Of the five senses, taste and smell are very closely related. To perceive a smell, molecules float into the nose and bind to tiny hairs called cilia, triggering neurons that pick up the odour. Taste buds on the tongue have taste cells that sense primary flavours. Occasionally, people experience heightened senses of taste or smell, making them more sensitive to flavours and odours.
During pregnancy, heightened levels of oestrogen and progesterone are responsible for many changes in the body. Women may experience both heightened sense of smell and taste. Heightened sense of taste during pregnancy is known as dysguesia. Dysguesia differs from the cravings or aversions that women may experience. This heightened sense of taste comes from changes in taste bud structure that causes women to experience tastes differently, making certain tastes, such as bitter flavours, much more acute.
Dysguesia may be due to the heightened sense of smell that women also experience during pregnancy. Higher levels of oestrogen can make even the slightest smells seem overwhelming. Heightened sense of smell is experienced by all women during pregnancy, and can be a primary contributor to morning sickness.
Body mass index
Body mass index may be a contributor to heightened sense of smell. People with a larger body mass index have a much higher sense of smell compared to those with a BMI in the normal range. This heightened smell may be the reason that people continue to eat even after they are full, leading to obesity. Obesity can also be linked to a heightened sense of taste, as foods that are high in sugar and fat pack strong flavours. This craving for flavourful junk foods is due to dysfunction of opipoid receptors in the brain that drive the palatability of foods.
Prolonged stress can contribute to heightened sense of smell. Sense of smell can also become more acute following an accident, injury or operation. This is triggered by our most innate survival instincts. When we are subject to prolonged stress, our adrenal glands kick into overdrive. That stress and fatigue can cause increased sensitivity to offensive odours, perfumes and even pheromones. Once the stress subsides and the adrenal glands have time to heal, sense of smell can return to normal.
While taste disorders are typically associated with the loss of taste, a taste disorder that heightens your sense of taste is a problem that affects around 25 per cent of the population. These people are known as supertasters. Affecting women more than men, supertasters experience such strong tastes that foods like coffee, alcohol, tomatoes, desserts, Parmesan cheese, green vegetables and certain condiments are unpalatable. Supertasters detect spicy, salty and bitter flavours that others cannot typically detect in foods. This is due to a greater density of taste buds. Supertasters have 10 to 100 more taste buds than the average person.