Report of Milk, Hormones, and Human Health Meeting, Boston, MA
Summary of Meeting on Milk Hormones and Human Health
Harvard Club, Boston, MA
10/23/06-10/25/06
Compiled by Baumrucker and edited by Rogers, Thatcher, & Collier
The meeting was funded by Ms. Demko, a resident of San Francisco, CA. Phone conversations with Ms Demko indicated that she held concepts that milk and specifically milk hormones (IGFs and steriods) were contributing to cancer. Conversations relative to a milk hormone meeting with Ms. Demko centered on my participation that would only be based upon a balanced approach and not be based upon a negative agenda. Separate negotiations between Ms. Demko and Michael Pollak, McGill University, resulted in a general agreement that the desired outcome of the meeting would be to identify what is needed in research ? ie: a workshop. In a separate phone conversation, M. Pollak assured me that this would happen. As an organizer, I submitted a list of ~7 scientists who could address the meeting concepts. From this list, 1 was selected and later, still another was added with some consultation with me.
The meeting was tapped and a stenographer was also recording the proceedings. Discussions about publication are continuing.
During the presentations and discussions on 10/23 & 10/24, the presentations were scheduled for a total of 20 minutes (presentation and discussions). Most presentations and discussions encompassed ~30 minutes – however, the discussions were allowed to continue as needed and all sessions went well beyond scheduled times.
Specific Presentations and discussions
C. Vobach, Sanofi-Aventis, Germany: a young scientist who trained with Cappecci (development of KO techniques – Utah), and is now located in Germany. She showed genomic evidence based on Xanthine Oxidase (KO), that the mammary gland may have evolved from the immune system. Transgenic XO-KO mice show that fat globule secretion is compromised and lactation fails.
Discussion/Concepts: Interesting hypothesis linking the mammary gland to immunology yet the speaker did not introduce previous hypotheses and evidence that show a mammary gland link to sebaceous skin glands.
L. Cordain, Colorado State University. Discussed the concept that change in the western diet, over thousands of years, is correlated with the increase in milk consumption. A major point was that although milk has a low glycermic index, it induces a very large insulin and IGF-I increase that he associated with cancer. He also hypothesized that because EGF receptors have been shown to occur on the luminal side of gut epithelial side (brush border side), that cow milk EGF could also be a major contributing factor.
Discussion/Concepts: Since a major growth factor component of saliva was EGF, how would milk EGF contribute? Furthermore, appearance of a luminal receptor does not indicate transcellular movement ? but rather may be the signal for epithelial proliferation. The latter has been demonstrated. It was stated that the EGF gene expression has not been detected in the cow and that published reports of EGF could be TGF-? and others agreed that this was likely. A search of NCBI genbank and the Ensambl bovine data base shows no EST or mRNA identified for expression of a bovine EGF.
P. Ellison, Harvard. He discussed energetic and developmental aspects and designated these to be ?predictive adaptive responses?. While birth weight of the fetus has an optimal set point, prenatal environment could affect the set point for postnatal development and phenotypic observations that occur later. He described the role of energenics on ovarian function (fertility) and E2 concentrations. He hypothesized that these adaptive responses may be correlated with later life cancer risks.
Discussion/Concepts: Interest in the adaptive responses was conveyed by the audience. Links to cancers was not discussed.
J. Bunting (the Milkweed). He was introduced as a person who actually owns a cow. He presented a short history of dairy and dairy products with a clear negative perspective of large dairies and their current manufacturing practices. He used modern practices (Ultra-filtration) and cheese making as examples of a changed product and used the term ?crude protein? as something undesirable.
Discussion/Concepts: Asked how the use of ?crude protein?, which is a protein measure, is a derogatory statement. Others brought up the uniformity of dairy products across the US.
F. Savino, University of Turin: His presentation aimed at understanding metabolic patterns of the neonate and the effect of breastfeeding. He showed blood concentrations of Leptin, IGF-I and Ghrelin in breast fed infants and their correlation with milk hormones.
Discussion/Concepts: Asked what was the binding affinity of the major leptin receptor and could a 2 ng/ml increase (breast fed) result in any difference in receptor signal. This scientist left the meeting after the first session.
C. Hoppe, Vet/Agr University, UK. She showed data from a number of countries that milk consumption stimulates growth and there is a correlation with IGF-I in the circulation. The important fact that was conveyed was that milk has a very unique mechanism that can not be explained by total nutrients when compared to equivalent diets.
