The best foods to feed your gut microbiome
The microbes in your gut can influence mental
health, heart risk, weight gain and even sleep,
which is why you need to eat a wider variety of
quality food.

Every time you eat, you are feeding trillions of
bacteria, viruses and fungi that live inside your
gut. But are you feeding them the right foods?

Scientists used to know very little about these
communities of microbes that collectively make up
the gut microbiota, also known as your gut
microbiome. But a growing body of research
suggests that these vast communities of microbes
are the gateway to your health and well-being —
and that one of the simplest and most powerful
ways to shape and nurture them is through your
diet.

Studies show that our gut microbes transform the
foods we eat into thousands of enzymes, hormones,
vitamins and other metabolites that influence
everything from your mental health and immune
system to your likelihood of gaining weight and
developing chronic diseases.

Gut bacteria can even affect your mental state by
producing mood-altering neurotransmitters like
dopamine, which regulates pleasure, learning and
motivation, and serotonin, which plays a role in
happiness, appetite and sexual desire. Some recent
studies suggest that the composition of your gut
microbiome can even play a role in how well you
sleep.

But the wrong mix of microbes can churn out
chemicals that flood your bloodstream and build
plaque in your coronary arteries. The hormones
they produce can influence your appetite, blood
sugar levels, inflammation and your risk of
developing obesity and Type 2 diabetes.

The foods that you eat — along with your
environment and your lifestyle behaviors —
appear to play a much larger role in shaping your
gut microbiome than genetics. In fact, genes have
a surprisingly small effect. Studies show that
even identical twins share just one third of the
same gut microbes.

Your ‘good’ microbes feast on fiber and
variety
In general, scientists have found that the more
diverse your diet, the more diverse your gut
microbiome. Studies show that a high level of
microbiome diversity correlates with good health
and that low diversity is linked to higher rates
of weight gain and obesity, diabetes, rheumatoid
arthritis and other chronic diseases.

Eating a wide variety of fiber-rich plants and
nutrient-dense foods seems to be especially
beneficial, said Tim Spector, a professor of
genetic epidemiology at King’s College London
and the founder of the British Gut Project, a
crowdsourced effort to map thousands of individual
microbiomes.

Even if you already eat a lot of fruits and
vegetables, Spector advises increasing the variety
of plant foods you eat each week. One fast way to
do this is to start using more herbs and spices.
You can use a variety of leafy greens rather than
one type of lettuce for your salads. Adding a
variety of fruits to your breakfast, adding
several different vegetables to your stir fry and
eating more nuts, seeds, beans and grains is good
for your microbiome.

What is the gut microbiome?

Gut microbiome research shows that the bacteria
inside you may influence your weight, energy
levels, even your choices.

These plant foods contain soluble fiber that
passes through much of your gastrointestinal tract
largely unaffected until it reaches the large
intestine. There, gut microbes feast on it,
metabolizing and converting the fiber into
beneficial compounds such as short chain fatty
acids, which can lower inflammation and help to
regulate your appetite and blood sugar levels.

In one study scientists followed more than 1,600
people for about a decade. They found that people
who had the highest levels of microbial diversity
also consumed higher levels of fiber. And they
even gained less weight over the 10-year study,
which was published in the International Journal
of Obesity.

Clusters of ‘bad’ microbes thrive on junk food
Another important measure of gut health is a
person’s ratio of beneficial microbes to
potentially harmful ones. In a study of 1,1oo
people in the United States and Britain published
last year in Nature Medicine, Spector and a team
of scientists at Harvard, Stanford and other
universities identified clusters of “good” gut
microbes that protected people against
cardiovascular disease, obesity and diabetes. They
also identified clusters of “bad” microbes
that promoted inflammation, heart disease and poor
metabolic health.

While it’s clear that eating lots of fiber is
good for your microbiome, research shows that
eating the wrong foods can tip the balance in your
gut in favor of disease-promoting microbes.

The Nature study found that “bad” microbes
were more common in people who ate a lot of highly
processed foods that are low in fiber and high in
additives such as sugar, salt and artificial
ingredients. This includes soft drinks, white
bread and white pasta, processed meats, and
packaged snacks like cookies, candy bars and
potato chips.

The findings were based on an ongoing project
called the Zoe Predict Study, the largest
personalized nutrition study in the world. It’s
led by a health science company that Spector and
his colleagues created called Zoe, which allows
consumers to have their microbiomes analyzed for a
fee.

Recipes to feed your microbiome

Add more spices, nuts, plants and fermented foods
to your diet
Once you start increasing the variety of plant
foods you eat every day, set a goal of trying to
eat around 30 different plant foods a week, says
Spector. That might sound like a lot, but you’re
probably already eating a lot of these foods
already.

The sample menu shows how in just three meals over
the course of the week you can easily eat 30
different plant foods.

One day, start your morning with a bowl of plain
yogurt topped with sliced bananas and
strawberries, a dash of cinnamon powder, and a
handful of mixed nuts (containing almonds, pecans,
cashews, hazelnuts and peanuts). Meal tally: 8
plant foods
Another day, eat a leafy salad with at least two
mixed greens, tomatoes, carrots, broccoli and
peppers. Add herbes de Provence, a seasoning that
typically contains six herbs, to grilled chicken
or fish. Meal tally: 12 plant foods
Later in the week, eat chicken seasoned with pesto
(it contains basil, pine nuts and garlic) and
enjoy a bowl of brown rice with onions and kidney
beans and a side of stir-fried veggies with green
and yellow squash, mushrooms and shallots. Meal
tally: 10 plant foods
Another way to nourish your gut microbiota is by
eating fermented foods like yogurt, kimchi,
sauerkraut, kombucha and kefir. The microbes in
fermented foods, known as probiotics, produce
vitamins, hormones and other nutrients. When you
consume them, they can increase your gut
microbiome diversity and boost your immune health,
said Maria Marco, a professor of food science and
technology who studies microbes and gut health at
the University of California, Davis.

In a study published last year in the journal
Cell, researchers at Stanford found that when they
assigned people to eat fermented foods every day
over a 10-week period, it increased their gut
microbial diversity and lowered their levels of
inflammation.

“We’re increasingly developing a very rich
understanding of why microbes are so good for
us,” said Marco.

Do you have a question for Anahad about healthy
eating? Email EatingLab@washpost.com and we may
answer your question in a future column.

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Love foods that love you back for happy, sexy health,

Hadley Finch

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