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Urology Pearls

Writer recalls childhood culinary treats

Madjar

The foodscapes of my childhood were always calling for culinary experimentation.

My parents took me to restaurants whose names suggested distant lands and exotic cuisines. There was “The Bulgarian” who seemed to always grill kebabs and koftas; “The Romanian” who was serving Ikra made of red caviar, Ciorba (Romanian for soup), and grilled brains; “The Turkish” whose Burekas filled with salty cheese and spinach were divine, and “Jack the Fisherman,” who cooked his fish in spicy tomato sauce. In the markets downtown and along the serpentine roads leading to my home on Mount Carmel, I could also taste the delights of the Middle-Eastern street cuisine; and at her home, my grandmother taught me the secrets of cooking; her recipes always started with “take an onion and chop it.”

It wasn’t just a land of milk and honey, because the Mediterranean sun gave watermelons a deeper layer of sweetness, and the tomatoes were as red as blood. My childhood was literally a melting pot into which all immigrants have poured their own ingredients, their sweat, sadness, and hope into a perfect concoction, a symphony of flavors.

I came into that world with the curiosity of a scientist. Deborah, my elementary school science teacher, was all about quenching my thirst for knowledge. I remember her pulling out a rolled map, a box of cotton swabs, and several small bottles containing different solutions. She opened the bottles, one after another, announcing their contents, “Salt water … sugar water … unsweetened chocolate mixed in cream … and lemon juice.” She said, “Today we’ll learn about the tongue and the sense of taste.” She then unrolled the map. The map showed a large, colorful, threatening tongue. According to the map, the tip of the tongue was where the sweet taste buds resided, the back of the tongue tasted bitter, and on each side of the tongue lied two, separate areas which tasted salt and sour. The middle of the tongue, according to the map, was there merely to hold it all together. Deborah dipped the tips of the cotton swabs in the different solutions and let us experiment by placing them over the different territories of the tongue. By the end of Deborah’s experiment, perhaps convinced by the power of suggestion, we were all sure that the map was accurate.

This wasn’t true. The tongue map was a misconception born in misunderstanding. It started when D. P. Hanig, a German researcher reported that different parts of the tongue seemed to have different sensitivities to different tastes. Hanig reported that these differences were small. But the paper was very long (47 pages!), was written in fluent German; and contained a diagram that was somewhat confusing. The X-axis of the diagram clearly depicted the different areas of the tongue, but the Y-axis, showing the sensitivity to the different tastes, lacked any numerical value. Four decades later, Harvard psychologist Edwin Boring took Hanig’s diagram and re-plotted it in a way that misrepresented Hanig’s original work. And the relatively minute differences between sensitivities in the different areas of the tongue became much larger. This is how the “tongue map” was born. Hanig was wrong. Deborah, my science teacher, trusted the map and so did many others, and I was easily convinced. Besides, the cotton-swabs dipped in sugar-water tasted so sweet that I was willing to believe anything. I was 7 at the time.

It is now evident that the human tongue has, on average, about 7,500 taste buds. The back of the tongue is more sensitive to bitter, and the front is more sensitive to other taste sensations, but all of our taste buds contain taste-receptor cells which are capable of distinguishing all five basic tastes (sweet, salty, bitter, sour, and umami (savory)). The taste buds are unevenly distributed–most are at the tip and front of the tongue; some are on the sides, and some at the back, and the very back of the tongue.

Each taste bud has the shape of a closed rose with its small opening facing the surface of the tongue. In each taste bud there are 50 to 150 cells, bundled together like a cluster of bananas. But all of these cells belong to only three different groups. One type is activated by substances that taste salty; another by substances that taste sweet, bitter, and savory; yet a third type is activated by substances that taste sour. Once activated, tiny electrical currents are produced, and the signal is propagated, through nerve fibers into the brain.

With only three different “electrical switches,” how could I have experienced the vast, diverse foodscapes of my childhood? And how can you sense so many different flavors? The plot will shortly thicken.