DiscussionConcepts: It was stated that this data is consistent with milk being a very special high quality food (biological value) and that because energy and protein affect the GH/IGF axis, the increase in growth and IGF in the circulation could explain these observations.
D. Gunnell, University of Bristol UK. Using epidemiology studies from the UK, he showed that milk intake in childhood was correlated with increased growth. Such increased growth is correlated with increased IGF in the circulation and increased pre-pubertal growth but this difference is not observed in adults. As little as 1/3 pint of milk appeared to be enough to cause a difference in circulating IGF (134 ng/ml to 142 ng/ml). Much of this difference was accounted for when protein was a co-varient in the analysis.
Discussion/Concepts: Questioned the significance of an 8 ng/ml increase in the circulation and its impact on any physiological event. Because FLOXED liver mice have 25% of the circulating IGF levels of wild type and yet have little effect and that most of the IGF in the circulation is bound to IGFBPs (perhaps 1% free), how could this difference be interpreted as being physiologically significant. It was suggested that the 1% free was not likely to be correct ? but the literature has no evidence of any different perspective relating to the circulating blood concentrations.
J. Holly, Univesity of Bristol UK. He related hepatic IGF synthesis and output as being coupled with protein intake and the GH/IGF axis. Interestingly, drinking milk as a child shows increased IGF in the circulation but lower IGF after age 25. However, he clearly made clear his opinion that milk is neonatal food, not adult food. He used the Got Milk marketing campaign to cartoon a negative perspective. He stated that there is insufficient milk IGF to account for circulating IGF mass, but something in milk is special and he hypothesized that milk insulin may be the factor.
Discussion/Concepts: Some discussion revolved around the Got Milk campaign as aggressive and not needed. The advertising campaign was defended as an attempt to mitigate the decrease in per capita milk consumption and the increased competition from soft drinks.
J. Richard Edwards (Brigham & Women’s Hospital, Boston, MA). She reported on her attempt to study milk consumption in Mongolian school children. Milk provision to these children resulted in increased growth when compared to a milk substitute (Diet was not presented). Those that consumed milk (3/4 liter) had higher blood IGFs. The idea of using milk from Mongolian cows (Bos tauras) that may be different in milk hormones (suggested that genetic changes over the last 50 yrs may contribute) was put forward and that this would be presented later.
Discussion/Concepts: Revolved around Mongolian cows that are mostly non-pregnant when the adults consume the milk because the natives use the milk to feed the calf. This was attributed to the concept that the modern dairy industry is milking pregnant cows and pregnancy would lead to increased circulating steroids. Consequently, more steroids would be in milk and impact the consumer. This was refuted, and a subsequent presentation would shed more light on this aspect. Others described the changes in circulating estrogens that would not be very different until the very last period of pregnancy, when the cow is not lactating in preparation for parturition.
Perspectives of Day One
The organizers clearly put together a series of speakers who described the special nature of milk and its impact upon growth most reporting correlations with changes in circulating IGF. The speakers also provided an aura of early exposure to milk (maternal & fetus) neonate, young children who consume milk may be changed in their circulating hormones during their lifetime (i.e., imprinting or adaptive responses). The first concept is very well established and its effect has not been isolated from the excellent food quality of milk. The impact on the GH/IGF axis was mainly avoided although repetitively put forward during discussions.
Day 2 10/24
S. Olson, University of Aaarhus, Denmark. This was a summary of the Danish national birth Cohort study that evaluated the consumption of cow milk during pregnancy and its impact on fetal birth weight. Milk intake was associated with higher birth weight and head circumference. Birth weight was greater in babies from mothers who consumed >4-5 glasses of milk per day when compared to no or little milk consuming mothers. Mid range drinkers showed no significant change in their babies. The study suggested that this was not due to the fat content, but rather something in the soluble fraction of milk.
Discussion/Concepts: It was suggested that perhaps GH is less pulsatile during pregnancy.
K Koski, McGill University. A Canadian female perspective has emerged that milk consumption is not good based on 1) too much fat 2) lactose intolerance 3) potential diabetes complications & 4) allergies. This is not held by Canadian men. The author hypothesized that low milk consumption may lead to inadequate protein, calcium and vitamin intakes and account for the low birth weight that was occurring in Canada. Additionally, vitamin D exposure in utero is correlated to bone mass development years later.
