The Science of Taste

Why do we need taste?

Survival: Taste is one of the body’s senses. Its fundamental role is to allow us to get nutrients and survive by sampling the chemical makeup of foods and beverages for nutrient content, palatability and potential toxicity.

Appetite regulation: Taste also guides our appetites and triggers physiological processes for absorbing nutrients and adjusting metabolism.

Enjoyment and meaning: As one aspect of flavour alongside smell, our sense of taste plays a role in our enjoyment of food, cultural identity and social connection, making it an important aspect of our daily lives.

How do we taste food?

1. Taste buds in the mouth

When we eat, chewing and saliva help break down the food into various chemical compounds. These compounds, called tastants, are sensed by taste buds on the tongue, soft palate, pharynx and gut. (Roper et al. 2017)

Zoom in: Each taste bud has its own specialised squad of 50 to 100 taste cells, arranged in clusters that look a bit like a garlic bulb. Each taste cell is a sensory receptor dedicated to sensing specific food compounds that produce one of the five basic tastes:

• Sweet signals the presence of simple carbohydrates
• Sour signals the presence of acidic substances, such as citric acid and acetic acid, commonly found in fruits
• Salty signals the presence of sodium
• Umami signals the presence of some amino acids, notably glutamate, associated with protein
• Bitter is associated with a variety of plant alkaloids and glycoside compounds.

2. To the brain!

Information from taste buds is conveyed to neurons in the central nervous system. How signals discriminating between sweet, sour, salty, bitter, umami and possibly other tastes are encoded is not entirely known and subject of debate. (Roper et al. 2017)

But it’s more complex than that….

More than 5 tastes?

• Fat may also be a taste: Growing evidence for fat receptors suggests that fattiness may also be categorised as a basic taste. (Hichami et al. 2021)
• Spicy is not a basic taste: Compounds in foods like chilli peppers or black peppers activate nociceptors in the mouth that cause irritation and/or pain.

Taste buds in the gut: Taste receptors are present not only in the mouth but in the gastrointestinal tract and many other organs in the body. They are involved in adjusting digestive processes and metabolism, like the speed of gastric emptying or the regulation of blood glucose levels. (Ekstrand et al. 2017)

Why do we all taste food differently?

Emerging research suggests that genetic predisposition and non-genetic factors such as life stage, eating behaviour and microbiota influence our taste perception.

1. Our genes

Variations in the genes encoding taste receptors can influence our perception of taste and food preferences.

Bitter taste: You might have heard of so-called “super-tasters” who intensely taste bitter compounds. That’s because they carry two copies of the tasting PAV variant (genotype PAV/PAV). People carrying one copy of the tasting variant are medium-tasters, while non-tasters carry two copies of the non-tasting variant called AVI.

Umami taste: There is evidence that differences in the perception of umami are common among individuals, with variations up to five-fold. Similar to bitter taste perception, a fraction of the population may carry “non-taster” gene variants for umami, but more research is needed.

Sour taste: One study suggests that genetic factors may be more important than environment to determine the pleasantness and intensity of sour taste. (Chamoun et al. 2021)

Eating behaviour: People with a higher sensitivity to bitter taste may avoid eating bitter-tasting foods such as cruciferous vegetables and leafy greens, which provide many health-promoting compounds.

2. The community of microbes in our mouth

Variations in the composition of microbes in the mouth may also underlie differences in how we taste food. This research is just emerging and ongoing!

Zoom in: The mouth hosts hundreds of microbes, making it the second most diverse microbiota of the human body after the gut. The tongue, especially, forms a unique site for the accumulation of saliva and microorganisms.

Taste perception & oral bacteria: In recent years, several studies have built up evidence for a close association between taste perception and specific oral bacteria. In some research, the presence of specific bacteria in the tongue film was linked to an increased taste sensitivity, especially to bitterness. For example, super-tasters and non-tasters had different microbial compositions in the tongue. (Cattaneo et al. Scientific reports. 2019)

How? Researchers suggest that microbes in the mouth may influence taste perception and food preferences through multiple mechanisms:

(1) By degrading food compounds and producing secondary metabolites

(2) By creating a physical barrier through biofilm formation that can limit the access of tastants to their receptors.

(3) By regulating the expression of taste receptors genes

3. Environment & Exposure

On top of biological predispositions, our environment and exposure to different foods can influence taste perception. One study found that frequent exposure to sweetened soft drinks changed sweet taste perception and increased the preference for sweet among individuals who originally disliked sucrose. A twin study demonstrated that environment was more influential than genetics on salt taste. (Kershaw et al. 2018)

How can we train our taste buds?

Our taste system is changeable and subjective to learning and experience.

