Raw milk, also known as farm milk, is legally sold in about half of the United States. Raw milk is milk from cows, goats or sheep that has not been pasteurized. In pasteurization, milk is heated to kill harmful bacteria and increase shelf life. Proponents of drinking raw milk say it confers a number of health benefits that are destroyed by pasteurization. However, the Centers for Disease Control and Prevention strongly advises against drinking raw milk as it may carry harmful bacteria.
Raw milk is nutritionally superior to pasteurized milk because heat alters and degrades some of the nutrients naturally found in it. Several heat-sensitive vitamins, including thiamine, riboflavin, and vitamins C, E and B-12, are destroyed in the pasteurization process and are found in smaller amounts in pasteurized milk than in raw milk. The fat content of raw milk -- 4 percent on average -- is higher than that of commercial whole milk, which is standardized at 3.5 percent. In a 2013 issue of the journal “Food Control,” Wendie Claeys and colleagues noted that animal- and feed-related factors account for more variation in the amount and fatty acid composition than does pasteurization. The authors also stated that pasteurization has little effect on the digestibility and nutritional properties of milk proteins and does not affect mineral content.
Raw milk is rich in microorganisms. In pasteurization, milk is heated to a high enough temperature to kill off any harmful microorganisms that may be present, the most common of which are campylobacter, salmonella and Escherichia coli. About 0 to 6 percent of raw cow milk in Europe is estimated to contain one or more of these harmful bacteria. However, pasteurization also destroys bacteria that may be beneficial to you, such as Lactobacilli and bifidobacteria, as well as bacteria that may help digest the lactose in milk. Claeys reports that the relevance and number of these bacteria are too limited to have any physiological effect for consumers.
Protection Against Asthma and Allergies
Several epidemiological studies, including one by Anna Lluis and colleagues published in 2014 in the “Journal of Allergy and Clinical Immunology,” reported that drinking raw milk early in life may reduce the risk for developing asthma, allergic rhinitis, hay fever, pollen allergy and atopic sensitization. Scientists have not yet identified which components of raw milk are responsible for this protective effect. In a 2010 report in "Clinical and Experimental Allergy," researchers suggested that the higher microbial load, higher milk fat or whey proteins in raw milk might be responsible for this protective effect.
Proponents of drinking raw milk claim that raw milk is more easily digested by those who are lactose-intolerant. Lactose is a sugar found in both raw and pasteurized milk and other dairy products. Individuals who are lactose-intolerant are unable to digest this sugar because their bodies do not produce lactase, the enzyme that digests lactose. Neither raw nor pasteurized milk contains lactase. Lactic acid bacteria in raw milk produce lactase, which may make raw milk more easily digestible for those who are lactose-intolerant; however, Claeys states in “Food Control” that the production of lactase by these bacteria is very limited at the refrigeration temperature required for storage of raw milk.
People who have a milk allergy may tolerate raw milk better than pasteurized. In the 2010 article in “Clinical and Experimental Allergy,” the authors reported that homogenization, a process that breaks up fat globules and prevents a cream layer from separating out of milk, favors milk allergy in animal models. However, these findings have not been confirmed in clinical studies on humans.
Raw milk may taste better than pasteurized milk as heating alters some of its flavor properties. Specifically, pasteurization produces a variety of sulfur-containing compounds that can impart a "cooked," "stale" or "acid" flavor, in the words of the "Food Control" researchers. Also, the higher fat content of raw milk may be more appealing to consumers.
- The New York Times: A Cure for the Allergy Epidemic?
- Centers for Disease Control and Prevention: Raw Milk Questions and Answers
- The Journal of Allergy and Clinical Immunology: Increased Regulatory T-Cell Numbers Are Associated With Farm Milk Exposure and Lower Atopic Sensitization and Asthma in Childhood
- FEMS Microbiology Reviews: The Complex Microbiota of Raw Milk
- Clinical and Experimental Allergy: Can Farm Milk Consumption Prevent Allergic Diseases?
- Food Control: Raw or Heated Cow Milk Consumption: Review of Risks and Benefits