Gut Health & Lung Cancer: Your Dietary Guide to Better Treatment Outcomes

The Gut-Lung Connection for Cancer Patients

Living with lung cancer means making every advantage count. Recent international research* has revealed that the bacteria in your gut can significantly impact your treatment success and quality of life:

  • Double the effectiveness of immunotherapy

  • Improve survival rates and treatment response

  • Reduce treatment side effects

  • Boost your immune system's ability to fight cancer

*Hakozaki et al - JTO 2025.

What is the Gut Microbiome?

Your gut microbiome is a community of trillions of beneficial bacteria living in your digestive system. For cancer patients, these microscopic helpers:

  • Convert fibre into compounds that kill cancer cells

  • Enhance your response to immunotherapy

  • Reduce inflammation and treatment side effects

  • Support your immune system during treatment

Your Power Foods: Supporting Treatment Through Diet

Fibre-Rich Foods (25-30g daily target) are crucial because gut bacteria convert fibre into butyrate, a powerful compound that directly kills cancer cells, reduces inflammation, and enhances immunotherapy effectiveness. Key sources include oats (4g per cup, gentle on stomach), lentils (15g per cup, high protein), sweet potatoes (4g medium, nutrient-dense), bananas (3g, helps with diarrhea), and cooked vegetables (4-5g per cup). During treatment side effects, white rice offers a gentler 2g fibre option when other foods are hard to tolerate.

Probiotic Foods for daily consumption contain live beneficial bacteria that enhance immunotherapy response and reduce treatment side effects. Natural yogurt provides Bifidobacterium and Lactobacillus strains that boost immunotherapy while being easy to digest. Kefir offers 30+ probiotic strains perfect for smoothies, while miso soup with Aspergillus oryzae helps soothe nausea. However, during severe immunosuppression periods, oncology teams may recommend avoiding raw fermented foods, so always follow medical guidance.

Prebiotic Foods feed beneficial gut bacteria and should be prepared gently during treatment. Cooked garlic and onions work well in soups and dishes, while ripe bananas are stomach-friendly and help with nausea. Steamed asparagus (cooked until very soft) and cooled potatoes (which develop resistant starch) provide additional prebiotic benefits while being easier to digest than raw versions.

Fill your plate with colours of the rainbow

The rainbow diet involves eating a variety of colourful fruits and vegetables rich in phytonutrients - substances that give plants their colour, flavour, and texture.

Plant foods with antioxidants and phytonutrients are especially beneficial during cancer treatment, helping reduce inflammation and supporting recovery.

Antioxidants should come from whole foods rather than supplements, as concentrated doses in supplements may interact negatively with cancer treatments (always consult with your oncology team).

You could aim to include 2-3 different coloured fruits or vegetables at every meal and at least one at every snack, incorporating the full spectrum throughout the week.*

Source:*American Cancer Society

Here we answer some commonly asked questions on nutrition and living with lung cancer

  • Work with a registered dietitian nutritionist who has specialized training in the nutritional needs of people with cancer.

    They can help you plan meals that give you the right number of calories and nutrients for your specific situation.

  • Sugar does not cause lung cancer.

    Sugar feeds all of our cells, even the healthy ones, so it is not recommended that you avoid all carbohydrates and sugar.

    Your body needs carbohydrates to function. Focus on balanced nutrition rather than eliminating entire food groups.

  • Try cold foods, add lemon or herbs for flavor, use plastic utensils if experiencing metallic taste, and experiment with different temperatures and textures.

    Consider trying new foods with different spices or marinades, and add strong flavors like lemon or lime juice.

What does European Gut Microbiome analysis tell us?

  • Lung cancer patients with high levels of Akkermansia bacteria = Better immunotherapy response

  • Those with diverse gut bacteria = Longer overall survival

  • Those whose fibre intake is above 25g daily = Improved treatment tolerance

    Key Beneficial Bacteria for Lung Cancer Patients:

  • Bifidobacterium: Enhances immunotherapy effectiveness

  • Akkermansia muciniphila: Associated with better treatment response

  • Faecalibacterium: Linked to longer survival

  • Lactobacillus: Reduces treatment side effects

*Source - Gustave Roussy - Oncobiome Consortium 2019

The Mediterranean diet

The Mediterranean diet consists of fruits, vegetables, cereals, legumes, nuts, seeds, fish, poultry, and eggs, with exclusive use of olive oil as the primary fat.

Research shows an 18% reduction in lung cancer risk, with studies demonstrating a significant negative correlation between Mediterranean diet adherence and lung cancer development.

Lung cancer patients following Mediterranean diet principles experience improved 6-month survival rates, fewer chemotherapy side effects, and reduced gastrointestinal complications during treatment.

Studies show strong relationships between Mediterranean diet components and better quality of life, grip strength, and functional performance in lung cancer patients.

*Taylor & Francis ‘Nutrition and Cancer’ journal

* Frontiers Mediterranean Diet Patterns in Relation to Lung Cancer Risk: A Meta-Analysis

*NLM - The effects of nutritional habits and physical activity on treatment response and survival in patients with lung cancer & Diet as a Factor Supporting Lung Cancer Treatment—A Systematic Review

Limiting High Fat, Salt, Sugar, and Ultra-Processed Foods

Highly processed and sugary foods, red meat, and alcohol should ideally be avoided during lung cancer treatment as they can potentially make symptoms worse and recovery harder.

Foods to limit include those high in salt, saturated fats, trans fats, and added sugars, which should be minimised. Ultra-processed foods contain excessive sugar, fat, and salt whilst lacking fibre and essential nutrients.

These foods can cause inflammation, worsen lung cancer symptoms, interfere with healing, and affect blood pressure, which may limit treatment options or cause complications.

Limiting these foods helps reduce side effects and enhance treatment effectiveness by supporting immune function and reducing inflammation that can promote cancer growth.

Source: *American Lung Association

  • Weight loss and muscle mass loss (sarcopenia) are associated with changes in gut microbiome composition. Maintaining muscle mass is strongly linked to better immunotherapy outcomes.

    Work with a registered dietitian to develop strategies for maintaining healthy weight and muscle mass.

  • Most probiotics are safe during chemotherapy, but some treatments require avoiding live cultures. Always check with your oncology team

  • Research indicates that fluoroquinolones, beta-lactamase inhibitors, and sulfonamides may be particularly problematic for immunotherapy effectiveness.

    Your oncology team will choose the safest options when antibiotics are medically necessary.