Hello and welcome to Nutrition Facts – the podcast that brings you the latest in evidence-based nutrition research. I’m your host, Dr. Michael Greger.
I know that facts have been in the news a lot lately, both real and fake. The concept of alternative facts is nothing new in the field of nutrition though, where powerful commercial interests have tried to not only keep people in the dark, but actively try to confuse them. That’s why I stick to the science: What’s the best available balance of evidence published in the peer-reviewed medical journals right now? That’s why I wrote my New York Times best-selling book, “How Not to Die”, why I created my nonprofit site NutritionFacts.org and, now, this podcast.
How sweet it is; or, should we say, how sweet is it? Today, we take a close look at artificial sweeteners. Recent research reveals that artificially sweetened beverages may be associated with depression or psychological disturbances. Here’s more about the study.
In a Harvard study of hundreds of thousands of coffee drinkers compared to non-coffee-drinkers, those drinking up to four or more cups a day only appeared to have half the suicide risk. What about more than four? A Kaiser Permanente study of 100,000 people found that suicide risk continued to drop, 80% lower at more than 6 cups a day. Now, eight or more cups a day, though, is associated with increased risk. Perhaps those with more severe forms of depression try to use very high doses of coffee as a form of self-medication to make themselves feel better but was, nonetheless, insufficient to elevate their mood.
It may also matter what goes into the coffee. The NIH AARP study of hundreds of thousands of Americans followed for years, found that frequent consumption of sweetened beverages, especially diet drinks, may increase depression risk among older adults, whereas coffee consumption may lower the risk. Whether soda, or fruit-flavored drinks, or iced tea, those artificially sweetened appeared to carry higher risk; same with hot tea or coffee. There was a benefit in coffee-drinkers compared to non-drinkers, but add sugar and much of that benefit disappears, and add Equal or Sweet ‘N Low, and the risk may go up.
Various effects of artificial sweeteners, including neurological effects, have been suspected. For example, aspartame, the chemical in Equal and NutraSweet, may modulate brain neurotransmitters, such as dopamine, serotonin. Although data have been controversial, inconsistent, scientific opinions range anywhere from safe under all conditions to unsafe at any dose.
The controversy started in the ‘80s, soon after aspartame was approved. Researchers at the Massachusetts College of Pharmacy and MIT noted that given the very large number of Americans routinely exposed, if only 1% of the 100,000,000 Americans thought to consume aspartame ever exceed the sweetener’s accepted daily intake, and if only 1% of this group happen coincidentally to have an underlying disease that makes their brains vulnerable to the effects, then the number of people who might manifest adverse brain reactions attributable to aspartame could still be about 10,000, a number on the same order as the number of brain and nerve-related consumer complaints already registered with the FDA before they stopped accepting further reports of adverse reactions to the sweetener.
Who might be especially vulnerable? Those with a history of depression. Researchers at Case Western designed a study to ascertain whether individuals with mood disorders are particularly vulnerable to adverse effects of aspartame. Although they had planned on recruiting 40 patients with depression and 40 controls, the project was halted early by the Institutional Review Board for safety reasons because of the severity of reactions to aspartame within the group with a history of depression. It was decided that it was unethical to continue to expose people to the stuff.
It’s interesting, normally when you study something, a drug or a food, the company usually donates it to the researchers because they’re, you know, proud of the benefits or safety of their product, but the NutraSweet Company refused to even sell it to them, but they managed to get their hands on some, and within a week there were significantly more adverse effects reported in the aspartame group than in the placebo group. They concluded that individuals with mood disorders may be particularly sensitive to aspartame, and therefore its use in this population should be discouraged.
In a review of the direct and indirect cellular effects of aspartame on the brain, it was noted that there are reports of aspartame causing neurological and behavioral disturbances in sensitive individuals–headaches, insomnia, seizures, but they go further and propose that excessive aspartame ingestion might be involved in the development of certain mental disorders and also in compromised learning and emotional functioning. They conclude that due to all the adverse effects caused by aspartame, it is suggested that serious further testing and research be undertaken to eliminate any and all controversies, to which someone wrote into the journal that there really is no controversy; aspartame really is potentially toxic stuff.
