My Take on Functional Tests: HTMA, DUTCH, GI-MAP
A couple years ago before I decided to become a Certified Intuitive Eating Counselor, I considered pursuing more education in functional nutrition. Many of my colleagues have gone this route, and frankly, it appears like they are making a decent living going this route. Registered dietitians are traditionally underpaid in most roles that we have, so I thought this could be a way to bring more income into my private practice. Additionally, I live in a community with many functional and alternative medicine providers who give recommendations beyond their scope of practice. For context, in the state of Wyoming (the state where I live and practice), it is illegal for someone to provide medical nutrition therapy if they’re not licensed to do so. The only people who can receive this kind of license in the state are registered dietitians. Click here to read more about Wyoming nutrition licensure laws.
It is hard for me to see people in my community invest hundreds and thousands of dollars in testing and supplement protocols with health providers who are unqualified to provide nutrition counseling and medical nutrition therapy. With that being said, I have to acknowledge why many seek out alternative or functional medicine. Conventional medicine providers have limited time to care for patients. Many patients feel dismissed by their medical doctors, especially if traditional labs are within normal ranges but the patient is still experiencing symptoms that are altering the quality of their everyday lives. I briefly worked as a clinical dietitian from 2015-2017, and I left the profession completely in 2017 due to burnout and feeling like I couldn’t make a difference give the fact that I had such limited time with patients in the inpatient and outpatient settings.
Before I dive into my professional viewpoints of these specific tests, I want you to know that if you’ve had good experiences with functional medicine providers, I am not trying to dismiss your experiences in any way. I want you to feel cared for by every provider you work with. I want you to feel heard. I want you to feel like you’re being treated like a human being instead of being reduced to lab values and metrics. Advocate for yourself. Ask questions. Get second opinions, especially since both systems - conventional and functional - can cause harm to patients if we take everything that every provider says as law or gospel.
I wrote about several tests widely used by functional medicine providers in my weekly newsletter, Pocket Snacks, and something I highlighted in the mindset part of the newsletter is how I want more health providers - conventional and functional - to practice humility and to be able to admit when we’re wrong. For example, I caused harm earlier in my career. I believed I could teach weight loss “the safe way.” As soon as I made the pivot to pursue my certification in Intuitive Eating, I knew I owed so many people an apology. On top of investing my own money to become a weight loss coach for a group program run by registered dietitians, I recruited people into this program and used my title as a registered dietitian in a very misleading way. I was wrong. I’m sorry to those I confused and harmed. I can’t change previous things that have happened in my life and career; however, I can acknowledge the mistakes I’ve made and pivot accordingly.
Not all functional providers are causing harm, but many are, especially in my mountain community. Disordered eating and undiagnosed eating disorders are a major problem in mountain towns like Jackson, Wyoming. Orthorexia is rampant, and many functional providers fuel that eating disorder with their protocols. A huge concern I have is that I see so many recreational and elite athletes under-fueling their bodies in endurance activities due to food fear, due to providers and influencers making them believe every food and ingredient is “bad” for us unless it’s “clean” and natural. Something I had to realize when I was recovering from OSFED, RED-s, and orthorexia: there is no food out there that is as unhealthy for your body/your gut as an eating disorder.
If you’re a functional provider who reads this post, I want you to remember that two things can be true at once: We can disagree about certain practices in the nutrition space while also holding respect for one another. My professional views about these tests do not reflect how I feel about you as a person, especially if we’ve never met in real life.
My reviews of these tests below include excerpts and selected research from Christy Harrison’s paid newsletter/podcast subscription for Rethinking Wellness as well as her book The Wellness Trap. I highly encourage subscribing to Rethinking Wellness, and I promise you this subscription is way more affordable ($5/month) than any of the tests I’m going to highlight below.
Hair Tissue Mineral Analysis (HTMA)
HTMA supposedly tests the mineral levels in your hair to find deficiencies and “imbalances,” which you can then ostensibly correct through food and supplements (often sold by the provider who ordered the hair analysis).
The problem is that hair can’t actually tell you those things. Like many problematic wellness practices, HTMA is based on a grain of truth: hair testing can help determine whether someone was exposed to illegal drugs, substances banned in sports, or actual poisons (although it has some limitations). But nutrients are a different story, and hair mineral analysis isn’t a precise enough method to use for general health and nutrition screening.
Researchers have known this for decades, going back at least to the 1980s—HTMA definitely is not “new science.” In 1985, a critical review of the evidence published by the Canadian Medical Association found that commercial hair analysis was “imprecise, unnecessary, and probably wasteful.” Minerals in hair don’t reliably indicate minerals in other body tissues—you could have low levels in your hair without having a deficiency, or you could have seemingly “normal” levels in your hair and actually be deficient.
What’s more, the review found, there was no scientific oversight or government regulatory control of information provided by commercial hair-analysis labs. “Therefore, the information may be inaccurate, misleading and even detrimental to the patient’s health,” the report concluded.
That same year, the Journal of the American Medical Association (JAMA) published a small study by medical doctor Stephen Barrett, who sent hair samples from two healthy teenagers to 13 different commercial hair-analysis companies. Barrett found that identical samples produced wildly different results when sent to different labs—and also when they were sent to the same lab under different names. In addition, the labs disagreed about what constituted “normal” values for many of the minerals.
