There is a lot of conflicting information about what additives may be in our dairy and meat products and what effect they have on us. It can be confusing to sort through all the noise. The truth is, there may not be clear answers, which makes knowing how to choose your food a difficult task.
Hormones are present in all animal products whether or not the animals have been treated with hormone supplements.
The US Food and Drug Administration (FDA) and a joint committee of the Food and Agricultural Organization and World Health Organization (FAO/WHO) state that the amount of these hormones that make it into food products is safe for eating. Hormones and steroids are given to livestock to help improve the production of dairy and beef. Some hormones that may be used in dairy cows include:
Beef cattle are often given steroid additives to increase growth and development. Common steroids include:
These additives have proven benefits for increasing milk and meat production, but it does not come without controversy.
High levels of hormones can cause problems in the human body, but can hormones we ingest in meat and dairy alter our hormone levels? Concerns come from 2 different issues. The first is how much of these additives we absorb when we consume dairy or meat products. Do these additives simply pass through our digestive system or does our body absorb them? How much remains in products after processing?
The second concern is how these steroids or hormones affect the human body. Some hormones are specific to cattle, others are similar to hormones found in humans. Do they all impact levels of human hormones?
The FDA monitors all food products and has stated that the hormones are safe, but many argue that is not the case. Below are some of the arguments from both sides:
Recombinant Bovine Growth Hormone (rBGH)
Critics of rBGH argue that milk from treated cows contains higher levels of this hormone than milk from non-treated cows. However, the FDA concluded that there is no evidence that a biologically active form is absorbed. Also, the bovine growth hormone is not active in humans. If this is true, even if it was absorbed by humans, it would not be expected to affect health.
Insulin-like Growth Factor-1 (IGF-1)
IGF-1 is naturally present in both cattle and humans. It plays an important role in milk production, bone growth, and cell division. Since it occurs in both, it is assumed that humans can absorb extra IGF-1 from milk. It is possible that higher levels of IGF-1 in the blood may be associated with an increased risk of some cancers, but no evidence has proven a link. The same connection has been made to estrogen levels and risk of breast or ovarian cancer, although again, no evidence is present at this time.
Some argue that rBGH causes higher levels of IGF-1 in milk. The FDA, however, has reported that there is similar amounts of IGF-1 in milk from cows treated with rBGH as there is in milk of untreated cows.
Cows treated with rBGH reportedly have higher incidence of infections in the udder (mastitis). These infections are treated with antibiotics. Like in humans, high use of antibiotics can create a resistance to certain bacteria making treatment difficult. It is unknown if the antibiotics used to treat the mastitis create harm in humans.
With beef cattle, the arguments are similar. One organization points to evidence associating women who eat meat during pregnancy with sons who have low sperm counts. The FDA argues that residues of additives in beef are negligible in comparison to levels that occur naturally both in cows and humans.
Authorities also point out that steroid hormone levels in beef, whether from treated animals or not, are far lower than those found in eggs or milk. Additionally, these levels are dwarfed by high levels of plant estrogens—or phytoestrogens—present in soybeans, wheat germ, cabbage, broccoli, and many other vegetables. Phytoestrogens act like estrogen on the body.
Remember that no evidence has made a solid connection with either side of this argument. Many store chains and buyers will not use dairy or beef from farms using extra hormones. Some countries have banned their use because of the harm that it may do to the animals, not humans.
Until more rigorous research is done, some might prefer to err on the side of caution. Among authorities that do advise caution, most say that pre-pubescent children are at greatest risk. Pregnant women may also want to use caution. Here are some tips if you want to keep treated products off your or your family members’ plate:
The Organic Farming Research Foundation
US Food and Drug Administration
Andersson AM, Skakkeback, NE. Exposure to exogenous estrogens in food: possible impact on human development and health. EurJ Endocrinol. 1999;140(6):477-485.
Bovine somatotropin (BST). US Food and Drug Administration website. Available at: http://www.fda.gov/AnimalVeterinary/SafetyHealth/ProductSafetyInformation/ucm055435.htm. Updated March 9, 2016. Accessed July 20, 2016.
Health concerns about dairy products. Physicians Committee for Responsible Medicine website. Available at: http://www.pcrm.org/health/diets/vegdiets/health-concerns-about-dairy-products. Accessed July 20, 2016.
Growth Hormones Fed to Beef Cattle Damage Human Health. Organic Consumers Association website. Available at: http://www.organicconsumers.org/articles/article_5543.cfm. Published May 1, 2007. Accessed July 20, 20156.
rBGH. Grace Communications Foundation website. Available at: http://www.sustainabletable.org/797/rbgh. Accessed July 20, 2016.
Recombinant bovine growth hormone. American Cancer Society website. Available at: http://www.cancer.org/cancer/cancercauses/othercarcinogens/athome/recombinant-bovine-growth-hormone. Updated September 10, 2010. Accessed July 20, 2016.
Vitale DC, Piazza C, Melilli B. Isoflavones: estrogenic activity, biological effect and bioavailability. Eur J Drug Metab Pharmacokinet. 2012;28(1):15-25.
Last reviewed July 2016 by Michael Woods, MD
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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