growth rates that greatly exceed those of humans. Cows nurse for a shorter time and are weaned, on average, at about 6 months; therefore cow’s milk must supply all the growth hormones and nutrition necessary to support a steep bovine growth curve.
It follows then, that when humans consume cow’s milk, the same strong growth response occurs. Primarily, milk proteins cause a steep rise in insulin—the master ‘storage’ hormone. This is counter-intuitive as dairy products are fairly low in carbohydrate and the rise in blood glucose is minimal compared to the unmatched sharp increase in insulin. Again, keeping this in context, it makes sense that milk protein would promote growth and nutrient storage independent of the carbohydrate concentration.
Additionally, there are several other naturally occurring hormones in milk that promote growth. Chronic exposure to these hormones provide opportunity for cancerous cell growth and it is not entirely surprising that milk drinking is correlated with an increased risk of cancers. Potentially problematic hormones include:
- IGF-1: IGF-1 is a potent growth hormone that remains active in non-pasteurized milk. Additionally, our human IGF-1 isoform rises concomitantly with a rise in insulin—as milk drinking causes a strong increase in insulin secretion, the levels of IGF-1 also increase. High circulating concentrations of IGF- 1 during childhood result in greater height as adults but also increase risk for breast, colon, and prostate cancers.
- Betacellulin: Found in cow’s milk, whey, and cheese—survives pasteurization. Betacellulin is a protein hormone that binds to receptors in the human gut called Epidermal Growth Factor Receptors. As the name implies, when activated, these receptors initiate growth and repair in the gut. This is a good thing—on a small scale. We secrete Epidermal Growth Factor in our saliva that binds these receptors and repairs gut damage. However, Betacellulin concentrations in milk far exceed the healthy amount we produce naturally. A single glass of milk has 10 times more Betacellulin than your body secretes over an entire 24-hour period. Epidermal Growth Factor Receptors follow a positive feedback mechanism, which means the more something binds to the receptor, the more receptors will appear at the site. Such uncontrolled, increased expression is one of the hallmarks of cancer.
- Steroid Hormones: It appears humans receive the majority of estrogen-like compounds from dairy products. Furthermore, the majority of milk is obtained from cows later in pregnancy, during which milk production increases, and the level of estrogens are at their highest. There are also several dihydrotestosterone (DHT) precursors present in varying concentrations.
- Links to Disease: Several epidemiological studies have linked dairy intake to the development of Type-1 diabetes, with the risk increasing the earlier dairy is introduced in the diet. Multiple Sclerosis, Crohn’s disease, Sjogren’s syndrome, and Celiac disease symptoms have all been alleviated, to some degree, by excluding dairy products from the diet.
One caveat to this research: undoubtedly, these studies have all used conventional, homogenized, pasteurized milk products from corn-fed cows. The fatty acid profile of pastured milk is completely different than its conventional counterpart. As there have been no trials examining health outcomes between groups consuming dairy products from conventional sources versus those consuming only non-processed, pastured dairy, we cannot definitively conclude that all dairy is harmful. We do know the fatty acid profile of butter from grass-fed cows is quite different and appears to be a healthy and beneficial saturated fat source. Perhaps more so, ghee (clarified butter) is a process by which residual milk proteins in butter are separated and removed by heating and the pure fat is retained. This is a tasty and healthy way to obtain omega-3 fats, CLA, and butyric acid—all necessary for gut health and to help decrease inflammation.
Lastly, in some instances, the growth-promoting properties of milk can be utilized for performance benefits. For example, an athlete who wishes to increase muscle mass might use milk in the postexercise window to take advantage of insulin sensitivity and glycogen-depleted muscles to optimize protein synthesis and muscle repair. In other words, milk is a good way to pack in a lot of ‘bang for your buck’–dense calories coupled with a potent growth and nutrient storage stimulus.
Conversely, individuals wishing to ‘lean out’, or drop a few pounds of body fat would be better served to avoid diary and choose another protein source post-workout, such as egg-white protein or meat.
Jess currently lives in Seattle, Washington, and frequently posts tips, recipes, and advice at http://stonewaycrossfitnutrition.blogspot.com/ She works with clients locally, and remotely..
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