A Taste Of Science : Why Some Foods Make Us Go ICK!

Love sugar and hate broccoli?

Your genes and microbes could be the reason!

A sip of fresh coffee brew.

A bite of a cookie (or two).

We rely on our taste buds (a lot!) to give us some of life’s best moments.

What’s interesting is that about twenty-five percent of us might not be able to taste most flavors, due to biological factors at play.

Discovered by German scientists Georg Meissner and Rudolf Wagner in the nineteenth century, taste buds and their communication with the brain determine how much or how little we perceive sweet, salty, bitter, sour and savory/umami flavors in food. The distribution and density of taste buds in the oral cavity and the gut, along with their modulation of signals sent to the brain, differs from person to person. Based on the level of taste sensitivity, one could be a non-taster, medium taster or super-taster.

Does this matter, from a health perspective? Science says it does.

The ability to taste different flavors in food is arguably the most important factor that determines eating behavior, and acceptance of different foods - thereby influencing nutrition and health outcomes.

There are some studies which suggest that super-tasters might be less likely to prefer certain vegetables in their diet, due to their bitterness. They might also consume more sodium by opting for more salt while eating bitter vegetables.

However, they might be doing themselves a favor on other occasions - because they are less likely to prefer sweet-tasting foods or fatty foods, when compared with their non-taster friends.

Certain biological factors have been investigated for their role in influencing taste perception in humans.

Polymorphisms in the TAS2R38 gene are strongly associated with bitter taste perception.

Variation in this gene affects taste transduction pathways in humans, especially for phenylthiocarbamide (PTC) and propylthiouracil (PROP) compounds, commonly found in foods. This is one of the reasons for inter-individual variation in bitter taste perception.

Variants in the TAS2R38 gene are known to alter the G-protein coupled receptor protein (produced in the receptor cells of the palate epithelium and tongue), resulting in reduced protein function and lessened bitter taste perception.

Taste perception is also modulated by the composition of bacteria that thrive in our oral cavity, as well as in the gut.

Our oral and gut microbes modulate taste signaling and the expression of taste receptors.

Bacteria tend to accumulate on the upper surface of the tongue, forming a biofilm along with saliva and mucus. The presence of certain bacteria can prevent chemicals in food from reaching the receptors, thus giving the host a reduced sense of taste. The production of bacterial metabolites such as lactate can also affect taste perception, by manipulating the concentration of chemicals in food (e.g. sucrose which confers a sweet taste) and thereby, their perception by the host.

The success of a dietary intervention often depends on personal motivation and ability to navigate around inherent preferences such as taste.

Understanding underlying factors like genetics, gut dysbiosis and oral health can empower practitioners to personalize their coaching in a way that optimizes patient adherence and overall experience.

References :

1. Keller, Kathleen L, and Shana Adise. “Variation in the Ability to Taste Bitter Thiourea Compounds: Implications for Food Acceptance, Dietary Intake, and Obesity Risk in Children.” Annual review of nutrition vol. 36 (2016): 157-82. doi:10.1146/annurev-nutr-071715-050916

2. Hayes, John E et al. “Explaining variability in sodium intake through oral sensory phenotype, salt sensation and liking.” Physiology & behavior vol. 100,4 (2010): 369-80. doi:10.1016/j.physbeh.2010.03.017

3. Kim, U K, and D Drayna. “Genetics of individual differences in bitter taste perception: lessons from the PTC gene.” Clinical genetics vol. 67,4 (2005): 275-80. doi:10.1111/j.1399-0004.2004.00361.x

4. Leung, Ryan, and Mihai Covasa. “Do Gut Microbes Taste?.” Nutrients vol. 13,8 2581. 27 Jul. 2021, doi:10.3390/nu13082581

5. Feng, Yunzi et al. “The Associations between Biochemical and Microbiological Variables and Taste Differ in Whole Saliva and in the Film Lining the Tongue.” BioMed research international vol. 2018 2838052. 14 Jun. 2018, doi:10.1155/2018/2838052

6. Gardner, A et al. “Intraoral Microbial Metabolism and Association with Host Taste Perception.” Journal of dental research vol. 99,6 (2020): 739-745. doi:10.1177/0022034520917142