hey guys, today we're going to take a look at artificial sweeteners. are they effective, are
they worth it, are they safe? a new study looked at the health consequences of consuming artificial
sweeteners. they focused on soda specifically, which is the number one source of added sugars
in a lot of western countries. when science is communicated on websites, in newspapers,
on social media, the problem is that a lot of times there's a focus on an isolated study,
especially if it has like a sensational or surprising finding. that's where this confusion of
eggs are good one day and bad the next comes from. but of course, studies don't happen in a vacuum,
they have a whole history and a context and if we understand a little bit of that context,
a lot of the confusion goes away. so some prior studies have found that people who consume
more diet soda tend to have higher risk of weight gain, diabetes, cardiovascular disease, even risk
of death. so what's the problem with this? it doesn't necessarily tell us if it's the diet soda
causing these problems. who are the people who are most likely to consume a lot of diet soda?
the ones who are already worried about their weight. people who are overweight,
obese and with a history of struggling with their weight. this reminds me of something i read once,
they came up with a program to help people quit smoking: dvds, group meetings, hypnosis
etc. then they wanted to know if the program actually worked, maybe to advertise about it,
so they ran a study. they looked at their former students who had already gone through the program.
lo and behold, they found that they actually had a higher rate of lung cancer than the average
in the population at large. so this got a lot of people panicked that maybe the program was
giving people cancer, maybe it was something in the the lining of the dvds or something.
but of course, you're selecting for a group of people that are all smokers, that probably
smoke quite a lot, that have smoked for years and who have struggled to quit, who maybe even have
other unhealthy habits that they also struggle to leave behind. this phenomenon is called reverse
causation, precisely because the cause and effect relationship is in the opposite direction of what
one might think at first glance. it wasn't dvds giving people cancer, it's the habit that causes
cancer that leads people to buy the dvds. reverse causation is not rare, it happens quite a bit in
biomedical science, we actually talked about it in the context of cholesterol and mortality, so it's
something that scientists always have in the back of their minds when looking at data like this. so
this new analysis tried to go a little beyond with their statistical approach and their methodology
to reduce the chances of reverse causation and to increase the odds that we're actually
looking at the effect of diet soda on health. so they looked at specific swaps: diet soda instead
of regular soda, head to head, water instead of regular soda and diet soda instead of water. they
also adjusted for several potential confounders, like fat mass at the beginning of the experiment,
to try to get fatness out of the equation, and they also adjusted for things like smoking,
exercise, alcohol consumption etc. okay so what did they find? diet soda generally outperformed
regular soda. people making that swap to diet soda tended to have lower body weight, lower bmi, lower
risk of coronary heart disease and lower risk of death. water also outperformed regular soda. not
news flash, I guess. that swap was associated with lower body weight, waist circumference, body fat,
bmi and lower risk of developing type 2 diabetes. and finally, when they compared water versus diet
soda, they didn't find any statistically significant differences. they looked at
body weight, bmi, type 2 diabetes and stroke, and there was no significant difference. now,
of course it's really hard to completely rule out an adverse effect of something, for example
the mean follow-up, the mean length of time that they followed the participants, was 17.5 years.
we can always hypothesize that maybe after 30 years something pops up. or maybe it's a different
disease that they didn't test for. so there's always a level of uncertainty, this is something
we have to get used to, we have this idea that science is black and white, 100% certainty, but
the reality is almost the opposite of that, it's actually a gradient of confidence, our confidence
gradually and incrementally grows as more and more evidence piles up. one thing we can do to increase
our confidence is look at randomized clinical trials. now, those are not going to last 17 years,
not even close, usually something like weeks to months, but we can ask if those
short-term changes generally align with the observations from these large population studies,
if they point in the same general direction, or if they indicate any concerns. so for example
this meta-analysis of randomized controlled trials found that sweeteners helped reduce body weight
and bmi compared to regular sugar. and there was no significant difference compared to water.
