How does the homogenization process affect the health properties of milk? Is unhomogenized milk better 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.
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 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.
There wasn’t (and still isn’t) any evidence that the widespread adoption of homogenization led to an increase in heart disease rates. Nonetheless, 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 this theory and most scientists considered the matter settled—but the notion that homogenized milk is a culprit in heart disease lives on in certain corners of the internet, among other outdated myths and rumors.
Does Homogenization Affect Digestion?
Some studies suggest that homogenization increases the digestibility of milk-- particularly in people with diseases that impair their ability to digest fats. Because the protein and fats are broken down into smaller particles, there is more surface area for enzymes to work on and this leads to more efficient digestion. If, however, you are lactose intolerant or allergic to milk, homogenization isn’t going to make milk any more or less tolerable for you.