Zinc Supplements for Taste Changes During Treatment

 

Review of Cancer 1998;82(10):1938-45.

A study published in the journal Cancer looked at using dietary zinc supplements to help decrease taste changes that can occur during radiation therapy for head and neck cancer. The results of this study tell us that a dietary zinc supplement, given at a dose of 45 mg of zinc three times each day, can decrease taste changes in head and neck cancer patients who are receiving radiation therapy. This article review discusses the findings of this study. We provide PRACTICAL information on what these findings mean, including information on safety concerns when using higher doses of dietary zinc supplements. Radiation therapy for head and neck cancer can result in numerous side effects including unpleasant taste changes. Dietary approaches that can be used to address these side effects will help individuals to tolerate their treatments better and improve their quality of life. It is hoped that this will result in more successful treatment of their disease.

Note: Numbers appearing at the end of sentences indicate research references. References are listed at the end of each article.

Background

One of the most common side effects from all types of cancer treatments is unpleasant taste changes (1). This can include loss of taste, as well as unusual and unexpected taste sensations, such as metallic or overly sweet tastes. In people being treated with radiation for head and neck cancer, taste changes occur nearly 100% of the time (2). This is a serious problem because taste changes can prevent people from eating well during cancer treatment. As many as 20 to 40% of all cancer deaths are related to malnutrition, so anything that interferes with eating during treatment must be addressed (3-7)!

Using dietary zinc supplements to help treat taste changes makes sense. This is because research tells us that having enough zinc in the diet is important for having a normal sense of taste in all people (8,9). A study published in the journal Cancer looked at the possible benefits of using dietary zinc supplements to help treat and prevent the unpleasant taste changes that can occur during radiation treatment for head and neck cancer (10). It is hoped that this type of research will help individuals diagnosed with head and neck cancer to tolerate their treatments better and improve their quality of life, which in turn may result in more successful treatment of their disease.

What The Researchers Studied

Eighteen people who had been diagnosed with a head and neck cancer and who were scheduled to receive radiation therapy participated in this study. These people were randomly assigned to receive either 45 mg of elemental zinc or a placebo tablet, three times each day. This means that 9 people received the zinc supplement and 9 people received the placebo. For this study, the placebo looked just like the zinc supplement, but it did not contain any zinc or other active ingredients.

None of the study participants or the researchers knew whether they were receiving the real zinc supplement or the placebo. Information on other important health factors, including type of disease body weight and weight loss, gender, and alcohol and tobacco use was collected and accounted for in the study.

The participants were instructed to begin taking their tablets at the first sign of changes in their sense of taste. By the fourth week of radiation treatment, all of the people in the study (100%) had begun using the tablet (either the zinc supplement or the placebo). The participants continued taking the tablet, three times each day, for one month after the end of radiation treatment.

What The Study Found

First, the researchers found that sense of taste already was impaired before the study even started. In other words, before the people began receiving radiation therapy, they had some trouble with their sense of taste. This was true for all of the people in the study.

Second, the researchers found that 100% of the people in the study reported experiencing taste changes at least once during treatment.

Third, the researchers found that the people who received the placebo (did not receive the zinc) had significantly greater worsening of their sense of taste when compared to the people who received the zinc supplement. In other words, taking zinc seemed to decrease how much the radiation affected sense of taste.

Finally, the researchers found that the people who received the zinc supplement had quicker recovery of their sense of taste after treatment ended. In other words, taking zinc seemed to help people recover their sense of taste faster.

What do these results mean?

If the people in this study are similar to most people who are receiving head and neck radiation treatment for cancer, this study tells us that taking 45 mg of elemental zinc, three times a day during treatment can decrease the unpleasant taste changes that commonly occur in these people.

This study does have some weaknesses. The biggest drawback to this study is size. Eighteen participants in a study are not very many. It is hard to know if these same results would hold up in a larger, more comprehensive study.

However, an important strength of this research is that the study was 'blinded'. This means that nobody knew if they were receiving the active zinc treatment or the placebo pill. In order for a treatment to be considered effective, it must provide better results than a placebo. This study met this important condition.

As well, getting enough zinc in the diet is related to sense of taste in all people, so it makes sense that adding extra zinc may help people recover sense of taste, especially if they are not eating well due to cancer and it's treatment. And other studies on this topic tell us that in people who may be low in zinc for a variety of medical reasons, adding zinc can help restore sense of taste (11-13).

In summary, despite the small size of this study, it provides important information regarding the role of zinc supplements for minimizing unpleasant taste changes during radiation treatment for head and neck cancer.

Should you use zinc supplements?

First, before you decide to take any dietary supplements, please discuss this with your doctor and your entire health care team. Some dietary supplements can interfere with medications that are used to treat cancer. For this reason, be sure you talk to your doctor BEFORE you start taking zinc or any other dietary supplements.

Second, when it comes to zinc supplements, more is not necessarily better. In order to get benefit and improve sense of taste, you need to take more zinc than you can get from diet alone. However, you should not take these higher doses of zinc long-term.

