Malnutrition and oral nutritional supplements

Dr Daleen Geldenhuys, an oncologist, helps us understand the causes of malnutrition while Meagan Atcheson, a dietitian, speaks on the role of oral nutritional supplements in oncology care.

Nutrition is a subject that everyone has an interest in and often have strong opinions about what is healthy and unhealthy. Public interest is at an all-time high and opinions are shared with cancer patients, albeit in a well-meaning manner.

As you get older, loosing muscle and bone mass become key areas where supplements to your dietary intake are emphasised. Patients with certain illnesses, such as emphysema (lung disease), use a lot more energy to breathe due to decreased surface area in the lung to absorb oxygen and therefore need more nutrients to fuel the energy need. These mentioned needs are added to the nutritional stress of a cancer patient.

Good nutrition is vitally important to ensure that a patient has the physical strength to undergo therapy, be it surgery, chemotherapy, radiation therapy, or targeted therapy.

People may blame diet as a cause of cancer along with stress factors, but often families think that if they can control the diet of the patient, they may also control the cancer.

What is malnutrition?

Malnutrition occurs when there is either a lack of proper nutrition or an excess of certain foods in diets; it includes under and over nutrition. However, it’s common for most people to think about malnutrition more in terms of undernutrition in chronic disease.

Symptoms are fatigue, dizziness, low blood glucose, low blood pressure and weight loss. This in turn has vast implications with regards to wound healing, immunity, and the proper functioning of the body.

Risk factors for malnutrition in a cancer patient

1. The cancer itself can be blamed for the malnutrition

Intake of normal food is difficult in patients with head and neck tumours where the tumour may obstruct the intake of food especially solid food.

The same applies to oesophageal and gastric cancers where the tumour may obstruct the organ, often allowing patients only to take liquids and sometimes causing complete obstruction, necessitating the placement of tubes or stents to allow feeding.

Severe pain during swallowing may also prevent the patient from eating or drinking.

Pancreatic cancer may result in a loss of digestive enzymes and may need medication to help with digestion.

Large intra-abdominal tumours or fluid accumulation (ascites) in the abdominal cavity may limit gastric filling and the patient will eat less.

Intermittent obstruction by colon tumours or tumours growing on the peritoneal lining may decrease bowel mobility and therefore no absorption of food can take place. This is often associated with vomiting.

2. Lack of appetite

Appetite can be affected by pain killers, especially morphine derivatives and combination agents that do have morphine derivatives in addition to paracetamol.

A low red cell count (haemoglobin) due to blood loss or side effects of therapy may decrease appetite. The treatment of anaemia is paramount to restore the appetite of a patient.

3. Side effects of therapy

Radiation to head and neck area with sensitivity in the oral cavity hinders swallowing and may also have a bit of swelling associated before the cancer shrinks.

After surgery for gastric cancer, patients are trying to cope without a stomach where food is partially digested and stored for systematic digestion. Volumes of food that can be tolerated is much less and often patient are not able to eat the correct number of kilojoules and other nutrients.

You need to remember that iron is absorbed in the first part of the small intestine (duodenum) and vitamin B12 in the last part of the small intestine (terminal ileum). Surgery to those areas can lead to deficiencies in iron and vitamin B12.

Chemotherapy affects the taste of food, the texture cannot be differentiated, and often platinum agents that are frequently used, leave a permanent metallic taste in the mouth, further compounding nutritional problems.

Targeted agents, taken orally, can cause small mucosal ulcerations in the mouth and intestine, leading to diarrhoea (increased transit time in the gastrointestinal tract) and can lead to malnutrition.

4. Cancer cachexia

This is a complex change in the metabolism of a person secondary to cytokine or hormone release by the tumour that can trigger inflammation and accelerated muscle loss. The body may use protein or muscle as a source of energy in the place of fat.

5. Specific diets

All diets have some merit in assisting the patient but to completely avoid certain foods because of anecdotal evidence may harm the patient more than the potential benefit.

Conclusion

Often, we overestimate the correct nutrients and underestimate the protein quantity that is needed for a diet to improve nutrition.

Food forms a large part of enjoyment in life and is often the centre of family activities. Feeling sick, missing out, and dealing with cancer and treatment can be a big stress to the patient, family, and friends.

Seeking the help of a registered dietitian with a special interest in cancer nutrition may assist many patients to have better nutrition, tolerate treatment, and improve quality of life.