Terry D. Etherton

A new scientific study by Vicini et al. published in the July issue of the prestigious Journal of the American Dietetic Association (JADA) reports the results of the first in-depth survey study comparing retail milk for quality, nutritional value and levels of different milk hormones, including bovine somatotropin (bST). The study that we published found that there were “no meaningful differences” in the composition of milk with the three different label claims.

Prompted by the recent trend in misleading food labeling based on dairy cow management, the study looked specifically at three label claims: conventional milk, recombinant bovine somatotropin (rbST)-free milk and organic milk.

While minor differences were observed in milk composition for the three labels, the differences were not “biologically meaningful.” The coauthors of the study concluded that label claims “were not related to any meaningful differences in the milk compositional variables measured.” The only difference among conventional, rbST-free and organic milk is price, according to the study, with milk labeled rbST-free or organic selling for anywhere from $1 to $4 more per gallon than conventional milk.

Because absence-claim labels can imply that the milk labeled rbST-free or organic is safer or better than conventional milk, the published report emphasizes the importance of consumers being mindful about how product labels impact the food they purchase, that purchase decisions should be based on science and not on perceptions created by retail marketing, which can be misleading.

This peer-reviewed paper is important because it will help health care professionals respond effectively to consumer questions and perceptions about different milk-label claims.

Specifically, the study revealed the following:

• Quality: Antibiotics were not detectable in any milk samples. This is a not surprising result since milk containing antibiotics is not permitted to enter the food system. Bacterial counts were less for conventionally labeled milk compared with organic or rbST-free milk, but the differences were small and not significant.
• Nutrient Composition: Protein concentration was greater in organic milk compared to either conventional or rbST-free milk, which both had similar protein content. Again, the difference is not significant, and protein in milk accounts for little of the recommended protein intake for humans. There were no differences in milk fat, lactose or solids among the three label types.
• Hormone Levels: There were no differences in concentration of bST in milk regardless of label type. Concentrations of IGF-1(insulin-like growth factor-1) in milk were similar in conventional and rbST-free-milk, both were slightly higher in comparison to organic milk. Concentration of the steroid hormone progesterone was greater in organic milk compared to conventionally labeled milk or milk labeled rbST-free. Conventionally labeled milk had less estradiol compared to organic and rbST-free milk with concentrations of estradiol in samples labeled organic and rbST-free being the same.

Milk samples for the study were obtained from all 48 contiguous states, though some states did not have rbST-free milk, and some did not have organic milk samples pasteurized by the more conventional, lower-temperature methods. Samples were obtained during a three-week period, and states with larger populations and greater milk production were oversampled.

Reference for the study:

Vicini J, T Etherton, P Kris-Etherton, J Ballam, S Denham, R Staub, D Goldstein, R Cady, M McGrath, & M Lucy. Survey of retail milk composition as affected by label claims regarding farm-management practices. J Am Diet Assoc. 2008;108:1198-1203.

Orion Samuelson is heard on WGN Radio, where he has served as Agribusiness Director since 1960. He and his associate, Max Armstrong, present 15 agricultural/business reports daily on WGN. They also host the hour-long Morning Show and Noon Show, both heard on Saturdays on WGN. Orion is also heard daily on more than 260 radio stations with his syndicated National Farm Report and on 110 stations with his syndicated Samuelson Sez. Orion and Max are seen weekly on rural channel RFD-TV, carried on Dish-TV and DirecTV on This Week in Agribusiness.

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A common “sound bite” in the arsenal of individuals who oppose rbST use in the dairy industry in the United States is that it is banned in most countries around the world, especially Canada and all the European nations to protect the milk supply. This is inaccurate and misleading. Here are the facts:

The Facts:

No country has a regulatory ban on rbST. Registration of rbST for commercial sale simply has not been completed in many countries.

No country has banned the importation of milk or milk products from the U.S. produced from cows supplemented with rbST (statement by U.S. Dairy Export Council).

There are 20 countries that have a current registration of rbST for commercial sale. Chile is the most recent country to grant registration which was achieved in 2006.

There are 56 counties which have confirmed that rbST use is safe and does not threaten the human food chain, including Canada, and most of the European Union. Confirmation of human safety is the first step in a registration process.

All countries have regulatory agencies similar to the FDA in the United States that must approve pharmaceuticals for commercial sale within those countries.

While there are countries in which rbST has not received registration for commercial sale, the registration process is still open; however in some countries the process has been suspended or blocked, sometimes through a legislative ban, for political or economic reasons.

Economic impact is not usually a reason that can be cited in most countries for denying the grant of a pharmacological registration. Only efficacy, human safety, and animal safety are the key determinants.

Typically, the ploy “questions that need further investigation regarding animal safety” is used to delay or suspend the registration process when there are economic or political considerations.

The economic consideration for countries like Canada and many European nations is their current domestic milk marketing system is based on a quota system which discourages increases in milk production in order to protect the marketplace for producers (see Sidebar section below).

Sidebar:

Numerous United States and international medical, scientific, and regulatory agencies have issued statements supporting and confirming the safety of rbST and that there is no threat to human health by rbST use (the list of agencies is presented below).

Quota Overview:

The primary purpose of a quota marketing system is to keep milk prices artificially high through supply limitation. Quota systems limit competition and therefore reduce the number of producers that exit an industry.

A producer has to own quota for every pound of milk produced in order to market all of their milk under the profitable market prices. Milk not covered by quota can only be marketed at severely discounted prices, making profit impossible for non-quota milk.

Quota is prohibitively expensive to obtain in order to discourage production increases thus discouraging the adoption of technology, farm expansion, and practices that improve production efficiency.