Discussion/Concepts: Expressed concern for low birth weight babies and thought that milk consumption by pregnant women would be helpful. Long term effect on babies is unknown, but there is no argument that milk consumption will reduce low birth weight baby syndrome.
G. Steinman, Long Island Jewish Medical Center. He has published expensively on the correlation between circulating IGF concentrations and twining. He made a clear statement that dietary IGF enters the circulation. He related this to the changing practices in the dairy industry that alter circulating IGF resulting in an affect on follicular development leading to increased twining. He used population studies to indicate that twinning rate changes when populations move from country to country or from country to city.
Discussion/Concepts: Steinman’s data are consistent with milk being a very special food that provides excellent nutrition that may contribute to healthy follicles. His reference to the rbST use in milk production leads to increased twinning in cattle was not supported by others. It was pointed out that there is not enough IGF in milk to be the agent that results in increased circulating IGF concentration there was general agreement from many. It was conceded that rbST treatment does not affect milk composition.
V. Han (University of Western Ontario). He presented evidence that both nutrition and exposure of the rodent placenta to IGFBP-1 had an impact on placental and fetal growth as well as IGF gene expression. He concluded that circulating (endocrine) and tissue (paracrine/autocrine) IGF Systems play different roles in the contribution of placental and fetal growth.
Discussion/Concepts: Some discussion on the contribution of the fetal genome and maternal environment relative to birth weight (Han 10-30% vs 60%, respectively).
X. Zhao, McGill University. He presented the current production practices of the dairy industry in comparison to 50 years previously indicating the great success rate to decrease animal numbers while increasing animal production (i.e., greater efficiency). He attributed this to genetics and the AI industry, nutrition, and management.
Discussion/Concepts: Non-agricultural attendee’s asked questions about the production practices that were aimed at gaining information and current dairy practices.
P. Neville, University of Colorado. She presented evidence of fatty acid patterns in milks of human, cattle and mice. She showed differences in chain length and PUFAs between the species and explained causative events (rumen contribution, synthesis, and transport). She described studies to use protected feeds to alter the fatty acid composition of milk.
Discussion/Concepts: Because the epidemiologists have moved away from milk fat as a correlate with cancer the questions revolved around basic biology.
G. Rogers (University of Tennessee). He discussed the genetic methods and directions that have occurred in the dairy industry over the past years. He specifically showed data to indicate that because of increased milk production capacity and decreased fertility, dairy cows spend more time being non-pregnant than 30-50 years ago. He described a dairy industry that produced a uniform product due to the blending of many cows/farms milk to become the average milk product across the US. He brought up the subject of the Minnesota dairy herd that represented 1964 genetics.
Discussion/Concepts: Further questions about the days open in relationship to pregnancy and acknowledgement of many of the epidemiologists that they were not aware of this concept. A question about the availability of milk samples from the MN herd, and Rogers said he would check up on it.
W. Thatcher, University of Florida. He presented reproductive events that could lead to the decline in fertility in dairy cows. He focused on estrogens and progesterone and showed that they are actually lower in high producing cows as a result of increased liver metabolism. Furthermore, lactating cows have lower circulating IGF-I than non-lactating cows.
Discussion/Concepts: Questions about the MN herd and circulating steroids ? Thatcher stated that hormone evidence has indicated subtle differences in progesterone and IGF-1 in circulating blood between unselected cows comparable to the 1964 MN herd as compared to current cows under the same environment that have been selected for milk yield. Plasma IGF-1 and progesterone are lower in current high selected cows. Measurements in milk between the two selection groups have not been carried out.
C. Tian, Univesity of Connecticut. She described the method of creation and use of transgenic milk for pharmaceutical, nutritional, and agricultural applications.
Discussion/Concepts:
C. Baumrucker, Penn State University. The occurrence of a wide array of endocrine factors that were detected in cow milk was discussed. Comparisons were made between concentrations of these factors between colostrum, raw milk and pasteurized milk. He described the 7 potential mechanisms that endocrine factors could appear in milk including milk somatic cells. He showed research that showed when mammary secretory hormones are highest and lowest and hypothesized their potential targets (if any). He refuted IGF (protein) hormone absorption after gut closure. He emphasized that a biological phenotype is necessary to demonstrate a hormone effect and that it needs to be repeatable in different experimental species. Growth factor induced neoplasia appears to be dependent upon high concentration and time. He showed modeling data that clearly indicates that dietary steroids are enzymatically altered by gut and liver enzymes (1st passage) to alter dietary levels to 2 orders of magnitude less for such bioactive components in the diet. He concluded that it is likely that not all hormones in milk have a function, either in the mammary gland or the neonatal GI tract. Rather they represent a normal appearance from active cells and tissue. Furthermore, he proposed that if growth factor concentration and time were keys to neoplasia and circulating hormones contribute less of an influence than autocrine/paracrine factors, than we need to know what is the hormonal milieu bathing the mammary gland (or other tissues) in adult life.
