The Benefits of Protein from Grass-fed vs Corn-fed Cows

Nicola Hobbs - Jan.11.21

Here at Reflex, we pride ourselves on creating the highest-quality products for our community of athletes and exercisers. This means we are committed to only using the finest quality ingredients, including only ever using whey from the milk of grass-fed cows — no antibiotics, no artificial hormones, and no whey from corn-fed cows.

Why use whey from grass-fed cows?

In the same way the food we eat influences our health and wellbeing, a cow’s diet strongly affects the dairy they produce. The nourishment we get from dairy (including milk and whey) depends on the lifestyle of the animals that produce them — especially their diet, access to fresh air, and access to pasture.

Grass-fed whey comes from cows that have grazed in pasture year-round instead of being fed a processed diet of grains (such as corn). This improves the quality of the whey as well as making it richer in certain nutrients.


Cows convert the food they eat into fatty acids during digestion which means an animal’s diet strongly impacts the fatty acid composition of the milk they produce, as well as the amount of protein, fat and carbohydrate it contains.

For example, grass-fed cows typically have two to five times more conjugated linoleic acid (CLA) and over 60% more omega-3 fatty acids (EPA and DHA) than conventionally fed, grain-fed cows — both of these fatty acids have anti-inflammatory properties.

The milk of pasture-raised, grass-fed cows also contains higher levels of the fat soluble vitamins A, D, E and K — all beneficial for heart health, reducing inflammation and healthy ageing, whilst milk from grain-fed cows have lower levels of these fat-soluble vitamins and antioxidants.

In summary, grass-fed cows are generally healthier than grain-fed cows, which means the milk they produce is healthier too — the dairy they produce tends to have more nutrients including fat soluble vitamins, CLA, DHA and EPA which all contribute to health and wellbeing.


Top tips when looking for grass-fed products

  • When buying dairy-based supplements such as whey and casein, make sure the dairy used is grass-fed — Reflex only use grass-fed dairy in all their products including Instant Whey Pro, 100% Whey and R-bars.
  • Outside of protein supplementation, when buying meat and dairy look for the Pasture for Life mark — this ensures the products come from animals with a high standard of animal welfare, natural diets, and wildlife friendly fields.

Ready to shop grass-fed protein? 

Shop now! Or, if you're not sure which Reflex protein to choose, read our guide to the different protein sources


Dhiman, T. R., Anand, G. R., Satter, L. D., & Pariza, M. W. (1999). Conjugated linoleic acid content of milk from cows fed different diets. Journal of dairy Science82(10), 2146-2156.

Elgersma, A. (2015). Grazing increases the unsaturated fatty acid concentration of milk from grass‐fed cows: A review of the contributing factors, challenges and future perspectives. European journal of lipid science and technology117(9), 1345-1369.

O’Callaghan, T. F., Hennessy, D., McAuliffe, S., Kilcawley, K. N., O’Donovan, M., Dillon, P., ... & Stanton, C. (2016). Effect of pasture versus indoor feeding systems on raw milk composition and quality over an entire lactation. Journal of dairy science99(12), 9424-9440.

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