Have you heard that
sugar-free sweets may not be as healthy as you thought? Fear not, Dr. Linda
Bartoshuk has collaborated with colleagues in horticulture to increase the palatability
of fruits and vegetables. That work led to a new way to sweeten foods and
beverages, which may reduce dependence on sugar and artificial sweeteners. Will
sugar enhancers replace artificial sweeteners? Dr. Bartoshuk tells us all about
it, plus she explains how you can tell if you are a supertaster and more.
As a woman, what was your
most challenging moment getting through college in the 50s?
wasn’t that bad, because Carlton College faculty were very sensitive about
female students. But when I got to graduate school at Brown, I wanted to work
with Dr. Carl Pfaffmann who refused to let me in his lab. This shocked me, and
his male students wouldn’t have it. They thought it was unfair, and one of them
taught me what to say and how to do a preparation that Pfaffmann
for. In return, Pfaffmann quite wrongly developed the impression that I was
unusual for a woman because I was quite aggressive and insistent. He liked
that, so he took me into the lab.
After I graduated, I gave a talk at Brown, and the female graduate
students wanted to know how bad it had been when I was there. The interesting
thing is that I didn’t perceive these problems at the time. It was true that
there weren’t very many women in science and math classes, but at that time I
perceived that to be choice.
What has been the most
beneficial project that you have taken part in?
It probably was the
discovery of supertasters, where I found out that our technique of measuring
sensations was not giving us valid comparisons. That’s when I realized that we
had to do it better. For example,
if you’re in the hospital, a nurse will ask
how much pain you are in on a scale from 0 (no pain) to 10 (most
you have ever experienced). If you feel your pain decrease
from seven to two, that’s a legitimate comparison. That means that
did decrease. But what happens
if the nurse compares your numbers with someone
else’s? Is that legitimate? No, because we don’t know what 10 means to each of
you. We have no idea if you’ve been in much worse pain than your roommate, and
that makes the comparison meaningless. I realized that this was true about
taste too. There must be differences here as well, and we have to be able to
make a legitimate comparison.
Since then, we have learned that a supertaster (e.g, someone with sixty
fungiform papillae in a 6 mm circle on the tip of the tongue) lives in a neon
food world compared to someone with fewer fungiform papillae (e.g., five in the
circle) who lives in a pastel taste world. As a psychologist, what really
interests me is that food behavior between these people is not the same. For
one thing, supertasters have much more extreme likes and dislikes. If we ask a
supertaster and someone who is not a supertaster to rate how much pleasure they
get from their favorite foods and how much displeasure they get from their
least favorite foods, the supertaster will give much more extreme ratings.
We’re now studying other things, and it looks like this is going to be true
about some emotional experiences as well.
How can we find out if we
supertasters or nontasters on our own?
you can do is put blue food coloring on your tongue. Fungiform papillae are the
round structures on your tongue that will not pick up the dye, so suddenly you
will have either light blue or pink circles on your tongue. Use a template of a
six millimeter hole—the size of a paper punch. You lay
that hole on the tongue,
so that the edge of the hole touches the tip, and you count how many you see.
The more fungiform that
you have correlates with taste intensity. My daughter
is at the extreme end with only five fungiform papillae’s in that circle. One
of the best supertasters that I’ve encountered had sixty. It’s a very big
difference, and you can see it if you get a bunch of people and stain their
tongues and look at them.
There are obvious
evolutionary advantages and disadvantages in being a supertaster. However, your
studies show that more women are supertasters than men. What could be some of
the reasons for this?
minute you hear that women are supertasters, you think, "ah!, it protects
fetus,” because bitter tastes tend to be a signal for poison. So you could
argue that supertasting women have an advantage because they can help protect a
fetus better by avoiding poisons, but I don’t know if that’s true or not.
Picture a Neanderthal tribe moving into a new area where they don’t know what’s
safe to eat. I imagine the chief sending his wife out because she is a
supertaster, so she tastes the bad plants as bitter and warns the rest of the
tribe. Now did this ever really happen? Heaven knows, but it helps you see what
a difference being a supertaster or not could make.
There are a couple other cases too. For example, pellagra is endemic in
areas of South American. One of the things that you can do to stave of pellagra
is to drink very strong coffee, because the ingredients in coffee metabolize
into the niacin that you are missing. If you look into these areas, you will
discover more nontasters than you would expect, because these are the people
can take the bitter coffee. In another area
in South America, plants are
goitrogens—meaning that your health is impaired if
you eat them. In that area,
there are many supertasters, because they were able to avoid these plants.
How is the new idea of
sugar enhancement different from an artificial sweetener?
to your nose in two ways. You sniff them and they come through your nostrils by
orthonasal olfaction. Or you put food in your mouth and the volatiles are
forced up your nose from the back of the throat through retronasal olfaction.
The brain treats the two routes differently. It sends orthonasal olfaction to
one part of the brain, and retronasal olfaction to another, combining it with
taste. When retronasal olfaction and taste come together to form flavor, they
can enhance each other through circumstances, which we are trying to
We did a study on tomatoes with Harry Klee who planted 80 different
heirloom tomatoes. What was interesting was that some of the tomatoes were
sweeter than the sugar content would have predicted. We did multiple regressions,
and it turned out that some volatiles—aka the simple gaseous odor in the
tomatoes detected through retronasal olfaction—enhance sweetness. The more of
those volatiles that are in a tomato, the sweeter that tomato is. Other
volatiles can suppress sweetness.
All of a sudden we were uncovering these volatile effects that we didn’t
know were operating in fruit. Then we wondered if we can take these volatiles
out of a fruit and put them in something else so that they’ll enhance a flavor,
and it looks like we can. A mixture of the correct volatiles with a small
amount of sugar will produce a much stronger sweet. In that way, we wouldn’t be
using it as a substitute sweetener. We’d be using it to intensify the sugar
that’s already there.
What can we expect from
you in the future?
commercial implications of finding a completely safe sweet enhancer are very
important to the university. Imagine if we could give you some kind of syrup to
add to something with a really bad taste, and the bad taste would go away. We
know that sweet inhibits bitter really well. We think that’s going to be
another direction to go in.
For the next few years, my job will be to get the basic research done
that will tell us the properties of this effect and whether it will work in
certain applications. If this is true, of course we all dream that it’s going
to be the next Gatorade, which made a fortune for the University of Florida.
Wouldn’t it be great if this enhancement of sugar did the same?
Now, is it a good idea to enhance sweet taste? That’s another thing that
should be examined. You know there is new research suggesting that artificial
sweeteners don’t help us lose weight at all. In fact, you gain weight with
them. This is work done by Swithers and Davidson at Purdue, and it’s really
good work. So is producing the sensation of more sweets with volatiles going to
be a good thing? We don’t know. But the point is that we can find out.
What advice can you give
an up-and-coming woman interested in math or science today?
people have given me practical advice, such as, "Well, it would be better if
you did this thing or the other.” But frankly, I don’t think any of that paid
off. What I think is important, is that you do something you love. Go with your
heart. If you’re doing work that you love, whether you’re wildly successful or
not, at least every day is an adventure, and that is something wonderful.