Is Homogenized Milk Bad for You?

Most commercial cow’s milk—including most organic milk—goes through a few stages of processing before it reaches the store shelf. It’s usually pasteurized in order to kill any pathogenic bacteria it may contain. You can read more about the pros and cons of unpasteurized, or “raw” milk, in my special two-part series on that subject.

Most commercially-sold milk is also fortified with vitamins A and D, in an effort to ensure adequate intake of these nutrients in the general population. Commercial milk is also usually homogenized—a mechanical process that breaks the fat globules into smaller droplets so that they stay suspended in the milk rather than separating out and floating to the top of the jug. Before milk is homogenized, some of the fat may be skimmed off to reduce the amount of fat in the end-product.

What is homogenized milk?

Homogenization was invented around the turn of the 20th century and quickly became the industry standard because people preferred the convenience of milk that didn’t have to be vigorously shaken to distribute the fat every time you wanted to use it. These days, of course, we tend to see food processing as something that reduces the nutritive value of foods.  And some have suggested that homogenization might have a negative impact on how the milk affects your body.

In fact, it’s getting more common to find milk that’s pasteurized but not homogenized. Sometimes it’s labeled “cream-line.” Let’s take a closer look at whether or not unhomogenized milk might be a better choice.

Is homogenized milk bad for your heart?

When you homogenize milk, you not only change the size of the fat globules, you also rearrange the fat and protein molecules—which could alter how they act in the human body. In the 1970s, Kurt Oster proposed the hypothesis that homogenized milk might increase your risk of heart disease.  Specifically, he theorized that xanthine oxidase, a compound that's created when milk is homogenized, might be absorbed intact into the blood stream, where it would deplete other protective compounds called plasmalogens and result in the formation of plaques and heart disease.

Researchers spent the next decade or so testing various aspects of Dr. Oster’s rather ornate hypothesis. Ultimately, research failed to validate any part of it. Xanthine oxidase does not appear to be abosrbed into the blood stream from the digestive tract. Drinking homogenized milk does not increase blood levels of xanthine oxidase nor does this compound appear to have any effect on plasmalogen levels.

Purveyors of nonhomogenized milk...

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