Nearly every aspect of cow’s milk inspires debate—from its fat, protein and sugar (lactose) content to the hormone residues it may contain, the pasteurization process it undergoes, and even its very suitability for human consumption. We’ve discussed all that, but some of our readers have raised concerns about something else: homogenization. You may wonder, what could be wrong with homogenized milk?
Well, it seems there are plenty of people who are promoting “non-homogenized” milk as a healthier option. You may see it on the shelves in health-food stores and some supermarkets.
Let’s get one thing out of the way first: non-homogenized isn’t necessarily raw milk (“raw” simply means not pasteurized). Though all raw milk is non-homogenized, not all non-homogenized milk is raw. And while raw milk poses definite health risks, non-homogenized milk does not unless it’s not pasteurized.
Ye olde milk?
When cow’s milk is not homogenized, its fat separates out, producing a layer of cream on top. Developed in the late 19th century, commercial homogenization is a mechanical (not chemical) process that breaks up the fat globules to such a small size that they remain suspended evenly in the milk, producing a uniform (homogeneous) consistency. It also gives milk a longer shelf life. “Nonfat” milk—formerly called skim milk because the fat was skimmed off—is also homogenized, since it contains some fat, albeit a very small amount.
According to its detractors, homogenized milk contributes to heart disease, diabetes and other chronic disorders, as well as allergies, largely by boosting the absorbability of an enzyme in milk called xanthine oxidase (XOD). They claim that the resulting higher blood levels of XOD increase disease-promoting inflammatory processes.
While it’s true that elevated activity of XOD (along with other enzymes) produced in the body can increase inflammation, the adverse effects of XOD in milk remain theoretical. In any case, the point is moot, because XOD is not absorbed from any food.
The notion that homogenization, and milk’s XOD in particular, is a health hazard was originally disproven by researchers from the University of California at Davis in a paper published in the American Journal of Clinical Nutrition back in 1983. Subsequent research has also debunked it.
In addition, studies have shown that homogenization actually improves the digestibility of milk and that it does not increase the risk of milk allergy or intolerance in children or adults.