Discussion/Concepts: Others agree with IGF not being absorbed and being the direct agent of increased IGF.
S. Sterk. EU Community Ref Lab. A chemist employed by the EU to conducts assays for food and residue content. She described milk hormone analyses involving LC-Mass Spec or GC Mass Spec and the multiple steps in preparing the sample. She related her data to that of published values and indicated differences but had confidence in her mass analysis.
Discussion/Concepts: This is the person who has conducted analysis of milk and was likely invited to provide credibility to their studies. Asked while mass is important, how does his relate to biological activity. She answers that biotech firms are developing immortalized cells that have transfected receptors that can be used as a bioscreen for hormones such as steroids. It was stated that bioassays are all over the board for many assays. It was generally discussed that multiple labs conducting assays was good, but that variation becomes a problem.
L. Frazier, Harvard Medical School. She has been trying to get labs to analyze different milk samples to test their hypothesis that commercial milk has different hormone levels (IGF and steroids: E2 and P4). With limited samples due to cost, she showed that steroids appear to be higher in older reports of the literature. Differences in the Mongolian milk (with limited samples) suggested some P4 differences, but none in estrogens and IGF.
Discussion/Concepts: The newly conducted analysis using newer MS analysis appears to be more representative of mass, but states that assays have been improving over the years. Frazier is looking for collaboration to conduct milk hormone assays at a more reasonable cost.
T. Morcol, Biosante Pharmaceuticals. She presented data and experiments to show that transgenic proteins expressed in mammary secretions are bound in casein micelles and that she could dissociate the proteins from the micelles. She also showed that a similar concept could be developed to move orally active molecules into the systemic circulation. It is obvious that the organizers used this concept to suggest that proteins in caseins may be absorbed.
Discussion/Concepts: The information suggests that casein micelle association would lead to GI absorption, but little milk IGF mass and little evidence (if any) of absorption would argue against this system. Furthermore, IGF and IGFBPs have been shown mainly in the skim supernatant (caseins removed).
S. Ito, University of Toronto. Human milk has organic pollutants that may pose health risks. He has identified a mammary drug transporter (BCRP) on the luminal side of cells that appear to be capable of transporting organic molecules into milk. Studies conducted in vitro with the Hep-G2 liver cells indicate that the Ah-receptor mediated pathway of organic modification is activated by milk organic compounds.
Discussion/Concepts:
Philipps, University of California-Davis. He discussed the occurrence of IGFs in milk, their surviving GI digestion, and showed evidence of their ability to regulate growth and differentiation of the GI tract. He also suggested that IGF absorption was detected in the portal blood and that trace amounts of IGF-1 appeared in the bile drainage from the liver.
Discussion/Concepts: Asked if this absorption was before or after gut closure (answer; not sure) and what mechanism would account for the bile appearance of the portal blood IGF since the liver has few IGF-IR. It was stated that others research with calves showed no change/appearance in blood IGF-1of calves. Furthermore, an intestinal clamp of calf GI, infused free IGF into the clamped section (in milk/PBS/etc.), and sampled portal blood showed no appearance of the IGF that was placed in the clamped GI section.
Sato, University of Yamanashi /G. Davaasambu, Harvard School of Public Health. Using ovarectomized rats, the researchers fed whole milk and evaluated uterine growth (bioassay of steroid measure). They showed a significant increase in uterine growth with the milk fed rodents. They also showed that Estrogen Sulfate (E2-S) was increased in the circulation 10X.
Sato presented trends in fertility rate of the Japanese population from 1948 to 2005 and inferred this was due to increased consumption of milk and dairy products. The audience recognized a multiplicity of confounding factors exist during this period of 60 years.
Discussion/Concepts: Regarding the rat studies, it was asked how much milk was consumed (did not measure; but lots). Questions about body mass/blood volume and milk consumption were discussed.
