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Nutrition Effects of Chemotherapy

More than 1.2 million people in the United States are diagnosed with cancer every year (Brown). Chemotherapy is a commonly used treatment for cancer patients that uses powerful mixtures of drugs to eliminate fast growing cells in the body, and prevent cancer cells from multiplying. While chemotherapy effectively mitigates cancer cells as the drugs travel through the body, normal, healthy cells can also be damaged in the process (“Chemotherapy.”). This elimination of healthy cells leads to side effects; many we may be familiar with, like hair loss and fatigue, but there are many less commonly known side effects, such as dry mouth and appetite loss.

Each chemotherapy drug and therapy sequence has different effects, and some patients will experience ill effects, many others will experience none. There is not one way to predict how each individual might react during treatment, so, appropriate medical attention throughout treatment and individualized recommendations are necessary to help mitigate ill effects. One category of chemotherapy side effects are gastrointestinal and nutrition related, and include: nausea, vomiting, diarrhea, constipation, taste changes, dry mouth, mouth sores, poor appetite, early satiety, and fullness (“Nutrition in Cancer Care”). These can have an effect on a person’s weight, body composition, ability to get all necessary nutrients and calories, interest in food and eating, and overall quality of life. In fact, malnutrition among cancer patients receiving chemotherapy is very high, around 40-80% (Vergara). Malnutrition can range from anywhere between mild to severe. Taking care of your body through a nutritious diet is always important, but especially when your body is fighting cancer and receiving aggressive chemotherapy treatments. Getting adequate calories, vitamins, minerals and nutrients allows your body to function at its optimum capacity, which is necessary to ensure that the treatment has the highest chance of attacking the cancer cells present. A closer look at these side effects, and their frequency and severity, will better show just how important keeping good care of your nutrition is during this time, and how adding, removing and changing specific diet and eating patterns can be beneficial.

Nutritional Side Effects

The main gastrointestinal side effects affecting chemotherapy patients are chemotherapy induced nausea and vomiting, constipation, and diarrhea (Mardas). In particular, nausea and vomiting are two of the most serious side effects that occur in 80% of chemotherapy patients (Lavdaniti). On top of causing a decrease in quality of life, and risk of non-compliance with treatment, nausea and vomiting can cause nutritional deficiencies, anorexia, mental distress and esophageal tears. Nausea and vomiting in chemotherapy patients can be classified into multiple groups. Acute is nausea and vomiting occurring in the first 24 hours after receiving treatment, while delayed onset occurs 24 hours or more after treatment. Anticipatory nausea occurs right before a new cycle of chemo is administered. This is often caused by classical conditioning and the thought of getting ill later. Chemotherapy naturally produces nausea when paired with conditioned stimuli, like sight or smell of the room, seeing the doctors and nurses or the needles that administer the drugs (“Nutrition in Cancer Care”). The likelihood that one suffers these side effects is based on many factors: such as location of tumor, type of drug, age (younger than 50 are more likely), gender (women are more likely), as well as past nausea and vomiting experiences with chemotherapy (“Nutrition in Cancer Care”). Additionally, diarrhea and constipation are also gastrointestinal side effects of chemotherapy. Constipation can be caused directly by the chemotherapy drugs, as well as change in diet and being less active. Diarrhea can be caused by cancer itself, as well as chemotherapy, and can lead to dehydration and malnourishment (“Side Effects of Cancer Treatment.”). Again, these are of utmost concern given that they can prevent the patient from being able to adequately fight the illness.

Two other common nutritional side effects of chemotherapy are taste changes and appetite loss. Taste changes are linked to the alteration of taste cell receptors, as well as drug secretions into saliva. Taste changes can lead to reduced appetite, weight loss, and malnutrition. It can also affect your relationship with food, through avoidance of eating in social settings and altered diet patterns (Boltong, Anna, and Russell Keast). In a study done of adults receiving chemotherapy as their main cancer treatment, the perception of sweet, salty and bitter did not change, but sour taste had an increased intensity. Overall, those same patients showed a decrease in general liking of foods when chemotherapy was finished. The most commonly disliked foods were caffeinated drinks, red meats, and citrus fruits (Boltong, Anna, and Russell Keast). Appetite loss is a combination of many other side effects including taste changes, nausea and vomiting, fatigue, and dry mouth and mouth sores, and can also lead to nutritional deficiencies and malnutrition (“Nutrition in Cancer Care”).

