Is rBGH safe?

What is rBGH

Since 1937, the dairy industry has known that the growth hormone bovine somatotropin (BGH) increases milk production in cows. Somatotropin increases milk supply by increasing the circulation of another hormone: insulin-like growth factor (IGF-1).

Up until the 1980’s, this hormone was used on a very limited basis and its source was bovine cadavers.

In 1994, Monsanto released Posilac, a synthetic recombinant bovine growth hormone (rBGH or rBST). This hormone is made in a laboratory using genetic technology and, in some cases, differs from natural BGH by one amino acid (methionine).

When dairy farmers use rBGH to increase milk production they can get up to eight more pounds of milk per day from a cow. Use of rBGH also increases instances of mastitis, which increases the use of antibiotics.

Safety Concerns

Concerns about rBGH focus on two issues:

  1. Does ingestion of rBGH increase the amount of IGF-1 circulating in the system of the consumer?
  2. Does the increased use of antibiotics result in an increase in antibiotic resistant strains of bacteria?

What the FDA says

The FDA approved rBGH as safe for consumption in 1993 after reviewing studies done by Monsanto. Studies included a 28-day oral ingestion, a 90-day oral ingestion and a nine-day subcutaneous injection in rats.

In its report, the FDA indicated:

Regarding ingestion of rBGH:

  • “Biologically significant amounts of rbGH” are not absorbed when people drink or eat products containing rBGH
  • There is evidence that consumption of rBGH produces an antibody response, but the “response was consistent with that produced by a number of food proteins and is not necessarily an indication of absorption of intact rbGH”
  • With regard to the antibody response, “at high doses these data appear to show some systemic anti-rbGH response” with the oral administration to rats.

Regarding cysts and tumors:

  • In“[n]either frequency nor severity” did cyst growth appear related to rBGH ingestion or injection.

Regarding IGF-1:

  • Cows treated with rBGH “produced a slight, but statistically significant, increase in the average milk IGF-I concentration” but the FDA determined it was within the range of normal.
  • Although recent studies show that IGF-1 can survive digestion, the vast majority of studies show that “very little IGF-1 is absorbed after digestion.”

Regarding antibiotics:

  • Use of rBGH does increase the need for antibiotics, and the veterinary committee “concluded that, while rbGH treatment might cause a statistically significant increase in mastitis, the human health risk posed by the possible increased use of antibiotics to treat the mastitis was insignificant.”

The FDA determined that there was no indication that any long term studies were needed.

Other points to consider:

As with most controversial topics, it’s hard to sort through the information.

Monsanto carries a lot of political weight and is known to treat critics harshly, two things that I think color the FDA approval, especially when I read sentences like

“As set forth in detail below, FDA believes that the Canadian reviewers did not interpret the study results correctly and that there are no new scientific concerns regarding the safety of milk from cows treated with rbGH.”

That sentence sounds to me like a dismissal of Canadian scientists and officials as being less competent and doesn’t instill me with confidence in the authors of the FDA report.

On the other hand, stories of Chinese babies developing breasts and girls hitting puberty at a younger age due to rBGH seem unreliable when there are no studies or facts to back them up.

I do think it’s important to note the following:

THE FDA REVIEWED ONLY STUDIES FROM MONSANTO when determining the safety of rBGH and no long-term studies have been conducted.

JAPAN, AUSTRALIA, NEW ZEALAND, CANADA, AND THE EU HAVE ALL BANNED the use of rBGH. Those countries follow the Precautionary Principle which states “if an action or policy has a suspected risk of causing harm to the public or to the environment, in the absence of scientific consensus that the action or policy is harmful, the burden of proof that it is not harmful falls on those taking the action.” In other words, those countries err on the side of caution when something may be harmful to the public or the environment. (I tend to think it also means that the U.S. is the ultimate long term study for all those countries when it comes to questionable food products like rBGH, cloned meat, dyes, and GMOs.)

PEOPLE CONSUME RBGH IN milk, cheese, yogurt, ice cream, butter, and all dairy products. It’s unclear whether the FDA took this into account when stating that amounts of rBGH  and IGF-1 absorbed are not significant.

The FDA points out, with regard to antibody response to rBGH, that “the vast majority of healthy infants and 15 – 30% of adults have antibodies to various dietary proteins, especially milk-derived proteins.”

In another part of the report, the FDA states that “IGF-1 is a protein normally found in all humans, and is not intrinsically harmful” and that it is “necessary for normal growth, development, and health maintenance.”

BECAUSE WE ARE CONSUMING THEM IN SO MANY PRODUCTS WITHOUT REALIZING IT, we may be consuming more rBGH and IGF-1 than we realize. If all of these “statistically insignificant” amounts add up, it might exacerbate and/or exaggerate what would otherwise be normal reactions – such as “normal” antibody response or “normal” growth and development.

EXPERTS TEND TO AGREE THAT ANTIBIOTIC USE in food animals is directly related to development of antibiotic-resistant strains of bacteria.

The bottom line:

Will you put your faith in the FDA, Monsanto, and the U.S. food system, or follow the Precautionary Principle in your own home? Only you can determine the answer, after reading this information, to whether you are comfortable consuming products containing rBGH.


Wikipedia entry on Bovine Somatotropin accessed on September 18, 2010.

FDA Report on the Food and Drug Administration’s Review of the Safety of Recombinant Bovine Somatotropin accessed on September 18, 2010. report RECOMBINANT BOVINE GROWTH HORMONE accessed on September 18, 2010.

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