I’ve been asked numerous times to do a Zoe review, and I wanted to, but I never had access to the materials until now.
After I wrote a small piece about microbiome testing for Men’s Health Magazine, Zoe contacted me and offered to send me a kit. Since Zoe isn’t available in Canada yet, they agreed to send it to my place in Florida while I was there.
Unfortunately, they dropped the ball and I never received the kit. That was disappointing.
The microbiome and gut health in general are hot topics right now, and there are a TON of companies and practitioners trying to monetize them. You can’t blame these people for trying – slapping a ‘gut health’ claim on anything seems to make people sit up and take notice.
Gut health for weight loss.
Gut health for bloating.
Gut health for periods and menopause.
Add an element of personalization, and you’re basically sitting on a gold mine.
Microbiome test kits like Zoe and Viome purportedly give you an accurate overview of your personal gut bugs and using that information, develop dietary recommendations that allegedly ‘feed them’ the way they ‘want to be fed.’
Luckily, I have a follower who has shared their entire Zoe experience with me, from the Zoe white paper, to the process, to her testing results and recommendations. This, and one of my favorite gut health experts who has been in contact with Zoe, are some of the resources that I’ve used to write this Zoe review.
What is Zoe?
Zoe is a gut and blood-testing kit that measures three things:
Your gut bacteria.
Your blood sugar.
Your blood fats.
Nobody, especially me, is saying that the microbiome doesn’t play a part in our metabolic and mental health. I think Zoe is absolutely correct when they say that non-communicable diseases such as diabetes and heart disease are huge killers, and that traditional dietary recommendations haven’t been all that effective in preventing them (although I’m not sure that many people actually follow the guidelines, anyhow).
As we know, disease risk is about more than just diet, so we need to keep that in mind.
Historically, we have relied on a one-size-fits-all approach for prevention. I think we’re getting better though at moving past that way of thinking.
But here’s the thing: can ‘harnessing the potential power’ in our gut microbes fill in those gaps? Does ‘precision nutrition’ like Zoe claims it provides, really have an effect on our risk for disease?
What’s real here, and what’s fantasy? What’s evidence-based, and what’s merely a prediction or theory?
We need to keep asking ourselves this throughout this process.
Zoe has based much of its existence on a series of research studies called the PREDICT studies, which are ongoing. The studies are being led by Tim Spector, a doctor and professor of genetic epidemiology at Kings College, London.
Spector is well-respected although some of his recent views about food and eating have been controversial – like in 2020, when he said that half of the population will gain weight from eating breakfast.
PREDICT has measured the individual glucose, triglyceride, and insulin responses of over 1000 participants in response to identical meals. It theorizes that a person’s response to a meal can be predicted by gut microbiome, sleep, exercise, circadian rhythm, and meal timing. PREDICT used the data to establish risk for heart disease in each participant.
I have to admit that the PREDICT studies are groundbreaking and fascinating. And I don’t say that lightly, as many of you know. It’s not every day that you see research that may actually change the face of nutrition.
I could go on and on about PREDICT, but what you really need to know is that thousands and thousands of results have been compiled and are used to predict how Zoe users will respond to certain foods.
But do these studies have an application right now?
This is a key question.
While it’s interesting to see data about peoples’ guts, how much of that is really ready to use in real life recommendations and nutrition therapy?
The Zoe process.
Zoe has four phases:
- Phase 1: completing the tests and sending them in. The tests require eating these special muffins for blood glucose and fat monitoring (they tell you the window of time after eating the muffins to do the blood fat sample), and sending in a stool sample.
- Phase 2: they send you your results in two reports about 4 weeks later. In the reports you’ll see an explanation of how based on my personal results to the tests, foods are scored. So the idea is that the foods I eat are scored differently than the exact same foods for someone else.
- Phase 3: you try to get a certain food score every day for 4 weeks. There is no off-limit food, but some foods score very poorly and will bring down your daily average. The app does track your macros and calories in the summary, but it doesn’t set goals for these. Also, it does not ask for your weight at any time.
- Phase 4: “thrive.” (Keep going and get a 75+ score most days.)
If you choose to be a part of the PREDICT study, Zoe will send you a blood sugar monitor to wear for 10 days. They’ll also send you a scale to weigh your food, which you’ll log on the Zoe app. This is only if you agree to be a part of the study – it’s not the usual route for everyone who buys the Zoe kit.
Research done in 2021 by Tim Spector on transit time suggests that if food moves through your system at a good pace, you’re more likely to have a healthy microbiome. Hence, the blue poo challenge.
The information in the Zoe reports is as follows:
Your ‘dietary inflammation profile.’ This profile is determined by your Zoe blood sugar and blood tests.
