Importance of nutrition during and after cancer

What is nutrition?

Nutrition is the process through which food is ingested and utilized by the body for growth, health, and tissue replacement. Nutrition is critical to one’s overall health. It is regarded to be essential in the treatment and management of nearly all diseases, including cancer. Many elements of your health, including your chance of developing chronic diseases like heart disease, diabetes, and cancer, are influenced by what you eat. 

Cancer is one of the most common causes of death in the world (Arends et al., 2016). However, studies show that simple lifestyle modifications like eating a healthy diet can prevent 30–50% of all cancers (Donaldson, 2004). If you have cancer, good nutrition is particularly important because the disease and its therapies might alter your eating habits. They can also influence how your body tolerates and utilizes nutrition. Before, during, and after cancer treatment, eating the correct foods can help the patient feel much better and stay stronger. Eating a healthy diet is one of the most common supplemental or alternative cancer treatments. 

Changing your diet during cancer treatment may be necessary to help you gain strength and survive the effects of the illness and its therapy. This may involve consuming foods that are not generally recommended while you are in good health. For example, you may require high-calorie foods to maintain your weight, or thick, cold foods such as ice cream, smoothies, or drinks because sores in your mouth and throat make eating difficult. When determining the best ways to acquire the nourishment your body requires, you must consider the type of cancer you have, your therapy, and any adverse effects you may be experiencing. Cancer patient’s nutritional requirements differ from one another. Your cancer care team can assist you in identifying your nutritional goals and developing strategies to help you achieve them. Eating well while undergoing cancer treatment may benefit you in the following ways:

  • Feeling good
  • Retaining your strength and energy
  • Maintaining your weight and nutrient stores
  • Effectively tolerating treatment-related adverse effects
  • Minimizing your risk of infection
  • Heal and recover more quickly.

Malnutrition can be caused by cancer and cancer treatments

Cancer and cancer treatments can have an impact on taste, smell, appetite, and the ability to eat enough food and absorb nutrients from meals. This can lead to malnutrition, a condition caused by a shortage of essential nutrients. Malnutrition can make a patient weak and fatigued, rendering them unable to fight infection or complete cancer therapy. Malnutrition may worsen if cancer spreads or progresses. 

Anorexia and cachexia are two of the most common causes of malnutrition among cancer patients. Anorexia is characterized by a decrease in appetite or desire to eat. It is a common symptom in cancer patients. If cancer progresses or spreads, anorexia may develop early in the disease or subsequently. Some people with cancer already have anorexia when they are diagnosed. Anorexia affects the majority of individuals with advanced cancer. Cachexia is a disorder characterized by weakness, significant weight loss, and loss of fat and muscle in cancer. It is prevalent in patients who have malignancies that interfere with eating and metabolism. It can happen in cancer patients who eat well but are not able to retain fat or muscle due to tumor growth.

Even if a patient appears to be eating enough, the body may not be able to utilize all of the nutrients from the meal. Cancer patients may experience both anorexia and cachexia.

Treatment of symptoms

Many patients find it difficult to eat adequately due to the symptoms of cancer and its treatments. Cancer treatments that have an impact on nutrition include Chemotherapy, radiation therapy, surgery, hormone therapy, immunotherapy, and stem-cell transplant. When cancer treatment affects the head, neck, esophagus, stomach, intestines, pancreas, or liver, it is difficult to obtain enough nutrition to remain healthy. 

When the adverse effects of cancer or cancer treatment interfere with normal eating, adjustments are required to ensure that the patient gets the nutrients they need. It is critical to consume foods rich in calories, protein, vitamins, and minerals. Meals should be designed to satisfy the patient’s nutritional needs and food preferences.

The following are some of the most prevalent symptoms associated with cancer and its treatment, as well as methods for treating or controlling them:

1) Anorexia

Anorexia is a lack of desire to eat or loss of appetite in patients. The following suggestions may be beneficial to cancer patients who are suffering from anorexia: Consume foods high in protein and calories. High-protein foods include the following: Beans, yogurt, eggs, chicken, fish, milk and milk products, nuts, seeds, and lentils.

Increase the protein and calorie content of your food, such as adding whey protein to foods like smoothies, or using protein-fortified milk.

Some traditional herbal teas have been shown to increase appetite, such as: Ginger tea, fennel tea, catnip tea, peppermint tea, and Panax ginseng tea.

When your appetite is at its peak, start your meal with high-protein items.

