Chapter 3 - Foods that can help and harm the gut

Chapter 3 - Foods that can help and harm the gut

 Foods that can harm gut health 

1. Alcohol 
Alcohol consumption is linked to over 200 conditions and diseases, including eight different cancers, liver, and gut disorders. It promotes the growth of harmful bacteria and contributes to inflammation. To reduce your cancer risk, it is recommended that you avoid alcohol.

You might want to try:
If you like to drink alcohol, consider limiting your intake or avoiding it completely if possible. Switching to alcohol-free alternatives can be helpful.

2. Ultra Processed Foods (UPFs)

Ultra-processed foods are foods that undergo lots of processing. This typically results in a food item that is low in nutrients that we need more of, such as fibre, and high in ingredients we want less of. These include added sugars, unhealthy fats, preservatives, and additives.

Research tells us that diets high in these foods are typically associated with a higher risk of gut diseases, such as inflammatory bowel disease and bowel cancer. These foods generally do not promote smooth digestion, nor do they nurture the diverse range of gut microbes that support our health.

You might want to try:
An inclusion approach, in which you make minimally processed and whole foods the centre of your diet. This will naturally reduce your intake of UPFs.

3. Red and processed meats 
High consumption of red and processed meats is linked to an increased risk of gut issues, including inflammation, and a higher risk of bowel cancer. Researchers believe this is due to a variety of mechanisms, including chemicals called haem, nitrites, nitrates, and compounds that are formed when cooking red meat at high temperatures (like grilling and barbecuing). The global recommendations are to limit red meat (aim for 1–2 times per week) and ideally avoid processed meat. 

You might want to try:
Focusing on rotating protein sources in your week, and choose good quality red meat if and when you have it.

Foods that support gut health 

1. Fermented foods 
Fermented foods are rich in naturally occurring probiotics (live bacteria), which may promote a healthy balance of gut bacteria. 

Examples include: 

• Yoghurt: Look for live cultures with no added sugars or sweeteners for maximum benefit. 
• Kefir: A probiotic-rich fermented milk drink. 
• Labneh: A soft cheese made from fermented Greek yoghurt. 
• Sauerkraut and kimchi: Made with fermented cabbage and vegetables, these provide prebiotics, probiotics, fibre, and vitamins. 
• Tempeh: Made from fermented soybeans, this is a nutrient-dense plant-based protein. 

2. Prebiotic foods 
Prebiotics are the food for our gut bacteria. Eating foods containing prebiotics allows our existing bacteria to grow in numbers, contributing to a balanced gut microbiome. Because of this, they play an important role in maintaining our digestion and gut health. 

Prebiotics aren’t in all plant foods, but they are in lots, including: 

• Garlic and onions: Both are excellent sources of inulin, a type of prebiotic fibre. 
• Bananas: Particularly less ripe bananas, which contain resistant starch. 
• Tinned beans/chickpeas/lentils: High in fibre and promote gut health. 
• Herbs and spices: A rich source of polyphenols, which encourage bacterial diversity. 

If you experience digestive symptoms like bloating and gas, and you have these foods often, try reducing the portion size and leaving a few days between having them. 

3. Fruits and vegetables 
A diet rich in fruits and vegetables supports gut health due to their high fibre and antioxidant content. 

Our advice: Aim for a rainbow of colours throughout the day and week to provide a wide range of vitamins and minerals. For example: 

• Red: Tomatoes, strawberries, red peppers 
• Orange: Carrots, sweet potatoes, mangoes 
• Green: Leafy greens, broccoli, kiwi 
• Blue/Purple: Blueberries, aubergine, blackberries, red cabbage, beetroot 
• White/Brown: Garlic, onions, mushrooms, potatoes, bananas 

4. Wholegrains 
When whole grain foods are fermented by our gut microbes, they produce short-chain fatty acids, which are known for their anti-inflammatory and bowel protective properties. Whole grains also provide soluble and insoluble fibre, which is essential for regular digestion and maintaining a healthy gut microbiome. 

You might want to try: Including foods like oats, wholewheat bread, brown or wild rice, and quinoa in your week. 

5. Healthy fats 
Research has shown that a diet rich in beneficial fatty acids is linked to a diverse gut microbiome. 

You might want to try: Include healthy fat sources in your week through foods such as: 

• Fatty Fish: Salmon, mackerel, anchovies, sardines, and herring. 
• Avocados: High in healthy fats, polyphenols, and fibre. 
• Nuts: Walnuts, almonds, hazelnuts, and Brazil nuts. 

Maintaining a healthy gut doesn’t need to be complicated. By focusing on whole, nutrient-dense foods, you can promote a healthier digestive system and overall well-being. When you make these foods the centre of your diet, it’s okay to enjoy foods that aren’t so beneficial for your gut health from time to time. 

Always consider consulting with a healthcare professional or registered dietitian for personalised advice tailored to your health needs