Health

How our gut microbiome changes with the seasons (and what it means for our diet)

By now, most of us have heard of our ‘circadian rhythm’, even if we’re not too sure what it really means. Simply put, it’s our body’s internal 24-hour clock, guiding what happens at different times of day. Pretty smart, right?

You’ve likely also heard of the gut microbiome, the term for the trillions of microorganisms — mainly helpful bacteria — living in our gut. This intricate ecosystem needs to stay balanced for good health.

But could our gut microbiome, like our body clock, change with the seasons?

Does our gut microbiome change with the seasons?

Recent studies suggest that human biology shifts throughout the year in response to seasonal changes. For example, our gut health may be influenced by diet, sunlight, and lifestyle shifts. However, winter’s colder temperatures and reduced activity levels can also contribute to higher blood pressure and insulin resistance in some people.

Meanwhile, winter and spring bring a rise in hormones related to growth, metabolism, and stress, hinting that humans might possess an ‘internal seasonal clock’ similar to our daily circadian rhythm. Together, these natural changes help our bodies adapt to seasonal demands, impacting our health throughout the year.

“Recent research highlights that these microbes fluctuate not only throughout the day but also across the seasons,” says Fiona Berry, corporate wellbeing expert and nutritional therapist. “About 60% of certain bacterial groups follow a distinct 24-hour cycle, while others change with the seasons in response to dietary patterns and environmental factors. Understanding these shifts can help us adapt our diets and lifestyle to support a healthy gut microbiome all-year-round.”

According to Fiona, one example of daily fluctuation involves a type of bacteria known as Actinobacteria, which tends to be lower in the morning but rises by the end of the day. Studies have also shown that these microbes, which are associated with processing fat, increase in winter. “This shows how our gut microbes align with the body’s natural circadian rhythms, responding to our eating patterns and energy needs at different times of the day,” she explains.

How to shift with the seasons

Fiona is passionate about seasonal living and claims that seasonal fluctuations in the gut microbiome are also significant, with diversity actually being higher in the winter months than in summer.

“While it might seem that summer, with its abundance of fresh fruits and vegetables, would increase gut diversity, research shows that the opposite is true,” she shares.

“In winter, as diets traditionally shift toward more fibre-rich root vegetables and preserved or fermented foods, microbial diversity increases.” According to Fiona, this is thought to be a result of the body’s adaptation to different seasonal demands and the types of nutrients available.

As a nutritionist, Fiona helps people adjust to transitioning through the seasons. “Historically, humans ate in tune with the seasons, relying on locally available foods to survive,” she says. “While modern conveniences allow us to access just about anything year-round, this has caused a disconnect between our diets and our environmental needs.”

Your winter gut diet

So is there anything we should avoid in winter? For Fiona, eating tropical fruits such as pineapples, for instance, might not align with what our bodies naturally crave or need. “While pineapple’s enzyme bromelain is great for soothing sore throats, our gut health benefits from aligning more closely with local, seasonal produce,” she says.

Embracing a diet rich in fibre-packed vegetables, such as carrots, beets and squash, is an easy way to support gut diversity during the colder months. For Fiona, these foods nourish beneficial bacteria.

“Fermented foods such as sauerkraut, kimchi, and kefir can introduce probiotics that aid in balancing the microbiome,” she says. “Additionally, using warming spices like ginger and cinnamon, along with prebiotic foods such as onions, garlic, and leeks, helps promote gut health during the colder months by feeding friendly bacteria.”

Here’s the ah-ha moment for Fiona: seasonal living isn’t about rigid rules but about tuning in to what your body needs now and preparing for the months ahead. “Instead of focusing solely on New Year’s resolutions, you can support your gut year-round by being mindful of what’s available locally and seasonally. This approach not only helps to keep the gut microbiome thriving but also aligns our lifestyle with nature, allowing us to benefit from the nutrients we need when we need them most.”

What’s certain is that, as we move through the seasons, our gut health and overall wellbeing stand to benefit from a more mindful, seasonal approach. Winter glistens with promise and by choosing foods that align with our body’s natural rhythms and environmental changes, we can better support our microbiome, boost immunity, and stay in tune with nature’s cycles.

So, as winter approaches, consider how you can nourish your gut — and in turn, your health — by letting the seasons guide you.