Table of Contents
Functional medicine testing.
If you have been looking into naturopathy, functional medicine or integrative health, you have probably come across a growing range of tests that promise to tell you more about your health.
You can now find testing for your genes, SNPs, hormones, gut microbiome, food sensitivities, nutritional status, organic acids, detoxification pathways and more.
For many people, this is appealing.
After all, who wouldn’t want to understand what is happening inside their body and have their treatment personalised specifically to them?
I understand the appeal.
But there is an important question that is sometimes missed:
Does knowing the result of a test actually help us make a better health decision or improve the outcome?
That is the question I think is worth asking before spending money on testing.
More testing doesn’t necessarily mean better healthcare
A test can measure something accurately without necessarily telling us what we should do about it.
There are really three different questions we need to ask:
1. Can the test accurately measure what it says it measures?
2. Does the result have clinical meaning?
3. Does using the test to guide treatment actually improve health outcomes?
These are not the same thing.
A test can be scientifically interesting and analytically accurate, while the interpretation of the result or the treatment based on that result may not yet have strong evidence behind it.
This distinction is particularly important with some of the newer tests marketed within functional and integrative health.
What about genetic and SNP testing?
Genetic testing can be extremely useful in medicine.
There are established genetic tests that can help diagnose inherited conditions, identify some cancer syndromes, establish carrier status and, in certain circumstances, help guide medication choices.
But this is different from the broad SNP panels that are increasingly offered as part of health optimisation programs.
You may be offered testing for genes such as MTHFR, COMT, GST, VDR or SOD2, for example, with the promise that the results will explain how you metabolise nutrients, hormones, medications or environmental compounds.
The genes themselves are real, and the biological pathways they are involved in are real.
The question is whether knowing that you carry a particular variant actually changes what we should do for you.
This is where the evidence becomes much less certain.
For example, finding an MTHFR variant does not automatically mean that someone has a “methylation problem” or that they need a particular form or dose of B vitamins.
Genes don’t work in isolation. Their effects can depend on other genes, nutrition, medications, environment, age, health status and many other factors.
Research looking at whether adding genetic information to nutrition counselling improves health outcomes has so far been limited and of low certainty.
So while genetic information can be valuable in the right clinical situation, more genetic information doesn’t automatically mean more personalised or better healthcare.
What about epigenetic testing?
Epigenetics is a genuine and fascinating area of science.
Our environment and behaviours can influence how genes are expressed, and factors such as nutrition, physical activity, ageing, sleep and environmental exposures can all interact with gene expression.
But this doesn’t necessarily mean that an “epigenetic age” test can tell us exactly what treatment you need or that changing a particular supplement or diet will reverse your biological age.
Again, the important question is:
Does using the test change treatment in a way that has been shown to improve meaningful health outcomes?
That is a much higher standard than simply demonstrating that a biological measurement can be made.
What about gut microbiome testing?
The microbiome is another area where the science is fascinating.
We now know that the trillions of microorganisms living in and on our bodies have important relationships with our health.
But there is a difference between understanding the importance of the microbiome and being able to look at an individual’s stool sample and say:
“This is your dysbiosis, and this is exactly what you need to take to correct it.”
Commercial microbiome testing can report the relative abundance of hundreds of microorganisms and may provide measures such as bacterial diversity or a “dysbiosis” score.
The difficulty is that we don’t yet have a universally accepted definition of what a healthy microbiome looks like for a person.
An international consensus statement on microbiome testing has highlighted the current limitations and the lack of sufficient evidence for routine use of many commercial microbiome tests in clinical practice.
That doesn’t mean the microbiome isn’t important.
It means that the science of the microbiome is developing faster than our ability to use individual microbiome test results to make precise clinical decisions.
You can still support a healthy gut microbiome through evidence-informed nutrition and lifestyle approaches without needing to know the percentage of every bacterial species living in your gut.
What about hormone testing?
Hormone testing is another area where context matters enormously.
There are well-established medical hormone tests that are extremely useful when there is a specific clinical question.
For example, thyroid hormones, reproductive hormones and cortisol can all be measured in appropriate circumstances.
But you may also come across comprehensive hormone panels that measure multiple hormones and hormone metabolites, sometimes using dried urine samples.
The fact that a laboratory can measure a hormone or metabolite does not necessarily mean that every pattern found on a large panel has a clinically established interpretation.
This is an important distinction.
Measuring something is not the same as knowing what it means.
And knowing what it means is not the same as knowing that treating it will improve your health.
What about food sensitivity testing?
This is one area where the evidence is considerably clearer.
You may have seen tests that measure IgG antibodies to dozens or even hundreds of foods and produce a report telling you which foods you are supposedly sensitive or intolerant to.
These tests are not recommended for diagnosing food allergy or food intolerance.
Food-specific IgG generally reflects exposure to a food rather than demonstrating that the food is causing symptoms.
If a food allergy is suspected, there are established approaches involving clinical history and, when appropriate, specific IgE testing, skin-prick testing or supervised food challenge.
