A process that involves the cells of your tongue and nasal passages causes the smell of food to affect taste. The conjunction of the senses of smell and taste allows your brain to define a food’s flavor. Certain lifestyle choices, vitamin deficiencies and illnesses can decrease your perception of flavor.

Flavor

Your brain perceives the singular sensation of flavor as a combination of a food's actual taste, smell and texture, according to the "Scientific American" website. A food's actual taste refers to the sensations that the cells in the taste buds are capable of detecting. These tastes are bitter, salty, sour and sweet. Sensory cells near the taste buds perceive textures of the food or drink, such as creaminess, spiciness and temperature.

Experimenting With Smell and Taste

The openings of your nasal passages contain the cells that perceive smell. These smell cells relay information to the mouth via olfactory referral. The "Scientific American" explains the phenomenon of olfactory referral by describing an experiment in which you hold your nose while chewing a strawberry jellybean. You will detect sweetness and sourness as your taste buds make contact with the jellybean, and your sensory cells will perceive a hard then soft feeling as you chew the jellybean. The sense of smell is absent because you temporarily block the flow of air through the nasal passages. Let go of your nose to allow the odor molecules from the jellybean to travel through your nasal passage to the cells that perceive smell. At this point you should perceive the strawberry flavor of the jellybean.

Taste Impairment

Your perception of flavor may be less keen if you smoke heavily, because of cigarette tar‘s potential to impair the taste buds. A deficiency of zinc or vitamin B-12 can also impair your sense of taste. Those who quit smoking eventually gain a better perception of flavor. Consult your doctor if you suspect a deficiency of vitamin B-12 or zinc as the cause for an impaired sense of taste.

Illnesses and Taste

Illnesses can also impair your sense of taste and your ability to perceive flavor. These illnesses can include a cold or the flu, gingivitis, a nasal infection, nasal polyps, sinusitis, strep throat and infections of the salivary glands. Your normal sense of taste will return once your illness passes. Always seek medical attention and follow prescribed treatment methods for your condition.