内容来源：https://lifehacker.com/health/diet-coke-water-glucose-study?utm_medium=RSS

内容总结：

近日一项由美国国立卫生研究院资助的临床研究显示，对于已养成饮用习惯的2型糖尿病患者而言，无糖饮料可能比单纯饮水更有利于血糖控制。

这项名为“SODAS试验”的研究由加州大学欧文分校和明尼苏达大学联合开展，共招募179名长期饮用无糖饮料的2型糖尿病患者。在24周的观察期内，继续饮用无糖饮料的受试者糖化血红蛋白（HbA1c）从7.19%微降至7.14%，而改饮水的对照组则从7.20%上升至7.44%。研究同时发现，无糖饮料组在空腹血糖、空腹胰岛素等指标上也呈现更优趋势，平均体重轻微下降约0.9公斤。

澳大利亚伍伦贡大学流行病学家吉迪恩·迈耶罗维茨-卡茨评价称，这项研究设计严谨且未受商业公司资助，“其科学性远超许多获得媒体报道的研究”。研究人员指出，对于血糖控制稳定的2型糖尿病患者，维持无糖饮料的饮用习惯或可作为糖尿病管理工具之一。

专家同时强调，该结论仅适用于特定人群，不能简单推广为“无糖饮料优于水”的普遍认知。研究作者表示，最可能的情况是饮用水与无糖饮料对血糖的影响基本相当，但现有数据至少表明，对已习惯饮用无糖饮料的2型糖尿病患者而言，强行改为饮水未必能带来健康获益。

中文翻译：

相信你一定看过那些时不时冒出来的研究，声称无糖汽水可能对人体有害（虽然证据从来都不够充分）。但你是否注意到最新研究发现：对2型糖尿病患者而言，无糖汽水比白水更有益？这不仅是真实的研究，其设计也相当严谨。一位未参与该研究的流行病学家向我指出，这项研究值得我们关注。

这位专家是卧龙岗大学的吉迪恩·迈耶罗维茨-卡茨，他曾在专栏中分析过此项研究。当我询问"该研究未被主流媒体关注是好事还是坏事"时，他表示："相比大多数获得媒体报道的科研，这项研究的可靠性要高得多。"该研究未接受任何饮料公司的赞助。

研究发现了什么

在这项名为"SODAS试验"（人工甜味剂饮料研究）的趣味性研究中，加州大学欧文分校与明尼苏达大学明尼阿波利斯分校的研究人员招募了有饮用人工甜味剂饮料习惯的2型糖尿病患者（包括但不限于我的挚爱——健怡可乐）。研究经费来自美国国立卫生研究院下属的糖尿病、消化和肾脏疾病研究所。

其中半数参与者被要求改喝白水，所有人每天可获得三份自选的无糖饮料或饮用水（包括无糖气泡水）。研究持续24周，共招募181人，最终179人完成试验——这对同类研究而言已算规模可观（比下文将对比的早期研究样本量多出一倍）。

研究人员通过血液检测主要观察糖化血红蛋白指标，这是监测糖尿病患者或糖尿病高危人群血糖控制水平的常规指标。糖化血红蛋白值越高，表明过去三个月左右的平均血糖水平越高。

结果显示：饮用人工甜味剂饮料组的糖化血红蛋白从7.19%微降至7.14%；而饮水组的该指标从7.20%上升至7.44%。

研究人员还收集了其他补充数据：空腹血糖、空腹胰岛素以及连续血糖监测显示的"血糖在目标范围内时间"均显示无糖饮料组更优。无糖饮料组参与者平均减重约0.9公斤，饮水组体重则保持稳定。研究者指出这种体重差异"具有统计学意义但无临床意义"，即差异真实存在但影响微小。

核心结论是：让2型糖尿病患者从无糖汽水改喝白水并无实质益处，甚至可能轻微损害其健康。

这对你（或许是我）的健怡可乐习惯意味着什么

我必须承认自己存在认知偏好——但这是基于长期观察的理性偏好。我钟爱健怡可乐，多年来也持续关注人工甜味剂研究。虽然不会宣称它是健康食品，但从未有证据说服我它有害健康（加糖汽水则另当别论，我们最好都避免饮用）。

如今这项规模合理、设计严谨、资金独立的研究表明：人工甜味剂饮料可能比白水更有益健康。尽管几年前相反结论的研究曾获媒体报道，这项新研究却未激起舆论涟漪。此前那项涉及81名糖尿病女性的减重试验显示，饮水组比无糖饮料组的糖化血红蛋白改善更明显。但当时有专家向"每日健康"网站表示："我认为无糖汽水的健康风险被夸大了。"（最新研究的作者则指出，两项研究不具备可比性，因为前者是减重试验而后者不是。）

关于特定食物的研究需要谨记：其结论通常仅适用于特定健康状况或人群。我们总想简单归类为"健怡可乐有益"或"有害"，但每项研究只是拼图的一角。例如本研究未涉及血糖控制不佳的糖尿病患者或非糖尿病人群，也未考察血糖指标之外的影响因素。研究甚至未专门针对健怡可乐，尽管它很可能是受试者最常选择的饮品之一。

