Headlines this week have declared that organic milk is more nutritious than regular milk after a new study found it has more heart-healthy omega-3 fatty acids. The implication: It’s worth it to spend an extra $2 to $3 a gallon to buy organic brands.
But here’s the fine print: The differences in omega-3 content was small and only applied to whole milk, not skim milk—which contains no fat. What’s more, Organic Valley, a farm cooperative that sells organic dairy products, provided the main funding for the study, and one of its employees was a study co-author.
While that doesn’t necessarily discount the findings—published in the journal PLoS One —it does call into question the sweeping recommendations made by the study authors that people increase their intake of “fat-containing” and “predominantly organic” dairy products. Switching to organic full-fat milk, butter, and cheese, the authors wrote, “should improve long-term health status and outcomes, especially for pregnant women, infants, children, and those with elevated cardiovascular disease risk.”
Boston University nutrition professor Joan Salge Blake told me these conclusions amounted to a load of cow dung. “I don’t think organic milk is worth the extra money,” she said, “and the last thing people should do is switch to fattier dairy products because they contain a lot of heart-damaging saturated fat and a lot more calories than skim milk.”
An 8-ounce glass of whole milk contains 150 calories and 8 grams of total fat—with nearly 5 grams of saturated fat—compared to skim milk’s approximately 80 calories and less than 1 gram of total fat. All of the negative drawbacks of the extra fat and calories outweigh the benefits conferred by the miniscule amount of extra omega-3 fatty acids, less than a fraction of a gram per serving.
The researchers who conducted the new study argued that cattle fed on organic grass—rich in omega-3s—produce milk with a more favorable ratio of omega-3 fats to omega-6 fats compared to cows on non-organic farms that are fed corn rich in omega-6 fats. They base that assessment on an analysis comparing more than 200 organic milk samples and more than 150 conventional milk samples from dairy farms throughout the country.
But there’s nothing wrong with eating omega-6 fats, said Salge Blake who also writes the Boston.com Nutrition and You! blog. “The challenge is getting more omega-3s in your diet,” she said, and eating fish will provide far more of them than switching to organic milk. The US Dietary Guidelines for Americans recommends replacing beef and chicken with seafood a few times a week to get more omega-3 fats. Salge Blake recommended aiming for two four-ounce servings of salmon, tuna, and other fatty fish per week.