Dairy cows fed on grass produce healthier milk
Source: Agencies |
June 1, 2010, Tuesday
|
Print Edition
Print Edition
IF milk does the heart good, it might do the heart even more good if it comes from cows grazed on grass instead of on feedlots, according to a United States study.
Earlier studies have shown that cows on a diet of fresh grass produce milk with five times as much of an unsaturated fat called conjugated linoleic acid (CLA) than cows fed processed grains.
Studies in animals have suggested that CLAs can protect the heart, and help weight loss.
Hannia Campos of the Harvard School of Public Health in Boston and her colleagues found in a study of 4,000 people that people with the highest concentrations of CLAs - the top fifth among all participants - had a 36 percent lower risk of heart attack compared to those with the lowest concentrations.
Those findings held true even when researchers took into account heart disease risk factors such as high blood pressure and smoking.
Campos said the new findings, published in the American Journal of Clinical Nutrition, suggest that CLA offers heart-healthy benefits that could more than offset the harms of saturated fat in milk.
"Because pasture grazing leads to higher CLA in milk, and it is the natural feed for cattle, it seems like more emphasis should be given to this type of feeding," she said.
Dairy products in the US come almost exclusively from feedlots, she added, and cow's milk is the primary source of CLA.
For their study, Campos looked to Costa Rica where pasture grazing is still the norm.
They identified nearly 2,000 Costa Ricans who had suffered a non-fatal heart attack, and another 2,000 who had not and then they measured the amount of CLA in fat tissues to estimate each person's intake.
Since CLA typically travels with a host of other fats, the researchers went a step further to tease apart its effects from those of its unhealthy companions.
The difference in risk attributed to CLA subsequently rose to 49 percent.
Earlier studies have shown that cows on a diet of fresh grass produce milk with five times as much of an unsaturated fat called conjugated linoleic acid (CLA) than cows fed processed grains.
Studies in animals have suggested that CLAs can protect the heart, and help weight loss.
Hannia Campos of the Harvard School of Public Health in Boston and her colleagues found in a study of 4,000 people that people with the highest concentrations of CLAs - the top fifth among all participants - had a 36 percent lower risk of heart attack compared to those with the lowest concentrations.
Those findings held true even when researchers took into account heart disease risk factors such as high blood pressure and smoking.
Campos said the new findings, published in the American Journal of Clinical Nutrition, suggest that CLA offers heart-healthy benefits that could more than offset the harms of saturated fat in milk.
"Because pasture grazing leads to higher CLA in milk, and it is the natural feed for cattle, it seems like more emphasis should be given to this type of feeding," she said.
Dairy products in the US come almost exclusively from feedlots, she added, and cow's milk is the primary source of CLA.
For their study, Campos looked to Costa Rica where pasture grazing is still the norm.
They identified nearly 2,000 Costa Ricans who had suffered a non-fatal heart attack, and another 2,000 who had not and then they measured the amount of CLA in fat tissues to estimate each person's intake.
Since CLA typically travels with a host of other fats, the researchers went a step further to tease apart its effects from those of its unhealthy companions.
The difference in risk attributed to CLA subsequently rose to 49 percent.
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