This study will explore the genetics of taste and taste deficits. The sense of taste plays a
crucial role in food choices, allowing people to identify beneficial foods (those with high
caloric value, which are typically sweet) and foods likely to be toxic (usually bitter
substances). The loss of sense of taste in older people plays a role in decreased appetite
and poor nutrition. Taste deficits may adversely affect people in ways that are not well
understood. This study will examine why some people (about one-fourth of all people in the
United States) cannot taste a substance called phenylthiocarbamide (PTC). The inability to
taste PTC is due to inherited factors that are not yet clear.
Individuals age 18 and older who can taste PTC and individuals who cannot taste PTC may be
eligible for this study. Participants will taste a number of liquid solutions until they
find one with a clear taste. Then they will taste another group of solutions and decide
which ones have that taste and which have no taste. Finally, they will taste a third group
of solutions until they find one with a different taste. About 2 tablespoons of blood will
be drawn from participants for genetic tests related to the sense of taste.
The primary goal of this study is to identify the underlying cause of deficits in the
ability to taste different commonly consumed substances, including the bitter compound
phenylthiocarbamide (PTC) as a model. Individuals will be tested to identify those who can
and cannot taste PTC, as well as for their ability to taste a variety of sweet, sour, salty,
and savory substances. Individuals will have 20 cc of blood drawn to obtain DNA. These DNA
samples will then be analyzed for variation in genes whose products are known to be involved
in taste perception pathways. Information about individuals DNA sequence variation will then
be correlated with their taste phenotype to identify the specific genetic variation that
causes phenotypic variation, providing molecular structure-function information in taste
- INCLUSION CRITERIA:
- Individuals age 18 years and older.
- Subjects must be medically healthy, with no cognitive impairment or physical
swallowing inability or impairment
- Must be able to provide informed consent
- Must be able to read and understand English.
- NIH employees or staff may participate in this study if they meet the eligibility
- Cannot be younger than 18 years of age
- Subjects with suspected or known cognitive impairment or physical swallowing
inability or impairment
- Subjects who are unable to provide informed consent
- Subjects who are taking any pyschoactive medications or medications that affect their
nervous system, such as antidepressants or anti-psychotics.
- Subjects who have known problems with these sense of taste
- Subjects who are currently using tobacco