Thursday, March 29, 2007

Raw Milk - Waiting

  • Raw milk contains compounds that fight infectious agents.
  • There is also a class of compounds that seem to promote positive immunity response.
  • The benefit to humans is not established.
  • One should avoid using one study to draw broad conclusions.
  • There is not enough information to make a proper risk analysis

The objective of this investigation is to research the findings of the power point presentation (PPT) of Dexter and Fallon with the ultimate goal of deciding on the scientific validity of health claims of raw milk. This article will look at the first few slides of the PPT.

While waiting for the delivery of the book The Untold Story of Milk from Amazon, I have decided to look at what information I can from the web sites recommended in the thread of at The Complete Patient web blog post entitled "The Nuances of Educating People About Raw Milk and Other Real Foods". In visiting the web site for the Weston A. Price Foundation I found the following PPT and will start to look into the claims it makes. As I have said before, I do not take the Weston A. Price Foundation as a non-biased source. Though some have questioned how anyone might benefit from advocating or misleading a concept that is not financially profitable, human nature being what it is there are many reasons why someone might take up advocacy for an idea or belief that does not pan out "in reality".

My intention with respect to the PPT is to go over, slide by slide, the claims and details. I am not a health professional (a bonus point no doubt among many...) so please feel free to correct me or direct me to areas you think I either missed or did not cover adequately. My goal is two fold. To find out details about the science or pseudo-science of raw milk claims and to show respect for people. Showing respect for people of course is a two way street so please let's try to avoid what happens so often on net.

We are told:
  • Consider the calf, born in the muck, which then suckles on its mother’s manure-covered teat. How can that calf survive?
  • Because raw milk contains multiple, redundant systems of bioactive components that can reduce or eliminate populations of pathogenic bacteria.
This is followed by the next slide:

  • Built-In Protective Systems in Raw Milk Lactoperoxidase

  • Uses small amounts of H2O2 and free radicals to seek out and destroy bad bacteria
  • In all mammalian secretions—breast milk, tears, etc.
  • Lactoperoxidase levels 10 times higher in goat milk than in breast milk
  • Other countries are looking into using lactoperoxidase instead to pasteurization to ensure safety of commercial milk

British Journal of Nutrition (2000), 84, Suppl. 1. S19-S25.
Indian Journal Exp Biology Vol. 36, August 1998, pp 808-810. 1991
J Dairy Sci 74:783-787
Life Sciences, Vol 66, No 23, pp 2433-2439, 2000
An investigation into the sources is in order. I checked the more easily accessible (for me) ones The British Journal of Nutrition and Life Sciences (side note, the reference for Life Sciences had a typo, the issue number should read 25 not 23.) These references pan out and confirm that raw milk does indeed have bacteriological fighting chemicals. In fact these compounds are now actively being mined (from raw milk no less) for potential use in preserving other food products.

This research lead to further reading why I found this interesting article:


Biodefense Properties of Milk: The Role of Antimicrobial Proteins and Peptides

Authors: Clare, D.A.; Catignani, G.L.; Swaisgood, H.E.

Source: Current Pharmaceutical Design, Volume 9, Number 16, June 2003, pp. 1239-1255(17)

Publisher: Bentham Science Publishers


Mammary fluids, colostrum and milk, deliver nature's first host defense systems upon birth, and these essential liquids are critical for survival of the neonate. The identification and characterization of anti-infectious proteins were among the early scientific discoveries and this group of proteins has long been recognized for promoting health benefits in both newborns and adults. Among the more widely studied are the immunoglobulins, lactoperoxidase, lysozyme, and lactoferrin. Recently, it was shown that agr-lactalbumin may also function in a protective capacity dependent upon its folding state. Some of these, especially lactoferrin, also display an immunomodulatory role in which case a totally separate cascade of host defense responses is initiated. It was noted that the mechanism of action for this cluster of sentry proteins does vary; thus, this protective strategy provides for a broad range of responsive reactions to infection. Presently, there is a major focus on the discovery of novel peptides that can be generated from existing milk proteins via proteolytic reactions. To date, this substrate list includes agr-lactalbumin, bgr-lactoglobulin, all casein fractions, and lactoferrin. Again, the immunoregulatory effects prompted as a result of the appearance of these peptides are currently being defined. Herein, we review the principal biological properties associated with each of these contributing milk components with a special emphasis on the role of biodefensive milk peptides. We envision future contributions emerging from this research field as an opportunity to develop effective new therapies to be used in treating infectious diseases and promoting health benefits in vivo.
This looks like a great deal of scientific gobbledygook no doubt, but in essence it not only affirms the findings stated in the PPT but also confirms statements made elsewhere that there is a potential immuno-benefit derived from some proteins that are "dependent upon its folding state" or tertiary structure. Such protein structures are easily lost when they are heated, such as when milk is pasteurized. The authors note, and we should too, that the exact immunoregulatory effects are not known. This is undergoing further research.

