A Guide to Gut Health
Gut health has been a hot topic in nutrition for a few years now, and while there’s still a lot we don’t know, it’s clear that a healthy gut has the power to influence many areas of our health, from digestion to immunity and mental health.
What does a healthy gut do?
Our gut bacteria break food down to an extent that our body couldn't without it - so we get more nutrition and energy from our food when our bacteria are healthy.
Our gut produces several B vitamins, and vitamin K which we normally don't get enough of from food.
Our gut is home to its own nervous system, and it's in constant contact with our brain. This is why stress affects the gut, and the gut affects stress. This connection is known as the gut-brain axis and disruption in this connection is known to contribute to a range of diseases including Parkinson's disease and IBS.
Our gut produces many neurotransmitters that are responsible for our mood and sleep patterns, such as serotonin, dopamine, and melatonin.
The gut plays a crucial role in regulating your immune system, and if this regulation stops working due to an imbalance in the microbiota, this can lead to diseases such as Inflammatory Bowel Disease, autoimmune diseases, and cancer.
A healthy gut is able to absorb beneficial nutrients while providing a barrier from harmful substances.
Gut health can impact hormone health because the gut removes excess estrogen from the body. If your gut isn’t functioning properly, excess estrogen won’t be removed, instead, it will be reabsorbed into the body. This can be an issue in perimenopause, or in conditions such as endometriosis where high estrogen is a factor.
What are possible signs of an unhealthy gut?
Food cravings
Bloating
Weight gain
Constipation or diarrhoea
Food sensitivities
IBS
Gas
Fatigue
Skin issues like acne or rosacea
Energy crashes (difficulty maintaining blood sugar)
Headaches
High estrogen (more on hormones and the gut below)
So if you have any of these it makes sense to consider whether your gut health is the cause. Many of these symptoms can also be signs of other issues, so see your doctor if you have any concerns.
There are lots of reasons your gut could be out of whack, including:
Taking antibiotics
Other medications (like NSAIDs and reflux medication)
Food poisoning or infection
How much alcohol you drink
The quality of your sleep
Stress
Lack of exercise
Inflammation
A significant change in your diet; for example if you move from one country to another where the food is very different
And of course, the food you eat
Foods for the Gut
There are lots of nutrients and foods that can be good for the gut, but in particular, you want to get:
plenty of fibre from fruit, vegetables, legumes, grains, nuts & seeds
antioxidants & vitamins, from fruit and vegetables
omega-3 fatty acids from salmon, chia and flax seeds - although it should be said that role of different types of fat in gut health is not yet super clear
minerals such as magnesium and calcium from nuts, seeds, legumes, eggs, and green vegetables
protein from plant sources and lean meat
probiotic bacteria from fermented foods like kefir
and drink mostly water
Fibre
Fibre has two major effects on gut health:
it’s the preferred food source for beneficial gut bacteria; and
when gut bacteria consume fibre, short-chain fatty acids (SCFAs) are created, and these feed the cells of the gut.
SCFAs are also crucial for regulating the immune system, and they're anti-inflammatory.
Fibre Requirements
Adult women: 25g per day
In Pregnancy: 28g per day
Lactation: 30g per day
Adult men: 30g per day
Types of Fibre
There are different types of fibre, classified on how much they ferment. For many people, the different types of fibre don’t matter, but some fibres can cause bloating and gas for some people. If you’re prone to bloating, it can help to look at the types of fibre you eat.
Prebiotic Fibre
Some fibre is prebiotic, which means it’s particularly good at feeding gut bacteria. Prebiotic fibre is found in wheat, chickpeas, lentils, firm bananas, berries, cooked and cooled potato (like in potato salad), onion, flax seeds, and citrus.
Getting enough fibre
Don't worry too much about the exact fibre content of foods. Instead, work on averages:
Fruit provides 3-5g fibre per serve (a serve is 150g)
Vegetables provide 1-2g per serve (a serve is 75g)
Nuts and seeds are, on average 10% fibre so a 30g serve is 3g fibre. Chia seeds are especially high in fibre, with 10g fibre per 30g seeds.
