Want to Get Healthier this Year? Go with Your Gut | Opinion

The new year is a time when many of us make plans for improving our health. That often means overcommitting to an impossible exercise plan or miserably munching on flavorless diet foods. But I'd like to propose an alternative. Why not make 2021 the year you revolutionize your health from the inside out, by supporting the trillions of bacteria living in your gut?

Collectively known as the gut microbiome, these tiny microbes have an outsized impact on our health. Not only do they play an important role in gut disorders like inflammatory bowel disease—our gut bacteria also influence wider aspects of health, from heart disease, weight and diabetes to how we break down and use the food we eat. Recent studies are even starting to link specific patterns of gut bacteria with psychological conditions such as depression.

No longer the obscure domain of microbiologists, the gut microbiome has become a hot topic in health. There's plenty of talk about "good" and "bad" bugs, with myriad diets and supplements aimed at manipulating the balance between the two. But given that there are thousands of different types of bacteria living in your gut—and each of us has a unique mix of microbes—it's been difficult to figure out friend from foe or uncover exactly how different species are linked to health.

A new research study from PREDICT—the largest investigation of nutrition and the microbiome of its kind—goes some way to solving that challenge. By combining in-depth microbiome analysis, detailed dietary information, post-meal nutritional responses and markers of weight and metabolic health from more than a thousand people, we've been able to gain unprecedented insights into the hidden world of the microbiome.

Using sophisticated computer algorithms, we've crunched all the data together to identify 15 "good" and 15 "bad" gut microbes that correlate with specific health measures, such as blood-sugar responses, inflammation, body fat and markers of heart disease.

For example, one of the "good" bugs, Bifidobacterium animalis, is linked to better insulin sensitivity, while having lots of Prevotella copri and Blastocystis microbes in your gut is associated with healthier blood sugar levels after a meal.

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A doctor wears a stethoscope as he see a patient for a measles vaccination during a visit to the Miami Children's Hospital on June 02, 2014 in Miami, Florida. Joe Raedle/Getty

We've also been able to match up these bugs with individual foods, food groups and nutrients. People eating a diverse range of healthy, plant-based foods were more likely to have "good" microbes in their gut. These "good" bugs were linked to markers of better health outcomes, such as good blood sugar and fat control, lower body fat and less inflammation.

That might seem pretty obvious, and many people will tell you that a plant-based diet is meant to be healthier. But we also found some surprises. Processed plant-based foods such as baked beans, sauces and juices were more likely to be associated with "bad" microbes. Some animal products (eggs, fish and yogurt) correlated with "good" bugs, while some processed meats such as bacon and sausages were more strongly linked with "bad" bugs.

This is the first time that such detailed panels of specific microbes have been linked with diet, weight and metabolic health in this way. In fact, some of the microbes we found haven't even been named yet.

These patterns were remarkably consistent across the thousand-plus people in the study. This means that we can start to use information about the gut microbiome to predict someone's risk of conditions like heart disease or diabetes. And because we can manipulate our microbiomes by altering what we eat, this opens up the opportunity to create personalized diets that can maintain or improve health and weight by enabling "good" bugs to flourish while suppressing "bad" ones.

For a start, you can improve your microbiome by eating a diet rich in a diverse range of plant-based foods, from fruits and vegetables to nuts, seeds, spices and whole grains. But we know that each of us has a unique microbiome, so there isn't a one-size-fits-all "best" diet that will work for everyone. We've now been able to translate our cutting-edge scientific research into an at-home test that offers everyone the opportunity to discover their unique mix of microbes and get personalized advice on how best to feed them.

When you eat, you're not just nourishing your body—you're feeding the trillions of microbes that live inside you. If you're planning on making 2021 the year you commit to getting healthier, a good place to start is by going with your gut.

Tim Spector MD is Professor of Genetic Epidemiology, King's College London, honorary physician at Guys and St Thomas' Hospital and scientific co-founder of health science company ZOE. He is author of two books about nutrition, The Diet Myth and Spoon-Fed. Follow him on twitter @timspector.

The views expressed in this article are the writer's own.