Artificial Sweeteners


Uploaded by C0nc0rdance on 29.07.2011

Transcript:
I want you to imagine it's 1878, and you're a young, 28 year old scientist named Constantin
Fahlberg working at Johns Hopkins on coal tar extracts. You head for home to have dinner
and you spot a bit of something on the back of your fingers, so being an evolved ape,
you lick it, or otherwise put your hand in your mouth. There's an intensely sweet flavor,
and you think, that's odd.
You've just discovered saccharin, or anhydro-ortho-sulphamine-benzoic acid, a substance over 200 times sweeter than
cane sugar. Congratulations, it will revolutionize the sweetener industry by starting a new class
of substances that are sweet without the same calories as sugars. It will also kick off
a search for other, similar substances that continues today.
We'll come back to saccharin in a minute.
Flash forward to 1937 at the University of Illinois. Graduate student Michael Sveda puts
down his cigarette, because, yes, he was smoking in the research lab, a common practice until
the 1970's. He was working on anti-pyretics, or anti-fever medications, but what ended
up on his cigarette was a substance called sodium cyclamate, brand name Sugar Twin.
Another lab, another day, 1965, James Schlatter, working for a company looking for stomach
ulcer medication, he was leafing through some lab papers, licked his finger, and the result
was aspartame, brand name Nutrasweet.
On to 1976, where a young Indian born scientist Shashikant Phadnis was evaluating new chemicals
for use in research products. His boss asked him to test a particular chlorinated form
of sucrose. He misunderstood and instead TASTED what would become sucralose, brand name Splenda.
Anyone else noticing a theme? I suspect the next big sweetener is waiting to be discovered
on the back of someone's lab book. I suggest any of you out there that work in labs begin
tasting every spill and stain on the bench.
Let's jump back to saccharin. Initially, it was recognized that it could benefit diabetics,
and it's low cost made it competitive with cane sugar, although many disliked the bitter
aftertaste. US President Teddy Roosevelt was quite a fan and user, and when the predecessor
of the FDA proposed regulation on the use of saccharin as a cheap substitute for sugar,
Teddy stepped in and formed his own scientific board to review the safety of saccharin. The
board returned a positive bill of health, and saccharin remained in use, thanks to Presidential
intercession.
Saccharin became very popular following sugar rationing during World War 2, and post-war
America continued to use saccharin as both a low-cost and low-calorie option. Everything
was great until the 1970's, when tests of the sweetener showed evidence of increased
risk of bladder cancer in rats. There were immediate calls to ban the substance, but
since it was the only diet sweetener on the market, it was left available but with a warning
label.
And so the world decided that saccharin was a carcinogen. The labels made that very clear,
and our memories are long on such things. Saccharin causes cancer. You knew that, right?
In late 2000, those labels were removed. They were removed because sachharin doesn't cause
cancer in humans like it does in rats. Rats have some distinctive urinary characteristics
that make them susceptible to saccharin's effects: they excrete protein complexes and
calcium phosphate in their urine. The saccharin was being excreted, but at high pH, it was
forming precipitates and this irritated the bladder lining, which resulted in a slight
increase in bladder cancer. If you have a pet rat, do not allow them to drink saccharin.
What about humans, though?
No linkage to human cancers has ever been well-demonstrated for saccharin. When the
unique properties of rat urine are taken into account, it appears to be harmless in them
as well. Most importantly for a possible carcinogen, saccharin doesn't interact with DNA, it's
not a mutagen, the mechanism by which most artificial substances promote cancer.
Admittedly, I hate the taste of saccharin, as do a lot of people. It has that terrible
bitter aftertaste and the flavor is just a little too fake tasting. But, even though
it's made from coal tar, it's about as safe as the sugar that's extracted from giant piles
of cane grass.
Switch focus to a more recent addition to the low calorie sweetener market in the US,
stevia or "stee-via" if you prefer. Stevia is a natural product extracted from a family
of shrubs and herbs. The key ingredient, a class of compounds called steviol glycosides,
are hundreds of times sweeter than sucrose, yet contribute very few calories, and can
actually be anti-inflammatory and have a positive effect on regulating blood sugar.
I want very much to love this sweetener, but there's a catch. Unlike saccharin, some or
all steviol glycosides are known to interact with DNA. Not much, mind you, and stevia has
been repeatedly cleared for carcinogenic activity, but it possesses the mutagenic potential that
saccharin does not. I'm not saying it's bad. I'm saying that escalating doses of it will
have escalating risks, where saccharin has a relatively flat risk.
I want to kick off this video with a short discussion of the appeal to nature fallacy.
