I'm sure that by now most of you have heard about the recent study about artificial sweeteners purportedly increasing the risk of diabetes and obesity due to changes in gut bacteria. Bill Lagakos wrote a fantastic blog post about the study, including the questionable way some of the results were reported. I definitely recommend reading Bill's article (as well as his book and blog, if you're not already doing so). But as a brief synopsis, the paper discusses the adverse metabolic effects experienced by mice, and potentially some humans, in response to changes in their intestinal microbiome after consuming saccharin (and by inference other artificial sweeteners). The human study looked at saccharin's effects on 7 people who didn't regularly consume artificial sweeteners. Just over half of these subjects exhibited changes in their gut microbiota and apparently declines in glucose tolerance, according to daily glucose tolerance tests (GTTs), although this is an area where the data was oddly reported. However, the initial bacterial composition of the "responders" likely differed from the 3 participants whose bacteria and GTT results did not change.
Sugar Substitutes: Yes or No?
The use of sugar substitutes -- particularly artificial sweeteners -- is one of the more controversial issues within the low-carb, whole-foods community. From what I've read online, as well as having talked to people about this quite a bit, intake seems to range from drinking several Diet Cokes and using Splenda in multiple cups of coffee every day to only using "natural" sweeteners like stevia in small amounts or avoiding sweeteners altogether. Since the study above came out and was widely circulated on social media, I've seen many arguments about the risks vs. benefits of using sugar substitutes, and some of them have gotten pretty heated. I can relate to the first line of Bill's post: "I didn't want to blog about the artificial sweetener study." The truth is that I'm ambivalent about the use of sugar substitutes and can understand the points being made by both sides.
I have a long history of artificial sweetener use, beginning at around age 12, when I started using them in an attempt to prevent further weight gain after putting on several pounds following puberty. I'm turning 48 next week, and although I can't quantify with any degree of accuracy how much artificial sweetener I've consumed over the course of the past 36 years, I'm fairly sure it was a lot more than the average person. I started with saccharin-sweetened Shasta and Tab, progressed to Equal (aspartame) once it became available, then Splenda, acesulfame potassium, sugar alcohols, and stevia within the past few years. A couple of times I took a brief break (including the few months I went "full Paleo" about 3 years ago) but always went back to using them. My weight stayed the same, and I didn't notice any difference in my appetite or intake whether I consumed them or not. However, research and anecdotal reports suggest that some people have a different experience.
Looking at Both Sides of the Argument
Obviously, I can't say whether changes occurred in my own microbiota as a result of fairly heavy long-term sugar substitute use, but I do know that in my own case, they haven't caused weight gain and, if anything, have likely helped me remain thin for the past 30+ years. Consuming sugar-free beverages and desserts allows me to treat myself to something sweet (an innate preference in humans) without ingesting empty calories or experiencing unstable blood sugar levels. I think they can play a supportive role in weight loss and diabetes for the many people who tolerate them. In terms of which to use, every sweetener has its advantages and drawbacks, including "natural" ones (which are often highly processed, just like artificial sweeteners), so it's up to each person to make a choice from among the growing list of available products. I just finished trying out some of the newer sugar substitutes (monk fruit and Just Like Sugar, which is inulin based) so I can include my own thoughts in the "Sugar Substitutes" section of the book I'm currently writing. They aren't bad, although not nearly as sweet as saccharin tablets, which is still my favorite after all these years, particularly in hot cocoa tea. (It's very simple and quick: Pour boiling water over a rooibos or other herbal tea bag, steep a few minutes, then add 1 Tbsp cocoa powder, 1 Tbsp cream or half-and-half, and sugar substitute to taste. Voila -- delicious hot cocoa tea with antioxidants galore!)
On the other hand, some people have legitimate adverse reactions to certain sugar substitutes, find that their sweet taste triggers cravings for sugar and other high-carbohydrate foods, or have trouble losing weight when consuming them. Others may simply not want to eat anything sweet other than fruit. In these cases, it makes sense to avoid them. But trying to discourage everyone else from using sugar substitutes doesn't sit well with me. Since the studies on them aren't definitive in terms of risk and we know that high sugar intake does increase the likelihood of developing diabetes and obesity, I'll go on record as saying that sugar substitutes are the better choice for many. Should they be considered a health food? No, and I certainly don't recommend overdoing them; this is one of the many nutrition areas where I believe the term "in moderation" applies. But if they can help overweight people or those with diabetes maintain low intakes of sugar without feeling deprived -- and experience better health as a consequence -- I think their use can be justified.
Could Bitter Be Better?
Now, after my defense of artificial sweeteners, I'm going to share something that may surprise you. As of this past weekend, I've taken another break from them. I decided to do this after one of my colleagues made a point about Americans disliking the taste of many bitter vegetables prized for their health benefits by practitioners of Ayurveda. Instead of indulging in bitter foods like coffee and chocolate in their natural state, we add sweeteners to mask the flavor. I thought about this, realized how true it is., and did a little research into bitter and astringent foods. I'm one of those rare people who actually enjoys eating unsweetened chocolate (I keep bars of 100% cocoa Ghiradelli chocolate and unsweetened Bakers chocolate in my pantry at all times), and although I typically sweeten my coffee, I also like it with just cream or half-and-half. So I'm interested to see how embracing bitter, unsweetened foods and beverages goes. This is an experiment, and I may go back to using sugar substitutes (given my past history, I'd say that's pretty likely). But I don't think the use or avoidance of them will have much of an impact on my health given that I eat a very healthy, balanced low-carb diet, exercise regularly, get enough sleep, etc. And by the way, unsweetened hot cocoa tea is a lot better than I thought it would be.
- Suez J, et al. Artificial sweeteners induce glucose tolerance by altering the gut microbiota. Nature 2014 Oct 9;514(7521): 181-6
- Lavin JH. Lavin JH. The effect of sucrose- and aspartame-sweetened drinks on energy intake, hunger and food choice of female, moderately restrained eaters. Int J Obes 1997 Jan;21(1):37-4
- Saha P, et al. Highlighting the anti-carcinogenic potential of an ayurvedic medicinal plant, Swertia Chirata Asian Pac J Cancer Prev. 2010;11(6):1445-9.