Gut microbiome

Your gut microbiome refers to the trillions of tiny organisms that live in your gut that play an important part in our health. They are often referred to as 'good bacteria.' Everyone's gut microbiome is different. Diet is the major influence of our gut microbiome.

It's believed that supporting a varied and balanced microbiome through diet may play an important role when you are having treatment for cancer. However, further research is required.

Choosing a diet high in fibre will help your gut microbiome. Choose a diet with as many different varieties and colours of wholegrain foods, nuts, seeds, fruit, vegetables and salads as possible.

Foods that may be harmful to your gut microbiome in large portions

  • Highly processed foods
    • Fast food and pre-packaged food and snacks
    • Ready-made frozen meals
    • Foods with artificial additives, emulsifiers, or preservatives
  • Refined sugars and sweeteners
    • Sugary drinks, sweets, pastries, desserts, biscuits
    • High-fructose corn syrups
    • Artificial sweeteners - aspartame, sucralose, saccharin
  • Excess red or processed meat
    • Bacon, sausage, hot dogs, deli meats
    • High intake of red meat like beef and lamb
  • Excess alcohol, especially spirits and high-sugar cocktails
  • Low-fibre diets, such as diets lacking fruits, vegetables, or whole grains,
  • Certain emulsifiers and additives, such as those found in many processed foods

Safety Considerations

Not all gut microbiome-related dietary intervention is safe for every person, such as:

  • When on active chemotherapy and/or immunotherapy treatment, fermented foods (probiotics) may increase your risk of infection and should be avoided
  • Many of high fibre foods may aggravate symptoms if you have digestive or bowel issues such as diarrhoea, bloating, cramps, inflammatory bowel disease (Crohn's or Ulcerative Colitis), an ileostomy, recent bowel surgery
  • If you are losing weight unintentionally or cannot eat the amount of food you usually would, this diet may contribute to worsening undernutrition - let your team at Velindre know if you are losing weight without planning to
  • Avoid very large/excesses portions or complete avoidances of any foods