Inflammation, driven by obesity, may reduce the number of taste buds on the tongue by 25 per cent, while affecting a person's sensitivity to the taste of food, researchers have found. Obesity is known to be associated with a chronic state of low-grade inflammation in the adipose tissue that stores energy in the form of fat. The adipose tissue further produces pro-inflammatory cytokines - molecules that serve as signals between cells - including one called TNF-alpha. Researchers noted that a high-fat diet increases the level of TNF-alpha surrounding the taste buds, making them less sensitive to the taste of food. "Our findings suggest that gross adiposity stemming from chronic exposure to a high-fat diet is associated with a low-grade inflammatory response causing a disruption in the balancing mechanisms of taste bud maintenance and renewal," said Robin Dando, Assistant Professor at the Cornell University in the US. A taste bud comprises of approximately 50 to 100 cells of three major types, each with different roles in sensing the five primary tastes (salt, sweet, bitter, sour, and umami). Taste bud cells turn over quickly, with an average lifespan of just 10 days. The turnover of taste bud cells normally arises from a balanced combination of programmed cell death (a process known as apoptosis) and generation of new cells from special progenitor cells. The study, published in the journal PLOS Biology, observed that the rate of apoptosis increased in obese mice, whereas the number of taste bud progenitor cells in the tongue declined, likely explaining the net decline in the number of taste buds.