Study Reveals ZOE Personalised Diets Yield Health Improvements 

9th May 2024 – by Aaruthy Suthahar

In a recent study published in the scientific journal Nature Medicine, researchers from ZOE, who are running the largest in-depth nutrition study in the world, examined the impact of personalised dietary advice versus general recommendations on cardiometabolic health. This study, involving 347 participants aged 41 to 70 years, sheds light on the effectiveness of tailored dietary programmes. 

Participants were randomly assigned to either receive personalised dietary guidance by ZOE or standard care advice based on the US Department of Agriculture Guidelines for Americans. The personalised dietary programme utilised various factors including food characteristics, individual responses to food, microbiomes, and health history to create personalised food scores over an 18-week period. 

Results showed a significant reduction in triglyceride levels, which are types of fat in the blood, among participants following the personalised dietary programme compared to those receiving standard advice. However, there were no significant changes in low-density lipoprotein cholesterol. Additionally, improvements were noted in other measures such as body weight, waist circumference, HbA1c levels (which is a measure of blood sugar over time), diet quality, and the variety of gut bacteria, particularly among participants who closely followed the personalised programme. 

It is noteworthy that participants following the ZOE programme reported feeling better, with improvements in mood, reduced hunger, better sleep, and increased energy compared to the control group. Those who closely adhered to the ZOE advice also experienced greater improvements in weight and increases in diet quality, associated with lower risk for heart disease and diabetes. 

Overall, the study shows the potential benefits of personalised dietary advice in improving cardiometabolic health outcomes, providing valuable insights for individuals seeking effective dietary interventions. TwinsUK members were instrumental in enabling ZOE to develop their personalised dietary programme through the original research study on personalised diets, PREDICT.  

Cycling for COVID-19 – Professor Tim Spector’s fundraising challenge

10th August 2020 – by Paz García

It’s time to limber up for Professor Tim Spector, as he will be cycling 100 kilometres and swimming 1.5 km this weekend in order to raise money for the COVID Symptom Study.

The COVID Symptom Study app has more than 4 million users in the UK and the regular logs by participants have enabled researchers to make key discoveries about COVID-19.

For example, the widespread use of the app provided crucial data for understanding the spread and progression of the virus, such as confirming that loss of taste and smell – anosmia – was a bizarre yet distinct symptom of COVID-19.

Professor Spector said:

“To our supporters, those who’ve donated and those who have diligently reported their symptoms on the CV-19 app, the COVID Symptom Study team are extremely grateful for your contributions.

“Thank you, and stay safe and well.”

To donate, visit Tim’s fundraising page available here.

Latest data from COVID Symptom Tracker app shows the lockdown is working

8th April 2020

The latest analysis of data from the COVID Symptom Tracker app, used by over 2 million people, shows the rate of new symptoms being reported nationally has slowed down significantly in the past few days.  The latest figures estimate that 1.4 million people in the UK aged 20-69 have symptomatic COVID, a fall from 1.9 million on the 1st April. 

These figures suggest that the nation staying home is having a big impact on the spread of the virus in the UK. The drop in new symptoms indicates that although the number of hospital admissions and deaths from COVID are currently rising, they should start to fall in about two weeks provided social distancing continues. This two week lag is caused by the delay between symptoms starting and becoming very severe.  

This data from millions of people lines up with what has been reported by NHS digital based on much smaller numbers. They show a decline in the number of calls to NHS 111 with COVID since the 22nd March.

While symptoms have been decreasing nationally, in all areas there are still many people with active symptoms of COVID. Therefore, this data supports both the success of lockdown, and the importance of maintaining it. It also shows that individual areas vary. Most of the country’s larger cities like London, Birmingham, Glasgow, and Liverpool continue to have very high levels of symptoms in the community, even this far into lockdown. Other hotspots include South Wales. There are significantly higher levels of symptoms across the Midlands, the North of England and Southern Scotland than in the South West of England. 

Lead researcher Professor Tim Spector said:

“It is really encouraging to see that the rate of new symptoms being reported is beginning to fall. Even though hospital admissions and deaths are still on the rise, we hope that these figures offer a much needed light at the end of the tunnel. 

We have been totally blown away by the public’s response to the app. On the first day we saw one million members of the public download the app making it one of the most successful first days for an app ever, and already probably the UK’s largest citizen science project. The altruism of the UK public combined with modern technology is allowing us to rapidly collect huge amounts of invaluable data to help us better understand this deadly virus.

