Is organic milk healthier?

photo: Donna P Feldman

The word “organic” on a food label is:

  1. a great marketing tool
  2. a guarantee that the food is healthier

Answer: 1.  You knew that, right?

Organic may conjure images of quaint family farms, with kindly people milking cows by hand, throwing home-grown grain to the chickens and picking wholesome vegetables from lovingly cultivated garden plots.  But today, organic is big business.  You’re just as likely to find organic soft drinks, chips, cookies, ice cream and frozen pizza in your local grocery store as to find organic vegetables or milk.

Despite the Health Halo image of “organic”, studies have never supported the claims of better nutritional quality.  Organic foods may be free of pesticides,  artificial fertilizers or growth hormones, but they don’t necessarily have more nutrients.  Nutritional content has more to do with soil composition, climate, moisture and plant or animal genetics.  A new study on organic milk proves that point, although it’s being interpreted to “prove” that organic milk is healthier.

The study (funded by organic agriculture organizations) examined only the omega-6 and omega-3 fatty acid content of organic vs. conventional milk, averaged over 12 months.  In other words, all the other significant nutritional aspects of milk were ignored:

  • protein
  • calcium
  • phosphorus
  • vitamin D
  • potassium
  • zinc
  • vitamin B12
  • riboflavin

Even saturated fat was not assessed, which is strange, because this study focused on high fat whole milk.  Hardly anyone drinks whole milk anymore because of the high saturated fat content.  Saturated fat is linked to heart disease.  People are increasingly drinking low fat or non fat milk.  Ironically, according to the data published with this study, the saturated fat content of the milk from organic cows was not any different from conventionally raised cows.

The focus was all about unsaturated fats, which make up less than 10% of the fat in whole milk.  The data indicate that organic milk had 25% less omega-6 content and 62% more omega-3s.  Sure sounds impressive.  But a 62% increase in a tiny number results in another tiny number.  Sockeye salmon has over 80 X as much omega-3 as organic milk.

The other problem: most of the omega-3 fats in milk are linolenic acid, the less biologically significant form of omega-3 fats.  By comparison, the omega-3 in salmon and other fatty fish is primarily EPA and DHA.

Why is organic milk higher in omega-3 fats?  One of the requirements for labeling milk organic is that the cows must spend a certain amount of time eating grass.  Grass is a source of linolenic acid, that less biologically active omega-3 fatty acid.  It ends up in the milk, boosting omega-3 content.  Conventional milk cows do not have to eat grass, although if they did eat grass, the milk would also be higher in omega-3.   Clearly, this wasn’t so much a study of organic milk as a study of the impact of grass feeding on milk.  The omega-3 content of milk has absolutely nothing to do with “organic” or lack of pesticides or hormones.  It’s all about grass.

Clearly this study cannot make any sweeping claims about the nutritional superiority of one milk over another, since only one nutrient was measured.  You may prefer organic milk because it’s free of pesticides, or because of cattle feed or other issues related to milk production.  That’s fine.  Just don’t buy organic milk based on the belief that’s it’s nutritionally superior.  Only one nutrient was measured in this study, and you can get vastly more of those omega-3s from one modest serving of salmon a week.

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