Healthier Milk?? Cows Fed Rapeseed Make Healthier Milk
By Mark Peplow
Rapeseed is rich in unsaturated fats, which pass through the cow's digestive system into its milk. One of these fats, called oleic acid, makes butter produced from the milk spreadable when cold.
Changing the composition of milk through the cow's diet is a well-established practice. "But this is the first time it has actually got through to the market place," says Anna Fearon, the food chemist at Queen's University, Belfast, who led the research team. The butter tastes just like normal, she adds.
'Naturally Spreadable Butter', as it is known, is already available from Marks and Spencer supermarkets, but the research behind it has only just been published in the Journal of the Science of Food and Agriculture1. About 150 farms in Northern Ireland now produce their milk in this way.
Better butter
To be marketed as 'butter', the product must be made entirely from milk fat. If any vegetable oil is present, the substance is relabelled as a 'spread', which is often less attractive to consumers. "We just put the vegetable oil in at an earlier stage," says Fearon.
The researchers found that the more seed they fed the cows, the more the milk's fat composition changed. Cows fed 1 kilogram of rapeseed a day, produced milk with 35% more oleic acid and 26% less palmitic acid - a type of saturated fat - than cows fed a normal diet.
Rapeseed is used to supplement the normal diet of food pellets and grass. "If we feed them raw seeds alone, they come straight out of the other end of the cow," says Fearon. The cows seem quite happy on their new diet, she adds. "We did a whole battery of tests to make sure the animals' health was not affected."
Eating this butter is not a quick way to reduce cholesterol, cautions Steer, since butter forms only a small proportion of our saturated fat intake. Fearon's butter only provides a healthier alternative if it underpins a balanced diet, she says.
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