Organic milk, alternative to fish for omega-3s?
differences in the feed given to organic herds, report researchers
in Wales.
A study carried out at the Institute of Grassland and Environmental Research (IGER) in Aberystwyth showed that cows fed red clover silage, the typical diet for an organic dairy herd, produced milk with significantly higher levels of polyunsaturated fatty acids than that produced by convential herds.
Omega 3 fatty acids are believed to help maintain a healthy heart, combat the effects of arthritis and help the development of healthy brains in unborn children. The best source of omega-3 is oily fish such as salmon and herring but research has shown that only a third of the UK population eat it regularly.
The UK's Organic Milk Suppliers Cooperative (OMSC) is now calling on the Food Standards Agency to recommend organic milk for its health benefits.
"Drinking just half a pint a day of organic milk as part of a healthy, balanced diet gives a useful additional source of this omega 3 fatty acid," said Sian Porter, a state nutritionist. Eating a matchbox-sized piece of organic cheese will provide nearly all the recommended daily intake of omega-3 fats.
The researchers collected bulk milk samples from 10 organic dairy farms and eight conventional dairy farms during the winter of 2002-2003 when all farms were feeding conserved forage.
An analysis of the fatty acid content in the milk samples found that alpha-linolenic acids made up 0.43 per cent of regular milk fat but 0.72 per cent of the fat in organic milk, an increase of 60 per cent.
The findings were consistent with previous studies looking at the effects of red clover on rumen micro-organisms. The Aberystwyth team had shown that red clover could protect against the conversion of polyunsaturated fatty acids into saturated fats, seen with normal grass forage. Red clover is used as an alternative to chemical fertilisers on organic pastures.
Analysis of milk samples did however find a higher level of palmitic acid, a negative factor in the nutrition value of dairy products. The researchers said further work was needed to explain this trend.
Further, there was no sign of a higher content of conjugated linoleic acid (CLA) in organic milk, thought to have anti-cancer and anti-obesity effects.
"Our previous research has shown that milk from cows fed clover can contain up to 240 per cent more omega 3 fatty acids than milk from cows fed grass and concentrate," said Dr Richard Dewhurst, joint leader of the nutrition and microbiology team at IGER.
Organic milk is produced from cows which are not given routine antibiotics, are not fed GM feed and have not grazed on pastures treated with artificial pesticides.
Recent data shows huge growth in sales of organic milk, with the market continuing to grow by more than 30 per cent year on year.