During meals, drink just minimal amounts of liquid.

If you don’t feel like eating solid foods, try beverages like shakes, smoothies, juices, or soups.

Consume smaller meals and nutritious snacks frequently throughout the day.

Eat your largest meal when you’re the hungriest, whether it’s for breakfast, lunch, or dinner.

To ease symptoms and aftertastes, brush your teeth and rinse your mouth at least twice daily. 

2) Nausea

Nausea is a sick feeling, with an intense urge to vomit. It is one of the most common adverse effects experienced by cancer patients during their treatment. The following suggestions may be beneficial to cancer patients who are experiencing nausea: 

  1. Choose foods that you enjoy. You should not force yourself to eat foods that make you feel ill.
  2. Instead of hefty meals, eat bland, soft, and easy-to-digest foods.
  3. Consume stomach-friendly meals such as bread, plain yogurt, and clear broth.
  4. Consume foods and beverages at room temperature (not too hot or too cold).
  5. Throughout the day, sip beverages slowly.
  6. If you have a nasty taste in your mouth, suck on hard candies like peppermints or lemon drops.
  7. Avoid foods and beverages with strong odors.
  8. Instead of 3 large meals per day, eat 5 or 6 smaller meals.
  9. Snacks and meals should not be skipped. An empty stomach may aggravate your nausea.
  10. Pre and post eating, rinse your mouth.
  11. Consult your doctor about using anti-nausea medications.


Vomiting can occur as a result of nausea and is aggravated by some cancer treatments. Other causes, such as food odors, gas in the stomach, or movement, can aggravate vomiting. Vomiting may also occur in the absence of nausea. The following suggestions may be beneficial to cancer patients who are experiencing vomiting: 

  • You should not eat or drink anything until the vomiting has stopped.
  • After the vomiting stops, sip small quantities of clear liquids.
  • Instead of three large meals per day, eat five or six little meals.
  • After you can consume clear liquids without vomiting, drink liquids that are gentle on your stomach such as thinned soup or milkshake.
  • Request medication to prevent or control vomiting from your doctor.

4) Mouth sores.

Soreness in the mouth or throat can be caused by cancer treatment or something else too. Consult your doctor to be sure the soreness isn’t caused by an infection. If you have soreness as a result of cancer therapy, it will usually go away with time. The following tips may be beneficial to cancer patients who are experiencing mouth sores: 

  • Cook food until mushy and tender.
  • Food should be cut into little pieces. To make food smooth, use a blender or food processor.
  • Foods should be eaten cold or at room temperature. Foods that are too hot might cause pain in the mouth.
  • Drink using a straw to avoid aching in your mouth.
  • Avoid the following items: Spicy foods, citrus fruits likes oranges, grapefruit, and lemon, ketchup, tomatoes, foods high in salt, raw vegetables, harsh and crispy food.
  • Rinse your mouth 3-4 times a day. Mouthwash containing alcohol should be avoided.
  • Consume soft foods such as custards, scrambled eggs, milkshakes, etc. 
  • Soreness can be relieved by eating cold foods like sherbet or popsicles.

5) Dry mouth.

Dry mouth is the most common side effect resulting from chemotherapy and radiation of the head or neck. A dry mouth, caused by a decrease in saliva flow, can make chewing and swallowing difficult, as well as alter the taste of food. The following suggestions may be helpful for cancer patients who are experiencing dry mouth:

  1. Consume foods that are easy to swallow.
  2. Sauces, gravies, or salad dressings should be used to moisten the food.
  3. Suck on lime-flavored, sugar-free candies, frozen cherries, and grapes, unsweetened popsicles, ice chips, or cubes, and try sour foods and beverages such as lemonade in tiny amounts to stimulate saliva.
  4. Drink plenty of water throughout the day.
  5. Avoid foods that can irritate your mouth (such as spicy, sour, salty, hard, or crunchy foods).
  6. After every 1 to 2 hours, rinse your mouth. Alcohol-containing mouthwash should not be used.

6) Lactose intolerance.

