Microbes and Microbiota: Benefits and Risks

Benefits of Milks from Humans and Cows

Recent report cites 42 studies demonstrating human health benefits of raw milk from cows, several documenting health protections beginning in utero!


Some colleagues in the audience of the Society for Risk Analysis (SRA) round table panel entitled Communicating Evidence for Benefits and Risks of Raw Milks generally accepted evidence that raw breastmilk is beneficial to development of healthy gut and immune systems in infants, but were skeptical of evidence for human health benefits of raw cow milk.

The SRA symposium introduced material from two events in partnering regions, one on breastmilk and the other on bovine (cow) milk. For readers interested in learning more about the breastmilk microbiota and its interactions with the neonatal immune system, click here for the slide set from the SRA symposium in New Orleans and here for my blog about the regional event with video from Cornell University College of Veterinary Medicine.


The second SRA regional event on bovine (cow) milk convened on November 29th in Liverpool, UK. Due to the short time period between the UK event and the SRA meeting in New Orleans, little evidence on cow milks was available for that event. This blog provides some additional information about the multi-year SRA project and relevant studies on benefits of cow milks.


In 2017, the joint project on the microbiota of raw milks launched with a webinar series. Slide sets from the webinars are available here. In addition, two working draft cumulative bibliographies were developed that document many of the peer reviewed studies identified that year, one emphasizing human clinical studies and outbreaks associated with raw milks, the other evidence of mechanisms of colonization resistance, innate protection against pathogens by microbes of the dense and diverse gut microbiota. These bibliographies will be updated in the future as the joint project continues.

Two recent studies are available that document health benefits of cow milks to humans, including pregnant mothers and their infants before and after birth. The first paper is a peer-reviewed study by Joseph Heckman (Securing Fresh Food from Fertile Soil, Challenges to the Organic and Raw Milk Movement), and the other is a report by British Columbia Herdshare (Health Benefits of Raw Milk).

Of great interest to me as a customer of a NY state dairy licensed to sell raw milk was an article about Maine’s licensed raw milk farms on the British Columbia Herdshare website. Maine licenses dairies and permits sale at farm stores, at farmers’ markets, and in grocery stores, as do many other states. However, NY state restricts sale to farm stores, limiting access for NY state residents who do not live near one of nearly 50 licensed dairies. The map below provides state-by-state information about raw milk laws in the US.

Available at this link:

Available at this link:

Canada and Australia currently prohibit raw milk sale, as well as herdshares.

Interested in more information about herdshares? This definition is provided on the BC Herdshare website. ‘A group of people co-owning one or more herd animals is a herdshare. A herdshare could be a cow-share, goat-share, sheep-share, etc. Herdsharing is not a new idea: American Colonial records show that in 1627, Edward Winslow “sold unto Capt. Myles Standish his sixth share in the red cow,” indicating one cow shared by several families.’

Please ask me any questions that puzzle you about breastmilk and cow milk studies, and I will respond in future blogs.

Margaret Coleman1 Comment