The findings form the papers mentioned above confirm the statements made in the first few slides of the PPT. The inference made by the PPT authors, Dexter and Fallon, that raw milk is thus fundamentally safe is given some credence. The problem for this understanding is that raw milk is traced to out brakes of illness so any understanding that raw milk is fundamentally safe needs to include an explanation for these out breaks. I will muse on some possibilities that might suggest areas that need further research. In addition the idea that some bacteria, which are useful or benign to the calf but potentially infectious to a human, exist is not addressed.

Many of the compounds mentioned in the articles referenced are peroxides, these compounds are known for their short lifetimes (they decompose readily) which is part of the basis of their effectiveness. This is not a surprise since milk, by its nature, is not meant to be stored at all. Thus pathogen out breaks linked to raw milk would suggest that many of the bacteriological fighting compounds in raw milk are short lived. The research question here is what is this period of time for a given bacteriological load? Other questions include does diet affect the production of these compounds and to what degree.

The other interesting finding is the possible immuno-benefit of some of these proteins. I must confess that due to time restrictions I am basing my discussion on the reading of the abstract rather than the article itself. I hope that by my next post (middle of next week) I will have read this article and have more to say. That said, questions that must be addressed at some point are, if these compounds provide immuno-benefit then why is the incidence of illness from raw milk so great? Is it an immediate, linear benefit or is it a benefit that is acquired over time? Do these compounds provide any benefit at all? Are compounds beneficial to cows beneficial to humans at all?

There is evidence that raw milk contains compounds that fight infectious agents as stated in the PPT of Dexter and Fallon. Such agents are sensitive to heating and thus are likely to be largely lost in the pasteurization process. It is unknown if these compounds have beneficial health impacts on the human body. There is also a class of compounds that seem to promote positive immunity response. To what degree, over what time frame, and if beneficial to humans is not known. Once again, the tertiary structure of these proteins is sensitive to heating and thus would be expected to degrade with pasteurization.

As with any health study one should use caution in applying one study too broadly. The human body is complex as is the interaction of the cow with her environment. Further research is needed as stated above to provide a better understanding of how these compounds work, what benefit they might have, and why raw milk is linked to higher incidence of illness. Such information is needed to make a proper risk analysis with respect to raw milk consumption.

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Monday, March 26, 2007

Raw Milk - The Investigation Starts

My wife has started to consider buying raw milk from a local dairy and of course the first thing I felt was concern. Raw milk is milk that has not been pasteurized so that any pathogen that might make it into the milk then makes it on into the consumer of the milk. So why go for raw milk then? Well there is a movement of people who believe that pasteurization destroys the beneficial aspects of milk and even can make people ill. This effort over the next few weeks will be to investigate from as scientifically sound a direction as possible the reality of the raw milk "debate" for lack of a better term. The goal is to lead to a decision as to whether I will support bringing raw milk into the family menu or not.

Looking at what governments and mainstream researchers have to say, there is no issue. Raw milk is dangerous. But as a scientist myself and with the knowledge that there is a lot to the universe that we do not understand I will try to approach the subject with as open a mind as I can. But what bias I carry will favor caution against raw milk.

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Friday, March 2, 2007

Asthma & the Elite Athlete

In an interesting article that was recently published in the scientific journal Sports Medicine entitled "Do Inhaled [beta]2-Agonists have an Ergogenic Potential in Non-Asthmatic Competitive Athletes?" I learned a few interesting tidbits.

  • Asthma is more common among elite athletes than the general population
  • Asthma is more common among endurance athletes (like long distance runners) and swimmers
  • Asthma is more common among those who participate in winter sports (I guess the intersection of this and the previous point would be long distance cross country skiers).

The point of the article was to show that the ban on a certain inhaled drug, [beta]2-agonists, was not needed due to there being no physical enhancement (ergogenic effect) on performance, even at super high dose. But an interesting side point is made that I'm not sure needed to be made, that:

  • oral administration of salbutamol seems to be able to improve the muscle strength and the endurance performance

I'm not sure it needed to be made because this method of administering this drug, orally, is already banned. But it might lead to some competitive virtually elite athletes* (Boulder is full of them) to consider using this substance.
clipped from

The prevalence of asthma is higher in elite athletes than in the general population. The risk of developing asthmatic symptoms is the highest in endurance athletes and swimmers. Asthma seems particularly widespread in winter-sport athletes such as cross-country skiers. Asthmatic athletes commonly use inhaled [beta]2-agonists to prevent and treat asthmatic symptoms. However, [beta]2-agonists are prohibited according to the Prohibited List of the World Anti-Doping Agency.
In three of four studies, even supratherapeutic doses of salbutamol (800-1200[mu]g) had no ergogenic effect. In contrast to inhaled [beta]2-agonists, oral administration of salbutamol seems to be able to improve the muscle strength and the endurance performance. There appears to be no justification to prohibit inhaled [beta]2-agonists from the point of view of the ergogenic effects.

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* virtually elite athletes: athletes that are highly trained and in the top percentages of their field in sports or competitions that are not judged or regulated by international or national organizations.

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