Today I see this nice little review put out by the Authority Nutrition group. It got me thinking about this default term: “evidence-based practice”. As health professionals, we are governed by this, and rightly so, but it can be grey. Pretty much everything that is clouded with debate these days has some sort of evidence behind it, but how do health professionals decide whether or not it’s worth providing advice on if consensus is not reached or if the evidence is unclear?

The reality is, when evidence exists without consensus, some tend to sway their decision to advise or not to advise towards their own personal beliefs / hypotheses. These factors should help those decisions being formed: Is it an observational study? Are there very small numbers in a trial? Is it an animal model? This might be grounds for a starting base of evidence with promise for an outcome somewhere down the track when some robust RCTs are conducted on humans, establishing cause and effect. On the other hand, if very little or no research exits while I would say that there is no evidence to suggest a relationship (be it beneficial or harmful), in my head I’m also thinking, that just because the research has not been done, it doesn’t mean that there is no relationship. Do you advise based on a hunch? Maybe, if you didn’t have a health professionals regulatory body watching your every move.

As a quick summary about the A1 / A2 milk issue, the protein component in milk, casein, has several sub-fractions, beta-casein being one of them, and within this category, A1 and A2 beta-casein exist. There are claims that A2 has health benefits and A1 is harmful. Regular milk contains both A1 and A2 beta-casein, but A2 milk contains only A2 beta-casein.
This review sums us the evidence nicely, which, in a nutshell, really looks like it is not strong enough for any clear conclusions to be made. So as a dietitian, I would probably not (and currently don’t) actively place emphasis on this in my provision of advice to clients, as a general rule. However you as the consumer need to make informed decisions, and as the article rightly says, if you feel like you tolerate A2 milk better than A1 milk for whatever reason, then you should probably choose it (irrespective of the state of the evidence). Why? Because there is NO risk of harm in making the A2 choice, despite the lack of evidence to support it. In NZ, I see it on the supermarket shelves now – (see picture), and yes it’s more expensive than regular milk: the choice is yours.

Do I drink A2 milk? No I don’t but I’m constantly re-evaluating my nutrition beliefs these days, so while today I don’t, tomorrow I might.