研究顯示 肥胖能讓味覺變得遲鈍
Obesity dulls the sense of taste, according to research that offers new insights into why some people enter a persistent cycle of weight gain.
最新研究顯示，肥胖會讓味覺變得遲鈍。這一發現對於瞭解爲什麼有些人會陷入體重增加的不斷循環提供了新的思路。
Researchers found that within eight weeks of becoming obese, mice lost 25% of their taste buds. The findings suggest that weight gain not only changes appetite but may also fundamentally alter the way taste is perceived.
研究人員發現，老鼠在變得肥胖的8周內失去了25%的味蕾。該發現表明，體重增加不僅會改變食慾，也可能從根本上改變味覺。
"Obesity is by nature very complex," said Robin Dando, a food scientist at Cornell University in New York and senior author. "There are a bunch of different factors that contribute to our state of obesity -- we think a change to taste is one of those, and one that people don't tend to consider."
美國康奈爾大學的食物專家羅賓·丹多稱：“肥胖從本質上說是非常複雜的。造成肥胖的因素很多--我們認爲味覺的改變是其中之一，也是人們往往忽視的一個因素。”
The findings are the latest to push back against the assumption that people become obese because they love food more than the average person and so find it harder to resist. "I think liking food more may not be what's going on," said Dando.
有觀點認爲，人們之所以變胖是因爲他們比一般人更愛吃，更難抵禦吃的誘惑。上述研究發現是反駁該觀點的最新例證。丹多說：“我認爲更愛吃可能不是真正的原因。”
Several converging lines of evidence now suggest the reverse may be true.
幾條綜合證據表明，情況可能恰恰相反。
Studies of brain activity have found that people with higher body mass index appear to find pleasant tastes relatively less rewarding -- as measured by their brain response -- and so may need to eat more to obtain the same dopamine kick.
對大腦活動的研究發現，身體質量指數較高的人似乎會覺得美味只能帶來相對較少的獎勵--根據他們的大腦反應來衡量--因此可能需要吃得更多才能獲得同樣水平的多巴胺。
Other work has shown that people with dulled taste sensitivity tend to gravitate towards sweeter, fattier foods.
其他的研究表明，對味覺遲鈍的人傾向於吃更甜、更油膩的食物。
The latest findings suggest obesity does not simply reprogramme taste perception at the psychological level.
最新研究證實，肥胖並不只是簡單地在心理層面上改變味覺。
In the study, the mice were fed either a normal or a fatty diet. After eight weeks, the mice on the high-fat diet weighed about one third more. The scientists found they also had about 25% fewer taste buds than the lean mice.
在這項研究中，老鼠被分成兩組，分別餵食正常的食物或油膩的食物。8周後，吃高脂肪食物的老鼠的體重比吃正常食物的老鼠重了大約三分之一。科學家還發現，它們的味蕾比瘦老鼠少了大約25%。
Taste buds comprise about 50 to 100 cells of three major types, with different roles in sensing the five primary tastes (salt, sweet, bitter, sour and umami). These cells have a rapid turnover, living an average of just 10 days.
味蕾由三大類大約50至100個細胞組成，在感知五味（鹹、甜、苦、酸和鮮）時起着不同作用。這些細胞更新迅速，平均壽命僅10天。
The findings suggest taste buds and their progenitor cells are particularly sensitive to damage from inflammatory chemicals that are raised in obesity, resulting in a rapid decline of the overall number.
該研究發現，味蕾及其其祖細胞對於肥胖時增多的炎性化學物質的危害特別敏感，造成整體數量迅速減少。
The study homed in on one specific inflammatory chemical that is elevated in obesity, called TNF-alpha, which acts as a messenger between the body's cells.
研究鎖定一種在肥胖時增多的炎性化學物質，它被稱爲腫瘤壞死因子（TNF-alpha），充當的是體細胞之間的信使。
The scientists found that mice that had been engineered to be genetically incapable of making TNF-alpha did not experience any reduction in taste buds, despite gaining weight, suggesting this compound may be the culprit.
科學家發現，經改造後使其基因沒有能力製造TNF-alpha的老鼠，儘管體重增加，但是味蕾並沒有減少，表明這種化合物可能就是罪魁禍首。
The team now plan to assess whether the same process occurs in people. "We're certainly not identical to mice in our physiology, but our taste buds work pretty similarly, and the same factors related to inflammation we think are responsible for taste loss are elevated when we become obese," said Dando.
該研究小組現在計劃評估人體是否會發生同樣的情況。丹多說：“從生理上講，我們當然跟老鼠不一樣。但是我們的味蕾作用很相似，我們認爲跟炎症有關的造成味覺喪失的同樣的因子在我們變肥胖時會增多。”
Dando said the findings could help devise new approaches to losing weight, with a greater focus on the influence of taste perception on what people eat.
丹多稱，這些研究結果可能有助於找到新的減肥方法，這些方法會更重視味覺對人們進食的東西的影響。
