December 1, 2008 (Vol. 28, No. 21)
Henry I. I. Miller, M.D. Physician and fellow Stanford University
rbST Has Been Unfairly Stigmatized by Activists
Milk occupies a special place in our lives and language. It has been dubbed “Nature’s most perfect food,” and we speak sentimentally of the “land of milk and honey” and the “milk of human kindness.” Dairy products represent important nutrient sources in much of the world, providing calcium and high-quality protein.
Fourteen years ago, after a lengthy review, the FDA approved a protein called recombinant bovine somatotropin (rbST), or bovine growth hormone, that stimulates milk production in dairy cows. “Recombinant” indicates that the protein is made with gene-splicing techniques, but the gene-spliced and natural versions are functionally indistinguishable.
A cow’s pituitary gland normally produces bST, one of a group of natural protein hormones that controls milk production. Thus, low levels of bST are found in milk from all cows, both supplemented and unsupplemented.
Comprehensive and sophisticated studies by academics and government regulatory agencies around the world have found no difference in the composition of the milk or meat from bST-supplemented cows.
From the beginning, farmers loved rbST, which is now used in approximately one-third of U.S. dairy herds, because it offered them greater yields per cow, more efficient use of feed, and higher profits; but things quickly soured. Activists were adamantly opposed to rbST, and they have continued to raise a variety of spurious, specious objections ever since.
An article published earlier this year by Cornell University Professor Dale Bauman and his colleagues in the prestigious Proceedings of the National Academy of Sciences concluded that the protein is a “valuable tool for use in dairy production to improve productive efficiency” (defined as milk output per feed resource input), and at the same time has “fewer negative effects of the environment than conventional dairying.”
This elegant study should put any remaining concerns to rest, but it won’t. The food kooks and enviro-fanatics won’t let facts get in the way of their prejudices.
When rbST is injected into cows, their digestive systems become more efficient at converting feed to milk. It induces the average cow, which produces about eight gallons of milk each day, to make nearly a gallon more. More feed, water, barn space, and grazing land are devoted to milk production, rather than other aspects of bovine metabolism, so that you get seven cows’ worth of milk from six.
This may not seem like a big deal, but when applied widely the effects are profound. For every million cows treated with rbST each year, 6.6 billion gallons of water (enough to supply 26,000 homes) are conserved. With much of the nation enduring a drought and many cities in the West experiencing water shortages, this is a significant benefit.
The amount of animal feed consumed each year by those million rbST-supplemented cows is reduced by more than three billion pounds. This helps to keep the lid on corn prices, even as much of the nation’s corn harvest is diverted to producing ethanol for cars. And the amount of land required to raise the cattle and grow their food is reduced by more than 417 square miles.
At the same time, more than 5.5 million gallons of gasoline and diesel fuel (enough to power 8,800 homes) are saved, greenhouse gas emissions are lowered by 30,000 metric tons (because fewer cows means less methane produced by bovine intestinal tracts), and manure production is decreased by about 3.6 million tons, reducing the runoff into waterways and groundwater.
Consumers are apparently happy to drink milk from supplemented cows, in spite of efforts by biotechnology opponents to bamboozle milk processors and retailers into believing that consumers don’t want it. In various surveys to ascertain the factors that influence consumers’ milk purchasing decisions, the predominant considerations have been: price (80 to 99%), freshness (60 to 97%), brand loyalty (30 to 60%) and a claim of organic (1 to 4%). Only the organic claim is even remotely related to rbST supplementation. Unless prompted, the consumers surveyed didn’t mention rbST as a concern.
Some milk suppliers and food stores have increased the price of milk labeled rbST-free, even though it is indistinguishable from supplemented milk, and offer only this more expensive option, preempting consumers’ ability to choose on the basis of price.
Activists’ purely speculative concerns about rbST—ranging from the destruction of small family farms to the risk of cancer —have proven baseless. Before approval by the FDA, rbST underwent the longest and most comprehensive regulatory review of any veterinary product in history. Three years before the FDA approved the marketing of milk from supplemented cows, its scientists, in an article published in Science, summarized more than 120 studies showing that rbST poses no known risk to human health.
These conclusions were affirmed over the next several years by additional scientific reviews conducted by the NIH, the Congressional Office of Technology Assessment, and the drug-regulatory agencies of Britain, Canada, and the EU, and by an issues audit done by the inspector general of the U.S. Department of Health and Human Services. These reviews noted that small amounts of bST are found in milk from all cows, supplemented or not. They also pointed out that, like other proteins, rbST is digested in the human gut, and that even if it is injected into the human bloodstream, it has no biological activity.
There’s no milk of human kindness from the antibiotech lobby, however. Disingenuous activists have unfairly stigmatized a scientifically proven product that has consistently delivered economic and environmental benefits to dairy farmers and consumers; and opportunistic retailers are ripping off their customers. Given the current mania about anything green or sustainable, shouldn’t activists embrace—and enlightened consumers demand—milk with a label that boasts, “A Proud Product of rbST-Supplemented Cows”?