We know, grocery shopping has gotten complicated. But the evidence for one supermarket choice is becoming increasingly clear – milk from grass-fed cows has more health benefits than other kinds of milk.

Cows, it seems, are healthier if their days are spent grazing on pasture (and probably happier, but that hasn’t been measured yet).

The alternative, even for some brands of organic milk, is that they are crowded onto feedlots where they are fattened up for high volume milk production by being fed grains. A recent study from the U.K. shows that milk from cows who grazed on organic pastures contained more good fatty acids such as omega-3 and conjugated linoleic acid (known as CLA9) than milk produced on intensive commercial dairy farms. CLAs have been shown to be effective in combating cancer, coronary heart disease and type II diabetes.

The study, conducted by the University of Newcastle, was published in the Journal of Science of Food and Agriculture.