What Are the Differences Between Grass-Fed, Organic, and Conventional Milk?
Alternative milks like oat milk may be the coolest new kids on the dairy-aisle block, but good old-fashioned cow's milk has been quietly refreshing its image on the sidelines. Its latest incarnation is a grass-fed variety, which actually harkens back to the way cows were raised pre-World War II. That is, before nitrogen became widely available for agricultural use, making corn and grain cheap to grow and feed to cattle in large quantities.
The wide-scale switch from grass to grain led to the concentrated animal feeding operations where conventional cow's milk is produced today, says registered dietitian-nutritionist Mckel Kooienga. These farms follow different protocols than organic farms—where cows have a diet made up of at least 30 percent grass, the rest being certified-organic corn or grain—and farms raising 100 percent grass-fed cows. As a result, the three types vary in how they impact cows and the environment, and, to a lesser degree, in nutritional value and taste.
If sustainability figures big in your purchasing decisions, you may want to choose grass-fed or organic milk. The large-scale factory farms producing conventional milk have been linked to environmental detriments, like air and water pollution stemming from how they store and process animal waste, says Kooienga. And because these facilities can contain a few thousand animals in one place, they may also create large concentrations of ozone-damaging methane gas, released by the livestock. By contrast, farms producing organic and grass-fed milk are typically smaller, allowing for more eco-conscious oversight.
And the organic ones, specifically, take it one step further: Their farmers are restricted from spraying pesticides, herbicides, or other synthetics on their land, says Tim Joseph, founding farmer of Maple Hill Creamery (which makes organic and grass-fed milk). That means these farms won't add to the larger eco issue of chemicals leaching into runoff and contaminating waterways. What's more, farms adhering to organic practices do not administer antibiotics to their animals. Although the effects of these drugs on people who later eat the meat (or drink the milk) from these animals are still being determined, we know frequent antibiotic usage can contribute to antibiotic resistance.
For avid milk drinkers, the nutritional differences between conventional, organic, and grass-fed types may be worth considering, but for those who just pour a little into their coffee or cereal, they won't be a game-changer. Generally, grass-fed milk has a better fatty-acid profile than the other kinds; it's higher in omega-3s—which support eye and brain health—and lower in omega 6s, which can up the risk of obesity and diabetes if consumed often. However, the difference in amounts across the board is small: Grass-fed milk has 0.05 grams of omega-3s in every 100 grams, compared to 0.02 grams in conventional, with organic falling in the middle. (For reference, a 100-gram serving of salmon has around 2.25 grams.) You can also find more iron and heart healthy CLA (conjugated linoleic acid) in the grass-fed variety, says nutritionist Sarah Adler. Again, you'll only really reap the benefits if you drink milk regularly.
You'll notice that grass-fed milk is tarter and tangier than its counterparts—or, by comparison, the others may taste a bit watered-down. The difference is more apparent in full-fat varieties, similar to the way conventional whole milk is richer and more flavorful than skim.
The Bottom Line
Going grass-fed may be a smart choice if you consume a good deal of milk—and choosing a variety that's both grass-fed and organic is the surest way to minimize your impact on animal health and the environment. But know that it comes at a premium. Grass-fed and organic types (including milks that fall into both categories) run three to four times as expensive as conventional ones. "If you can, buy it directly from a local farm instead of a grocery store," suggests Kooienga, "so that you're supporting those farmers who abide by sustainable and humane practices, while enjoying a slightly more nutritionally sound option."