L. Hilakivie-Clarke, Georgetown University. The observations that increased birth weight and breast cancer risk are correlated suggests that uterine/fetal events may affect the risk of developing breast cancer. She presented data that fetal factors in rodents leading to high birth weight induce epigenetic changes in the mammary gland and are likely to alter developmental programming of genes that regulate the mammary gland.
Discussion/Concepts:
Perspectives of Day Two
Overall, this was a very busy day with all speakers going over time (20 min total is not enough when discussion is included). The sections were aimed at milk and prenatal growth and twinning; differences in traditional vs current dairy production (aimed at changes in milk hormones as a result of genetics); milk bioactive components and possible means of ?hormone absorption?; and milk effects in animal models. There was excellent exchange of information.
Day 3 -10/25
S. Liu, University of California LA. Discussed the epidemiological data that suggests dairy products lower the risk of type 2 diabetes. He reported studies of consumption of dairy products and other dietary components that show low-glycemic load that affects glucose homeostasis. He discussed mitochondrial oxide production that may contribute to tissue damage.
Discussion/Concepts: This author clearly described the total picture of epidemiology and dairy consumption and suggested differences from the conclusions of others.
F. Hu, Harvard School of Public Health. He discussed the role of calcium in the maintenance of body weight. There are a number of reports that indicate Ca2+ intake is positive (wt gain), negative, or no effect. The more recent studies indicate no effect.
Discussion/Concepts: Because milk Ca2+ is used as a means to justify milk and dairy consumption perhaps the no effect on weight gain is seen as some erosion of the dietary guidelines?
C. Adebamowo, University College Hospital, Nigeria. He discussed dairy intake of teenagers and the associated risk of developing acne. He suggested that bioactiave factors (hormones) in milk may affect skin glands and increase acne expression. NHSSI and a GUTS study indicated that >3 glasses of milk per day was associated with increased risk of acne. Analysis indicated that the positive association of milk was correlated with milk androgen, IGF-I and -lactoalbumin content.
Discussion/Concepts: Clearly, the authors suggest that something in milk (hormones?) can increase acne risk.
W. Willett, Harvard School of Public Health. Discussed the correlations between growth rates and breast cancer. Showed epidemiological data on the correlation between milk consumption and risk of breast cancer in pre-menopausal women. The various reports appear to be equivocal.
Discussion/Concepts: All of the data would be supported by the concept that milk is an excellent nutritional source and very little if any association of milk consumption with breast cancer in pre-menopausal women.
E. Giovamucci, Harvard School of Public Health. Discussed evidence of milk intake and prostate cancer in men. While milk consumption has been associated with prostate cancer, the strongest correlation was with aggressive prostate cancers. Milk calcium and IGF were correlated with prostate cancer. However, the Melbourne Cohort study showed that prostate cancer incidence and milk consumption was not significant unless the cancers were expressed as aggressive grades.
Discussion/Concepts: The data appeared to be equivocal for risk of cancer ? yet the aggressive cancer concept is difficult to grasp as it is well known that cancers starve other tissues to grow (monopoly on blood flow and nutritient use). The epidemiologists seem to be suggesting that excellent nutrition is bad during aggressive cancer expansion, but do not suggest that an individual with aggressive cancer should be consuming poor nutrition.
J. Barron, Dartmouth Medical School. Presented evidence that milk consumption reduces the risk of colorectal cancer and suggested that Ca2+ may have a role in altering the reduction in risk. Stated that some milk components are altered by processing (pasteurization; ie: lactoferrin).
Discussion/Concepts:
A. Wolk, Karolinska Institute, Finland. She presented data to show that human adipose could be assayed for milk fatty acids that the human can not synthesize in order to correlate epidemiology studies with true milk consumption. While only 1% or less of adipose fat is C15:0/C14:1, making analysis difficult, these fatty acids had a correlation of 0.6 & 0.8, respectively with dairy intake. CLA in adipose was 0.4 correlated with dairy intake. Colorectal cancer risk was reduced by dairy intake and ovarian cancer risk was increased by milk consumption.
Discussion/Concepts:
S. Warner, Harvard School of Public Health. Discussed the Pooling Project of Prospective Studies on Diet and Cancer (International compilation) and the effects of dairy products, calcium, Vitamin D, and lactose in the risk of ovarian cancer. No associations were observed for dairy foods or calcium while a modest increase in risk was associated for lactose intake.
