A matter of taste
Posted on homepage: 6 September 2021 (GMT+10)
Food does more than nourish our bodies. It also brings us pleasure as we experience a rich variety of tasty flavours. This testifies to a loving Creator who made us in His image and endowed us with the ability to savour and relish food.
The Bible is sprinkled with the word ‘taste’. Sometimes it means to experience something, whether good (like God Himself—Psalm 34:8) or bad (such as death—Hebrews 2:9). At other times it implies eating, but it can also convey what we normally understand by it—to taste the flavour of our food (Exodus 16:31, Job 6:6). And our body’s taste system is remarkably well-designed.
Not all are aware that the experience of tasting the full flavour of our food depends on more than our tongue’s ability to taste (known as gustation). In fact, the tongue can only detect a limited range of tastes—it used to be thought only four: sweet, sour, salt, and bitter. However, in recent years ‘umami’—Japanese for savoury—has been added. Umami foods include mushrooms, cheeses, and yeasty things like Vegemite and Marmite.
Food has a huge range of flavours, sometimes subtle and complex, far too many for just this handful of options (or combinations of them—think ‘sweet and sour’) to encompass. Fully appreciating the flavour of our food also depends crucially on our nose’s sense of smell (olfaction)—as anyone who has lost that sense can testify. The two senses operating together give us what we generally understand as ‘taste’—the nose even more so than the tongue. This is one reason a steak ‘tastes’ better when hot—the higher temperature means that more aroma molecules are given off. It’s also why we often can’t taste nearly as well if we have a heavy cold.
How does taste work?
Simply put, the system consists of a sensor, a medium by which information is transferred, and a processor. Most people have a basic understanding of these system components as they apply to seeing and hearing—instantly recognizable in Figure 1.
Our sense of taste similarly involves sensing, information conversion, transmission, and processing (Figure 2).
Could taste evolve?
Let’s take the ability to detect bitter as an example. Evolutionists often point out that bitter foods can be poisonous—the bitterness is usually from alkaloids, many of which are toxic. So tasting them before swallowing is advantageous. They must envisage something like this:
- The ability to distinguish ‘bitter’ arises through random genetic mutation;
- This survival advantage (avoiding some potentially life-threatening foods) enables the organism to produce more offspring that also have this new adaptation;
- The ability to taste bitter foods spreads through the population;
- The adaptation is now established.
It may sound straightforward, but let’s look more closely at points 1 and 2. Actually, “Humans have about 30 genes that code for bitter taste receptors”! 1Let us assume that just one of those taste receptor genes codes for a modest-sized protein, 100 amino acids long. To be conservative, let’s assume that only 30 of these have to be in exactly the right place, i.e. there is great redundancy in the sequence. There are 20 amino acids to choose from, so the chance of getting the right sequence is 1/2030 (1/1039). To put this into perspective, if the odds of winning a lottery are a billion to one, you are much more likely to win that lottery 4 times in a row.
And even if some new type of taste bud arose perceiving some aspect of bitterness for the first time, would this really give a survival advantage? Remember that the ‘bitter’ taste is the outcome of the cooperation of 30 genes. If the chance of one small gene arising randomly is vanishingly small, what are the odds of such a far more complex system being produced by such a mechanism, even when selection is considered? Remember that natural selection cannot cherry-pick individual mutations. If a creature inherits 100 mutations, of which only one is advantageous and the rest neutral or slightly harmful (i.e. does not render the creature dead or infertile), then it cannot simply keep the one that helps and discard the rest.
All of the slightly harmful ones contribute to its genetic burden. How many of these would it have to take on board in order to have a good chance of getting the ‘right’ ones?
We have only considered ‘bitter’ taste, but there is also amazing complexity involved in the other tastes: the sweet taste detects simple carbohydrates, an energy-rich food; salty detects the important electrolyte sodium chloride; and umami detects glutamates, derived from proteins. But even these receptors would be useless on their own. They must be part of a coordinated and sophisticated system involving the transmission of the information and its interpretation by the brain.
In short, the fine-tuning seen in all of the elaborate detection mechanisms involved in taste is a very strong indication of design by the omniscient, benevolent Creator, as opposed to an unguided process of random mutations ‘filtered’ by natural selection. The burden of proof is clearly on the evolutionist to provide actual evidence or at least a plausible scenario for how the taste system arose in the first place.
The terrific tongue
What about the taste organ, the tongue? The little bumps on your tongue are not taste buds, but papillae, of which there are four types, three of which contain taste buds in tiny pits under them (Fig.3). Saliva dissolves and transports the chemicals from food to the taste buds. This watery solution is really a chemical signal, holding information about the food source. It makes contact with gustatory hairs in the taste pore, an opening in the pit wall (Figure 3). These hairs form the tip of each taste bud and are connected to approximately 50 to 150 taste receptor cells (the sensors).2
You may have been taught that different areas of your tongue are responsible for different tastes, but this is not so. There are very tiny differences in the ability of different areas to detect certain tastes, but taste buds in every part of the tongue can detect every one of the five tastes.3 Scattered taste buds are also found in the lining of the throat, the soft palate, larynx and even the upper esophagus.4 But unlike those in the tongue, they are not in papillae.
Design versus storytelling
Tasting is not the only system with complex components of this sort. Such systems exist throughout our bodies, including smell, sight, hearing, and touch, but also in man-made devices, such as gas detectors, computers, etc. (I worked in the gas industry for many years, with instruments designed to detect and measure gas levels.) Unquestionably man-made devices are designed: numerous precisely manufactured parts, organized correctly to function according to a predetermined purpose. Why would we think any differently of far more sophisticated systems in our bodies? Evolutionary story-telling might persuade people superficially,5 but if one looks deeper, there are wondrous designs that testify to a wonderful Creator.
Creation-believers have a very good explanation for why we are able to taste food; it is because “every good gift and every perfect gift is from above, coming down from the father” (James 1:17).
As the palate tastes food, so the ear tests words (Job 34:3). What better words to hear—and obey—than God’s Word: “How sweet are your words to my taste, sweeter than honey to my mouth!” (Psalm 119:103).
References and notes
- PTC: The Genetics of Bitter Taste, learn.genetics.utah.edu/content/basics/ptc; accessed 6 Apr 2020. Return to text.
- Reed, D. et al., Diverse tastes: Genetics of sweet and bitter perception, Physiology & Behavior 88(3):215–226, 2006. Return to text.
- Munger, S., The taste map of the tongue you learned in school is all wrong, smithsonian.com, 23 May 2017. Return to text.
- Simpson, K.L, in Fundamental Neuroscience for Basic and Clinical Applications (5th Ed.), 2018, cited in sciencedirect.com. Return to text.
- Johansen, M., Is evolution pseudoscience? Creation 29(4):25–27, September 2007. Return to text.