Is Organic Milk Better For You? One Study Says Yes

 @rpalmerscience
on December 09 2013 6:11 PM
milk
Organic milk tends to have higher levels of omega-3 fats, according to a new study. Flickr via Creative Commons/mhaithaca

Sure, organic food is pricier, but do those extra dollars and cents buy you better nutrition? One team of scientists says that with milk, the answer’s yes.

As of 2012, about 4 percent of all dairy products sold in the U.S is organic, according to Reuters. Under U.S. Department of Agriculture guidelines, dairy products are only worthy of the organic label if they come from cows that get at least 30 percent or their diet from grazing outside, and are fed only organic feed that contains no meat or poultry byproducts, and are not given antibiotics or growth hormones. But sometimes those production differences can drive up the cost of a gallon of organic milk to higher than a gallon of gasoline.

But eating healthier costs more even if you’re not going organic. Maybe the premium on organic foodstuffs means an even better product? A 2012 review by Stanford University researchers casts doubt on this, finding that there is a lack of strong evidence that organic foods are significantly more nutritious than conventionally farmed foods, though eating organic may reduce your exposure to pesticide residues and antibiotic-resistant bacteria. But the scientific jury is still out.

One point in organics’ favor comes in the form of a paper published on Monday in the journal PLoS ONE. A team of scientists led by Washington State University researcher Charles Benbrook -- who is also a science advisor for the Organic Center, a group that aims to “convene credible, evidence-based science on the environmental and health benefits of organic food and farming” -- analyzed around 384 samples of organic and conventional milk from across the U.S. over an 18-month period. The study was funded in part by the Cooperative Regions of Organic Producer Pools (CROPP) and its brand-name company Organic Valley, which sells organic products, including dairy.

In their nutrition research, Benbrook and colleagues focused on the ratio of two different kinds of fats in the milk: omega-6 and omega-3. Eating way more omega-6 fats than omega-3s is thought to be a health risk, and many of us eating “Western diets” are getting a lot more omega-6s. But organic milk, it turns out, could be a good source of omega-3s. Benbrook and colleagues found that the average omega-6 to omega-3 ratios nationwide in organic milk was about 2.3, while for conventional milk, the figure was 5.8.

"We were surprised by the magnitude of the nutritional quality differences we documented in this study," Benbrook said in a statement.

Their results do seem to jive with some other studies. In 2006, researchers from the University of Glasgow sampled milk from organic and conventional dairy farms in the U.K. and found a consistently lower ratio of omega-6 to omega-3 fats. Newcastle University researchers came to a similar conclusion in 2011, but said that the short-chain surplus of omega-3s found in organic milk were limited in health benefits in comparison to the longer-chain omega-3s found in fish.

But some dairy experts are skeptical.

"I think it is unfair to attribute the milk fat changes to organic farming practices," Mark Hanigan, a professor of dairy science at Virginia Tech, wrote in an email. Feeding cows a "high forage" diet rich in grass, legumes and silage -- fermented vegetable matter -- as well as "allowing access to pasture alters the milk fat regardless of whether the cows are being fed organically."

If organic farming practices do make a difference, then drinking organic milk might be a way for consumers to shore up their omega-3 levels. Benbrook and colleagues think that replacing 3 servings a day of conventional dairy products to 4.5 servings a day of organic dairy products could tamp a hypothetical woman’s omega-3 to omega-6 ratio down from 11.3 to 2.3, a figure thought to maximize heart health.

“Surprisingly simple food choices can lead to much better levels of the healthier fats we see in organic milk,” Benbrook said.

Benbrook has a history of wading into the midst of some scientific tussles; both other scientists and journalists have criticized some of his papers that link a rise in GMO crops to increased pesticide use. And he’s hardly hesitant to respond in kind-- Benbrook criticized the Stanford review that found little nutritional advantage for organics, saying that the scientists left out important data and didn’t properly define what makes a food “significantly more nutritious” than another food, and pointed to individual studies that show organic farming leads to increases in some nutrients like vitamin C.

“Hopefully in the years ahead, improved methods under development… to compare food nutritional quality and safety will shed clearer light where now the shadows seem to be constantly shifting,” Benbrook wrote in September 2012.

SOURCE: Benbrook et al. “Organic Production Enhances Milk Nutritional Quality by Shifting Fatty Acid Composition: A United States-Wide, 18-Month Study.” PLoS ONE published online 9 December 2013.

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