Are there hormones in milk?

Jan 25, 2018 | Food and Nutrition | 0 comments

The Dirt:
Yes! All milk contains naturally-occurring hormones. But, consumer perception is that the hormones in milk that has been treated with rBST may cause early puberty in children or increase the chances of getting cancer. The reality is that none of this is true. How did the consumer perception of milk get such a bad reputation and what does the science say?
This day and age, you would be hard-pressed to find a multimillion dollar industry free of controversy. Dairy farmers certainly know this reality all too well. The consumer perception of hormones in milk products is an example of marketing claims gone awry. Because of consumer misunderstanding, the dairy industry changed without any regard for the science. Despite many validated scientific studies and numerous regulatory approvals, the use of rBST (recombinant bovine somatotropin) has been significantly reduced from dairy farming because of the fear generated by misinformed consumers and tactful marketing claims.

What is hormone-free milk?

There is no such thing! As you may remember from our milk journey, all milking cows are females that have recently given birth and have hormones. Just like humans! In fact, if female cows didn’t produce hormones, they would not be able to have babies and produce milk. Once a cow has given birth, she produces milk for approximately 10 months.

What is rBST or rBGH?

BST, or bovine somatotropin, is a naturally occurring protein hormone produced by a female cow’s pituitary gland. Somatotropin regulates the cow’s metabolism and determines how efficiently a cow converts her feed into milk. Bovine somatotropin (BST) is commonly referred to as Bovine Growth Hormone (BGH). rBST is the synthetic version of BST— it is an exact replica of the naturally-occurring BST hormone, just recreated in a lab. After decades of scientific research, scientists recognized that cows supplemented with additional somatotropin produce on average 10-15% more milk every day. Supplemental hormones are also used by dairy producers to regulate reproduction. There is absolutely no discernible difference between milk from treated or untreated cows. In fact, when comparing treated versus untreated milk, it is impossible to detect the use of rBST.
In the 1970s, the biotechnology company, Genentech, discovered the gene for BST and proceeded to synthesize the hormone to create rBST. Pharmaceutical companies were then able to commercialize the technology in order to sell the product to farmers. Monsanto, for example, licensed Genentech’s patent and was the first company to receive approval from the FDA. Monsanto then sold their product to dairy farmers and cows across the United States were then given rBST to increase the milk production.
Keep in mind, milk is a commodity and for this reason it is very hard to distinguish the milk from one dairy cow to another. Farm profitability depends entirely on the available milk supply and consumer demand— i.e. if the combination of farm production costs is higher than milk prices dairy farms lose money. For instance, in 1997, Oakhurst Dairy in Maine was struggling to differentiate their company from larger competitors. The owner of Oakhurst decided to give financial incentives to their dairy farmers and in return asked them to sign a pledge rejecting the use of additional hormones. Thus began the marketing and enticing consumers to drink ‘rBST free’ milk.

Even Oakhurst Dairy, which prides itself on being “America’s first Farmers Pledge” against rBST must also include “FDA states no significant difference in milk treated with artificial growth hormone” on their label. (Source: WGME)

How do we know rBST is safe?

BST (and the synthetic rBST) is a hormone that is specific to bovines. The human body does not produce it or have a need for it. So, if you are an avid milk drinker, you can rest assured that your body does not recognize the BST present in milk and because it is a protein, the human body will effectively break it down (just like any other protein) and eliminate it. Therefore both BST and rBST have no impact as a growth hormone in humans.
In 1993, the Food and Drug Administration (FDA) approved the use of rBST in cattle. The World Health Organization Committee (WHO) and the Food and Agriculture Organization (FAO) followed suit and deemed rBST safe for consumer use. In fact, over 90,000 scientific reviews and studies were published on the safety of rBST on both humans and cows.
According to The American Cancer Society, consumers should not fear the insulin-like hormones, “at this time, it is not clear that drinking milk, produced with or without rBGH treatment, increases blood IGF-1 levels into a range that might be of concern regarding cancer risk or other health effects.”

Mary Kraft is a dairy farmer from Fort Morgan, Colorado. She explains hormone use in milk production and why she feels confident that the milk we all drink is safe and healthy. Source:

While rBST has been proven not to affect human health or the nutritional quality of milk, the studies are mixed as to whether it causes mastitis (udder infections), reduction in fertility, and lameness in cows. These alleged side effects along with the results from a 2003 meta-analysis confirming these findings, resulted in several countries banning the use of rBST. However, 11 years later, a 2014 meta-analysis, sponsored by the American Veterinary Medical Association, showed no ill-health effects to cows. Given these conflicting opinions, the D2D team was curious about what the farmer had to say— after all no one cares more about having healthy dairy cows than a dairy farmer! When speaking with various dairy farmers, they all agree that that the health of the cow really depends on the the farmer. Dairy cows are Olympic athletes. If they are pampered, fed correctly, and properly cleaned they will stay healthy. Like a high performing athlete, if they are neglected and not properly taken care of, they will get sick. For example, if they are given rBST and their udders are not monitored and cleaned there is an increased risk of mastitis, but if they are taken care of the farmer can eliminate that risk!

 The Sustainability Factor

There is a positive environmental impact with the use of rBST. Dr. Normand St-Pierre, a retired dairy specialist from Ohio State University, examined a recent study that calculated the amount of various pollutants that were inevitably not produced with the use of rBST.

In the study, the milk created by the one million dairy cows that were supplemented with rBST inevitably reduced the amount of cows needed to create the same amount of milk. This reduced manure excretion by 3.3 billion pounds per year. And, emissions of CO2 were reduced by 1.3 billion pounds per year—the equivalent of over 350,000 family cars.

The point? Technology often improves efficiency at the farm gate. In the case of rBST, the environment benefited through fewer carbon emissions and the consumer benefited through more affordable milk and milk products. Technology can lead to efficiency – more milk with less water, waste, and land use. From a farmer’s (and consumer’s) perspective this is a positive in terms of business and environmental impact.

What about the labels?

The ‘BST Free,’ ‘rBST Free’, or ‘rBGH’ labels are often used as marketing gimmicks. This continued marketing ploy drives consumer perception. American farmers work with very thin margins. Our farmers are expected to produce viable dairy products on a specific amount of land, water, and resources. The average farmer produces roughly 38,000 glasses of milk a year, with the average consumer consuming roughly 325 glasses of milk a year. Why not allow farmers to produce this using fewer cows rather than putting stress on our environment?

Labels can be confusing. Here not only are customers assured that this milk is free of hormones, but also states that the use of rBST in dairy farming is safe.

Consumer perception wins – at what cost?

rBGH is practically a non-issue today—most producers no longer use rBGH. In 2007, a government study projected that roughly 17% of US cows were treated with rBST and that number has continued to decline. But understanding this social controversy is very important. Do we just ignore the data?  Do we ignore conclusions from organizations like the American Cancer Society? Remember, they are trying to prevent cancer, not cause it! Consumer safety will always be the focus of our farmers and food producers, and as consumers we’ve got to make sure we separate fact from fiction. As we have seen with GMOs, consumer perception can negatively affect successful food technology.

The Bottom Line: Rest assured that our dairy farmers do not want to make consumers sick. They feed themselves and their families the same milk that they produce for consumers. Milk is nutritious, accessible, and affordable. While we understand the health benefits of milk, we should also be aware of the scientific ability to expand American dairy farming and feed a growing population!


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