7 Daily Habits to Improve Your Gut Health and Boost Your Brain Power

The gut is more than just a digestive organ; it is the body's second brain.

Your intestines, which stretch from your mouth to your butt, house the nervous system that controls digestion and also plays a role in your mental health.

The gut doesn't write poetry or solve math problems, but like the brain, it contains a wealth of nerve cells. And the gut functions more independently of the brain than any other organ. The gut communicates with the brain through the vagus nerve (the gut-brain communication highway), the gut microbiome (a population of bacteria and other microorganisms), the immune system, hormones, and neurotransmitters.

All of this means that your gut and your brain are intricately connected, and we still don't know how it works. But we do know that there are some simple habits you can adopt to improve your gut health and boost your brain power. Here are some of them:

Eat more fiber 'workhorses' to boost brain function

We're told fiber simply keeps your bowels moving, but it's actually Clark Kent. Fiber is the indigestible part of food that our gut bacteria love to eat, so it's essential for gut health.

Fiber is also important for the brain: One study found that every 5 grams of fiber was associated with a 5 percent lower risk of depression. Other research from my research department at King's College London found that people over 60 who took a daily prebiotic fiber supplement (a type of fiber that feeds the good bacteria in your gut) performed better on memory tests used to detect early signs of Alzheimer's disease. A review of 14 studies found that prebiotic fiber supplements improved mood and provided both immediate and long-lasting benefits to memory, particularly the ability to recall words and events.

Fiber is the closest thing we have to a “superfood”. In the UK the recommended intake is 30g of fiber a day. More is thought to be better, but most people in the UK only get 18-20g a day.

To get more fiber in your diet, focus on eating foods that are high in fiber, including beans (8g fiber per half a can) and legumes such as chickpeas (8.3g per half a can).

Switch to rye bread (6g per slice) instead of white, and keep a jar of nuts and seeds next to the kettle so you can add them to your breakfast (one cup of chia seeds has 5.1g). Forget the idea that you have to eat loads of bland salads to increase your fibre intake: lettuce has just 1.5g fibre per 100g (but still contains lots of beneficial phytonutrients).

The more fiber you can get in your diet, the better you'll feel. Make eating fun, stress-free, and without taking up too much time or energy.

Eat oily fish twice a week for healthy brain cells

Omega-3 fatty acids are very important for keeping brain cells healthy. Our bodies cannot synthesize omega-3 fatty acids, so we must get them from our diet. Oily fish is one of the best sources of omega-3 fatty acids.

Eating a lot of oily fish is one of the most powerful dietary protective factors for protecting the brain in old age. One study found that people who eat more fish have healthier blood vessels, which may reduce the risk of Alzheimer's disease and vascular dementia.

Another study found that people with higher blood levels of omega-3 fatty acids had better thinking skills and healthier brain structure than those with lower levels. Additionally, omega-3 fatty acids feed gut bacteria, increasing the diversity of healthy gut bacteria.

If you don't know what oily fish are, just remember SMASH, which stands for Salmon, Mackerel, Anchovies, Sardines and Herring. The late Michael Mosley popularized this acronym, and it's great.

I sometimes eat sweets to avoid stress.

There's nothing healthy about eating burgers, cookies, and cake, but treating yourself every once in a while is better for your gut and your brain than stress eating.

Long-term, constant stress can affect your gut health and inhibit the growth of “good” bacteria in your gut, so even if you're eating perfectly, if you're constantly stressed it's not the best approach.

The key is to enjoy something sweet without feeling guilty or stressed. In one study, subjects were provided with a doughnut. Half were instructed to feel compassion for themselves about eating the doughnut, while the other half were instructed to just eat it. The latter group ate significantly more at their next meal, compared to the group that focused on enjoying the snack.

In another study, chocolate lovers were asked to abstain from chocolate for a week. They craved chocolate more than those who didn't abstain, and when given the chance to eat it again, they ate twice as much.

So including a little something tasty every day will help you maintain a balanced diet and won't do any harm to your gut (though a sugary diet will).

5 colors a day to improve your mental health

Some scientists and nutritionists say you should eat 30 different kinds of plants a week, but the evidence for this is surprisingly weak. Instead, focus on eating five different colors of veggies a day: think red tomatoes, purple eggplants, and yellow bell peppers.

By eating a variety of vegetables, you can get plenty of dietary fiber and various polyphenols, a type of antioxidant.

Polyphenols promote the growth of “good” bacteria in the gut. Polyphenols have been linked to a lower risk of depression, slower cognitive decline, fewer mental fatigue problems, and improved brain performance.

To get your five colors a day, choose stir-fried mixed vegetables, choose frozen forest fruits instead of frozen raspberries, and vary the salad leaves you eat.

Drink 1-3 cups of coffee daily to boost cognition

Coffee has been linked to a diverse and healthy gut flora, which is thought to be due to its high polyphenol content (which accounts for a large portion of your daily intake of 800-1,600 mg).

This drink is also good for your brain: It's the original cognitive enhancer, and drinking 1-3 cups a day has been shown to help prevent cognitive decline.

It doesn't matter whether you drink instant coffee bought from the supermarket or splash out on a mug of barista-brewed coffee every day: research shows that both are rich in polyphenols.

However, coffee can worsen digestive issues like irritable bowel syndrome and inflammatory bowel disease in some people, so opt for decaffeinated coffee or tea if this is the case.

It's also important to stop drinking caffeinated coffee in the middle of the day, as the caffeine remains in your bloodstream even after you've sobered up and can impair the quality of your sleep, even if you have no trouble falling asleep after an espresso in the evening.

To improve your memory, eat two servings of fermented foods a day (cheddar cheese and olives)

Growing interest in the health benefits of fermented foods has led to kombucha (a tea drink), kimchi (cabbage), and kefir (a milk drink) becoming increasingly available.

There's a good reason for this: Studies have shown that drinking kefir improves relational memory (your ability to remember faces or where you put your keys)—this may be because it helps your gut make metabolic products that have an anti-inflammatory effect on the brain, keeping your cognition healthy.

Another study linked drinking kefir daily to improved emotional resilience, which may be the result of gut microbes helping to produce a calming neurotransmitter called GABA.

However, you don't need to drink kefir every day. Fermented foods include some cheeses, yogurt, fresh olives, sourdough bread and relishes, but most of the evidence is for yogurt and kefir. Aim to consume fermented foods at least once or twice a day.

Eat dinner early to boost your mood

Time-restricted eating has been gaining popularity in recent years, which is a fancy way of saying the time you should have your first and last meal or drink of the day (remember, the countdown starts when you have your coffee).

Your gut bacteria prefers a feeding window of 8-10 hours, which would be something like having breakfast at 9am and dinner at 7pm.

A study from King's College London found that most people eat over a 12-hour period, but after splitting their eating into 10 hours for four months, people reported 11% improved mood, 22% more energy and 11% less bloating.

Try not to eat dinner too close to bedtime, otherwise your body will try to digest food at the same time as you sleep, which will inevitably result in poorer quality sleep. It is said that a shorter meal window increases the diversity of gut bacteria, improves digestion, and reduces hunger.

Narrated by Emily Craig

The life-changing science of diet for your genius gut, your second brain A book by Dr Emily Leeming has been released.

The Telegraph, London