The gut-hormone connection: how your food impacts every area of your health

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What are hormones?

Hormones are chemical messengers produced in the endocrine glands, which are secreted into the bloodstream. They impact your emotions, appetite, weight, libido and mental health. They play an integral role in many of your body’s major processes, including growth and development. Hormones have the power to impact gut health and digestion, liver detox, dictate how your hair grows, how clear or glowing your skin is and influence how anxious you feel. By learning to work with our hormones and eat mindfully, we can start to balance ourselves from the inside out.

What does a hormone imbalance really mean?

A hormone imbalance, put simply, means having too much or too little of a hormone. Sometimes, even a small imbalance left untreated over time can cause issues. Our hormone balance is directly influenced by the food we eat, the exercise we do (or don’t do), how much restorative sleep we get and stress levels. Essentially, this means any of these factors can throw your hormones out of that delicate balance – which has potential to cause irregular periods (if you’re a menstruating woman), polycystic ovary syndrome (PCOS), thyroid disorders, acne and chronic fatigue.

Discover more about how your diet can affect periods with our health expert guide to 10 diet changes to try for a better period.

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How are your gut and hormones connected?

Your gut is responsible for more than just digesting food, the health of your gut has a direct impact on your hormones. Your gut produces more neurotransmitters (chemical signals used by the nervous system) than your brain. A startling 95% of serotonin (the ‘happy hormone’) and 50% of dopamine are produced in the gut. This is relevant to your health and wellbeing because serotonin plays a fundamental part in regulating your mood, mental and emotional health, and is strongly connected to anxiety, insomnia and depression. What’s more, low serotonin levels are linked to constipation, which proves we need to feed the gut microbiome with high-fibre foods. Scientific research suggests that diets low in tryptophan decrease serotonin levels, which encourages your microbes to take more serotonin from the food you eat. To improve your mood, mental health and cognition you need to start by getting more tryptophan into your meals.

What is tryptophan?

Tryptophan is an essential amino acid needed for growth and many metabolic functions. It comes from food (or supplements) and our bodies convert it to 5-hydroxytryptophan, then serotonin, then melatonin. The liver can also use tryptophan to produce niacin (vitamin B3), which is needed for energy metabolism and DNA production. So you can imagine, if your gut microbiome is lacking in serotonin-supportive bacteria, how much of an effect this could have on how happy, motivated and mentally stable you feel. Tryptophan-rich foods include oats, bananas, dried prunes, cacao, dark chocolate, milk, tuna, wholegrains, chicken, pumpkin, sesame seeds and tofu.

Chicken breast piece in a honey-sesame sauce with long-stemmed broccoli

Melatonin: your master sleep hormone

The pineal gland in the brain is responsible for melatonin production, which promotes feelings of sleepiness, regulates your sleep-wake cycle, normalises your circadian rhythm (your internal body clock) and supports your immune system. Adequate melatonin levels ensure that you get the restorative sleep needed for a balanced hormone system and, therefore, good energy and consistent mood. One handy sleep tip is to prioritise eating complex carbs in your evening meal as this supports sleep hormones by blunting cortisol, raising serotonin and increasing GABA levels (an anti-anxiety neurotransmitter) – all the good stuff our bodies will thank us for. Read our full expert guide on how to have a better night's sleep for more advice.

Avocado and Spinach Fusilli in Two Bowls

The gut-oestrogen axis

As well as being home to serotonin, your gut microbiome houses a collection of bacteria (the oestrobolome) that modulate oestrogen levels. Too much circulating oestrogen can cause PMS symptoms and hormone conditions such as PCOS, endometriosis and fibroids, and low circulating oestrogen levels can present as irregular periods, vaginal dryness and irritability. It can also impact your metabolism, energy levels and libido, and make you more susceptible to certain diseases. Most commonly, breast cancer (in cases of oestrogen excess) and osteoporosis, particularly in post-menopausal women because oestrogen acts as a natural protector of bone strength. Too much or not enough oestrogen is thought to be caused by your gut microbiome being low in bacterial diversity, due to a lack of fibre varieties, as well as low intake of pre- and probiotic foods. Don’t worry, though, this can be naturally treated by eating a consistently healthy, balanced diet brimming with protective plant foods.