Your blood sugar control score shows how well your body processes certain carbohydrates. If you experience large blood sugar spikes after certain foods, this may increase risk for inflammation. Zoe hypothesizes that understanding which foods causes these spikes (and then limiting those foods) may help with satiety and energy levels, as well as risk for diabetes and heart disease.
Here is my follower’s blood sugar control score:
Your blood fat control score shows how well your body processes fatty foods. The lower the score, the higher the risk for inflammation.
Here’s my follower’s blood fat score:
One of Zoe’s huge selling points is that we’re all different, and therefore respond differently to food. According to Zoe, your scores are comparisons of you to thousands of people, and can predict how you’ll respond to various foods. This ‘helps you find the best foods for your body,’ even if you’ve never tried those foods before. AI and the thousands of results profiles in the Zoe database figure all of that out for you.
But can correlations on a population level apply to each one of us? Here’s where things get sort of sticky. The research looks good in Zoe’s result package, but how does it translate to real life? I called in my expert to translate.
Here’s what she said.
Zoe has established some correlations between dietary patterns and certain microbes, and in some cases between groups of foods and certain microbes.
This is really no surprise, because microbes have pretty specific nutrient needs and are forced to live off the host’s diet. So if you’re eating a diet high in refined carbs and protein–lacking the microbe-accessible carbs found in whole grains, fruits, and veggies–you will be colonized by microbes that can make energy from proteins and don’t rely heavily on carbs.
Coincidentally, those are some of the potentially pathogenic ones that produce carcinogenic compounds when they ferment proteins to produce energy.
I’m 99% sure they just used the foods that had the ‘strongest’ correlations, which were weak-moderate at best.
Meaning, the foods Zoe predicts will be best for you, are based on AI, and while this emerging science is very interesting, we don’t know how relevant the associations are between the data and you as an individual. And the correlations they found between how foods impact people on a population level weren’t super strong.
We do know that a wide variety of foods, in particular foods that are whole, minimally processed, and fibre-rich, makes our gut bugs happy. There’s not a dietitian in the world who doesn’t recommend this way of eating, even without Zoe. It’s just common sense.
As I said that the beginning of this post, disease risk and metabolism are not only functions of what we eat; they can also be genetic. It’s impossible to remove all health risks just by changing diet, although that’s not what Zoe is saying the app does.
Zoe promises that you don’t have to count calories; you just need to eat the right type of high-quality food. Nothing is off-limits, but for ‘best results,’ you’ll eat a wide variety of high-scoring foods that feed your own personal good gut bacteria and optimize your glucose.
I’m sure nobody’s results are telling them to eat highly processed, low-nutrition foods – so when you make changes to your diet to include more whole and minimally processed foods, you may feel better overall and lose weight. But can choosing the right foods help us lose weight through our microbiome?
Fundaro had this to say:
From what I can tell, the Zoe test doesn’t measure gene expression, or the activity of the microbes. So we can see who’s there, but not what they’re doing. And since it’s a stool sample, it’s just a proxy for the actual gut biome.
Meaning, basing a set of recommendations on the microbiome you have on Tuesday, doesn’t necessarily make sense, two weeks later. In fact, the microbiome can change rapidly, due to what we eat, medications we take, or lifestyle changes like travel. How do those changes impact our sugar and fat ‘inflammation scores,’ and our overall results, over time?
We aren’t sure.
These tests are showing you which microbes are thriving as a result of your current dietary habits, and they’re probably deducing what your diet is lacking based on the diversity (low fiber diversity = low microbe diversity) and abundances of microbes (ex, low Bifidobacterium = probably eating a diet low in FODMAPs).
Yes, the microbiome can influence how much energy we absorb from our food, maybe by a couple hundred calories, but at the end of the day, if we want to lose weight, we still need to establish a calorie deficit. If our microbes are harvesting more energy than we accounted for, we just need to make an additional adjustment until we reach our intended rate of weight loss.
Zoe isn’t hacking the laws of thermodynamics. Phew!
In my opinion, the entire ongoing Zoe process seems complicated. Aside from counting up scores to try to get 75+ most days, the app also helps with ‘meal sequencing,’ which is essentially when to eat foods for the best possible effect on health.
Sorry, but this is a lot of information.
At what point do we just EAT, and not feel the need to drill down every bit of food into a number? Even if this information has some validity, do we really need to ‘hack’ our health like this?
Some of the recommendations that Zoe gives may be helpful, especially when it comes to eating more whole foods and plants. If that causes a positive change in habits, that’s great. But the research continues to be limited in terms of how accurate and meaningful Zoe is to the state of our microbiome over time, and our everyday life.
But the flip side of this is that tracking everything you eat and turning food into numbers has limited value when it negatively affects our state of mind.
Zoe and microbiome testing kits may offer interesting results, but for now, I think their value is limited.