You are born with 9,000 taste buds, which work in tandem with your sense of smell as your sense of taste relies primarily on odors. Your sense of smell and taste change as you age. Between the ages of 40 and 50, the number of taste buds decreases, and the rest begin to shrink, losing mass vital to their operation. After age 60, you may begin to lose the ability to distinguish the taste of sweet, salty, sour, and bitter foods. The sense of smell does not begin to fade until after the age of 70; its decrease exacerbates the loss of taste for those affected. The exact cause of these changes is up for debate.