• The transient life of taste cells: Although the sense of taste is already developed very early in life, there is a permanent renewal of taste cells throughout life. Taste cells have an average life span of 10 to 14 days – so about 10% of taste cells are renewed in each taste bud every day. That’s because the tongue is incomparably affected by external and internal stimuli. (Rohde et al. 2020)
• Throughout life: From childhood to adulthood, our taste buds evolve. In adulthood, environmental and/or cultural experiences rather than genetic predispositions appear to be more correlated to taste perception and eating behaviour. (Chamoun et al. 2017)

Why develop our tasting skills

• Enjoyment and meaning: By paying attention to the various tastes and flavours of food, we fully engage in the sensory experience of eating and enjoying food. Slowing down to savour a delicious meal and experience its nuances can create moments of happiness and contentment – an opportunity to be fully present and cultivate inner peace.
• Health and well-being: The senses of taste and smell are essential determinants of food choice, which contributes to long-term health. We are slowly shifting our focus from rigid understandings of health to engaging with taste and the sensory experience of eating, opening up space for individuality and making life more meaningful. Research found that taste-focused labelling increases healthy food selection and enhances the enjoyment of nutritious options.
• Meal satisfaction: The sensory experience of taste, in concert with texture, contributes to our feeling of fullness and contentment after a meal.

Don’t let one bad experience with a food (like broccoli or mushrooms!) deter you from eating it all together. There are always more ways to eat it that might please your taste buds.

Reality check: Here are all the tips we found through research and talking to people about taste. They are general ideas to make your own and adapt depending on your needs and reality. For many, busy lives or a limited budget can challenge paying attention to taste.

1. Learn and talk about taste!

The demand for tasting educational programs is on the rise, with industries like wine, tea, coffee and chocolate leading the way. Understanding taste can create a whole new perspective on eating a meal and enhance our appreciation of food. It encourages us to explore food in different forms and preparations, beyond the simplistic notion of good and bad taste.

In practice: Explore the taste of whole plant foods too by talking taste and flavour with those around you and connecting with food enthusiasts, farms and agricultural organisations who are passionate about the vibrant flavours of fresh produce.

2. Taste exposure and variety: Try foods many times in different forms

Researchers suggest at least 10 exposures to a food before determining your true preference. It works by a process of familiarisation and learned safety. Prolonged exposure could produce physiological changes that make the foods more enjoyable. (Schier et al. 2019)

In practice:

• Start with small portions and gradually increase how much you try over time.
• Make it a regular habit to try the food or offer it to your child at least once a week, incorporating it into different meals.
• Explore different combinations and pairings.
• Remember other senses: Sight, touch and smell are not to be forgotten! Try exploring the vegetable in different forms – whole, sliced, grated, peeled, raw and cooked.

3. Positive associations: Slow down and engage

Our taste system has some degree of flexibility. Foods that are initially aversive, like bitter-tasting vegetables, can develop positive associations.

In practice:

• Connect with the process of getting, cooking and preparing the food: Appreciate who was involved in the growing process and production, the sun and soil it took to grow the food and where in the world it came from.
• Pair vegetables with enjoyable experiences: Create an enjoyable eating environment by putting away distractions, using your favourite plate or tablecloth, lighting a candle, sharing with those you love, eating outside…
• Enjoy the sensations: Pay attention to colour, texture, aroma and sounds, when cooking, preparing and eating. Eat slowly, chewing each mouthful and taste the individual ingredients and seasonings.

Special tips for children

• Frequent exposure: Offering the same foods frequently was reported to be an effective way of encouraging children to eat vegetables. Research suggests that children generally require between 5 to 10 exposure at regular intervals to increase their intake of vegetables. (Nekitsing et al. 2018)
• Engaging children in the kitchen: Encourage them to participate in meal preparation and expose them to a variety of ingredients.
• Shared taste experiences: Children learn about their food likes and dislikes by direct contact with foods, through tasting, feeling, seeing and smelling and also by observing their food environment, like the eating behaviours of others. Shared taste experiences can help them become aware of their individual tastes, while at the same time developping social skills. (Leer et al. 2018)

Sources

Taste mechanisms

• Roper et al. Nature Reviews Neuroscience. 2017
• Taruno et al. European journal of physiology. 2021
• Kinnamon et al. 2019
• Rud et al. Current Opinion in Food Science. 2023

Factors influencing taste

• Rud et al. 2023
• Schwartz et al. 2021
• Rohde et al. 2020
• Kershaw et al. 2018
• Cattaneo et al. Scientific reports. 2019

Developing taste

• Leer J, Wistoft K. Taste in food education: A critical review essay. Food and Foodways. 2018 Oct 2;26(4):329-49.
• Daniel et al. 2016