Individuals with lactose intolerance cannot completely digest lactose (the sugar found in milk and milk products). As a result, they experience diarrhea, gas, discomfort, abdominal cramps, and bloating after consuming dairy products. Patients who comfortably digest milk and milk products before radiation or chemotherapy treatment may develop an intolerance. This is not a very common development. Small quantities of milk products can still be handled by most people. The following tips may be helpful for cancer patients who are experiencing symptoms due to lactose intolerance: 

  • Prefer lactose-free milk products such as hard cheeses (like cheddar) and yogurt.
  • Lactose-free or low-lactose milk products should be consumed. Many grocery stores sell foods labeled “lactose-free” or “low lactose”, such as lactose-free milk and low-lactose yogurt.
  • Only the dairy items that cause you difficulties should be avoided. If it is tolerable, consume tiny amounts of dairy products such as milk, yogurt, or cheese.
  • Plant-based milk, which does not contain lactose, can be used instead of standard dairy milk. Individuals who are lactose intolerant or allergic to milk proteins usually prefer plant-based milk over cow’s milk due to their common advantages of being lactose-free, cholesterol-free, and low in calories. Examples of some plant-based milk are Almond milk, soy milk, coconut milk, etc. 
  • Consume calcium-rich foods like broccoli and greens.
  • When eating or drinking dairy products, consider lactase pills. Lactase is an enzyme that breaks down lactose to make it simpler to digest.

7) Weight gain.

Weight gain is prevalent during treatments for breast and other cancers, in women undergoing hormone therapies, and as a result of chemotherapy-induced early menopause. Weight gain may be partially caused by a change in food and exercise routines, such as eating more to cope with stress or sickness and being less active owing to fatigue. The following tips may be useful for cancer patients who have gained much weight during their cancer treatment: 

  • Consume plenty of fruits and vegetables and beans. 
  • Include fiber-rich meals such as whole-grain bread, cereals, and pasta.
  • Consider eating lean meats.
  • Select low-fat milk and its products.
  • Consume fewer saturated fats, such as butter and sweets.
  • Low-fat cooking methods should be preferred, including broiling, steaming, grilling, and roasting.
  • Consume less salt and sugar.
  • Eat only when you’re hungry. If you eat just because of boredom, consider engaging in activities that you enjoy, so that you can stop eating unnecessarily. 

Additional ways of getting nutritional support during cancer treatment 

Nutrition therapy involves dietary supplemental drinks and assistance to enteral and parenteral nutrition, along with dietary advice and adjustments. The following methods are used for feeding a patient who cannot receive the correct quantity of calories and nutrients by the mouth:

1) Enteral nutrition: Enteral nutrition is the administration of nutrients in liquid form (formula) to a patient via a tube implanted in the stomach or small intestine. The nutrient formula usually contains water, protein, lipids, carbohydrates, vitamins, and minerals. 

2) Parenteral nutrition: When a patient is unable to consume food orally or by enteral feeding, parenteral nutrition is given. Parenteral feeding does not involve the stomach or intestines digesting food. Nutrients are injected directly into the patient’s bloodstream via a catheter put into a vein. Proteins, lipids, vitamins, and minerals are examples of nutrients provided in parenteral feeding.

General dietary recommendations to reduce the risk of cancer

  • Make efforts to be as lean as possible without being underweight or malnourished. 
  • Every day, engage in physical activity for at least 30 minutes. Sedentary behavior should be limited.
  • Sugary beverages should be avoided.
  • Consume more veggies, fruits, whole grains, and legumes such as beans and lentils.
  • Avoid or limit the intake of red meats (beef, pork, and lamb) and also processed meats.
  • Limit the consumption of salty and sodium-processed foods. 
  • Don’t take supplements to prevent cancer.
  • Limit your intake of fast foods and other processed foods that are loaded with carbohydrates, fats, and sugars.

Certain foods possess cancer-fighting and cancer-preventive properties

No single food can defend you from cancer on its own. However, studies indicate that a diet rich in vegetables, fruits, whole grains, legumes, and other plant foods reduces the risk of many cancers. Many specific minerals, vitamins, and phytochemicals have been shown in laboratory experiments to have anti-cancer properties. A comprehensive nutritional strategy is most likely to be useful. According to scientists, adopting the proper cancer diet may lower your cancer risk by 70% and may also aid in cancer recovery. Some of the most well-researched and proven anti-cancer foods are mentioned below: 

  • Apples
  • Asparagus
  • Beans
  • Blueberries
  • Broccoli
  • Carrots
  • Cherries
  • Cinnamon
  • Cranberries
  • Cruciferous vegetables such as cauliflower, brussels sprouts, and kale. 
  • Flaxseeds
  • Garlic
  • Grapes
  • Nuts and seeds 
  • Oranges
  • Raspberries
  • Soy and soy products
  • Spinach
  • Strawberries
  • Tea
  • Tomatoes
  • Turmeric 
  • Walnuts 
  • Whole grains

Most of these foods are rich in antioxidants. Antioxidants are compounds that protect the body by inhibiting the oxidation process. They shield the body from the harmful effects of free radicals (byproducts of the body’s natural metabolic processes). Free radicals assault healthy cells, causing DNA alterations that allow cancers to thrive. Some of the major antioxidants that may help in the prevention and treatment of cancer are Beta carotene, vitamin C (ascorbic acid), vitamin E, and lycopene. 