But what do they mean excessive ingestion? Well, the latest study on the neurobehavioral effects of aspartame consumption put people on a high aspartame diet compared to a low aspartame diet. But, even the high dose at 25 mg/kg was only half the kind of limit set by the FDA. So, the FDA says one can safely consume 50 a day, but after just eight days on half that, participants had more irritable mood, exhibited more depression, and performed worse on certain brain function tests and these weren’t people with a pre-existing history of mental illness; these were just regular people.
They conclude that given that the higher intake level tested here was well below the maximum accepted daily intake level (40 in Europe, 50 here), careful consideration is warranted when consuming food products that may affect neurobehavioral health. Easier said than done, since it’s found in over 6,000 foods, apparently making artificial sweeteners impossible to completely eradicate from daily exposure. Impossible? While that may be true for the great majority of Americans, it’s only because they elect to eat processed foods. So that’s another reason to stick to whole foods. Then, you don’t even have to read the ingredients’ lists, because the healthiest foods in the supermarket are label-free; they don’t even have ingredient lists.
Sugar is no longer considered just empty calories, but an independent risk factor for cardiovascular disease. So what happens if you switch to artificial sweeteners? Here’s what we found out.
Recommendations to limit sugar consumption vary around the globe, with guidelines ranging from limit sweet desserts to one every other day to keep sugar consumption to 4 or less occasions per day. In the U.S., the American Heart Association is leading the charge, proposing dramatic reductions in the consumption of soft drinks and other sweetened products. They recommend sticking to under about 5% of calories a day from added sugars, which may not even allow a single can of soda. Why the American Heart Association? Because the overconsumption of added sugars has long been associated with an increased risk of cardiovascular disease, meaning heart disease and strokes. We used to think that added sugars were just a marker for an unhealthy diet. At fast food restaurants, people are probably more likely to order a cheeseburger with their super-sized soda than a salad.
But the new thinking is that, no, the added sugars in processed foods and drinks may be an independent risk factor in and of itself, worse than just empty calories, but actively disease-promoting calories, based on data like this.
This is how much sugar the American public is eating. Only about 1% meet the American Heart Association recommendation to push added sugar consumption to 5 or 6% of your daily caloric intake. Most people are up around 15%, and that’s where cardiovascular disease risk starts to take off, with a doubling of risk at 25% of calories, and a quadrupling of risk for those getting a third of their daily caloric intake from added sugar.
We went from eating 7 pounds of sugar every year 200 years ago, to 50 pounds, to now over 100 pounds of sugar. We’re hardwired to like sweet foods, because we evolved surrounded by fruit—not Fruit Loops. But, this adaptation is terribly misused and abused today, hijacked by the food industry for our pleasure, and their profits.
Why are we consuming so much sugar despite knowing how much it can harm us? Well, yes, it may have an addictive quality. Yes, there’s that hard-wiring, but the processed food industry isn’t helping.
Seventy-five percent of packaged food products in the United States contain added sweeteners, mostly coming from sugar-sweetened beverages, like soda, thought responsible for more than 100,000 deaths worldwide, and millions of years of healthy life lost.
No problem. Why not just switch to diet? By choosing diet soda, can’t we get the sweet taste we crave, without the downsides? Unfortunately, routine consumption of diet soft drinks is associated with increases in the same risks that many seek to avoid by using artificial sweeteners.
Here’s what studies have found for the increased risk of cardiovascular disease associated with regular soda, and here’s the cardiovascular risks associated with diet soda. In other words, the belief that switching to diet soda will reduce long-term health risks is not well supported by scientific evidence, and instead may contribute to the very health risks people were seeking to avoid in the first place. But why? I mean, it makes sense why drinking all that sugar might increase stroke risk, with the extra inflammation and triglycerides. But why, in this pair of Harvard studies, did a can of diet soda appear to increase stroke risk the same amount? Yes, maybe the caramel coloring in brown sodas, like colas, may play a role, but another possibility is that artificial sweeteners may increase the desire for sugar-sweetened, energy-dense beverages and foods.
