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There are other trusted sources besides health-care professionals. If you are
wading through the information on the Internet, stick to trusted sources like
known universities—Yale, Harvard, the Mayo Clinic, or Johns Hopkins.
There are also many
research institutions like
the National Institutes of
Health, the National Cancer
Institute, and the Muscular
Dystrophy Association.
There are professional
organizations for every
specialty, like the American
Academy of Pediatrics and
the American Academy of
Neurology. There are also
patient or disease advocacy
groups like the Multiple
Sclerosis Society.
But there are also a lot of
posers. Anyone can create
a snazzy website and make
it seem like they’re an
impressive organization.
Therefore, here are some
red
À
ags to look out for:
Beware of so-called institutes or organizations that seem to be doing nothing
more than promoting a single individual. Beware of sites that seem to be
trying to sell you something; they are probably distorting information to
make that sale. Also, beware of outliers. If you’re visiting various sites
that all seem to have one opinion, but Bob’s Institute of Syndrome X has a
completely different opinion, it’s probably Bob’s Institute that you should
be wary of. There are also well-meaning but misguided patient and disease-
oriented groups. There are groups that honestly want to do what’s best for
patients, sufferers, and society, but they don’t have a culture of science.
Don’t be afraid to ask questions of your health-
care providers.
© Hemera/Thinkstock.
4
Lecture 1: Medical Knowledge versus Misinformation
Finally, there is no substitute for just thinking critically. At the end of the
day, you have to think for yourself. Here are some more tips for reading
information on the Internet: (1) If something sounds too good to be true, it
probably is. If someone’s promising you
the cure for cancer, you should be a little
wary of that. (2) Don’t trust testimonials.
They are just anecdotes, and as we say,
the plural of anecdote is anecdotes, not
data. Sites use testimonials to support
their claims because they don’t have the
scienti
¿
c evidence to back them up. (3)
Look for contrary information and opinions. If someone is trying to sell you
a product, treatment, or therapy, speci
¿
cally go out of your way to see what
the critics of this are saying. (4) Finally, is there published, peer-reviewed
evidence? That’s the ultimate currency of medical information. Having a
peer-reviewed article is not a guarantee that the results will hold up over
time or that they’re accurate, but it’s at least a good starting point. To search
for this research yourself, go to the website PubMed.org.
Over the next 23 lectures, we’re going to go on a journey together through
many medical facts and myths. I will also discuss many controversial topics.
Some of these topics may touch very close to home on beliefs that you
have, and I ask you to listen with an open mind. My job is to go through
the scienti
¿
c literature, to try to make sense of the science as we understand
it today. Sometimes that may lead to conclusions that are not necessarily
popular or that are controversial. I also try to separate out real controversies
within the scienti
¿
c community itself from false controversies—ones where
the scienti
¿
c community is generally on the same page, but there are still
public opinions that are contrary. I’ll also try to make clear when I’m giving
you my own opinion or interpretation that may not be the de
¿
nitive answer
on a particular problem.
Ŷ
The best source of
reliable information is still
health-care professionals.
5
Note: Additional references for most lectures are listed at the end of
the Bibliography.
Bausell,
Snake Oil Science
.
Centers for Disease Control (website).
Ernst and Singh,
Trick or Treatment
.
Mayo Clinic Online Reference.
Sagan,
The Demon-Haunted World
.
Sampson and Vaughn,
Science Meets Alternative Medicine
.
Science-Based Medicine
(blog).
1.
How do we know which treatments are safe and effective for
which conditions?
2.
What role do you think informed consumers should play in their own
health care?
Suggested Reading
Questions to Consider
6
Lecture 2: Myths about W
ater and Hydration
Myths about Water and Hydration
Lecture 2
So-called juicy foods like fruit contain a great deal of water, maybe
60%–70%. There are some surprising foods, like a cooked hamburger,
that have 40%–50% water.
A
bout 65% of the adult body by weight is made up of water. We all
need water to survive, yet there are many misconceptions and much
false information out there about this most basic element of life.
How much water should we drink every day? If you are dehydrated, should
you drink beverages with caffeine in them? Are expensive water puri
¿
ers
really worth it?
The primary mechanism by which we maintain our hydration is thirst.
Thirst is a powerful emotion that motivates us to eat and drink. Thirst
actually serves two functions. First, it regulates the concentration of salt and
other electrolytes in our blood—a property of the blood and tissues called
osmolality. Also, it regulates the overall volume of water in our bodies.
The other primary mechanism by which our bodies regulate our own
À
uid
is urination. Many people ask how useful urine color is in determining
our overall state of hydration. It turns out that it’s actually a pretty good
rough marker.
Another way our body loses water is through sweating. Sweating primarily
is a mechanism to regulate body temperature, but it involves excreting saline
from our sweat glands. In hot and dry environments or with physical activity,
sweating can be a signi
¿
cant source of water loss. This may dramatically
increase the amount of
À
uid we need to drink in order to replace what we
lose through sweat.
One of the big myths of water is how much water we should drink every day.
Typically, you’ll hear that you need to drink eight 8-ounce glasses of water
per day. This myth probably originates from the Food and Nutrition Board,
which calculated the average water needs of an average adult with average
activity and environment and came up with the
¿
gure of 64 to 80 ounces per
7
day. However, in that same report, they also noted that most people get 20%
of their
À
uid intake from food. Thus, even if you need 64 or 80 ounces, you
don’t have to drink it all as water, and you don’t have to go out of your way
to count up how many glasses of water you’re drinking.
What about thirst myths? I’ve often heard that by the time you’re thirsty,
it’s too late—you are already dehydrated. When you think about it, that
doesn’t really make much sense, because thirst has evolved over millions
of years to be a mechanism to tightly regulate how much
À
uid we need in
our body. It wouldn’t work well if you didn’t become thirsty until after
it was too late. In general, you
can rely on your thirst. You will
become thirsty long before you are
actually dehydrated. Thirst works,
and you don’t have to force
À
uid
when you don’t feel like drinking.
What about the myth that caffeinated
drinks do not hydrate and in fact
will make your hydration worse?
This is based on a kernel of truth, as many myths are. Caffeine is a weak
diuretic; therefore, if you drink a lot of caffeine, it could plausibly make you
lose
À
uid. However, the diuretic effect of caffeine is actually very mild, and
the
À
uid in most caffeinated beverages will more than compensate for this
effect. If you’re out on a hot summer day and all you have is a caffeinated
beverage to drink, go ahead and drink it. It will still hydrate you.
What about special situations in which we need to pay more attention to
our hydration? In hot weather, we sweat more to cool ourselves off, and we
therefore lose more
À
uid. Whenever you’re in a warm or hot environment,
make sure you have access to
À
uid so that you can hydrate continuously.
Fortunately, our bodies also acclimate to a hot situation by holding onto
more
À
uid. Athletes often push human endurance to its limits, and water is
no exception. Athletes can lose as much as 2 liters of sweat per hour. That
means they may need to drink 12 liters of
À
uid in a day in order to just
maintain their hydration.
The diuretic effect of caffeine is
actually very mild, and the
À
uid
in most caffeinated beverages
will more than compensate for
this effect.