You couldn't wish for a better example of it. Saccharin, which is made from oily coal
residue, is the epitome of artificial and chemical. Stevia, which is a fairly crude
extract of a leaf that has been used safely by people in South America and Japan for decades,
is the epitome of natural products. And yet their origins in the lab or the forest make
no difference in determining their safety.
Ultimately, we may conclude that stevia is a much safer product than saccharine, or that
they're both safe, but it's not where they come from that determines this. Carcinogens,
mutagens and toxins are found everywhere in nature. Pefectly safe substances can be made
from petroleum, coal tar, or industrial wastes. It's wrong to assume the other way as well.
Not every sweet-tasting stain on a lab notebook is going to be a boon to mankind, but until
we empirically test something for safety, there is no way to generalize based entirely
on where we found it.
There is an element of vitalism in this argument. A belief in the immaterial essence of something.
An artificial substance will carry with it the essence of something from the harsh lights
and acrid smell of the lab, where a natural substance carries only the warm sunshine and
soft earth. A simple reality check on substances like tobacco, mycotoxins and poison dart frogs
will dispel this, but it's still a tough instinct to shake, and it deeply colors people's perceptions
of artificial sweeteners.
There's another application of the appeal to nature fallacy, and that's the "argument
from evolution" fallacy. It's tempting to say that because we evolved to eat nuts and
roots that this diet is optimal for our biology. It sometimes happens that this is true, that
natural selection has weeded out undesirable traits or behaviors or eliminated toxins,
or that our physiology adapted to compensate for some external force. On the other hand,
natural selection is a very poor innovator. It's just as happy with a "good-enough" solution
to a problem as to the optimal solution. It's a hallmark of evolution that it never invents,
it only adapts existing structures to new tasks. So it's not a reasonable argument that
natural selection validates a diet or behavior as being optimal.
With this perspective in mind, let's examine just a few of the major low-calorie sweeteners.
Unfortunately, there are so many non-caloric sweeteners that I've had to narrow the field.
I've selected aspartame, sucralose, stevia, acesulfame potassium and some common sugar
alcohols as examples. We'll have to keep the details to a minimum to keep this short. Citations
in the underbar.
Before we start, I want to discuss the generalized benefits of low-calorie sweeteners.
1. It seems a bit redundant, but they're low-calorie. Unlike HFCS or sucrose, they don't contribute
to an excess of sugar calories which presumably means that consuming the same portion contributes
less to caloric excess, which can contribute to obesity.
2. They have a low glycemic index. With the notable exception of sugar alcohols which
we will get to, low-calorie sweeteners don't cause blood sugar spikes, which is important
for people with blood sugar dysregulation.
3. Here's a big one: they don't contribute to bacterial erosion of tooth enamel, so dental
health is improved.
I could add lower cost here, but I personally don't think that's the case to the consumer
anymore. Intense sweeteners have become associated with more expensive diet forms of popular
products.
What about the possible generic risks to any sweetener?
1. Over-compensation. This is a big one, and VERY controversial right now in the research
community. People MAY, and I emphasize MAY, give themselves permission to eat foods bad
for them if they also consume a product perceived as diet or low-calorie. Think of someone on
a weight-reduction diet who orders a Diet Coke with their McDonald's Triple Cheeseburger
and Large Fries. They might buy the Diet Coke and justify the rest because they're cutting
back on calories on the soda.
The research to date has found very little evidence of this. Most studies support the
use of low-calorie sweeteners for weight loss, but there are a few, especially on non-human
models, that show a paradoxical weight gain and the cause is not entirely clear.
2. Addiction to sweetness. Low-calorie sweeteners reinforce our brain's demand for sweeter flavors.
This might mean that we prefer foods with harsher additive derived flavors, rather than
adjusting to the softer sweetness of unmodified foods. I'm an advocate of a diet rich in vegetables
and fruit, but it would seem harder to get kids to eat strawberries for dessert if they
get used to supersweet candy or sugar-sweetened cakes and cookies.
Again, there is very little evidence to support this intuitive conclusion. When people are
presented with a choice of foods after drinking either sucrose sweetened or artificially sweetened
drinks, they still made the same choices, either good or bad.
3. Uncoupling the expectation of satiety and the blood sugar spike. Recent research has
focused on whether people eat more food after drinking a sugary drink or an artificially
sweetened drink. Our bodies anticipate meals, and begin preparing well before the first
calorie of food enters the mouth. If we anticipate a blood sugar spike, but none happens, what
effect will that have?
