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Is too much stress making you feel anxious, depressed even? Is it affecting your performance at work?

In our time-pressured, over-committed world, it can feel hard to know how to manage our stress effectively.

Maybe you have already added meditation, exercise and sleep to your stress resilience toolkit, but is there something you’ve overlooked that could also make a difference?

The discoveries from the new research looking into the connection between our gut and brain health are compelling.

It’s changing not just our understanding of how the MGB (microbiome-gut-brain) axis works but also its significance in determining our mood, level of anxiety or depression. The new field of neuropsychiatry and psychobiotics is leading the way in determining the importance of our food choices to our overall mental health and cognitive wellbeing.

MGA, HPA, what’s the deal with stress and all these acronyms?

When we’re subjected to prolonged stress the HPA (hypothalamus-pituitary-adrenal) axis is stimulated to release our stress hormones including cortisol.

The role of cortisol is to ensure the body has sufficient energy by mobilising the release of glucose and fatty acids from the liver with glucose being the brain’s primary source of energy.

It’s also important in helping to reduce inflammation and support the immune system. But at toxic levels, this function becomes impaired putting us at increased risk of developing a mood disorder, chronic fatigue or metabolic disorders including diabetes and obesity.

From a cognitive perspective, too much stress dampens down our mental bandwidth impacting our thinking skills, attention and memory. 

We start to lose that mental energy required to handle learning to remember when dealing with a task associated with the stressful event, made even harder when the stressors are unpredictable, protracted or you’re feeling as if you have no support.

The Gut-Brain Connection

If you’ve ever suffered from anxiety you may have noticed the accompanying unpleasant gut effects ranging from nausea, stomach churns to diarrhoea.

Studies have shown how cortisol works as a messenger in the MGB axis (microbiome-gut-brain) linking the nervous, endocrine and immune systems possibly via the vagus nerve.

The hypothalamus being concerned with hunger and emotions is why under stress some of us will choose to alleviate our distress by eating even though we may not be hungry, while others lose their appetite completely.

Cortisol being common to the HP and MGB axis means under conditions of severe stress, toxic levels can harm the gut, microbiome and our neurons.

Safeguard Your Gut and Microbiome

This is why making healthy food choices is so important. Our comfort foods are often high in fat, salt or sugar all of which are potentially harmful to our gut health through the promotion of an overgrowth of the less friendly microbes.

Sugar is Sweet but Lowers Mood

Research has shown how consuming too much added refined sugar in our diet contributes to a lowering of mood; meaning our comfort foods while providing temporary solace, make us feel worse in the long-term.

And it’s important to remember that natural sugars as found in our fruits and vegetables are not a problem.

In the SMILES trial, Felice Jacka and her team at the Mood and Food Institute at Deakin University showed how a group of people with clinically diagnosed depression who followed a modified Mediterranean diet while reducing the intake of processed foods over 12 weeks produced remission or significant reduction in depressive symptoms.

This ModiMed diet designed by Rachel Opie of LaTrobe University is rich in fruit, vegetables, whole grains, oily fish, olive oil, seeds and nuts, some dairy and limited red meat.

Starting the ModiMed Diet

Rather than focusing on what you can’t have (which automatically leads to a sense of deprivation and craving), this is about adding in small positive healthy choices; such as an extra portion of vegetables to your plate, having a meatless meal once a week, or drinking an extra glass of water every day.

Eating well and healthily isn’t focused on weight loss, though you may find the kilos disappearing when you consistently make the better choices and your energy levels rise.

The Best Foods to Combat Anxiety and Depression

Of course, it’s never about a single food source, rather the combination, so heading to the fresh produce section of the supermarket or your local farmer’s market is a great place to start.

Stress has been shown to lower certain nutrients essential to our mental well-being including magnesium, the B vitamins, folate and zinc.

That’s why eating a wide variety of different foods can help to ensure you have access to as wide a variety of these essential nutrients as possible.

Chill Out With Probiotics

Probiotics have become all the rage following the introduction of fermented milk drinks a few years back Since then fermented foods have been making a come back. Fermented foods have been an important part of the human diet around the world for many centuries adding to the healthy commensal population of “good” microbes that produce more GABA, a calming neurotransmitter and simultaneously stimulating the brain’s GABA receptors to sooth those brain areas activated by stress.

A systemic review and metanalysis of the existing clinical and preclinical literature suggest that Lactobacillus (L.) rhamnosus has the most evidence supporting an anti-anxiety effect in our furry rodent friends, with the most benefit being shown in those rats exposed to high levels of stress or who had gut inflammation.

Good to know. Now, all that needs to be shown is whether the same holds true for humans. While you’re waiting for that outcome it might be better meanwhile to simply enjoy your live cultures of yoghurt, kefir, kimchi, kombucha, miso and brined olives.

Don’t Forget to Feed your Healthy Microbes

It’s not just us who benefits from healthy food choices, our good gut microbes flourish on a healthy diet of fibre, starch resistant foods, and polyphenols help to keep the balance of good vs. bad microbes tipped in favour of the good.

These are found in foods such as green banana flour (yes this is a real product, but look for the Australian manufacturer as their processing technique retains the resistant starch), green bananas, potato salad, cold cooked pasta, raw onion and garlic (just stand downwind), asparagus, Jerusalem artichokes, leeks and oats.

Prebiotics, like probiotics, are thought to assist in regulating mood and brain function with one study from Oxford University showing that prebiotics lowered stress through a reduction in cortisol and improved emotional processing.

Reduce Stress with Mindful Eating

Can’t remember what you ate for lunch today? Don’t worry you’re not alone. Mindless eating is what happens when we eat on the run, grabbing something (hopefully edible) in our rush and often not tasting or enjoying our food.

By contrast, mindful eating is about slowing everything down and taking the time to notice; what’s on your plate, the smell, taste and texture of the food and to recognise those quiet signals from our body telling us we’ve eaten enough.

Mindful eating has been associated with lower cortisol and stress that also reduces the tendency to overeat.

Your Gut Microbes Need You

With the impact of too much stress manifesting as increasing levels of anxiety and depression in society it’s up to all of us to boost our stress resilience by including healthy food choices which can be summarised as:

  1. Choosing to include a wide variety of fresh foods in your diet as possible.
  2. Enjoy some probiotics in the form of fermented milk and foods.
  3. Add in some prebiotics, the high-fibre less digestible foods to nourish the healthy gut microbes.
  4. Avoid or reduce your intake of heavily processed food especially those that contain high levels of added refined sugar (read the labels!)
  5. Make mealtimes a mindful and social experience, taking your time to taste and savour all the delicious components of your food in the company of family and friends.
Dr Jenny Brockis

Dr Jenny Brockis is a medical practitioner and internationally board-certified lifestyle medicine physician, workplace health and wellbeing consultant, podcaster, keynote speaker and best-selling author. Her new book 'Thriving Mind: How to Cultivate a Good Life' (Wiley) is available online and at all good bookstores.

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