需要明确的是，完全可能不存在实际差异——白水与无糖饮料对血糖和健康的影响基本等同。迈耶罗维茨-卡茨认为这或许是最合理的解释，但我们不能排除无糖汽水可能有助于2型糖尿病患者控制血糖的可能性。例如，它们或许能满足人们对甜味的渴望，从而帮助避免摄入其他含糖零食。

研究人员总结道："如果血糖指标已得到控制且稳定，维持现有人工甜味剂饮料摄入量或许是持续管理2型糖尿病的有效手段。"迈耶罗维茨-卡茨对此表示认同："最保守地说，在糖尿病控制方面无糖饮料与白水没有差异；往好了看，无糖饮料或许还略胜一筹。"

英文来源：

I’m sure you’ve seen the studies that come out from time to time showing that diet sodas are arguably kinda-sorta bad for you. (Their evidence is never very strong.) But did you see the new study that found diet soda was better than water for people with type 2 diabetes? Not only is it a real study, it was well-designed and we should be paying attention to it, according to an epidemiologist I talked to who was not involved in the study.
That epidemiologist is Gideon Meyerowitz-Katz of the University of Wollongong, who wrote about it here. When I asked him if it was a good or a bad thing that this study had mostly escaped notice by news media, he said “this is far more robust than most of the science that gets media coverage.” The study was not sponsored by any commercial drink company.
What the study found
In the delightfully named SODAS trial (Study Of Drinks with Artificial Sweeteners), researchers at the University of California, Irvine, and the University of Minnesota, Minneapolis, recruited adults who had type 2 diabetes and who had a habit of drinking artificially sweetened beverages (including, but not limited to, my one true love Diet Coke). The study was funded by the U.S. National Institutes of Health’s National Institute of Diabetes and Digestive and Kidney Diseases.
Half of them were asked to switch to drinking water instead, and everyone was provided with three servings a day of either their diet drink of choice, or a water of their choice (unsweetened seltzer included). The study ran for 24 weeks. There were 181 people enrolled, of which 179 finished the study, which is considered a fairly large group for a study of this type. (It's twice as large as an older study I'll contrast it with below.)
The main outcome the researchers studied was hemoglobin A1C (HbA1C) as measured by a blood test. This is a common test used to monitor glucose control in people who have diabetes or are at risk for it. The higher your HbA1C, the higher your blood glucose has probably been over the past three months or so.
The results: HbA1C got slightly better in the group that was drinking artificial sweeteners: from 7.19% to 7.14%. It got worse in the group that was drinking water, from 7.20% to 7.44%.
The researchers collected a few other metrics, for good measure. Fasting glucose, fasting insulin, and “time in range” as measured by a continuous glucose monitor all favored the diet drinks group. The people in the diet drinks group lost a little bit of weight (on average, two pounds) while those in the water group had stable weights. The researchers referred to this difference in weight loss as “statistically significant, but not clinically significant.” In other words, probably real, but too small to matter.
Bottom line: there was no real benefit to the people in the study switching from diet sodas to water; if anything, doing so may have slightly hurt their health.
What this means for you and your Diet Coke habit
OK, maybe I mean me and my Diet Coke habit. I fully admit to being biased here, but in an educated way. I like my Diet Coke. I’ve also been keeping an eye on research about artificial sweeteners over the years, and while I won’t necessarily defend my soda as health food, nothing has ever convinced me that it’s bad for me. (Sugar-sweetened sodas are a different story; those, we should probably all avoid.)
Now, we have a reasonably large, well-designed, independently-funded study showing that artificially sweetened drinks are possibly better for you than water. I still haven’t seen any news coverage of it, even though a study with the opposite results got coverage a few years back. That study involved 81 women with diabetes in a weight-loss trial, and their HbA1C improved slightly with water compared to diet drinks. Even so, one expert that Everyday Health spoke to about it said that he was “of the opinion that the health risks of diet sodas are overstated.” (Meanwhile, the authors of the most recent study point out that comparing that study to theirs isn’t quite apples-to-apples, since it was a weight loss trial and this one is not.)
That’s an important point to remember about any study on a specific food: they usually apply to a specific medical condition or population. We like to file them away in our mind as “Diet Coke good” or “Diet Coke bad,” but each study only gives us a piece of the puzzle, not a generality. For example this study tells us nothing about Diet Coke’s effects on people who have poorly controlled diabetes, or who don’t have diabetes at all; and it doesn’t say anything about measures other than those related to blood sugar. It didn’t even specifically study Diet Coke, although it’s likely that Diet Coke was one of the more popular beverages participants chose.
To be clear, it is entirely possible that this isn’t a real effect, and and that water and diet drinks are basically equivalent when it comes to your blood glucose and your health. Meyerowitz-Katz says this is probably the most likely explanation, but we can’t rule out the possibility that diet sodas may help glucose control in type 2 diabetes. Maybe they satisfy a sweet tooth and help people avoid other sugary snacks, for example.
The researchers write that their main takeaway is that “maintaining usual [artificially-sweetened beverage] intake may be a tool to continue to help manage T2D if glycemic measures are controlled and stable.” Meyerowitz-Katz agrees: “At worst, there is no difference between diet soft drinks and water when it comes to diabetes control. At best, the diet drinks might be sightly better.”