• February 20, 2019 2 min read

    Up until the 1970s, dairy producers saw whey as only a by-product in the cheese-making process. You may also know it as the liquid that gathers on the top of yogurt. Now, whey is recognized as an excellent source of high quality protein. (1)

    Whey protein concentrate contains from 30 to 70% protein. The premium product, whey protein isolate, removes the fat and lactose in natural whey for a product that is 90% protein.

    But the processing method isn’t the only thing that affects the whey protein you buy. What a cow eats goes into its milk, and whether it’s grass fed or grain fed can make a difference. Here’s what you need to know about how a cow’s diet affects the product you consume.  


    Grain-fed cows are bred and grow up in feedlots, or Concentrated Animal Feeding Operations (CAFOs). Instead of grass, CAFO animals eat grains and corn—often in unsanitary conditions. The crowding and poor nutrition often require injections of antibiotics to avoid sickness that can spread quickly in close quarters. Steroids are also used to increase muscle mass.

    Grass-fed cows, however, eat their natural, nutrient-rich food source in a healthy environment. This obviously requires more land and makes the products from grass-fed cows more expensive. 

    Nutritional Differences

    A cow cannot produce milk with more nutrients than it gets from its diet. So, compared to feedlot cattle, grass-fed cows  produce milk—and whey—with higher levels of omega-3, vitamins B and E, CLA, potassium, magnesium, and calcium. Omega-3 fatty acids are strongly linked to a cognition, mood, and a reduced risk of heart disease, and CLA shows promise in fighting cancer and aiding weight management. (2)  

    What’s more, the nutritional differences can mean what’s not in the whey. Most grass-fed operations do not use steroids, pesticides, and antibiotics. These substances can pass into milk and whey as well, and can have damaging effects for humans.


    These substances, good and bad, are carried in the fat content of proteins. Both whey concentrate and isolate contain residual fats, with a higher percentage in whey concentrate. That means this by-product passes down to you what the source cows consume. The omega-3 and CLA fats, as well as the higher vitamin content, offer improved immune support and amino acid nutrients. (3,4) Whey from grass-fed cows gives a clear nutritional and health advantage over grain fed.

    Benefits of Whey

    Whey as a whole can offer consumers many benefits – regardless of its source. But whether your interest in whey is for weight loss, lowering cholesterol, or preserving lean muscle, choosing a product from grass-fed cows, raised in healthy conditions, will help support your goals. (5)