Let food be thy medicine: on nutrition as component of healing in oncology

Diet and nutrition form the foundation of good health and longevity. Our diets play a dual role when it comes to health and disease: a balanced diet preserves health and lowers the risk of non-communicable diseases, while a consistent nutrient-rich diet during cancer treatment upholds healing, recovery and energy levels.

For individuals undergoing cancer treatment, nutrition becomes far more than a matter of general wellness — it becomes a vital component of healing. Cancer and its treatments place immense stress on the body, resulting in a greater need for energy, protein, vitamins, and minerals. Adequate nutritional intake supports tissue repair, maintains immune function, preserves healthy body weight, and enhances the body’s ability to tolerate and recover from medical therapies. When these needs are unmet, patients face a greater risk of malnutrition and cancer cachexia, a serious condition marked by involuntary weight loss, muscle wasting, weakness, and reduced physical capacity.

In addition, cancer-related fatigue is a common, distressing symptom experienced by patients.  Nutrient-dense foods, help stabilise energy levels by reducing inflammation, preserving muscle mass, and maintaining metabolic balance. Thus, nutrition plays a both supportive and a therapeutic role.

Surgery, radiation and chemotherapy can create substantial nutritional challenges. While they increase the body’s energy and protein needs, they also often cause side-effects (loss of appetite, nausea, vomiting, mouth sores, difficulty in swallowing and diarrhoea) that result in reduced food intake causing weight/muscle loss and fatigue. Hence, some patients may require liquid diets or small frequent meals via enteral/tube feeding (a method of delivering liquid nutrition via a tube directly into the stomach, when a person is unable to eat or swallow safely by mouth), or parenteral (intravenous) feeding.

Therapeutic diets are designed to maintain nutritional status, support metabolic functions, address disease-related symptoms, minimise side-effects of treatments, and speed up overall recovery. These diets are planned by dietitians in collaboration with oncologists and are tailored to meet the unique needs of each patient.

High-protein diet: During treatment, the body requires more protein to repair tissues, maintain muscle, and support immune function and a high-protein diet helps counteract side-effects of disease and treatment.

Neutropenic diet:Patients with low white blood cell counts, usually due to chemotherapy-induced neutropenia, are at increased risk of infections. A neutropenic diet emphasises hygienically prepared, well-cooked foods that minimise exposure to harmful microorganisms.

Ideally, nutritional screening should be done at the time diagnosis and the patient should be optimised prior to treatment commencement (pre-habilitation) as this can significantly improve outcomes.

Nutrition care must always be individualised. Factors such as cancer type, treatment modality, stage of disease, side-effects, and cultural food preferences should be considered. Dietitians play a crucial role in providing evidence-based guidance by following established nutrition protocols.

During treatment, patients should consume culturally familiar, easy-to-digest foods; eat small, frequent meals; maintain hydration; increase protein intake; follow a balanced diet; and ensure strict food hygiene.

Diet, nutrition and lifestyle changes are life-long partners to good health. We live in a world that is saturated with fast foods, sugared drinks, processed foods and unhealthy snack choices. These, alongside a reduction in wholesome home-cooked meals, has tilted the balance towards the rise of non-communicable diseases. It is imperative, therefore, to increase our knowledge about the role of diet on our health.

Several scientific reviews note that a Mediterranean type of diet lowers cancer risk through a high intake of fibre, antioxidants, and healthy fats. The mechanism of action is reduction in oxidative DNA damage which is the central driver of carcinogenesis.   Additionally, several Indian spices (such as turmeric, ginger, cumin and coriander) are rich in bioactive compounds that display antioxidant properties and are also known to modulate key signalling pathways. Contrastingly, diets high in processed meat, refined grains and added sugars, in the absence of fibre-rich foods, can increase cancer risk.

In summary, for a healthy diet and lifestyle:  increase intake of wholegrains, vegetables, fruits, lentils, beans, nuts and seeds; reduce fast foods, red and processed meats; limit sugar‑sweetened drinks and alcohol; quit tobacco; maintain a healthy body weight and remain consistently physically active.

Looking ahead, both for our health and the planet’s, the EAT–Lancet Commission proposes a “universal healthy reference diet” that is largely plant-based, environmentally sustainable and capable of preventing diet-related non-communicable diseases.

Every bite we eat is our first medicine: the choice towards good health can be made from well within the confines of our kitchens, and the time to make this choice is now.

(Dr. Rama R. is associate professor & head, department of epidemiology, Cancer Institute (WIA). r.rama@cancerinstitutewia.org; Dr. Parvathy K. is dietician, department of dietetics, Cancer Institute (WIA) diet@cancerinstitutewia.org; Dr. Mahalakshmi Rangabashyam Shetty is consultant, The Head and Neck Clinic & professor of practice, department of medical sciences and technology, Indian Institute of Technology, Madras. mranagabashyams@iitm.ac.in)