A just-released New Zealand study says sheep milk's protein is more easily digested and its fats are more readily converted into energy than cow milk.
Scientists from the University of Auckland-based Liggins Institute and the Crown research institute AgResearch ran a clinical trial with support from sheep milk producers Spring Sheep Milk Co. and Blue River Dairy LP.
'Sheep milk nutrient bioavailability and digestive comfort: A randomised control trial' is believed to be the first human study in the world to investigate how differences in the composition of New Zealand sheep milk affect ease of digestion, digestive comfort, and the body's ability to make use of milk protein.
The participants, 30 women who normally avoided drinking dairy, consumed 650ml 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.
"We already knew that sheep milk is different from cow milk," said study co-lead Dr Amber Milan, a research fellow at the Liggins Institute and researcher for AgResearch.
"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," said Dr Milan.
The trial had shown that New Zealand sheep milk was not just compositionally different to cow milk, but had inherent properties which meant it was digested differently.
"We have, for the first time, confirmed that the protein in sheep milk is more readily digested compared to cow milk," she said.
Spring Sheep's Food Technology Research & Development Manager Natalie Macbeth said the result of the clinical trial was good news for consumers who struggled with the digestion of cow milk.
"It's great to be able to provide them with solid evidence that further supports the benefits of sheep milk," said Macbeth.
New Zealand now has more than 20,000 sheep for milking through 16 different producers.
Significant new investment is going into milk processing and supply to overseas markets, which currently include China, Taiwan, Malaysia and Vietnam.
While sheep milk is traditionally used to make cheese and yoghurt, New Zealand businesses are leading the way in developing high-value nutritional products including sheep milk infant and toddler formula, specialist nutritional formulations and drinks.
The researchers presented their findings at the Food Structures, Digestion and Health International Conference in Rotorua in October and are submitting their findings for publication in a scientific journal next year.