Discussion/Concepts:
Summation after Presentations
Pollak, Willet and Camargo were scheduled to provide prospective (no one else was scheduled). Nevertheless, comments from the attendees were made to refute or provide direction for the future.
M. Pollak-McGill University. Summaried his perspective with a concept that milk production has increased and the dairy advertising campaign (Got Milk) was to get the public to consume more. It was pointed out that milk consumption per capita was what it was in the 1950s and it was produced by less than 50% of the cow numbers. Pollak’s response was whatever. Pollak continued with the need to conduct research as to whom and when milk may be consumed by the public. He also focused on milk bioactive components and their role in the unique food aspect of milk.
Carlos Camargo, who has served on the US dietary guidelines committee, discussed how the milk consumption guidelines (3 cups/day) were maintained. He clearly suggested that the topic of less (1 or 2 cups?) was considered, but that milk is in a separate category and that politics may be involved. The comments about how milk “won” at the dietary guidelines committee and political considerations was an interesting perspective.
Water Willet stated that the Dairy Industry had been successful in maintaining the dairy recommendations. His perspective was that the litany of milk effects on birth weight, twinning, acne, mammary, and prostate cancer was sufficient to warrant a different perspective. He said that milk did not prevent osteoporosis. His final conclusion was that milk intake should be reduced to 1 glass per day.
Baumrucker stated that all of the epidemiology data and risks are consistent with milk being a very unique food that provides highly nutritious and digestible food source to humans. Evidence of IGF being absorbed is scant and the mass is likely insufficient to contribute to blood circulating mass. Holly and Hon supported this concept. Furthermore, evidence gathered from snapshot concentrations of hormones in blood reflects many contributions (tissues), but that local tissue events (autocrine/paracrine/intracrine) are likely more important. Because nutrition (energy and protein) is directly linked to the GH/IGF axis, milk with excellent digestibility and high biological value would be expected to and has clearly been shown to stimulate growth.
Overall Perspective and Future Directions
The meeting concluded that the hormonal content of dairy milk is, at present, incompletely defined. However, analyses of milk hormones are confounded by variation of assay techniques and bioactivity measures. Future research needs to incorporate experimental evidence that determines phenotypic alterations.
The epidemiology data clearly shows that milk is a unique food, but the overall compilation of the many studies indicates an equivocal block of data when related to disease. The concept that milk hormones as causative agents that alter human phenotypic expression has not been established.
Overall the conference was a success in indicating that some of the hypotheses that were based on the altered genetics of modern dairy cattle and increased hormones in milk was unlikely. In addition, it opened a dialog that needed to occur between human epidemiologists and dairy scientists. The concept of IGF in milk was absorbed and had systemic effects was diminished by little evidence of absorption and insufficient total mass in milk relative to endogenous GI sources.
The focus on steroids (estradiol and progesterone) in milk was considered. The hypothesis that genetics has changed cows to cause more circulating steroids and most cows are pregnant (more steroids) causing more to be present in the circulation and therefore higher concentrations in milk. It was shown with experimental evidence that 1) genetics has increased milk production but also increased the period after parturition when cows are not pregnant, resulting in a greater proportion of the milk production going to market originating from non-pregnant cows.; 2) that commercial milk is not from just pregnant cows, but rather dairy producers are using a blend of all milk to make a consistent product. 3) that only during the very last period of pregnancy, would steroids (ie., estrogens/progesterone) be appreciably increased and that most of this period is during the dry period (non-lactating period; 2 months) prior to parturition. Questions about the difference in 1960 genetics and current genetics (relating to the MN herd) has shown that the subtle differences in reproductive hormones (i.e., decreases in progesterone and IGF-1 in plasma) may contribute to reduced fertility of modern dairy animals but very unlikely to increased alterations of such hormones in milk.
The meeting was conducted with good general interest and overall respect for each attendee. Discussions were not stifled, yet certain important questions and topics need to be addressed in future research and meetings. There was an excellent exchange of information concerning modern dairy production. Milk steroid consumption by pre-pubertal children is of interest because there is evidence to support this period in children (short term studies) as one more susceptible to influence epigenetic expression. Nevertheless, there is no clear picture of diet induced changes (mass/when consumed/etc.) and their impact over longer periods in the human life period.
The discussion revolving around milk as a very special food is supported by epidemiology studies and does not alter the dairy industry assertion that milk is a highly nutritious food. The established link between the GH/IGF axis with nutrition (energy and protein) needs to be explored relative to milk consumption.