Organic milk

Organic milk refers to a number of milk products from livestock raised according to organic farming methods. In most jurisdictions, use of the term "organic" or equivalents like "bio" or "eco", on any product is regulated by food authorities. In general these regulations stipulate that livestock must be: allowed to graze, be fed an organically certified fodder or compound feed, not be treated with most drugs (including growth hormone), and in general must be treated humanely.

There are multiple obstacles to forming firm conclusions regarding possible safety or health benefits from consuming organic milk or conventional milk, including the lack of long term clinical studies. The studies that are available have come to conflicting conclusions with regard to absolute differences in nutrient content between organic and conventionally produced milk, such as protein or fatty acid content. The weight of available evidence does not support the position that there are any clinically relevant differences between organic and conventionally produced milk, in terms of nutrition or safety.

In general, all livestock used to produce organic milk must be maintained using the methods of organic farming as defined in the jurisdiction where the milk will be sold, and generally must be certified in order to be marketed as organic. In general, these laws require that livestock be allowed to graze on pasture, be fed organic certified feed (which may not include byproducts of animal slaughter), and that the animals not be treated with drugs (although it is also illegal to withhold necessary drugs from a sick animal in order to maintain that animal's organic status).

Studies have examined chemical differences in the composition of organic milk compared with conventional milk. These studies generally suffer from confounding variables, and are difficult to generalize due to differences in the tests that were done, the season of testing and brand of milk tested, and because the vagaries of agriculture affect the chemical composition of milk. Treatment of the foodstuffs after initial gathering (whether milk is pasteurized or raw), the length of time between milking and analysis, as well as conditions of transport and storage, also affect the chemical composition of a given batch.

A 2012 meta-analysis of the scientific literature did not find significant differences in the vitamin content of organic and conventional plant or animal products, and found that results varied from study to study. The authors found 4 studies on each of beta-carotene and alpha-tocopherol levels in milk; differences were heterogeneous and not significant. The authors found few studies on fatty acids in milk; all (but for one) were of raw milk, and suggest that raw organic milk may contain significantly more beneficial omega-3 fatty acids and vaccenic acid than raw conventional milk. The authors found no significant differences between organic raw milk and conventional milk with respect to total protein, total fat, or 7 other vitamins and fatty acids tested. A different review concluded, "Results to date suggest that the nutritional content of organic milk is similar to that of conventional milk. There may be a different profile of fatty acids in organic milk, with a higher proportion of PUFA (polyunsaturated fatty acids) relative to other fatty acids, but this effect does not appear to be consistent. This difference will be smaller in fat-reduced milk."

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