A 2001 study set out to see if anything had changed in the 16 years since Barrett’s paper, and especially since the 1988 passage of the Clinical Laboratory Improvement Act (CLIA), which regulates clinical testing. But in 2001 the situation was still very much the same. “Hair mineral analysis from these laboratories was unreliable, and we recommend that health care practitioners refrain from using such analyses to assess individual nutritional status or suspected environmental exposures,” the researchers wrote. “Problems with the regulation and certification of these laboratories also should be addressed.”
More than a decade further on, these issues remained. A 2013 study of three different hair-analysis labs found that each lab reported different mineral deficiencies, which resulted in conflicting recommendations for supplements and treatments. One lab even reported different deficiencies for two samples of the same hair.
The main reason for these wide variations is that labs basically just make up their own definitions of “normal” because there are no established reference ranges for minerals in human hair. The ranges considered “normal” for blood tests can also vary a bit from lab to lab, but those variations are tiny compared to the large discrepancies in ranges for hair analysis.
Those inconsistencies exist in part because there’s no standard procedure for taking samples, preparing hair for analysis, or extracting minerals, as a 2013 systematic review noted. Until those things are standardized and scientifically validated, it’s impossible to come up with reliable reference ranges for hair analysis. Each testing company has its own protocols, which may or may not lead to internally consistent results at a given lab, but there’s still no evidence-based definition of “normal.”
DUTCH Test
DUTCH testing is newer, but I wouldn’t necessarily call it “new science,” and I also wouldn’t recommend it. DUTCH stands for Dried Urine Test for Comprehensive Hormones, and the test is billed as a way to “optimize hormone health and address hormone-related symptoms such as fatigue, weight gain, hair loss, and mood swings.” It measures several reproductive hormones and their metabolites (or breakdown products) including estrogens, androgens, and progesterone.
That all might sound great to a layperson, but not to experts in hormone health. In general, the DUTCH test is not used or endorsed by endocrinologists (medical doctors who specialize in hormones), but rather by alternative, integrative, and functional-medicine providers. Like many tests in those fields, it doesn’t have solid evidence behind it, and in fact several endocrinologists and OB/GYNs have spoken out against it. As endocrinologist Disha Narang told dietitian Abby Langer for her 2021 review of the DUTCH test:
“Metabolites are never used in clinical practice. It’s very rare for any of the metabolites to be low—that would mean you have dysfunctional enzymes that convert estrogen. In my experience, the DUTCH is used by providers like naturopaths to say ‘your metabolites are low’ and sell you a supplement.”
Dr. Jen Gunter also wrote about the DUTCH test in this 2022 post, where she explained:
“This test claims to measure and provide results about estradiol, estrone, and multiple estrogen metabolites. There is no indication for testing for estrogen metabolites for any reason. When we do recommend hormone testing in menopause, and that is uncommon, the gold standard is a blood test.
The DUTCH test is also advertised to providers by its manufacturer as a way for providers to grow their hormone replacement therapy practice. That is always a major red flag for me. ‘Here, you can make more money if you use our test.’”
There have been a few small studies of DUTCH testing published in reputable journals, but they were conducted by the test manufacturer (Precision Analytical), so we have to take them with a big grain of salt—especially since there doesn’t seem to be any other scientific research on the test by independent groups. The studies mainly showed that there were no significant differences between liquid urine and dried urine samples, but that doesn’t mean the test is clinically useful in any way for measuring hormones.
GI-MAP
Many functional medicine/nutrition providers will tell you the GI-MAP is the “gold standard” for addressing gut health concerns. But a 2020 study (linked here for you) showed that this test is far from the standard we should be using and trusting for answers when it comes to our gut health. “Researchers collected human feces that didn't contain any of the bacteria or parasites that the GI-MAP tests for, and used seven samples of that ‘clean’ feces into 16 samples and ‘spiked’ each one with one of the germs that the test looks for. The GI-MAP test missed 20% of the spiked samples, and it produced false positives for a whopping 74% of the samples – meaning it claimed to detect specific microbes where they weren't present at all.”
The discussion section of the study I linked for you is absolute 🔥:
"In this study’s qualitative analysis the GI-MAP assay could not attain the sensitivity of the BioFire multiplex assay, and its specificity was surprisingly low. The extreme number of false positives could lead clinicians to treat patients in the absence of any true pathogen.
Although there is a need to develop rapid molecular testing assays for characterization of the gut microbiome, physicians and patients need to be aware that all stool analysis assays may not provide consistent results with both false-positive and false-negative results possible. The clinical implications for diagnosis and treatment of gastroenteritis is potentially significant because of missed diagnoses, and the use of antibacterial or antiparasitic agents in the absence of true infections. The limitations of the GI-MAP method reported here may restrict its applications for the diagnosis of gastroenteritis."
I know that was a A LOT of info, links, and research. It's so tricky to navigate what's actually healthy for us in this world. It’s hard to know who to trust… Truthfully, you get to decide what and who you believe. But if something sounds too good to be true, it probably is! That's the case with these tests and the supplements providers will try to sell you to “heal your gut.” Be careful out there. Ask questions. Get second opinions. Advocate for yourself! And add The Wellness Trap to your reading list to help you sift through all the conflicting messages and recommendations!
“A well-fed body is a resilient body.”