If you are going to use dietary zinc supplements, do not use them for longer than two to three months. S hort-term zinc supplementation can improve sense of taste. However, l ong-term zinc supplementation can DECREASE immune function. Also, too much zinc over the long-term can interfere with how your body absorbs and uses other nutrients.  For these reasons, use zinc supplements for two to three months total and no longer than this.

If you want to take a dietary zinc supplement, please keep the following points in mind:

  • The dose of zinc used in this study was 45 mg of elemental zinc, taken three times per day.
  • Most zinc supplements come with the zinc in a form other than elemental zinc. The most common form is zinc sulfate.
  • In order to receive 45 mg of elemental zinc, you will need to take about 200 mg of zinc sulfate. To summarize: 45 mg elemental zinc = 200 mg zinc sulfate.
  • Different forms of zinc may be absorbed differently in your body. Therefore, if you want to try this approach, it is best to stick with the form of zinc that was studied. This is zinc sulfate.
  • Talk to your health care team before you start taking zinc supplements or any other dietary supplement.

Total Approaches For Addressing Side Effects

If you are receiving head and neck radiation treatment, taking a zinc supplement may noticeably help with your sense of taste. But, whether or not you take a dietary zinc supplement, remember that there are many, many ways you can help yourself feel better during cancer treatment. Along with dietary zinc supplements, use the following tips to help yourself as healthy as you can during head and neck cancer treatment:

  • When it comes to cancer treatment, the first thing to remember is that if you have side effects from treatment, discuss it with your medical care team!
  • Do not suffer in silence! Talk, talk, talk to your nurse or doctor about options to feel better during treatment.
  • While some side effects are difficult to avoid, others can be treated very successfully with different types of medical and lifestyle approaches.
  • Even if your medical care team has prescribed medications for symptoms, there may be other options that will work better. Don't be afraid to ask for more help if you need it.
  • Use all the help you can get. If you have questions about symptoms, meet with your doctors, nurses, social workers, dietitians, support groups, pharmacists, or whomever else you need to help you formulate a plan to feel better. Each of these different care providers specializes in different approaches to wellness. A combination of approaches, for example medications, plus diet changes and relaxation techniques, is usually best.

Finally, eat as well as you can during treatment! This will help you feel better and heal faster.

NOTE: If you are in cancer treatment, these diet changes may not be right for you. Vitamins, minerals and other nutrients can interfere with your cancer treatments! Please discuss your nutrition needs with your health care team.

References

1. Grosvenor M, Bulcavage L, Chlebowski RT. Symptoms potentially influencing weight loss in a cancer population. Correlations with primary site, nutritional status, and chemotherapy administration. Cancer. 1989;63(2):330-334.

2. Mossman KL. Gustatory tissue injury in man: radiation dose response relationships and mechanisms of taste loss. Br J Cancer. 1986;(suppl 7):9-11.

3. Ottery FD. Pharmacologic management of anorexia/cachexia. Semin Oncol. 1998;25(2 suppl 6):35-44.

4. Ottery FD. Definition of standardized nutritional assessment and interventional pathways in oncology. Nutrition. 1996;12(suppl 1):S15-S19.

5. Ottery FD. Supportive nutrition to prevent cachexia and improve quality of life. Semin Oncol. 1995;22(2 suppl 3):98-111.

6. Ottery FD. Rethinking nutritional support of the cancer patient: the new field of nutritional oncology. Semin Oncol. 1994;21(6):770-778.

7. Ottery FD. Cancer cachexia: prevention, early diagnosis, and management. Cancer Pract. 1994;2(2):123-131.

8. Mahajan SK, Prasad AS, Lambujon J, Abbasi AA, Briggs WA, McDonald FD. Improvement of uremic hypogeusia by zinc: a double-blind study. Am J Clin Nutr. 1980;33(7):1517-21.

9. Henkin RI, Patten BM, Re PK, Bronzert DA. A syndrome of acute zinc loss. Cerebellar dysfunction, mental changes, anorexia, and taste and smell dysfunction. Arch Neurol. 1975;32(11):745-51.

10. Ripamonti C, Zecca E, Brunelli C, Fulfaro F, Villa S, Balzarini A, Bombardieri E, De Conno F. A randomized, controlled clinical trial to evaluate the effects of zinc sulfate on cancer patients with taste alterations caused by head and neck irradiation. Cancer. 1998;82(10):1938-45.

11. Atkin-Thor E, Goddard BW, O'Nion J, Stephen RL, Kolff WJ. Hypogeusia and zinc depletion in chronic dialysis patients. Am J Clin Nutr. 1978;31(10):1948-51.

12. Hambidge KM, Hambidge C, Jacobs M, Baum JD. Low levels of zinc in hair, anorexia, poor growth, and hypogeusia in children. Pediatr Res. 1972;6(12):868-74.

13. Henkin RI, Schecter PJ, Friedewald WT, Demets DL, Raff M. A double blind study of the effects of zinc sulfate on taste and smell dysfunction. Am J Med Sci. 1976;272(3):285-99.

Publish Date: 08/2004

This content was last reviewed August 15, 2010 by Dr. Reshma L. Mahtani.
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