“YoSince our bodies are unique, our food needs are also different. ” This is the core tenet of British health science company Zoe, a leading proponent of personalized nutrition (PN). Since its launch in April 2022, 130,000 people have signed up for the service, which at one point had a waiting list of 250,000 people. It proposes “smarter foods” using CGM). A choice for your body. ”
Like other companies working in this field, Zoe has all the hallmarks of serious science. Its American equivalent, Levels, has a number of respected scientists on its advisory board, including Robert Lustig, who famously warned about the harms of refined carbohydrates like sugar. Zoe was trained by scientist Tim Spector at King’s College London and claims to have been “created using the world’s most advanced science”.
The problem for the personalized nutrition industry is that this is still a young field of research, and the field as a whole doesn’t yet have enough evidence to believe that it has discovered valuable new interventions that are more helpful than standard advice. A Food Standards Agency report said last year that “glucose monitoring and gut microbiome analysis have the potential to become more robust and practical,” but the report added: “Glucose monitoring and gut microbiome analysis could become more robust and practical.” “By comparison, the benefits of PN appear somewhat modest,” concluded the paper, speaking for many experts. About healthy eating. ”
One of the big problems is that personalization has reached its limits and relies heavily on a few key biomarkers. Let’s take advantage of CGM. These allow the wearer to see fluctuations in blood sugar levels, especially postprandial peaks, in near real time. Zoe’s theory is summarized by Spector as follows: “If you have multiple spikes in blood sugar throughout the day, your average blood sugar level will rise. We know that increases your risk of diabetes and heart disease.” The idea is that if you can see what causes the biggest spikes, you can adjust your diet to flatten them.
However, most scientists remain unconvinced that non-diabetic CGM users can glean useful health information from CGM. Nicola Guess, an academic dietitian and researcher at the University of Oxford who specializes in the dietary prevention and management of type 2 diabetes, said: ‘Glucose levels in people without diabetes are linked to overall metabolic health, not to mention overall health. It’s just a small part of it.” “Variation between individuals is large, and some people may have more peaks and larger peaks than others, even though the average blood sugar level is the same.” Doctors use standard fasting or HbA1c blood tests to detect blood sugar levels. , can accurately diagnose diabetes or prediabetes. In contrast, Guess says, “data from CGM has no such diagnostic value,” something Zoe agrees with.
Another problem is that many personalized nutrition studies are based on analysis of vast amounts of data collected by users. This reveals many connections between diet, blood sugar levels, weight, etc. However, these “cross-sectional” studies only find associations, not causation. Therefore, the existence of an association between larger spikes and higher average blood sugar levels, even in healthy people, tells us nothing about causation. Higher spikes may be the result of an underlying metabolic problem rather than the cause of the problem. If so, suppressing the spikes would be addressing the symptoms of the problem, not the cause.
Worse, Guess explains, with very large datasets, cross-sectional studies will inevitably produce false positives. That is, “just as buying an iPhone on Tuesday is associated with risk of Crohn’s disease,” a statistically significant but virtually random association.
Given these scientific limitations, Shivani Misra, a diabetes researcher and consultant at Imperial College London, says she sees no evidence for the theory that healthy people should try to flatten their blood sugar curves. talk. She decries what she calls “glucose-centrism” encouraged by CGM. This, she sees, is “too unilaterally focused on her one indicator of metabolism”, even though there are “other inputs that cannot be captured”. “I think people are looking to glucose as a marker just because we have the technology to measure blood sugar levels,” Guess says. Personalized nutrition often starts with what can be measured, rather than what is most important to our health.
TThe usefulness of stool analysis is also questionable. Again, the basic premise behind the test is reasonable. James Kinross, reader in colorectal surgery at Imperial College London, also agrees: “The microbiome is highly individualized, and that’s probably what most influences our risk of different diseases and our response to different drugs.” I agree that this is an important determining factor.” But like many other experts, he believes we still don’t know enough about what a healthy microbiome looks like. The best advice for cultivating a healthy gut microbiome remains eating lots of whole foods, especially fibrous plants, and minimizing your intake of broad-spectrum antibiotics.
Most importantly, there is no such thing as good bacteria and bad bacteria. Bacteria can be good for some people and bad for others.Let’s take an example Escherichia coli, contained in most internal organs. It is a variety with many variations. Jacques Lovell, professor of microbiology and immunology at the University of Maryland, explains: E Escherichia coli It will cause you severe diarrhea, some of which are essential for your health. ” This test therefore lacks clinical validity, meaning there is “no clear way to say how this maps to healthy or unhealthy.”