So far, the majority of studies point to no difference between sugar and, say aspartame
containing beverages on hunger, food selection and food intake, but it's worth further research.
The rest I'll save for discussion on the particular sweetners.
1. Aspartame. I did briefly discuss aspartame in my video on MSG, because they're related
compounds. Aspartame is aspartic acid and phenylalanine joined with a methanol backbone.
Both of these subunits, called amino acids, are found throughout your body, as part of
proteins. The methanol is processed very rapidly in your liver and detoxified.
Now if you are the type who forwards emails about aspartame being linked to MS or lupus,
there's very little I could do to convince you. The same for people who think Joe Mercola
is an authority on health research or who believe that the government is controlling
your brain waves through secret military broadcasts.
For those of you who care about evidence and understand how science works, aspartame is
one of the most studied sweeteners. We're pretty certain that for healthy, normal people,
there are no adverse effects below a certain threshold that your body can handle. That
amount is around 50 milligrams per kilogram of body weight. So a 160 pound person could
handle 3600 milligrams, or 3.6 grams.
A packet of Equal contains about 33 milligams, so about 110 of those in a day would exceed
your daily allowance. Diet Coke, on the other hand, contains about 131 mg per can, so more
than 27 of those per day would be a real problem. Of course, you'll need to do some label-hunting
to find all the diet products that contain aspartame.
Certain rare individuals with a condition called phenylketonuria should avoid anything
with aspartame in it, as they're unable to break down excess phenylalanine and it builds
up to toxic levels.
Is aspartame linked to chronic disease? Animals have been subjected to amounts 100 times the
safe level in humans for periods of months with no increase in cancer or chronic disease.
The weight of the published evidence is that consuming a safe level of aspartame does not
increase your risk for any disease.
I anticipate someone is going to cite the claim that in a critical review of papers
on safety, those studies that were funded by industry were 100% in support, while papers
by independent agencies identified problems in 92% of cases. I spent a little time reviewing
the two lists, and I identified the cause of the disparity. The industry supported papers
were tests of safety in dietary consumption. The independent papers were in one of three
categories: 1. Known activists opposed to excitotoxins.
2. Using aspartame to induce an animal disease model not observed in humans.
3. Documenting cases of sensitivity to aspartame with symptoms like dizziness, headaches, or
mood disorders not revealing serious chronic disease.
I have no doubt that funding sources bias research, but in this case the very worst
effect found was an increased potential for seizures in certain animal models at extremely
high doses. The same effect has not been observed in humans at safe doses.
2. Sucralose
Sucralose is a chlorinated sugar compound. The marketing slogan is "Made from sugar so
it tastes like sugar" which is attempting to harness the argument from nature. Three
of the hydroxyl groups in sucrose have been replaced by chlorine. As a result, it's largely
unmetabolized and therefore low calorie. It also makes it about 600 times sweeter than
sucrose, so very small amounts are needed. So little is needed that it's almost always
sold with a filler material, usually a blend that includes maltodextrin, which is itself
a sugar.
Critics of sucralose will point out that organochlorides or chlorocarbons are not common in nature
and include a number of particularly nasty toxins. However, sucralose, of all the sweeteners,
seems to have the strongest evidence in favor of safety. Rat studies have been conducted
at escalated doses over a two year time course from fetus to late adult, and the rats had
no increase in disease or cancer, and a general reduction in weight gain, although this was
found later to be complicated by the fact that the high sucralose was less palatable
to rats. The rats that were fed 3% sucralose did have elevated risk of certain renal conditions
at older ages, but this was attributable to the fact that so much sweetener was being
processed by the kidney that is sometimes mineralized there, much like the issue saccharin
had in rats. At relevant doses, there was no risk escalation. I still think we need
to keep an eye on any substance that is excreted in urine, but there's no good evidence to
be especially concerned about this in Splenda-type products.
One initial study in the 90's found some shrinking of the thymus in a rat population, but this
result couldn't be repeated by other groups, and it's likely it was a statistical fluke.
An interesting source I came across is the CSPI, or Center for Science in the Public
Interest, a research watchdog group with no industry ties or support. They tend to be
hyper-sensitive to risks and lean towards anti-corporate perspectives, but while they
are critical of lack of data on aspartame and some other sweeteners, they rate sucralose
as safe, the only sweetener to get this rating.
I'll be honest, I found that pretty compelling. They scrutinize both the research and regulatory
data before making a call, and it says a lot that they put sucralose in a category of safe
to consume. If you must drink sweetened sodas, I think looking for Splenda-sweetened wouldn't
be a terrible idea.
