Cow’s milk has been a nutritious, dietary staple for children and adults for ages. Today, we're witnessing an increase in the frequency of cow's milk allergies and it's fueling a debate between proponents of pasteurized milk and raw milk. Whichever side you’re on, research continues to investigate the reasons for an apparent increase in cow milk allergies, the safety and nutrition of raw milk, dangers of milk consumption and healthy alternatives for children who cannot drink milk. Let's take a look at 10 shocking facts about cow's milk.
Cow Milk Facts
1. Maternal Antibiotic Use is Linked to Cow Milk Allergy (CMA)
A 2013 study out of Finland looked at the connection between a mother's antibiotic use and its impact on infants. Reviewing data from national records, infants diagnosed with CMA had a direct association with mothers who had taken antibiotics during pregnancy. Infants that were given antibiotics following birth also showed a greater tendency to the cow milk allergy. 
2. Cow's Milk Affects Breastfeeding
With the increases in childhood allergies, including CMA, research has begun to explore the relationship between maternal diets and its effect on human milk in breastfeeding mothers. Infants of mothers who consume cow's milk show higher levels of specific proteins known to increase immune response and lead to allergy development. The good news is that mothers who restricted cow milk consumption reduced the chance of their infants developing a cow milk allergy. 
3. Raw Organic Milk Contains More Fatty Acids
The arguments for raw organic milk are loud and plentiful. Although some remain skeptical, the science is quickly changing minds. A study published just this year discovered that organic milk contains 62% more omega 3 fatty acids than conventional milk. 
4. Milk From "Factory" Cows Can Be Highly Suspect
Many big corporations keep cows in filthy conditions. Some may even pump them full of hormones (rBGH) to stimulate milk production. A concern side effect of this practice is mastitis or the infection of mammary tissue – the tissue which produces milk. This can lead to milk contamination by pus and bacteria. One bacteria is Methicillin-resistant staphylococci (MRS). This antibiotic-resistant bacteria has proven extremely virulent and difficult to control.  E. coli is another bacteria readily found in cow’s milk, and one resistant to powerful antibiotics like streptomycin and tetracycline. 
5. Lactose Free Has Drawbacks
Children with CMA raised on lactose-free formulas or milk-free diets have been observed having concerns with developing proper bone mass. A Polish study of 66 children with CMA examined the impacts of lactose-free formulas on nutrition and bone health. The lactose-free children had similar nutritional levels of calcium, phosphorus, sodium and magnesium. But, they had higher vitamin D deficiencies and lower levels of the chemical markers needed for bone formation.  Based on this study, any child raised on a lactose-free diet should be monitored to ensure adequate nutritional and medical care.
6. Cow's Milk May Contain Antibiotic and Hormone Residue
Cows are often given antibiotics to treat the diseases they develop, especially cows that have been loaded with growth hormone (rBGH). Although many strains have become resistant to antibiotics, they remain a first step in addressing infections. To make sure antibiotic residues remain within approved levels, researchers continue to develop new ways to detect these antibiotics.  Of course, this means with every glass of milk you’re getting cow antibiotics unless you purchase raw or organic... or even better – goat's milk.
7. Raw Milk Consumption is Associated with Fewer Allergies
Cow's milk allergies is a hot topic of study in Poland. Another polish study explored the effect of raw milk on allergy and asthma in Polish children and adults from a rural town. The researchers observed that raw milk consumption led to a lower occurrence of asthma and allergies, although hay fever and chronic nasal congestion occurred less frequently in the non-farmers who consumed raw milk.  These results support the hypothesis early exposure to raw milk offers protective effects against allergies and other autoimmune related diseases.
8. Raw Milk is More Nutritious
Raw-milk advocates argue raw milk is more nutritious and promotes health much better than its pasteurized counterpart. Whether this is true or not, science has shown raw milk retains nutrients destroyed by pasteurization. Pasteurization has been found to reduce levels of B1, B2, B12, folate and vitamin E. 
9. Raw Milk is Safe
Pasteurization is far more of a recent idea than consuming raw milk. Louis Pasteur developed pasteurization to protect wine from microbes and bacteria. For decades after this process was developed, raw milk continued to be consumed around the world. The process of milk pasteurization wasn’t introduced until the early nineteenth century when proponents of milk pasteurization sought to protect children from the filthy and spoiled milk being sold.
Until then children (and adults) had consumed raw milk for millennia. Many obviously survived, however with consideration to cleanliness the number who did not as a result of raw milk provided from unclean sources, or that had gone bad is unknown.
A text called The Untold Story of Milk, by Ron Schmid, provides extensive detail into the safety and nutrition of raw milk, particularly in the chapter "The Safety of Raw vs. Pasteurized Milk." 