The last main side effects that can have an effect on nutritional status of chemotherapy patients are mouth sores and dry mouth. Mouth sores are often a result of the strong chemotherapy drugs affecting the healthy cells in your mouth. The cells are therefore unable to fight off infections and bacteria, and mouth sores occur (“Managing Mouth Sores.”).These sores can make it difficult to eat, as certain foods can irritate and increase the pain of the sores. Dry mouth, also called xerostomia, can also occur in chemotherapy patients, usually due to irritation to the salivary glands. Having a dry mouth, and lack of saliva can make it harder for patients to swallow, making eating and drinking certain foods challenging (“Managing Mouth Sores.”).

Managing the Side Effects

Diet and eating strategies:

While the many side effects mentioned above can seem overwhelming, it is important to remember there is no guarantee a patient will suffer from any or all of them, as chemotherapy has such varying effects on individuals. The good news is the side effects mentioned above can be managed through specific diet recommendations and eating strategies, supplements, medications and with the help of registered dietitians and doctors.

Firstly, there are many diet and eating strategies that can help to alleviate and get through some of these side effects. There are many ways to manage nausea and vomiting. Eating bland, dry foods and avoiding food and drinks with strong odors, as well as greasy foods can be a good strategy to help mitigate these effects. The temperature of food can also affect nausea, and it is best to let food cool or choose cold foods. Nausea can be heightened by an empty stomach, so eating small, appealing foods throughout the day is best. Lastly, drinking enough fluid is very important, to keep hydrated. To manage diarrhea, drinking plenty of liquid to replace lost fluids is also key, as well as avoiding high fiber and high sugar foods, greasy foods, alcohol and spicy foods. Lastly, if constipation is an issue, increasing your activity level, even if it’s just walking and keeping up your fluid intake will be helpful (“Nutrition in Cancer Care”).

To combat taste changes and appetite loss, focus on eating foods you still enjoy and foods that appeal to your sense of smell, eat small portioned nutritious foods throughout the day, try to be active to increase appetite and eat foods that are nutrient dense. Eating strategies for mouth sores and dry mouth include choosing easy to chew and swallow foods and avoiding citrus and spicy foods, which can irritate the sores. For dry mouth in particular, focus on eating moist foods, and drinking non-sugary fluids (“Nutrition in Cancer Care”).

These dietary changes can seem daunting to make all at once, which is where a registered dietitian can become an integral part of the team. Dietitians can monitor patients for malnutrition, create diet plans that work with your side effects, needs and preferences, recommend meals and recipes, and set nutritional goals. Working with a dietitian can help to ensure your nutrition status is in the best standing, to keep you strong, reduce complications and increase your quality of life during and after chemotherapy (Hinson).

Supplements and Medications

Exploring supplements and medications may be beneficial in conjunction with dietary modification and strategies. To further combat nausea and vomiting, ginger supplements have been proven to help. In a study (Yekta) conducted of 80 women undergoing chemotherapy for breast cancer, half the patients were blindy given a placebo pill, while the other half were given a ginger supplement 250mg Zintoma, a capsule made from ginger root powder. All the patients received the pills every 6 hours, combined with antiemetic medication (anti-nausea medication). The instances of vomiting in the group taking the ginger supplements and medication were significantly lower than those of the group taking the placebo pill and medication (Yekta). In another study (Ryan) of 576 cancer patients undergoing chemotherapy treatment, patients were randomly assigned placebo pills, 0.5g of ginger, 1g of ginger and 1.5g of ginger in addition to antiemetic medication. The study concluded that all doses of ginger had a significant reduction in acute nausea severity, and the largest reduction with 5g and 1g of ginger supplement (Ryan). While ginger may not be a miracle worker, and should still be combined with doctor recommended medications, it may be beneficial to try supplements and even ginger teas.