Furthermore quota is a capital asset and can be borrowed against in many countries.

A quota system is difficult to abandon once adopted because vested people and financial institutions with liens against quota value would lose net worth. Consequently, they fight to preserve the status quo. This makes it apparent why the availability of a production-enhancement technology with the impact of rbST would be disruptive to domestic marketplace status quo in countries with a quota system.

Scientific/Medical/Health/Governmental Organizations that have confirmed the Human Safety of milk and meat products from cows supplemented with rbST (list is not inclusive)

• American Cancer Society
• American Council on Science & Health
• American Dietetic Association (ADA)
• American Medical Association (AMA)
• Canadian Animal Health Institute
• Canadian Dietetic Association
• Canadian Institute of Biotechnology
• Canadian Medical Association
• Canadian Network of Toxicology Centres
• Canadian Pediatric Society
• Children’s Nutrition Research Center, Baylor College of Medicine
• Council on Agricultural Science & Technology
• European Union’s Committee for Veterinary Medicinal Products (CVMP)
• Federal Drug Administration (FDA)
• Food & Agriculture Organization of the United Nations (FAO)
• Food & Nutrition Science Alliance
• Food Marketing Institute
• Grocery Manufacturers of America (GMA)
• Health Canada (Royal College of Physicians & Surgeons)
• Institute of Food Technologists (IFT)
• International Dairy Foods Association (IDFA)
• Joint FAO & WHO (World Health Organization) Expert Committee on Food Additives (JECFA)
• National-American Wholesale Grocers’ Association
• National Dairy Council
• National Institutes of Health (NIH)
• The American Academy of Family Physicians Foundation
• Toronto Biotechnology Initiative
• University of California – Berkeley
• University of California – Davis
• U.S. Congress Office of Technology Assessment (OTA)
• U.S. Dairy Export Council
• U.S. Surgeon General’s Office

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Recently, there have been a number of comments on Dairy-L and occasionally a popular press article, which have proclaimed that Cornell University has developed a test for bST use in dairy cows; the articles have sometimes quoted Dr. R.C. Gorewit, the originator of the “test”, and referred to a 1997 patent he obtained for the test. These articles have led to a large amount of confusion: the following addresses some of the most frequently asked questions.

1. Gorewit’s claim for a “test” is based on associated changes in a protein referred to as FABP (fatty acid binding protein). However, Gorewit’s ideas represent speculation based on limited work. Neither he nor anyone else has demonstrated an actual correlative relationship between FABP in milk and use of bST.

2. Gorewit’s “test” is based on comparing rates phosphorylation of FABP. This involves isolating globular membranes that surround the milk fat droplets (MFGM) and purifying them by column chromatography techniques. The FABP fraction is then collected and concentrated by ultra-filtration. The entire procedure for isolation and purification of FABP from MFGM has to be repeated three times. Finally, samples of the resulting FABP preparation are incubated with radioactive phosphate, specifically adenosine triphosphate (gamma P32-ATP), and the extent of radioactive P32 incorporation is determined. The amount of radioactivity represents the basis for comparisons between samples in the “Gorewit test”.

3. FABP is related to maintenance of mammary cells and, thus, it will vary widely. Factors such as milk yield, persistency of lactation, stage of lactation, pregnancy, parity, breed, diet, season,environmental temperature and animal health all affect the maintenance of mammary cells. All of these factors would give expected changes in FABP similar to those speculated to occur with bST. Recent research has shown that the mammary gland contains several different FABPs and they may also function in the intercellular transport of fatty acids, accretion of lipid droplets in the cell cytoplasm and control of lipid metabolism. Further details on the different FABPs, their sequence and post-translational modifications can be found in the review by Dr. I. Mather (J. Dairy Science, 2000 83:203-247).

4. Gorewit’s claims about the effect of bST on FABP can be best described as speculation based on a small number of observations. His data involving comparisons of individual cows includes a single milk sample from a cow that had not received bST and a single milk sample from each of 5 cows reported to be receiving bST. Gorewit’s “herd comparisons” involves only two milk samples – one from a herd using bST and one from a herd that does not use bST. Obviously, these limited observations do not represent a scientific study, and are not adequate to allow for publication in a peer-reviewed scientific journal. However, Gorewit did publish these observations in first issue of a Pakistani journal. This same issue of the Pakistan Journal of Nutrition (Vol. 1, Number 1; 2002) includes three other papers by Gorewit that are unrelated in scientific content but similar in that they also represent limited observational data that would be unlikely to meet the standards required for publication in peer-reviewed scientific journals.

5. Any test for bST that is used in food labeling would have to be approved by the FDA, which requires validation using accepted scientific practices, just as they require for other tests currently used to verify label claims for food and feed products. Validation will include demonstrations of repeatability, sensitivity, variability and accuracy. None of these has been reported with FABP, and it is doubtful whether the actual methods used for FABP could ever meet such rigorous standards. In fact, Gorewit has not reported any additional designed studies on FABP since his original observations.”

6. On several occasions over the last 20 years, individuals have claimed to have “discovered” a test for bST use. All of these claims have proven to be inaccurate, and one of these was an earlier claim by Gorewit which involved a different test. In addition to Gorewit’s patent on using FABP as a test for the use of bST, he has other patents involving milk proteins and in some instances the discoveries and claims in these have also been shown to be incorrect.

Conclusion: There is no validated test for bST use in dairy cows. Milk from bST-treated cows does not differ in nutrient content or in the content of any of the trace constituents including bST and IGF-1.