3. Stevia
I think steviosides will ultimately be a safe and useful sweetener, they have a long tradition
of apparently safe use in Japan and South America, and they have some really great side
effects. They are anti-inflammatory, as I mentioned, and they seem to help regulate
blood sugar properly. There is some weak evidence to suggest that products in stevia may be
useful in treating chronic diseases.
Steviosides are almost completely untouched by our digestive system, but the gut bacteria
often process it from stevioside to steviol, which usually exits the body in feces, but
steviol can be a nasty substance at extremely high doses. In pregnant hamsters, at levels
100 times the level humans might consume, it caused severe toxicity to both the mom
and fetus. It also caused defects in sperm production in male hamsters, and we know it
interacts with DNA, which is usually an indication that it can lead to both cancer and birth
defects. Very recently studies have also raised some concern about effects of excretion in
the kidney, something we also saw in aspartame and sucralose.
Right now, you can't sell stevia extracts as a sweetener. The FDA looks the other way
if they're labeled as dietary supplements, which is a loophole I've never liked. However
a purified component of stevia called RebA has been approved as a commercial sweetener.
It's manufactured by Cargill and Merisant, and marketed by Coca Cola as Truvia or Purevia.
You'll see Truvia sweetened products on the shelf very soon, if you haven't already.
The CSPI and some toxicologists from UCLA urged the FDA not to approve stevia or RebA
until further studies can be completed, and I have to say I agree, but in 2008, they granted
RebA generally recognized as safe, or GRAS status. On the other hand, applications in
Canada and Europe were rejected.
4. Acesulfame Potassium
I'm going to call this one ACK for short. It's about 200 times sweeter than sugar, and
like sucralose, it largely passes through the body unmetabolized. However, unlike sucralose,
there is some evidence that it looks just enough like a carbohydrate to stimulate a
dose-dependent insulin response, which makes me a bit concerned.
What bothers me most about ACK is the lack of data. It's a bit odd to find over a thousand
papers on aspartame in PubMed, but only 100 on ACK. I'm not the only person to notice
this. There were really only three large-scale tests of toxicity done, and none of them were
very powerful tests. There were even some troubling findings around cancer risk. My
only explanation is that this work was done in the 1970's in the US, and there was a growing
need for some sweetener to replace saccharin.
The CSPI and I agree here as well. I would probably avoid ACK, when possible, or keep
my consumption to a very low level. I'd really like to see more testing done here. A modern
revisit to ACK's safety is probably long overdue.
The reason why this deficiency really bothers me is the new trend for blending sweeteners.
Manufacturers are looking to find a combination of intense sweeteners that have certain properties
like aftertaste and bulk, hiding bitter flavor components, or shelf-life stability. If an
unsafe sweetener is blended with a safe one, it will be very hard for those of us with
concerns to control our intake.
5. Sugar alcohols
I want to end on sugar alcohols, which are not necessarily low-calorie nor low-GI. In
fact, your body can utilize some sugar alcohols quite effectively, after some processing.
There's a lot of variation in this category. Only erythritol and arabitol would qualify
as intense sweeteners, or low-calorie. Sorbitol and maltitol, frequently used by low-carb
dieters, are actually higher calorie than the same sweetness of sucrose. One of the
more common places to find sugar alcohols are in candies and sugarless gum.
Sugar alcohols are almost certainly non-carcinogens and non-mutagens, but if you've ever eaten
too much of them, you know what the primary problem is: gastrointestinal distress. Somewhere
between 10 gram and 40 grams you cross a threshold where you have gas, bloating, diarrhea, and
this can even be severe in sensitive people.
The challenge is that this inflammation can lead to abnormal digestive function which
can lead to obesity, so it can be self defeating. My simple suggestion is to avoid all sugar
alcohols except xylitol, which you should be careful not to over-consume.
In my last video on sweeteners, I covered sucrose and high fructose corn syrup. I concluded
that both were equally bad. They represent the collision of our desire for sweetness
with the continuous availability of caloric sources of sweetness, and they put us at risk
for chronic disease and obesity.
With the high intensity sweeteners, we still satisfy that craving for sweetness, but with
fewer calories. It's a solution to a problem that's sorely needed. If I had to choose a
sweetener on the basis of safety, I would probably prefer Sucralose. The ones I have
concerns about are ACK and stevia.
The best solution, I suspect, isn't the product of a laboratory. It's a modification of behavior.
We need to adjust our taste palettes to the natural flavors of healthy foods. Given the
choice between sucrose, high fructose corn syrup and almost any of the sweeteners on
this list, I'd say whatever you can do to avoid excess of sugar calories is probably
best.
Thanks for watching.