By Dr Michael Barakate and Dietitian Belinda Elwin
If you have a weakness for unhealthy foods, a distaste to vegetables (think Broccoli!), but a desire to eat better, it’s worth knowing that your palate isn’t fixed. In fact your tastebuds are actually trainable – which can be great news for your health.
How do we experience taste and what role does smell play?
Taste and smell are special senses. They provide information about the composition of our surroundings. Taste is an immediate sense – a final checkpoint for the acceptability of food before it enters the body. Smell is a more distant sense allowing us to detect small concentrations of airborne substances.
The smallest functional unit of taste are the taste buds which can be found on the tongue, as well as the back of the throat and the roof of the mouth. Each taste bud contains several taste receptor cells. Taste buds can detect sweet, sour, salty, bitter and savoury. Taste compounds interact with the tops of these specialized cells, which then transmit taste information through nerves to the brain.
The olfactory system is the sensory system used for olfaction, or the sense of smell. The olfactory bulb is a bundle of olfactory neurons. These neurons interact with the odour compounds in the nasal cavity. The neuron interacts with any odour compounds present and transduces, or converts, the odour compounds into a neural signal that then carries odour information to the brain. Unlike most neurons in your body, olfactory neurons actually regenerate throughout your lifetime. It is speculated that this is necessary since the neurons interact with environmental chemicals and can be damaged over time.
Chemesthesis relates to the sensation resulting from the physical properties of a food or beverage in the mouth, including texture and temperature. This sensation contributes to the experience of flavour. Chemesthetic sensations arise when chemical compounds activate receptors associated with other senses that mediate pain, touch and temperature perception. These chemical-induced reactions do not fit into the traditional sense categories of taste and smell. Examples of chemesthetic sensations include the burn-like irritation from chili pepper, the coolness of menthol in mouthwashes and topical analgesic creams, the stinging or tingling of carbonation in the nose and mouth, and the tear-induction of onions.
The results of many studies indicate the sensations of taste and smell interact. The way most people use the term “taste” relates to the sensations experienced when eating a food or drinking a beverage. Smell is definitely a large portion of the experience. Scientifically, taste refers to the sensations elicited by stimulation of the taste receptor cells and smell refers to the stimulation of olfactory neuron, both of which play an important role in the experiencing of foods and beverages. The term flavour relates to the combined perception of taste, smell and chemesthesis.
Is it true that we start out life with a sweet tooth (for milk) and our tastes change as we age?
Children’s taste buds are very sensitive to all flavours. For this reason, children do not need strongly flavoured foods and often will prefer food that is blander. However, children can become accustomed to foods with added sugar, salt and fat if they are exposed to it.
How our tastes change, eg. how we develop a palate for certain flavours
As we age, our number of tastebuds gradually diminishes and hence our sensitivity to different flavours decreases. This explains the use of flavour enhancers such as salt, fat, sugar and spices and why adults may prefer stronger flavours.
What can influence taste – an experience, illness, familiarity with food, ageing?
Recent studies show that an infant’s taste and food preference can be developed whilst they are still in the womb. If a mother eats a healthy diet and wider variety of food then a child is more willing to trial the same foods when they start eating solids. This also relates to the degree of a child’s fussiness when starting solids. The same can be said for foods that are high in sugar, salt and fat. So it is best to avoid those and opt for foods that are healthy for both you and your child.
The foods and flavours we were brought up with tend to stick with us into adulthood. This is why being a good role model to children is so important.
Experiences that were traumatic and associated with food will often result in food aversions due to psychological factors. For example, people who experience food poisoning are frequently put off by the same food for many years after the event.
Therapy associated taste change
The perception of taste changes for those people who undergo chemotherapy, radiotherapy and other forms of treatment. During and after therapy foods can taste metallic or extremely bland.
The taste buds can be “trained” with repeated exposure to flavour. One example relates to the use of salt as a food preservative, causing people to become accustomed to high salt levels. Because people become habituated to the taste of very salty foods, many people now prefer the salty taste.
As discussed previously, as we age, we tend to like more flavoursome foods, with a higher concentration of herbs, spices, fat, salt and sugar.
The temperature of food can make flavour more or less intense. This is why cold foods are recommended for people suffering from nausea.
Other factors can influence taste including, the time of day, gender, degree of hunger, availability, and the frequency that a food is eaten.
You can actively change your taste / tastebuds to enjoy healthier foods and like unhealthy foods less
You should know that you can definitely change your preference for certain tastes. It is thought that the taste buds regenerate approximately every two weeks. Following this theory, we should be able to alter or “retrain” our tastebuds in a couple of weeks. However, this will involve self restraint if you are used to frequently having sugary, salty, or fatty foods.
We can therefore teach ourselves to like new flavours or to change our sensitivity to sweet, salty or fatty foods. For example, we can desire them much less and be more satisfied with a smaller portion of naturally sweet foods.
Following a healthier diet will become easier the longer that we follow it and the more our tastebuds become accustomed to those foods.