It’s time to go again to the A Moment of Science mailbag. A listener writes:
Dear A Moment of Science,
I keep hearing about how diet soda is bad for you. This is troubling, since I drink lots of the stuff because has zero calories. So, is diet soda really bad? And if so, why?
Well, the most accurate we can offer to the first question is “maybe.” As for why? We don’t really know.
Linking Studies
To elaborate, a few studies have found links between sweetened beverages including fruit drinks and regular and diet soda and depression.
For example, one study by researchers at the National Institutes of Health looked at survey data from more than 260,000 people. Those who drank at least four cans of regular soda per day were 30 percent more likely to have been diagnosed with depression. People who drank diet soda were even more prone to depression, at 31 percent.
And people who drank four or more cans of fruit drinks were the most vulnerable, being 51 percent more likely to be diagnosed with depression.
Correlation Does Not Equal Causation
To be clear, the study found an association, not necessarily a causal link. In other words, it’s not clear that drinking diet soda actually causes depression.
But it’s also possible that something in sweetened drinks does in fact cause or at least raise the risk for depression. More research will help sort that out.
So it seems reasonable to conclude that if you have a family history of depression, it may not be a bad idea to lay off sweetened drinks. Even if studies have not proven that they trigger depression, there is a link.
無糖汽水會使人沮喪嗎?
又到了抽取《科學(xué)一刻》信箱來信的時(shí)間了。一位聽眾這樣寫到:
親愛的《科學(xué)一刻》欄目:
我聽說無糖汽水對身體有害。
這可是件麻煩事,因?yàn)樽詮奈衣犝f無糖汽水不含熱量后我就喝了很多。所以說,無糖汽水真是有害的嗎?如果是,那原因呢?
好了,我能給第一個(gè)問題最為精確的回答是“可能”。至于為什么?我實(shí)際上也不知道。
相關(guān)研究
確切的說,少有研究發(fā)現(xiàn)甜味飲料,包括果汁,含糖和無糖汽水與沮喪情緒有關(guān)。
例如,國立衛(wèi)生研究院研究人員做了一項(xiàng)26萬多人的調(diào)研,每天飲用超過四罐含糖汽水的人,就有30%被診斷出可能患有沮喪情緒癥。31%飲用無糖汽水的人更容易情緒沮喪,飲用四罐或者更多果汁的人更加脆弱,高達(dá)51%的人可能會遭受沮喪情緒的困擾。
相關(guān)聯(lián)系不等于因果關(guān)系
需要說明的是,這一研究找到的是相關(guān)性,而不是必然的因果聯(lián)系。
換句話說,還不清楚無糖汽水是否真的會導(dǎo)致情緒沮喪。但是,依然有可能的是甜飲料中的某些物質(zhì)確實(shí)導(dǎo)致或者至少增加了情緒沮喪的風(fēng)險(xiǎn)。更多研究將會支持這一結(jié)論。因此,似乎有理由認(rèn)為,如果有抑郁癥家族史的人,停止飲用甜味飲料可能不是個(gè)壞主意。即使研究沒有證明它們能觸發(fā)抑郁,但也據(jù)有相關(guān)性。