Another way to supplement your nutrition during chemotherapy is through supplemental beverages. If you are not consuming enough energy to meet your needs, nutritional drinks like Ensure, can be easier to get down than food, and pack enough nutrients and calories to equal a meal. These can be drunk cold, which tends to be easier to get down if dealing with taste changes and nausea. Supplemental drinks can not only be used as a meal replacement but also in between meals to help boost nutritional status or be drunk throughout the day if early satiety is a side effect (“Nutrition in Cancer Care”). Talk with a dietitian if you feel supplemental beverages would be beneficial to your chemo care, for advice on which brands and how often they should be utilized.

You may believe during chemotherapy is a great time to experiment and up your herbal supplement and vitamin and mineral intake to maximize your health, but the opposite is actually true. Unless specific vitamins and herbs are recommended by your doctor, for things like nutritional deficiencies, it’s best to focus on getting all your vitamins and minerals from whole food sources. Herbal supplements can also interfere with prescription medications (Adams). Supplements are also not regulated by the FDA so you can never be fully confident what the bottle says you are taking is accurate. It is best to consult with your doctor and dietitian before taking any herbal or vitamin and mineral supplements you feel would be beneficial to you.

Lasty, as mentioned briefly before, there are prescribed medications that can help relieve the discomfort of many of these chemotherapy nutritional side effects, like nausea, mouth sores, dry mouth, and even appetite changes. Expressing your concern with your doctor and allowing them to recommend and prescribe the best medication for you is the best approach.

Bottom Line

While going through chemotherapy is no doubt challenging, treating your body with care, by feeding it nutritious foods will help your body fight during and after treatment. Remember that everyone experiences chemotherapy differently, and everyone deals with the side effects differently. Be sure to reach out to resources, like dietitians and your medical team as you are not fighting alone, and they can be extremely beneficial in helping to manage your nutrition related side effects to keep you on track to your healthiest self.

Written by Carley Higgins on behalf of Supriya Lal, RD


Adams, Molly. “Should You Use Dietary Supplements during Cancer Treatment?” MD Anderson Cancer Center, MD Anderson Cancer Center, 5 June 2019,

Boltong, Anna, and Russell Keast. “The Influence of Chemotherapy on Taste Perception and Food Hedonics: A Systematic Review.” Cancer Treatment Reviews, vol. 38, no. 2, 2012, pp. 152–163., doi:10.1016/j.ctrv.2011.04.008.

Brown, J., et al. “Nutrition during and after Cancer Treatment: A Guide for Informed Choices by Cancer Survivors.” CA: A Cancer Journal for Clinicians, vol. 51, no. 3, 2001, pp. 153–181., doi:10.3322/canjclin.51.3.153.

“Chemotherapy.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 5 Mar. 2020,

Hinson, John. “What Is an Oncology Dietitian?” SE Radiation Oncology Group, John Hinson Https://, 12 Apr. 2018,

Lavdaniti, Maria, and Nikolaos Tsitsis. “Investigation of Nausea and Vomiting in Cancer Patients Undergoing Chemotherapy.” Health Psychology Research, vol. 2, no. 3, 2014, doi:10.4081/hpr.2014.1550.

“Managing Mouth Sores.” Managing Mouth Sores: Chemotherapy and Prostate Cancer - UCLA Urology,

Mardas, Marcin, et al. “Link between Diet and Chemotherapy Related Gastrointestinal Side Effects.” Współczesna Onkologia, vol. 2, 2017, pp. 162–167., doi:10.5114/wo.2017.66896.

“Nutrition in Cancer Care (Pdq®)–Health Professional Version.” National Cancer Institute,

Ryan, Julie L., et al. “Ginger (Zingiber Officinale) Reduces Acute Chemotherapy-Induced Nausea: A Urcc Ccop Study of 576 Patients.” Supportive Care in Cancer, vol. 20, no. 7, 2011, pp. 1479–1489., doi:10.1007/s00520-011-1236-3.

“Side Effects of Cancer Treatment.” National Cancer Institute,

Vergara, Nunilon, et al. “Quality of Life and Nutritional Status among Cancer Patients on Chemotherapy.” Oman Medical Journal, vol. 28, no. 4, 2013, pp. 270–274., doi:10.5001/omj.2013.75.

Yekta, Zohreh, et al. “Ginger as a Miracle against Chemotherapy-Induced Nausea.” Iranian Journal of Nursing and Midwifery, vol. 17, no. 5, July 2012.

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