Cancer patients who experience taste and smell loss because of disease or treatment are at high risk for weight loss and nutritional deficits that can compromise their overall treatment success, according to study results presented at the annual meeting of the Association of Chemoreception Sciences (U.S.). The small study involved 33 lung cancer patients.

Although not all cancer patients lose weight with the disease, those who do so tend to have a poorer prognosis for treatment outcome and long-term survival, said Jennifer Garst, M.D., study coauthor. The research team is continuing the study to explore whether the addition of flavor-enhancing powders, derived from actual foods such as cheese, bacon, garlic and fruits, can improve appetite.

"Weight loss has long been a hallmark of cancer, but it has been considered an inevitable byproduct of the disease process and chemotherapy drugs, rather than as a treatable symptom that can affect outcomes," said Susan Schiffman, Ph.D., study presenter. "If we can show that taste and smell deficits are responsible for the weight loss in a specific population of patients, then we can intervene and potentially improve patient outcomes."

More than just a nuisance, taste and smell deficits have been associated with reduced levels of T-cells and B-cells in elderly patients, said Schiffman.

In previous studies conducted by Schiffman, elderly patients who ate foods enhanced with powdered flavors like beef, bacon, and cheese showed significantly higher levels of B-cells and T-cells than when they ate the same foods without enhancers.

The causes of appetite and taste loss are many, said Garst. Chemotherapy drugs are known to alter taste and smell by blunting the normal turnover rate of taste and smell receptors on the tongue and in the nasal passages. Radiation treatments can also damage taste and smell receptors, giving food a metallic flavor. Tumors themselves may also secrete a protein that suppresses appetite.

Although certain drugs can improve appetite and taste sensation, some of them - such as the steroids - carry their own risks and unwanted side effects. The current study was designed to measure the impact of taste and smell deficits on patients and to investigate a non-drug alternative to make food more appealing.

In the study of 33 lung cancer patients undergoing chemotherapy, the researchers assessed the patients' own perceptions of taste and smell deficits, then scored their ability to detect and recognize odors and flavors presented to them in a laboratory. Patients who reported the lowest degree of taste and smell ability and who scored the lowest on the psychophysical measurements, also experienced the most weight loss, body-mass loss and nutritional deficits.

Half the patients were then given powdered flavor enhancers - extracts of natural foods combined with amino acids -- that strengthen the smell and taste of foods. The remaining patients received no enhancers. All patients received nutritional advice and worksheets explaining what foods help to alleviate dry mouth, constipation, diarrhea, and other treatment side effects.

As the study continues, the team hypothesizes that the patients who receive flavor enhancers will lose less weight and show higher immune status at their eight-month checkup than patients who do not receive flavor enhancers.

"As oncologists, we can become so focused on the medical treatments of the disease that we overlook the importance of factors like weight loss and nutritional status. Both of these factors have a huge impact on quality of life and long-term survival," said Garst. "The patients themselves are very excited about this study because it improves the pleasure they derive from food and it can positively impact performance status."