Insights & Discussion
The alleged benefits of raw milk, including improved nutrition, prevention of lactose intolerance, or provision of "good" bacteria, lack scientific basis and are considered myths.
The review aims to bring clarity to the ongoing public debate on the benefits and risks of raw milk consumption. It delves into the historical context of pasteurization and how it significantly reduced the incidence of illnesses associated with raw milk. Furthermore, it critically analyzes the prevalence of pathogens in raw milk, revealing that up to a third of all samples could be contaminated with human pathogens, regardless of being sourced from healthy animals or milk appearing to be of good quality.
The study also critically investigates the widely claimed benefits of raw milk. It notes that claims about raw milk's ability to impart improved nutrition, aid in the prevention of lactose intolerance, or provide 'good' bacteria are not grounded in scientific fact but are rather myths.
Regarding the hypothesis that consuming raw milk might protect against allergies and asthma for children growing up in farming environments, the study acknowledges some epidemiological data suggesting a lowered risk. However, it cautions against attributing this protective effect directly to raw milk consumption since numerous environmental factors are likely involved.
Discover Related Insights
The type of dairy production system can influence the overall and specific levels of microRNAs, potentially affecting the functional potential of dairy products.
2022 Veterinary Sciences Differences in the microRNAs Levels of Raw Milk from Dairy Cattle Raised under Extensive or Intensive Production Systems Abou el qassim L, Alonso J, Zhao K, Le Guillou S, Diez J, Vicente F, et al.
Experimental Study Raw Milk
The research initially observed levels of microRNAs present in fat and cellular components from tank milk collected from farms using both intensive and extensive dairy production models. They commenced by sequencing microRNAs from three different milk samples from each production method. These selected microRNAs, which showed notable variance in both the fat and cellular content between the two production systems, were then further validated by conducting quantitative PCR on tank milk samples procured from an additional twenty different commercial farms.
The team discovered that the differences in the amounts of microRNAs were most significant in the fat portions of the milk. Here, they found that both the overall levels of microRNAs and the levels of specific types were considerably higher in milk from the intensive production system when compared to the extensive system. They also undertook a pathway analysis of the bovine mRNA targets for these specific microRNAs. While the precise reasons for these discrepancies in microRNA levels are yet to be determined, the research strongly indicated that the choice of production system could have a direct impact on both the microRNA content and the potential functionality of dairy and other agri-food products.
Consumption of raw milk early in life appears to provide protection against asthma and allergies, regardless of whether children live on farms or in rural, non-farm areas.
2020 The Journal of Allergy and Clinical Immunology: In Practice The Beneficial Effect of Farm Milk Consumption on Asthma, Allergies, and Infections: From Meta-Analysis of Evidence to Clinical Trial Brick T, Hettinga K, Kirchner B, Pfaffl MW, Ege MJ
Meta-Analysis Allergy Asthma Raw Milk
Whoever did the research carried out a comprehensive literature review, identifying twelve relevant publications from eight unique studies. Their approach involved a meta-analysis to substantiate the protective effect of raw milk consumption in early life, particularly for ages ranging from less than one year old to five years old. They further analyzed the impacts of raw milk on not only asthma but also other ailments such as wheezing, hay fever, allergic rhinitis, and atopic sensitization. Moreover, evidence was provided about the beneficial effects of raw milk for children, both living on the farms and those in rural sectors but not on farms.
Moreover, in the interpretation of results, it was clearly evident that the consumption of raw milk had an independent effect, separate from other farm exposures. In essence, even children not residing on farms theoretically can still gain from the benefits of raw milk consumption. However, they express a strong sense of caution, advocating against the consumption of raw milk due to the possibility of life-threatening infections. Furthermore, the distinction between raw farm milk and industrially processed milk was underlined to highlight differences in cellular components, fat fraction, and heating degrees. Preliminary findings link these characteristics and attributes of raw milk to heat-labile molecules and components found in its fat fraction.
Lactic acid bacteria strains isolated from indigenous Bangladeshi raw milk demonstrate strong probiotic potential and antimicrobial activity against various pathogens.
2020 Journal of Dairy Science Characterization and evaluation of lactic acid bacteria from indigenous raw milk for potential probiotic properties Reuben RC, Roy PC, Sarkar SL, Rubayet Ul Alam ASM, Jahid IK
Experimental Study Raw Milk
The researchers isolated and evaluated lactic acid bacteria (LAB) from raw milk indigenous to Bangladesh, focusing on its probiotic potential. To do this, they conducted a series of tests examining the LAB’s antagonistic activity towards several harmful foodborne pathogens, their survivability under gastric conditions, tolerance to phenol and bile salts, adhesiveness to ileum epithelial cells, aggregation abilities, hydrophobicity and α-glucosidase inhibitory activity. They also assessed these strains’ antibiotic susceptibility, covering key antibiotics widely used in medical and veterinary practices.
The research spotlighted four LAB strains, identified as Lactobacillus casei, Lactobacillus plantarum, Lactobacillus fermentum, and Lactobacillus paracasei, as possessing strong probiotic potential. This was primarily due to their shown ability to inhibit all tested pathogens to varying degrees and competitively exclude pathogens at certain viable counts. Their antimicrobial activity was attributed to their production of bacteriocin, organic acids, and low-molecular-weight substances. Additionally of note was their resistance to several antibiotics; all four strains resisted oxacillin, and three out of four resisted vancomycin and streptomycin. The study concludes by suggesting the potential for these LAB strains to be considered probiotic candidates for application in the food industry post in-vivo evaluation.
Unpasteurised milk and dairy products intake could potentially alter gut microbiome composition which may influence psychological functioning.
2020 Nutrients Recipe for a Healthy Gut: Intake of Unpasteurised Milk Is Associated with Increased Lactobacillus Abundance in the Human Gut Microbiome Butler MI, Bastiaanssen TFS, Long-Smith C, Berding K, Morkl S, Cusack AM, et al.
Experimental Study Gut Microbiota Lactobacillus Raw Milk
In this observational study, the impact of dietary change involving unpasteurized dairy consumption on gut microbiota and psychological state was observed among participants of a 12-week residential cookery course on an organic farm. Twenty-four participants, who primarily consumed food from the farm including unpasteurised milk and dairy products, provided faecal samples at the beginning and end of the course. Concurrently, they completed self-report questionnaires touching on mood, anxiety, and sleep aspects and nutrient intake was monitored via a food frequency questionnaire. Gut microbiota analysis was carried out using 16S rRNA gene sequencing and measurement of faecal short chain fatty acids.
Post-course, there was a significant growth in the relative abundance of a specific bacterial genus in the gut, associated with unpasteurised milk and dairy product intake. Furthermore, an increase in a particular faecal short chain fatty acid, valerate, was observed together with an elevation in the functional richness of the microbiome profile. The latter was determined by measuring the predicted neuroactive potential using a unique gut-brain module approach. Despite safety concerns, the consumption of unpasteurised milk and dairy products seemed to promote the growth of probiotic bacterial genus, known to be beneficial for various physical and mental health outcomes.