Of course, while the anti-raw milk group will argue raw milk is unsafe the facts remain simple:
- Raw cow’s milk has more nutrition than pasteurized milk.
- Raw cow’s milk was consumed for thousands of years before pasteurization existed.
- Consuming contaminated or spoiled raw cow’s milk, as with any food, can cause illness, disease, and potentially death.
10. Cow's Milk May Be a Cancer Danger to Some
Hormone sensitive cancers such as breast or prostate cancer can be influenced by phytoestrogens. Cow’s milk contains these hormonal substances. Researchers sought to identify whether the amount of estrogens could be influenced by the dietary sources of cows. The outcome showed the estrogens were present regardless of the cow’s diet. 
A 26 year study of 68,000 women supports this idea. Women, especially post-menopausal women, with greater dairy intake over the period of the study had higher rates of endometrial cancer.  This 2012 publication suggests the health value of cow milk should be considered on a more individualized basis. Because contrary to the dairy industry’s marketing line, "Milk does your body good’" milk may not be an ideal food for everyone and many are seeking out alternatives.
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- Järvinen KM, Westfall JE, Seppo MS, James AK, Tsuang AJ, Feustel PJ, Sampson HA, Berin C. Role of maternal elimination diets and human milk IgA in development of cow's milk allergy in the infants. Clin Exp Allergy. 2013 Oct 28. doi: 10.1111/cea.12228.
- Charles M. Benbrook, Gillian Butler, Maged A. Latif, Carlo Leifert, Donald R. Davis. Organic Production Enhances Milk Nutritional Quality by Shifting Fatty Acid Composition: A United States–Wide, 18-Month Study. Published: December 09, 2013. DOI: 10.1371/journal.pone.0082429.
- Seixas R, Santos JP, Bexiga R, Vilela CL, Oliveira M. Short communication: Antimicrobial resistance and virulence characterization of methicillin-resistant staphylococci Portuguese isolates from bovine mastitis. J Dairy Sci. 2013 Nov 13. pii: S0022-0302(13)00779-0. doi: 10.3168/jds.2013-7130.
- Metzger SA, Hogan JS. Short communication: antimicrobial susceptibility and frequency of resistance genes in Escherichia coli isolated from bovine mastitis. J Dairy Sci. 2013 May;96(5):3044-9. doi: 10.3168/jds.2012-6402. Epub 2013 Mar 15.
- Rowicka G, Ambroszkiewicz J, Struciska M, Dylg H, Gobiowska-Wawrzyniak M. [The evaluation of selected parameters of calcium and phosphorus metabolism in children with cow's milk allergy]. Med Wieku Rozwoj. 2012 Apr-Jun;16(2):109-16.
- Conzuelo F, Gamella M, Campuzano S, Reviejo AJ, Pingarrón JM. Disposable amperometric magneto-immunosensor for direct detection of tetracyclines antibiotics residues in milk. Anal Chim Acta. 2012 Aug 6;737:29-36. doi: 10.1016/j.aca.2012.05.051. Epub 2012 Jun 4.
- Soza?ska B, Pearce N, Dudek K, Cullinan P. Consumption of unpasteurized milk and its effects on atopy and asthma in children and adult inhabitants in rural Poland. Allergy. 2013;68(5):644-50. doi: 10.1111/all.12147. Epub 2013 Mar 27.
- Macdonald LE, Brett J, Kelton D, Majowicz SE, Snedeker K, Sargeant JM. A systematic review and meta-analysis of the effects of pasteurization on milk vitamins, and evidence for raw milk consumption and other health-related outcomes. J Food Prot. 2011 Nov;74(11):1814-32. doi: 10.4315/0362-028X.JFP-10-269.
- The Safety of Raw versus Pasteurized Milk. (last accessed 2013-11-15)
- Nielsen TS, Höjer A, Gustavsson AM, Hansen-Mřller J, Purup S. Proliferative effect of whey from cows' milk varying in phyto-oestrogens in human breast and prostate cancer cells. J Dairy Res. 2012 May;79(2):143-9. doi: 10.1017/S0022029911000902. Epub 2012 Jan 27.
- Ganmaa D, Cui X, Feskanich D, Hankinson SE, Willett WC. Milk, dairy intake and risk of endometrial cancer: a 26-year follow-up. Int J Cancer. 2012 Jun 1;130(11):2664-71. doi: 10.1002/ijc.26265. Epub 2011 Sep 17.
†Results may vary. Information and statements made are for education purposes and are not intended to replace the advice of your doctor. If you have a severe medical condition or health concern, see your physician.