First, consider peer-reviewed studies demonstrating antiviral properties of a suite of bioactive components of raw mammalian milks, including bovine milk [4,5,7-9,12-14,16,17,19]. Multiple researchers note that some of the antiviral components of milk are likely function synergistically, meaning effects are greater in combination than independently, an observation particularly relevant in complex gut ecosystems of humans that include innate and adaptive immune systems. Many of these bioactive components of raw milk are also sensitive to heat and may be absent, inactive, or present in lower concentrations in pasteurized milks. Considering the extensive literature on antiviral activity in milk, clinical researchers [3] applied deep scientific knowledge to recommend that infants not be deprived of raw breastmilk due to the presence of viruses. The benefits of feeding raw breastmilk including its antiviral components to infants outweighs the very small risk of infection, from their perspective as clinical researchers, one associated with the Italian Association of Human Milk Banks.
Defense Against Pathogens in the Human Digestive Tract
Next, consider the gauntlet of defenses against foodborne pathogens in the human digestive tract [1,6,18]. These defenses include physical (stomach acidity, peristalsis), chemical (digestive enzymes), and cellular (innate and adaptive immune system, microbiota) factors that, acting simultaneously or sequentially, inactivate pathogens, including viruses, and/or suppress infectivity and virulence of ingested pathogens. Researchers [11] note that HPAI is an enveloped virus, susceptible to disruption and degradation in stomach acids, unlike the 16 viruses known to be transmitted to human by the oral route [6]. Further, FDA and USDA determined in 2010 that HPAI “is not considered to be a foodborne pathogen” even though virus was isolated from poultry muscle and the interior of eggs.
Host chemical and cellular defenses include: complement; defensins; enzymes; interferons; interleukins; pattern recognition receptors (Toll-like receptors 3, 4, and 7; NOD-like receptors; RIG-1 receptors); and an array of host cells (dendritic cells, B cells, intestinal epithelial cells, macrophages, monocytes, natural killer cells, T cells) and cells of the gut-associated microbes or microbiota. Also, the gut microbiota include not only commensal (non-pathogenic) bacteria, but also commensal viruses that can modulate infectivity and virulence of pathogens [10].
CDC Data on Transmission Sources
Now, consider that the microbial ecology of raw milks including antiviral activity as described briefly above aligns with recent CDC data for all transmission sources from 2005 to 2020 [15]. This CDC dataset included 3,807 milkborne illnesses (2,111 associated with pasteurized milk) linked to bacterial pathogens, but lacks any viral illness associated with milk, raw or pasteurized. The predominant virus in this CDC dataset was norovirus, associated with 8,199 illnesses from leafy greens reported over this 16-year period. No norovirus illnesses or any other viral illnesses were reported in milk.
What is known about HPAI transmission to humans is that it is rare, requiring prolonged direct contact with infected, sick, and dead animals, generally birds, now dairy cows, that can lead to mild flu-like symptoms or eye inflammation, some progressing to fatal infections, according to WHO. Again, HPAI in humans is linked to transmission via animal contact, not by foods.
It seems that occupational exposure resulted in infection of a farm worker handling ill cows, with developed of one symptom in the worker, eye redness (conjunctivitis), consistent with transmission by animal contact. HPAI has been detected in dairy cows in Texas, Kansas, New Mexico and Michigan as of April 2. The dairy animals and rare humans affected have recovered.
Cross-disciplinary evidence demonstrates that raw milk from healthy cows is not inherently dangerous, consistent with the CDC evidence of trends for 2005-2020 [15] and evidence of benefits and risks [2]. There is no scientific evidence that HPAI in raw milk causes human disease.
Please consider the references below and pose questions in the comments. You may be interested to learn more about these recent peer-reviewed publications.
This article was originally published on Peg Coleman’s website here: https://www.colemanscientific.org/blog/2024/4/7/where-is-the-evidence
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