See, the problem with artificial sweeteners is that there’s a disconnect that ultimately develops between the amount of sweetness the brain tastes and how much blood sugar ends up coming up to the brain. The brain feels cheated, and figures you have to eat more and more and more sweetness in order to get any calories out of it. As a consequence, at the end of the day, your brain says, okay, at some point I need some blood sugar here and then you eat an entire cake, because no one can hold out in the end.
If you give people Sprite, Sprite Zero, or unsweetened carbonated lemon-lime water, and you don’t tell them what is what, and what the study’s about, and then, later on, you offer them a choice; they can have M&Ms, spring water, or sugar-free gum. Guess who picks the M&Ms? Those that drank the artificially-sweetened soda were nearly three times more likely to take the candy than either those that consumed the sugar-sweetened drinks or the unsweetened drinks. So, it wasn’t a matter of sweet versus non-sweet, and it wasn’t a matter of calories versus no calories. There’s something about noncaloric sweeteners that tricks the brain.
Then, they did another study in which everyone was given Oreos, and they asked people how satisfied the cookies made them feel and, again, those that drank the Sprite Zero (the artificially-sweetened Sprite) reported feeling less satisfied than either the normal Sprite or the sparkling water. These results are consistent with recent brain imaging studies demonstrating that regular consumption of artificial sweeteners can alter the neural pathways responsible for the pleasure response to food. The only way to really prevent this problem, to break the addiction, is to go completely cold turkey and go off all sweeteners, artificial, as well as table sugar, and high fructose corn syrup. Eventually, the brain resets itself, and you don’t crave it as much.
We’ve always assumed that consumption of both sugar and artificial sweeteners may be changing our palates or taste preferences over time, increasing our desire for sweet foods and, unfortunately, the data on this were lacking–until now.
Twenty folks agreed to cut out all added sugars and artificial sweeteners for 2 weeks and, afterwards, 95% found that sweet foods and drinks tasted sweeter or too sweet, and said moving forward they would use less or even no sugar at all and most stopped craving sugar within the first week, 6 days. This suggests a two-week sugar challenge, or even one-week challenge, may help reset taste preferences and make consuming less or no sugar easier and, so, maybe we should be recommending it to our patients. Eating fewer processed foods and choosing more real, whole, plant-based foods make it easy to consume less sugar.
So, as it turns out, after all this, there are two sweeteners that are actually health-promoting. Which is healthier? In alphabetical order: agave nectar, blackstrap molasses, brown rice syrup, corn syrup, date sugar, dark brown sugar, light brown sugar, maple syrup, honey, raw cane sugar, plain old sugar sugar, or turbinado sugar. Two actually have some significant nutrition, but the rest are pretty much a wash. Let’s start filling this in. Should we start with an easy one to launch us off? Table sugar versus raw, pure, organic agave nectar. Which is worse? Does sugar have less nutrition or does agave nectar have less nutrition or do they both have the same? Remember how I asked if we should start out with an easy one? Well, I guess the answer is no. They both have exactly the same nutrition; which is to say, basically none.
There are only two health-promoting sweeteners, only two sweeteners that are actually good for you: molasses and date sugar. They’re both good, but out of curiosity, which one falls to second place. Do you think molasses is less healthy than date sugar or does date sugar fall to second place? The healthiest sweetener on the planet is date sugar. Date sugar is not really sugar; it’s just whole dried dates, pulverized into powder. As the only whole food up there, no wonder it’s number one. It’s the only thing I ever use in baking. Because it’s a whole plant food, it has fiber, though, so there is a thickening effect, which is great for smoothies or hot chocolate.
But what if you want to sweeten your tea or coffee? You don’t exactly want thick tea. Now, you could add sugar, but then you’re adding empty calories, and if you drink as much tea as you really should, that can add up.
To see any graphs, charts, graphics, images, or studies mentioned here, please go to the Nutrition Facts podcast landing page. There, you’ll find all the detailed information you need plus links to all the sources we cite for each of these topics.
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Thanks for listening to Nutrition Facts. I’m Dr. Michael Greger.