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Taste for sweets is more complex than we knew, scientists say

March 7, 2011
Courtesy of Mon­ell Chem­i­cal Senses Cen­ter
and World Science staff

The ways in which our taste cells de­tect sweets is more com­plex and rich at the mo­lec­u­lar lev­el than sci­en­tists have tra­di­tion­ally real­ized, a study has found. Re­search­ers hope to har­ness the find­ings to to de­vel­op strate­gies to help peo­ple limit their sug­ary crav­ings.

The study in­di­cates that taste cells sport sev­er­al sug­ar-de­tecting struc­tures that were pre­vi­ously un­known.

“De­tect­ing the sweet­ness of nu­tri­tive sug­ars is one of the most im­por­tant tasks of our taste cells,” said Rob­ert Mar­gol­skee, a mo­lec­u­lar neuro­bi­ol­o­gist at the Mon­ell Chem­i­cal Senses Cen­ter in Phil­a­del­phia and lead au­thor of a new re­port on the re­search. “Many of us eat too much sug­ar and to help lim­it over­con­sump­tion, we need to bet­ter un­der­stand how a sweet taste cell ‘knows’ some­thing is sweet.”

Sci­en­tists knew be­fore the stu­dy, he ex­plained, that a mo­lec­u­lar struc­ture on taste cells called the T1r2+T1r3 re­cep­tor is the main mech­an­ism by which the cells de­tect many sweet com­pounds. These in­clude sug­ars such as glu­cose and su­crose and al­so ar­ti­fi­cial sweet­en­ers, in­clud­ing sac­cha­rin and as­par­tame.

But it now seems there are more such sen­sors, ac­cord­ing to Mar­gol­skee and col­leagues. Sev­er­al sen­sors known to ex­ist in the in­tes­tine and the pan­cre­as al­so have turned out to ex­ist in our taste cells, they ex­plained. “The taste sys­tem con­tin­ues to amaze me at how smart it is and how it serves to in­te­grate taste sensa­t­ion with di­ges­tive pro­cess­es,” said Mar­golskee. The find­ings are pub­lished in the re­search jour­nal Pro­ceed­ings of the Na­tio­n­al Aca­de­my of Sci­en­ces.

The var­i­ous sug­ar taste sen­sors may have dif­fer­ent roles, he went on. One from the in­tes­tine that de­tects the sug­ar glu­cose, and al­so found in the sweet-sen­si­tive taste cells, may help ac­count for why a pinch of salt added to baked goods en­hances sweet­ness. This sen­sor, known as SGLT1, trans­ports glu­cose in­to sweet taste cells, but only when sodi­um—a com­po­nent of ta­ble salt—is pre­s­ent.

In the pan­cre­as, a di­ges­tive or­gan, a sug­ar sen­sor known as the KATP chan­nel mon­i­tors glu­cose lev­els and trig­gers re­lease of the hor­mone in­su­lin when they rise. The stu­dy’s au­thors spec­u­late that KATP may func­tion in sweet taste cells to mod­u­late taste cell sen­si­ti­vity to sug­ars ac­cord­ing to met­a­bol­ic needs.

“Sweet taste cells have turned out to be quite com­plex. The pres­ence of the KATP chan­nel sug­gests that taste cells may play a role in reg­u­lat­ing our sen­si­ti­vity to sweet taste un­der dif­fer­ent nu­tri­tional con­di­tions,” said Ka­ren K. Yee of Mon­ell, an­oth­er of the in­ves­ti­ga­tors.


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The ways in which our taste cells detect sweets is more complex and rich at the molecular level than scientists have traditionally realized, a study has found. Researchers hope to harness the findings to to develop strategies to help people keep their sugary cravings under control. The study indicates that taste cells sport several sugar-detecting structures that were previously unknown. “Detecting the sweetness of nutritive sugars is one of the most important tasks of our taste cells,” said Robert Margolskee, a molecular neurobiologist at from the Monell Chemical Senses Center in Philadelphia and lead author of a new report on the research. “Many of us eat too much sugar and to help limit overconsumption, we need to better understand how a sweet taste cell ‘knows’ something is sweet.” Scientists knew before the study, he explained, that a molecular structure on taste cells called the T1r2+T1r3 receptor is the main mechanism by which the cells detect many sweet compounds. These include sugars such as glucose and sucrose and also artificial sweeteners, including saccharin and aspartame. But it now seems there are more such sensors, according to Margolskee and colleagues. Several sensors known to exist in the intestine and the pancreas also have turned out to exist in our taste cells, they explained. “The taste system continues to amaze me at how smart it is and how it serves to integrate taste sensation with digestive processes,” said Margolskee. The findings are published in the research journal pnas. The various sugar taste sensors may have different roles, he explained. One from the intestine that detects the sugar glucose, and also found in the sweet-sensitive taste cells, may help account for why a pinch of salt added to baked goods enhances sweetness. This sensor, known as SGLT1, transports glucose into sweet taste cells, but only when sodium—a component of table salt—is present. In the pancreas, a digestive organ, a sugar sensor known as the KATP channel monitors glucose levels and triggers release of the hormone insulin when they rise. The study’s authors speculate that KATP may function in sweet taste cells to modulate taste cell sensitivity to sugars according to metabolic needs. “Sweet taste cells have turned out to be quite complex. The presence of the KATP channel suggests that taste cells may play a role in regulating our sensitivity to sweet taste under different nutritional conditions,” said Karen K. Yee of Monell, another of the researchers.