We would like to take this opportunity to thank every single person who is already participating and would urge everyone else to download the app and check in every day, whether you are experiencing any symptoms or feeling fine.”

Developed by researchers at King’s College London and healthcare science company, ZOE, the COVID Symptom Tracker has been used to log symptoms by over 2 million people across the UK, with over 10 million individual reports so far. Members of the public are using the app to track their daily health whether they are healthy or showing potential COVID symptoms. It is also being used by healthcare and hospital workers nationwide so their increased risk can be recorded.

The research team at King’s College London and ZOE are working round the clock to analyse the data to generate new insights about the disease and its progression. For example, they have discovered that loss of smell or taste is more predictive of COVID in the population than the classical symptoms of fever and cough. An interactive map allowing anyone to see the distribution of COVID in their area is available at as well as frequent science updates.

The researchers have developed a statistical model which analyses millions of COVID Symptom Tracker data points, including thousands of people who have had tests for COVID, in order to predict which combination of symptoms indicate someone is likely to test positive for COVID. This model is then applied to the UK population aged 20-69 and then mapped to the regions of the country accounting for age and gender differences to provide maps over time. The most predictive individual symptoms, in order of importance were: lack of taste & smell, fatigue, shortness of breath, fever and persistent cough. The model estimates that 3.5% of these app users would be positive if tested. As contributors continue to share symptoms, and we link it to other health records, the model will become more accurate and sophisticated.

The app is available to download from the Apple App Store and Google Play from the links at

Professor Tim Spector wins award for gut bacteria research

13th December 2019 – by Paz Garcia

Professor Tim Spector has been awarded the 2019 DuPont Nutrition & Biosciences Microbiome Science Award, in recognition for his leadership and pioneering work in the microbiome field.

Professor Spector is Director of TwinsUK, which he founded in 1992. Over 14,000 twins take part in TwinsUK, which is the richest collection of health research information on a cohort worldwide.

Professor Spector’s research in recent years has focused on the microbiome – the millions of bacteria that live in our gut – and its relationship with health. This has led to the world’s largest personalised nutrition study of its kind, called PREDICT.

Speaking ahead of the award ceremony in Denmark, Professor Spector paid tribute to all the twins who take part in TwinsUK:

 “We now have a better understanding of how the microbiome is intimately linked with our health. I am excited to continue working in this field as we unravel the relationships between our genetics, the food that we eat, the bacteria in our guts and our health.

“I would like to take this opportunity to say thank you to everyone involved in TwinsUK, and in particular the twins. After all, our twins were giving up stool samples for microbiome science long before it became mainstream.”

Could a glass of red wine improve your gut health?

28th August 2019 – by Paz Garcia

Drinking red wine is linked with an increase in gut bacteria diversity, according to the latest research from TwinsUK.

White wine had a similar although much smaller effect, while researchers found no association between other types of alcohol and gut bacteria variety.

In addition, twins who drank more red wine than their co-twin had more diverse gut bacteria.

Previous research suggests that a more varied community of bacteria in your gut leads to a healthier gut.

First author Dr Caroline Le Roy, from the Department of Twin Research, King’s College London, explained:

“We’ve known for some time that red wine has some health benefits, which likely come from certain molecules called polyphenols.

“Our research shows how red wine is associated with an increase in gut bacteria diversity.

“At this time however we cannot say that drinking red wine directly causes an increase in gut bacteria diversity – we need more research first.”

What did the researchers do?

The team analysed food and drink questionnaire responses and gut bacteria diversity in 916 female TwinsUK participants. The researchers also looked at a number of other factors such as weight and blood cholesterol levels.

The researchers then checked their results by carrying out a similar analysis on participants in two other studies from The Netherlands and the USA.

What did they find?

Participants who reported drinking red wine had greater levels of gut bacteria diversity than non-red wine drinkers.

The team also found that red wine consumption was linked with lower levels of obesity and “bad” cholesterol, which was in part due to associated changes in gut bacteria communities.

What does this mean?

The researchers believe the main reason for the association is due to the many polyphenols in red wine. Polyphenols are defence chemicals naturally present in many fruits and vegetables. They have beneficial properties and mainly act as a fuel for our microbes.

Professor Tim Spector, senior author on the study, explained:

“Although our results are very consistent, they are only associations and do not imply causation.