For suspected food intolerance, a structured dietary approach with appropriate elimination and reintroduction may provide much more useful information than a large commercial food panel.
This is a good example of why a personalised approach doesn’t necessarily require a personalised test.
What about organic acids testing?
Organic acids are real biochemical compounds and organic acid analysis has an established role in diagnosing certain inherited metabolic disorders.
But commercial “functional” organic acid testing often goes much further, using variations in metabolites to make claims about areas such as energy production, detoxification, neurotransmitters, nutrient status or gut health.
Some of these interpretations are much less well established.
Again, the question isn’t whether the molecule exists.
It is:
Has this particular result been validated for this particular clinical purpose, and does acting on it improve outcomes?
What about heavy metals and detoxification testing?
There are circumstances where testing for genuine heavy-metal exposure is appropriate.
If someone has a relevant occupational or environmental exposure, for example, there are established tests that can be used to investigate it.
This is different from broad testing designed to demonstrate that someone has accumulated “toxins” and therefore needs a detoxification program.
The same principle applies:
There needs to be a clear clinical question, an appropriate test and an evidence-based response to the result.
So, do functional medicine tests work?
This is actually a difficult question to answer with a simple yes or no.
Some tests used within functional and integrative medicine are well-established medical investigations.
Some are promising areas of emerging science.
Some have limited evidence for their clinical usefulness.
And some tests are being used for purposes for which they have not been adequately validated.
There is also a difference between evidence that a functional medicine approach helps people and evidence that a particular functional test improves outcomes.
A person may feel considerably better after working with a functional or integrative practitioner.
That improvement may be very real.
But it doesn’t necessarily mean that a particular laboratory test caused the improvement.
People can improve because of changes in nutrition, sleep, exercise, stress, medications, supplementation, education, support and many other aspects of their care.
This is why clinical trials comparing testing-guided treatment with appropriate care without the test are so important.
The question I think is more useful
Rather than asking:
Is this a functional medicine test?”
I think it is more useful to ask:
“What clinical question is this test going to answer?”
And then:
“What will we do differently depending on the result?”
If the result is abnormal, what changes?
If it is normal, what changes?
And perhaps most importantly:
“Is there evidence that acting on this result improves outcomes?”
Those questions don’t mean that we need to reject new or emerging science.
Quite the opposite.
They allow us to be curious about new science while still being careful about what we turn into clinical practice.
The sophistication of the test isn’t the same thing as the usefulness of the test.
When might additional testing be useful?
The usefulness of any test depends on the clinical question it is being used to answer.
For someone presenting with a straightforward, previously unaddressed health concern, a detailed history, clinical assessment and appropriate standard investigations may provide enough information to guide treatment. More testing is not necessarily better, particularly when the result is unlikely to change what we do.
For someone with persistent or complex symptoms, particularly when appropriate investigations have already been undertaken without providing a clear explanation, it may be reasonable to consider whether additional testing could answer an unresolved clinical question.
However, this doesn’t mean that a functional medicine testing panel is automatically the next step.
The important questions are:
What are we trying to find out?
Is the test validated for that purpose?
What would we do differently depending on the result?
And is there evidence that acting on the result improves outcomes?
In other words, testing should be guided by clinical reasoning rather than used routinely or simply because a test is available.
Sometimes an additional investigation can provide useful information. Sometimes it won’t add anything meaningful to what we already know.
The goal is not to collect as much information as possible. It is to gather the information that can help us make better decisions about your health.
How I approach testing in my practice
I don’t believe that more testing necessarily means better healthcare.
My approach is to start with you.
We talk through your health history, your current concerns, your lifestyle, medications and supplements, what you have already tried and what you want to achieve.
From there, I assess what is most important to address and whether further investigation is warranted.
Where appropriate, I work with standard medical pathology and established clinical tests. There may also be situations where additional testing is useful, and I can discuss that with you or recommend medical investigation or referral when appropriate.
I don’t routinely order large functional medicine testing panels simply because they are available.
For me, a test needs to have a reason for being there.
What are we trying to find out?
Will the result change what we do?
And is the information useful enough to justify the cost, time and potential worry that testing can create?
That doesn’t mean I think every new test is useless.
It means I want to understand what the test can genuinely tell us — and what it can’t.
Personalised healthcare doesn’t have to mean more tests
I think this is an important point.
Personalised healthcare is sometimes presented as though it means having your genes, hormones, microbiome and nutritional status mapped before anything can be understood about your health.
It doesn’t.
Personalisation can come from listening carefully to your history, understanding your circumstances, looking at the whole picture, using appropriate investigations and then seeing how you respond to treatment.
Sometimes a test is an important part of that process.
Sometimes it isn’t.
The goal isn’t to collect as much information as possible.
The goal is to collect the information that helps us make better decisions about your health.
References:
Jones et al. — functional/CAM laboratory testing
Porcari et al. — microbiome testing
Leave a Reply