this one found that sweeteners reduced energy intake compared to regular sucrose,
by about 250 to 500 kilocalories a day, which is pretty dramatic, and accordingly, they reduced
bmi. okay, so they seem effective, that's good to know. but some people worry they may mess up our
metabolism, like raise glucose or cholesterol, so are they safe? in this same trial, there was
no significant effect of sweeteners on glycated hemoglobin, so hemoglobin a1c, insulin resistance,
cholesterol or triglycerides. this one looked at the components of stevia specifically. stevia is
not artificial, it's a natural extract of a plant, but it's one of the common sweeteners that people
use so we're looking at that as well. so in this study it seemed to reduce diastolic blood pressure
and fasting glucose and there was no significant effect on blood lipids like
cholesterol and triglycerides. this one looked at saccharin specifically. that's the component
in sweet´n low. and it had no significant effect on glucose metabolism after two weeks of taking
the sweetener. their glucose and insulin response to a meal was unchanged. now, i've seen a couple
of studies that did report a change in some of these parameters in an undesirable direction
so we'll go over them real quick so you have the full information. for example,
this one found no significant effect of artificial sweeteners on triglycerides or cholesterol,
although when they looked specifically at people with normal ldl-cholesterol levels, there was a
slight increase of 4 points, 4 milligrams per deciliter, so small but something to bear in
mind. and this one looked at sucralose, which is a component of splenda, and after 10 weeks of taking
it they found no significant change in the vast majority of parameters, including fasting glucose,
hemoglobin a1c, insulin, insulin resistance and triglycerides and cholesterol. they did find
some differences specifically in the response to a meal, what's called postprandial response.
postprandial glucose and insulin were a little higher after the trial than before. it was a small
difference but it was statistically significant. so that's a summary of what I've seen,
overall these sweeteners seem to help with weight loss compared to sugar and most studies indicate
safety, with no major difference in the vast majority of the measurements, with a couple of
observations here and there that do point to some uncertainty and the need to keep researching. now,
quick note on funding, this study per se was not funded by industry but the authors disclose a
number of ties to the food industry, from beef to the almond board to sweetener associations
and a bunch of other players in big food. that's stuff like funding they got for previous projects
or speakers fees or advisory positions. stuff like that. so i thought this would be a good
opportunity to touch on funding for a minute, because it's something that i normally don't
focus on but it's a common question from viewers. who funded the study? where did that funding come
from? the reason i normally don't focus much on it is that the source of funding doesn't change
the appraisal of the science. normally when you're going through a study, there's a number
of specific things you're looking for in terms of the methodology and how it's conducted, and if the
study is shoddy methodologically, i don't care if the authors paid for it out of their own pocket,
that study is not going to have a lot of weight. and vice versa, if it's methodologically robust,
really well conducted, world-class, top-notch, the funding source alone is not going to change
that. that's not to say that biases don't exist. key distinction. right? incentives matter, we're
all human and there are analyses showing industry funded studies have a higher rate of findings that
are favorable to that industry. but that doesn't help me when i'm evaluating a specific study. how
do i know if this one is robust and reliable? methodology. so there are issues with industry
funding in many fields of biology and medicine, not specific to nutrition, there are other
organizational, institutional issues as well, like the publishing industry, how that works,
sort of the incentives, it's good to be aware of all of that but none of that means that we dismiss
evidence strictly based on funding. i've heard people say that if i dismiss a piece of data
strictly because of funding without having anything scientific to object to, the bias may
actually be on my end, and there's some truth to that. and i see this all the time, i post studies
on social media and often you see complaints, if it's a study showing some benefits of
dairy there'll be somebody called vegan Steve, if it's benefits of whole grains it´ll be low carb
bob or something like that, and you can often tell they haven't actually looked at the study,
it's this reflexive thing "oh that funding is probably coming from the dairy industry". so
it's become kind of a crutch to dismiss results that are undesirable. so we don't want to do that,
we want to judge science based on its merits. the way we increase our confidence in a given finding
is reproducibility. we want to see it replicated by different teams, in different countries, across
different studies. so i'll continue to keep an eye on this field, if compelling evidence of harm
comes up, i'll make another video, i don't have a horse in this race, i don't consume artificial
sweeteners or regular table sugar, i don't drink soda of any kind, so for me, if artificial
sweeteners turn out to be mega safe or whether concerns pop up, fine with me either way. for now,
most of the evidence suggests relative safety, at least within the context where it's been tested,
with some uncertainty for sure, but i haven't seen any clear evidence of harm. there's been
some scary data in mice, for example, but animal research is basically hypothesis-generating,
often things just don't pan out in humans. one thing that happens a lot in animal research
is they concentrate compounds a lot, hundreds, sometimes thousands of times, and one advantage
of artificial sweeteners is precisely that they are much sweeter than regular sugar.