“We would need to carry out studies where humans or animals were given red wine in order to test whether red wine – or rather the polyphenols it contains – is causing an increase in gut bacteria diversity and limiting weight gain in turn.”

The researchers stressed that it is still advised to drink alcohol in moderation, although they have a recommendation for your tipple of choice:

“If you have to choose one alcoholic drink, then red wine is definitely the one to pick as it may have a positive effect on your gut bacteria and wider health.”

When it comes to food, one size doesn’t fit all

10th June 2019

Spaghetti on a fork with a tomato on top

What foods are best for us? People, scientists and doctors alike have been asking this question for centuries.

Today, we moved one step closer to finding the answer as the first results from the largest scientific nutrition study of its kind were announced.

The verdict: no two people’s responses to individual foods are the same – even between identical twins.

These findings demonstrate that one-size-fits-all dietary guidelines are too simplistic, and that a personalised approach to nutrition is likely to provide better long-term health benefits.

The study, which included more than 1,000 participants, was carried out by an international team led by researchers from King’s College London, Massachusetts General Hospital and nutritional science company ZOE.

Professor Tim Spector, Professor of Genetic Epidemiology at King’s College London and lead researcher on the study explained its significance:

“The sheer scale and detail of our scientific project is such that for the first time we can explore tremendously rich nutrition data at the level of an individual. Our results surprisingly show that we are all different in our response to such a basic input as food. It was a real shock to see that even identical twins have such different responses.”

The results were announced today at two prestigious international conferences.

Why did they do this research?

King’s College London is the home of TwinsUK, a long-running study looking at health and lifestyle in over 14,000 twins, led by Professor Spector.

He noticed that identical twins – who have identical genes – have very different food preferences and responses. This led him to team up with two technologists to create ZOE and set up a series of scientific studies along with King’s College London’s Department of Nutritional Sciences to look at personal responses to foods.

The company is now developing a home-based test and an app that can measure and make predictions about an individual’s nutritional responses, helping people choose the best foods for them to manage their weight and overall health.

ZOE co-founder and CEO Jonathan Wolf explained:

“For most of us, the food we eat is the most important medicine we take. And yet we are all profoundly confused about what is good for us. We believe that combining science and machine learning can solve this, by understanding for the first time our individual responses to food.”

ZOE co-founder and President George Hadjigeorgiou continued:

“We believe that everyone deserves to understand how they respond to food so that they can make confident decisions about what to eat and be in control of living a healthier and more enjoyable life.”

What did they do?

More than 1,000 volunteers – largely pairs of twins – took part in the study, called PREDICT.

Participants had to eat certain set meals and log every single item of food or drink they had for two weeks.

The researchers analysed how blood levels of sugar, insulin and fat change in response to specific meals over two weeks, along with data on activity, sleep, hunger and gut bacteria.

What did they find?

The team found that there was a wide variation in blood responses to the same meals, which is only partly explained by genes.

The proportions of nutrients such as fat, proteins and carbohydrates listed on food labels explained less than 40% of the differences between individuals’ responses to meals with similar amounts of calories.

In addition, identical twins often had different responses to identical foods, and shared just 37% of their gut bacteria – only slightly higher than the 35% shared between two unrelated individuals.

What does this mean?

These findings show how responses to food are highly individualised, and that nutritional advice needs to be tailored to each individual.

Dr Sarah Berry, Senior Lecturer in Nutritional Sciences at King’s College London and Scientific Advisor at ZOE explained:

“For the first time, we’re expanding large-scale nutritional research beyond blood sugar. These findings show that the responses to food of a number of key metabolic markers – including triglycerides, insulin and blood sugar – are highly individualised. No one has been able to combine data on this scale before.”

In addition, the results suggest that personal differences in metabolism due to factors such as gut bacteria, meal timing and exercise are just as important as the nutritional composition of foods.

Dr Andrew Chan, Professor of Medicine at Harvard Medical School and a gastroenterologist at Massachusetts General Hospital commented:

“It is reassuring that our genetic makeup only partially explains how our bodies respond to food. This underscores that our metabolism is not fixed – we have the power to change it. One exciting avenue is to tailor our diets to the bacteria in our gut that helps us metabolise nutrients.”

What’s next?

The team has now launched PREDICT 2, an expanded home-based study that is recruiting more than 1,000 participants across the US.

This will help ZOE to continue developing their technology to help people choose the best foods for them.

Find out more about the study results and the science behind them at

The word 'PREDICT' on a navy square


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