Medical Nutrition in Cancer Care

Many people think about nutrition in everyday terms: eating well, getting enough protein, or having a balanced diet. But, for some people with cancer, getting the nutrients they need from their normal diet is not possible. When this is the case, a healthcare professional may recommend medical nutrition which can play an important role in making sure they receive the right nutrients and sufficient calories to support their body’s increased nutritional needs during cancer.

Medical nutrition refers to products that are legally classified as "food for special medical purposes". These products must be used under medical supervision.

Medical nutrition describes various forms of foods and drinks that are specially designed to help patients meet their specific nutritional needs, when normal diet cannot. It is used to support people whose bodies are not getting what they need from food and drink alone, for example, during cancer and its treatment. Medical nutrition must be taken under the supervision of a medical professional like a dietitian.

Medical nutrition comes in several different forms, including oral nutritional supplements. (ONS) and tube feeding, also known as enteral nutrition. 

There are many different flavours and types of oral nutritional supplements, so people can choose what they like best and keep their intake varied, including:

• Milkshake style
• Drinking yoghurt style
• Juice style
• Dessert style
• Powdered

Medical nutrition, which can be both high in calories and protein, may be needed if cancer or its treatment affects what a person can eat or drink. For example, somebody with cancer may experience:

• Loss of appetite
• Early satiety (feeling full after eating a small amount of food)
• Taste changes, like a metallic taste in the mouth
• Nausea (feeling sick) or vomiting (being sick), or
• Difficulty swallowing

Cancer treatment (particularly chemotherapy and radiotherapy), can affect what a person eats or drinks and how well the body absorbs and uses nutrients from food. Cancer itself can drive inflammatory processes and speed up the body’s metabolism, or the rate it burns energy, causing muscle to break down faster than normal. This is called cachexia (1).

It is worth noting that not all weight loss during cancer is cachexia; weight loss can happen for a number of reasons, which is why it is always worth discussing any changes with your care team.

As a result, many people with cancer experience malnutrition (2), when the body isn’t getting all the nutrients it needs to function properly. 

Medical nutrition is designed to address the specific nutritional needs of people with cancer, helping to maintain weight and muscle mass at a time when this can be particularly difficult. Maintaining weight and muscle mass during treatment is important, as it can have a meaningful impact on treatment outcomes.

There is no specific ‘cancer diet’ or special foods that cause or cure cancer. But getting the right nutrients does matter if you are living with cancer.

People with cancer often have higher protein needs than healthy adults (up to 1.5g per kg body weight), to help maintain muscle strength and meet the higher energy demands of treatment, to help maintain muscle strength, as well as to have enough calories for energy (3, 4). They also need key micronutrients like vitamin D, which is commonly low in people with cancer (5).

Any vitamin or supplement doses should be carefully adjusted based on your blood test results and individual needs, under the guidance of your care team.

So, what’s the difference between medical nutrition and a regular diet?

• Regular food can help provide good nutrition but it is not always sufficient to cover the nutritional needs of patients with cancer, or even possible for them to consume regular amounts of food, and this can create a nutritional gap.
• Medical nutrition products help fill that gap, because they are specially designed to address the nutritional needs of patients. For patients with cancer, this can be with oral nutritional supplements, that pack a lot of energy, protein and micronutrients into a small volume to address the increased nutrient demand despite the reduced appetite.

In other words, when a regular diet is not enough to meet the body’s needs, medical nutrition options, like oral nutritional supplements, can be helpful for people living with cancer. Medical nutrition must always be used under the guidance of a healthcare professional, ideally an oncology dietitian, who can match the product and volume to individual needs.