so for example, aspartame is 200 times sweeter than sugar, and sucralose in splenda is
600 times sweeter. stevia is intermediate, 2 to 400 times sweeter than sugar. so that means
that to achieve the same level of sweetness you need a much smaller amount. in fact, when you
use those little packets, a lot of that powder is filler, it's not sweetener molecule per se.
now, there is an exception, people who have a condition called phenylketonuria, it's a rare
genetic disorder and people who have it should avoid aspartame specifically because they have
a hard time metabolizing one of its components. also, for people with gut sensitivities like ibs,
some sweeteners might cause gastrointestinal symptoms, especially the alcohols like sorbitol
or mannitol. another common concern that comes up with artificial sweeteners is the effect on
cancer. so there are associations with cancer in some studies, for example this study published
this year got a lot of buzz, they found intake of artificial sweeteners, especially aspartame
and acesulfame potassium, were associated with a higher risk of cancer. now, i think there
are plenty of caveats to these findings, first, there's inconsistency, the association is seen
in some studies but not others, and second, it could just be reverse causation as we saw,
people who have a history of obesity, which is a risk factor for cancer, so they take sweeteners,
rather than the sweeteners themselves causing cancer. the truth is, i don't think anyone
can say with 100% certainty. another common question is the effect of artificial sweeteners
on the microbiome, and there isn't that much evidence on it, there are a few trials published
and there is some inconsistency. so the artificial sweetener and microbiome question
stems largely from this study, published eight years ago. they found changes in the microbiome
of lab mice that were given artificial sweeteners, so they ran a pilot experiment
with seven people where they gave them saccharin, which is sweet´n low, for a few days and saw
some changes that mirrored the mouse findings. now, because of the small size and the design,
this was always going to be preliminary and needed confirmation, so this trial tested that idea,
and it was a double-blinded placebo-controlled randomized trial with 54 participants
so much more compelling. and they gave half of the volunteers saccharine for two weeks
and did not see that effect on the microbiome that was reported in the smaller study. now,
to make matters a bit more interesting, because science likes to keep us on our toes, another
trial published only a couple months ago this year looked at people taking sucralose, so splenda, and
did see some changes in microbiome composition. the exact effect of that change in bugs in our gut
is not clear, the microbiome is very complex, we don't even understand it completely yet,
so i think these are valid, interesting questions that hopefully more science will answer. so here's
the bottom line from everything we've looked at, here's the advice i would give maybe a
close family member based on the available science that I've seen: if someone's drinking
a lot of regular soda and if diet soda helps them cut back, that seems like a good move,
the data is pretty compelling that artificial sweeteners are healthier than regular sugar. on
the other end of the spectrum, for somebody like me who isn't consuming any soda,
i don't see any reason to start consuming diet soda. so those two are pretty straightforward,
where it gets interesting is people who are consuming diet soda, should they cut back? and
that's a bit of an educated guess, it's a judgment call, right? what i would tell my hypothetical
family member is, if you can cut back without it being this massive struggle, this suffering,
and without risking falling back on regular soda, then i would treat the diet sodas, the
artificial sweeteners, as training wheels. but if there's a risk of relapsing back to regular soda,
then you're better off staying on the diet soda with the artificial sweeteners. bear in mind,
dose is always an important factor, these results are for typical levels of consumption,
if somebody's having ungodly amounts of diet soda like 30 cans a day or something crazy like that,
then who knows, all bets are off. another concept that might help think about all this
is time. most of the evidence, and the strongest evidence, is shorter term, over weeks or months,
so our confidence in the safety of these products is going to be highest for that time span
and slowly decrease with years and decades of use. using sweeteners consistently for 40 years might
be perfectly safe, it's just that our ability to say for sure decreases with the passing of
time. there are significant areas of uncertainty in the research and there are valid questions so
to say that we're 100% sure there is no issue it's just not true. but also, to confidently
claim that artificial sweeteners are toxic and damaging as i've seen sometimes on social media,
is not serious and not evidence-based. okay, among all the options available, is there one product
that's better or safer? i haven't seen consistent evidence of superiority of any of them in these
analyses. some people seem to prefer stevia, i think because it's natural, i haven't seen
any evidence of harm so far. one obvious strategy for somebody who wants to cut back on diet sodas
is to transition to water or tea or coffee or some juice, and you can add sweetener to taste
initially and then slowly lower the amount over time and wean yourself off gradually.
for some more ideas on how to cut back on refined sugar, check out this video, and this one goes
over weight loss in general. let me know your thoughts below, take care, see you next time