Apart from antioxidants, these foods are also rich in phytochemicals. Plants produce substances known as phytochemicals (“Phyto” means “plant”). Fruits, vegetables, grains, beans, and other plants possess them. Many of these phytochemicals are known to protect cells from damage that could result in cancer. Some researchers and experts believe that eating more phytochemical-rich vegetables, fruits, as well as other plant foods could reduce your cancer risk by as much as 40%. Some examples of phytochemicals that are shown to be helpful in the prevention and treatment of cancer are Anthocyanins, carotenoids, flavonoids, indoles, glucosinolates, and phenolics. 

Both antioxidants and phytochemicals are known to help in the prevention and treatment of cancer. Apart from preventing DNA damage by combating free radicals in the body, they also help in stimulating the immune system, block substances we consume from becoming carcinogens, reduce inflammation that makes cancer growth more likely to happen, and also help in regulating hormones.

Cancer patients may explore specialized diets to improve the efficacy of their treatment, minimize adverse effects from therapies, or treat cancer itself. Numerous popular diets make various claims in the name of anti-cancer diets or cancer-preventive diets. And, while part of what they contribute may be valuable, views may sometimes appear as facts, making it difficult to distinguish between proof and opinion. Some of the common nutrition trends in cancer care: 

1) Vegan diet.

Vegan diets consist entirely of plant foods and exclude all animal products. They have the highest fiber content and the lowest saturated fat content of any vegetarian diet. Vegan diets appear to be connected with the best long-term health in some studies, and they are the only diet plan that has been linked with atherosclerosis reversal in a small number of patients. Aside from meeting the recommendation for a plant-based diet, the data is insufficient to draw any conclusions about a vegan diet as a specific choice for lowering cancer risk, according to AICR’s Third Expert Report.

Some major food groups included in vegan diets are Fruits, vegetables, whole grains and cereals, plant-based milk and its products, nuts, and seeds, legumes (beans, lentils, and peas). 

2.) Mediterranean diet.

The Mediterranean diet prioritizes whole grains, vegetables, fruits, and beans. The majority of the fat comes from olives, olive oil, and nuts. A growing number of researches link the Mediterranean diet to a lower risk of cancer. A “Mediterranean-style” dietary pattern appears to minimize the risk of weight gain, overweight, and obesity. This is significant since there is compelling evidence that excess body fat raises the risk of at least 12 different cancers. 

Major inclusions in the Mediterranean diet are vegetables, fruits, nuts and seeds, olive oil, legumes, low-fat dairy, fish, whole grains, etc. 

3) Ketogenic diet.

A ketogenic diet restricts carbohydrates while increasing fat consumption. The diet’s goal is to reduce the quantity of glucose (sugar) that tumor cells can use to grow and replicate. It is a difficult diet to adhere to since precise proportions of lipids, carbohydrates, and proteins are required. There are only a few human studies available, and the majority of them were not designed to assess effectiveness. The risk of vitamin shortages, undesired weight loss, and other potential adverse effects suggests that a Ketogenic diet should only be considered under the guidance of a skilled medical professional.

Major inclusions in the ketogenic diet are low-carbohydrate vegetables, avocados, and berries, nuts and seeds, healthy oils, eggs, meat, fatty fish, butter, cheese, and cream. Major exclusions in a ketogenic diet are grains or starches, fruits except for berries, beans and legumes, sugary foods, low-fat products, unhealthy fats.


Optimal nutrition can improve cancer patient’s quality of life and treatment, as well as aid in preventing malnutrition. It is best to have a healthy, balanced diet with enough protein and calories. Although no diet has been proven to cure cancer, vegan and Mediterranean diets may reduce your risk or improve therapy. People with cancer are often recommended to eat a healthy, balanced diet to maintain their quality of life and achieve optimal health outcomes.