Sheep milk’s protein is more readily digested and its fats are more readily converted into energy compared to cow milk, a New Zealand study has shown. The milk’s unique composition could make it a good option for the very young and the elderly, sports nutrition, and people who are looking for alternatives to cow’s milk, researchers say.

Scientists from the University of Auckland-based Liggins Institute and the Crown Research Institute AgResearch ran the clinical trial.

The participants, 30 women who normally avoided drinking dairy, consumed 650 mL of either cow milk or sheep milk on two separate occasions. Afterwards, the women reported on their digestive comfort, appetite and liking, and provided breath and blood samples. During the trial neither the women nor the researchers knew who was drinking what at the time.

Study co-lead Dr Amber Milan, a research fellow at the Liggins Institute and researcher for AgResearch, says, “We already knew that sheep milk is different from cow milk. It has more nutrients per glass: more protein, fat, vitamins and minerals. For example, sheep milk has almost twice the level of calcium and zinc, compared to cow milk.

“What our trial has shown is that New Zealand sheep milk is not just compositionally different to cows milk, but has inherent properties which means we digest it differently,” says Dr Milan.

“We have, for the first time, confirmed that the protein in sheep milk is more readily digested compared to cow milk. Sheep milk delivered more of the branched-chain amino acids (BCAAs) leucine, valine and isoleucine than cow milk. Amino acids are building blocks for protein, and these kinds are important for forming muscle protein.

The higher total fat levels do not produce a higher spike in blood triglycerides, probably due to the different types of fat in sheep milk. Sheep milk delivered more of some so-called ‘good fats’ (medium-chain fatty acids and conjugated linoleic acid, or CLA) than cow milk.

Aisling Flanagan