COVID-19 and diet: What's the link?

The ongoing coronavirus pandemic has focused the nation’s attention on their health and nutrition.

With more than 6.8 million confirmed cases of COVID-19 and almost 200,000 deaths in America, we are bearing a terrible burden from this unexpected and strange new disease.

Data from over 4 million COVID Symptom Study app users has shown that obesity, type 2 diabetes, and poor metabolic health are three significant risk factors for worse COVID-19 outcomes. These risk factors are heavily influenced by the food we eat, alongside a complex mix of physiological and social factors. 

At the same time, there is growing attention to the systemic economic and racial disparities that affect the lives of many Americans. Findings from the COVID Symptom Study suggest that frontline healthcare workers of color are at a fivefold increased risk of COVID-19 infection compared with their non-Hispanic white colleagues. These disparities are also reflected in the underlying statistics about increased metabolic conditions such as obesity, type 2 diabetes, and heart disease, which disproportionately affect African Americans and other ethnic minority groups.

So, what do we know about the link between COVID-19 and diet?

How and what we eat are front and center - now more than ever. Yet, in response to the stresses of the pandemic, many of us are snacking more and moving around less. There is also a lot that we still don’t know about how diet impacts our chances of catching COVID and its severity.

To better understand these links, the COVID Symptom Study app will be launching one of the largest nutrition surveys in the world in the app later this week. ZOE is the company that built the COVID Symptom Study app and the data science around the study, working with researchers at Mass General Hospital, King’s College London, and Stanford Medicine. This research will advance our understanding of the link between the food we eat and the risks of COVID. 

With over 4 million app users, this study has the potential to be one of the largest nutrition research projects ever undertaken and will provide key insights towards future diet and lifestyle recommendations for the general population to help fight this disease and other nutrition-related health outcomes. This questionnaire is an amazing opportunity for scientists to gather a vast amount of data that will also help in future exploration of the links between diet, lifestyle behaviors, and our health.

You can find out more about this research and download the COVID Symptom Study app here.

However, some things are already clear. There are links that exist between the food we eat, our metabolic health (e.g. blood sugar control after meals), and COVID-19. It is also evident that simple "one-size-fits-all" dietary solutions to lose weight and improve long-term health don’t work because it turns out there are huge differences in individual responses to the same food. These differences are what we have been investigating over the past three years.

The story behind ZOE

This journey started 25 years ago when Prof. Tim Spector started his study of 13,000 twins and was surprised to discover that even identical twins, who share all their genes, have very different responses to the same foods. He went on to discover that differences in nutrition and the gut microbiome were the main things that explained how identical twins could end up with very different weights and health.

Tim set up ZOE three years ago with data scientist co-founders to build on this research and make it available to the public. 

Over the past three years, the team of scientists behind the COVID Symptom Study has been working on PREDICT, which is the world’s largest in-depth nutritional research program to date. This program of research was developed with ZOE with the aim of better understanding how and why we all respond to food differently in order to move beyond a “one-size-fits-all” approach to nutrition. And eventually, to create a personalized nutrition program that puts cutting edge science in the hands of everyone.

It is thanks to collaborations with these leading researchers and institutions that we were quickly able to use our expertise in personalized data science and machine learning to develop the COVID Symptom Study app in March 2020. The COVID Symptom Study app is a not-for-profit initiative that was launched by ZOE at the end of March 2020 to support vital COVID-19 research. With over 4 million contributors, this study has played a key role in helping us better understand why the disease affects people so differently.”

Our groundbreaking discoveries

Our nutrition research has shown that losing weight and improving your overall metabolic health relies on an intimate understanding of your own body.

In June 2020, the first findings from our PREDICT 1 study were published in Nature Medicine.  Based on detailed data collected from over 1,100 participants in the US and UK, we showed that everyone responds to food in their own way.

Even identical twins, who share almost 100% of their genes, can have very different metabolic responses to exactly the same meals (Figure 1)! This suggests that there really is no one "right" way to eat and that nutrition needs to be tailored to each individual.

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Some other key findings from PREDICT include:

• Your genes don't determine how your metabolism works - Genetics plays a minor role in determining blood sugar, fat, and insulin responses to the same meal. We found that even identical twins, who share all their genes, can respond very differently to the same foods.
• Your microbiome influences your nutritional responses, health, and weight - We discovered 15 "good" and 15 "bad" gut microbes with strong links to diet and metabolic health. This is exciting, as it suggests that the gut microbiome can be altered by what we eat and is an important target of precision nutrition.‍
• Dietary inflammation varies up to tenfold, even in healthy adults - We use this term to capture the unhealthy metabolic effects that can be triggered after we eat (Figure 2). If repeated often enough, dietary inflammation can contribute to weight gain and diet-related metabolic diseases.

Figure 2: Dietary inflammation involves a complex chain of unhealthy metabolic effects that can be triggered after we eat which, over months and years, can contribute to unfavorable health outcomes

COVID: The catalyst for rethinking what we eat

It's now clear that obesity and poor metabolic health are key players in determining how COVID-19 will affect each of us. Additionally, there is another important factor that may connect diet and COVID-19 outcomes too - the role of our gut microbiome, which can be altered by what we eat and plays a significant role in determining how we respond to food.

While the pandemic has been a tragedy on a global scale, it has provided us with an opportunity to think about how to best achieve optimal health. The healthier you are, the better your chances of remaining that way over the months to come, and the better it is for us as a nation.

However, it's also clear that standard "one-size-fits-all" approaches are not working. The future of nutrition must be based on an understanding of how each person’s body works in order to move us all closer to our best health.