Additionally, Lovell published a paper detailing several studies that question the accuracy of stool testing laboratories. Some of the studies were unable to reliably identify the bacteria in the gut, and some U.S. studies found different results for the same samples.
“My view is that Zoe is personalizing something that isn’t important,” Guess says. “It’s LDL cholesterol and blood pressure that are killing people, not just in the UK but around the world.” Data is not measured by Zoe, she points out.
The main obstacle to personalized nutrition is that the world of health science has the ability to both conduct cutting-edge research and provide well-established advice, but it is difficult to do both. Companies like Zoe are trying to ride both horses at the same time. On the other hand, Zoe is a research project and is in a continuous process of analyzing user data and looking for new insights. On the one hand, we provide advice to users based on work already in progress.
Sarah Berry, associate professor at King’s College London and Zoe’s lead scientist, bites this bullet. As for Zoe’s science, she admits, “It’s fair to say it’s controversial and controversial,” because “new things that emerge are always more controversial.” It is. Still, she justifies that Zoe is “ahead of the curve” by “waiting until we get more RCTs.” [randomised control trials] There’s no doubt about this causal relationship, and I don’t think we’ll ever get to the point where we can give people practical advice. ”
Misra says he does not believe this theory. “Well-designed research is ground-breaking, cost-effective, and policy-changing enough to actually change people’s outcomes decisively. I can give numerous examples. One of these is research into low-calorie diets aimed at putting type 2 diabetes into remission. “This was a randomized controlled trial, and it was a very influential study. Within three years, this study became national policy and everyone had access to remission programs. .”
Zoe also obscures another important distinction. Healthcare providers are subject to many onerous legal constraints. However, Zoe now operates as a wellness company, and as Lovell says, the company operates “without the regulations that apply to clinical and medical operations.” That’s why the disclaimer at the beginning of the Insights report sent to everyone who completes Zoe’s two-week monitoring reads, “Your insights are not the result of a clinical trial…Before making any changes to your diet, please consult your doctor.” Please.” he warns.
However, the entire program is designed to encourage dietary changes and gamify eating to help users achieve a Zoe score of 75 out of 100 or higher on their daily food intake. The company’s marketing is littered with health claims, with its homepage telling people to “eat for your body and health,” “improve your gut health,” “reach a healthy weight,” and more. It lists benefits such as “improves overall health.”
WWhen I asked Berry about this tension between offering advice so clearly and yet denying such things, she said she needed to contact me. Although she pressed for this, she received no such clear explanation. “Why aren’t regulators more interested in this?” Kinross asks. “I’ll never know.”
But Zoe insists it is “scientifically proven to be effective”. This comes as the first peer-reviewed study on the program was published this month. There were also some positive but modest results. An average weight loss of 2.46 kg, while significant, is less impressive after 4 months. However, various other biomarkers, including blood pressure, insulin, glucose, and postprandial triglycerides, remained unchanged.
More importantly, the study compared Zoe’s participants to a control group that was far from a blind test. They were simply given standard dietary advice and a helpline to call. It was completely predictable that people who tracked all their meals with Zoe for 18 weeks would end up eating healthier. Nor was the study group as a whole representative of the general population. 86% were female, with an average BMI of 34 (above 30 is considered obese).
Mr Guess has already posted a blog detailing criticism of the study, while Mr Kinross said the trial was aimed at “convincing lay people that this is what I call marketing science: that this has value. It appears to be designed to produce “enough science to
When asked about the design of the experiment, Berry acknowledged that “if you want to purely test the validity of the Zoe Score, you need to match the delivery method,” with both groups using the same app. This would enable research to “examine how the actual advice itself compares to standard care advice delivered in the same way”. But while Berry says that’s a good thing, the actual study aimed to test the “effectiveness of the Zoe program” as a package, comparing it only to “standard care.” . That seems like a strange purpose. If Zoe’s USP is personalizing advice, why would he intentionally design a study that doesn’t test those elements?
Meanwhile, consumers are actually paying personalized nutrition companies to have their bodies monitored to a degree that Kinross deems “Orwellian.” Zoe requires his one-off payment of £300 penny short and a monthly subscription of £24.99. “People don’t understand the value of the data they’re paying for,” he says.
Problems like this arise when personalized nutrition is a research project and people are paying a lot of money to be its guinea pigs.