Legumes vary - lentils contain 6g per serve, and chickpeas contain 11g per serve (a serve is 150g of cooked legumes).
Meal Planning to Get Enough Fibre
Using the average fibre content of foods above, you can plan your day around this general structure for getting enough fibre:
Breakfast with 10g fibre from fruit, veg, nuts, seeds or grains
Example: chia pudding with fruit and nuts
Snack with one serve of fruit (5g)
Example: vegetables sticks and hummus
Lunch with 5-10g fibre from vegetables, legumes, nuts, seeds or grains
Example: Salad plate with chickpeas and vegetables
Snack with one serve of nuts & seeds (3g)
Example: yogurt with fruit and nuts
Dinner with 5g fibre vegetables, legumes, nuts, seeds or grains
Example: lentil and vegetable curry, or salmon with 2-3 serves vegetables
Antioxidants
Antioxidants are important for gut health because they are anti-inflammatory and they support the immune system.
Antioxidants include vitamins A, C, and E, and are found widely in fruit and vegetables, particularly citrus, berries, tomatoes, tea, and green leafy veg. If you eat a diet high in fruit and vegetables, and you eat a variety of colours in those fruits and vegetables, you should be getting enough.
Other Nutrients and Foods
Calcium is needed for muscle function, and your gut is a whole lot of muscle. Get it from dairy food, nuts and seeds, green leafy vegetables, and fortified dairy alternatives. Vitamin D is essential for calcium absorption.
Magnesium is needed for sleep, digestion, and muscle function. It's found in nuts, seeds, tofu, green leafy vegetables, banana, raspberries, and black rice.
Fermented / probiotic foods are foods like kefir, kombucha, and sauerkraut that contain live bacteria. Eating these can improve the diversity and abundance of your gut bacteria, but they need to have enough bacteria to actually make it to your gut - look for food containing 10^9 'colony-forming units' or CFUs.
Probiotic dairy like kefir and yogurt has the most research behind it so I recommend that over kombucha or other fermented foods, if you’re looking for a gut health benefit.
Any probiotic foods or supplements can take around 4 weeks to start working, and once you find one that works for you, you'll need to continue taking it as the bacteria don't permanently colonise your gut.
Water is the best thing to drink for your gut.
Food and drink to avoid or limit for gut health
There are a few foods that have been shown to have negative effects on the gut.
Red meat and processed meats - have been shown to cause inflammation in the gut, and are strongly associated with bowel cancer.
Alcohol - can lead to both constipation and diarrhea, can damage the gut lining, and disturbs the absorption of nutrients. Alcohol can also indirectly affect gut health by interfering with sleep.
Caffeine - stimulates the gut, which can be great if you're constipated, but it can also cause bloating in people with IBS. Coffee is acidic which can irritate the gut, but you can mitigate this by having dairy or nut milk with it. Caffeine also decreases the absorption of magnesium, which is important for digestion. This doesn't mean you shouldn't have it - just keep it in moderation (1-2 cups per day), and don't have it on an empty stomach.
Processed foods - because they're often high in sugar, salt, and saturated fat, and low in vitamins and fibre, processed foods can lead to inflammation which is damaging to the gut. However, this really depends on the food, as most foods have undergone some level of processing.
High-GI carbohydrates - high-GI carbs lead to a spike in blood sugar, which triggers a stress response in your body, which is damaging to the gut. Low-GI carbs are always better. If that's not possible, make sure to have some protein and healthy fats with a high-GI meal, as that will slow down the absorption of the carbs.
High-FODMAP foods, if you are sensitive to them.
Gluten-containing foods, if you have coeliac disease or are sensitive to them.
I hope that’s been helpful! Gut health is a fascinating and ever-evolving area of nutrition and I hope this article has given you a few new ways to nurture your gut.
Disclaimer: this article is for informational purposes, is not medical advice, and should not be used to diagnose or treat any medical condition.
