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Student Questions: Energy Shots and Sunscreen

Skeptoid answers another round of questions sent in by students.  

by Brian Dunning

Filed under Feedback & Questions

Skeptoid Podcast #268
July 26, 2011
Podcast transcript | Listen | Subscribe


Hot Tap Water
Don't drink hot water from the tap.
(Photo credit:

Although I ran, I've again been caught by students from around the world, and peppered with questions about what's science and what's silly. Today's classroom asks about the usefulness of those popular caffeinated energy shots; the various Internet myths about sunscreen products; the meaning of the word "information" when thermodynamics are invoked to prove creationism; companies that claim to offer the secrets of suppressed miracle cures for cancer; and whether drinking hot water from the tap is as risky as some rumors say it is. Let's get started with energy shots, from a young man in southern California:

Hi, Mr. Dunning. What's your take on those 5-Hour Energy Shots, and how they affect the users after the supposedly energetic five hour period?

Despite the manufacturers' claims, the only active ingredient in such energy drinks is caffeine. Caffeine is a psychoactive stimulant. It does not provide your body with energy fuel, like food does; instead it temporarily reduces drowsiness and increases your alertness. Anxiety is a primary side effect, and it's this that gives us the feeling of jumpiness. Caffeine temporarily increases our ability to tolerate both mental and physical work, and the effect usually wears off in 3 to 4 hours.

The amount of caffeine found in these beverages is controversial. It's common for testers to find more than is reported on the label. Generally they contain about the same as a cup of coffee, somewhere around 175 to 200 mg. This is about six times what the average caffeinated soft drink contains. That little bottle at the checkout stand packs the whallop of an entire six-pack of cola.

Many of these manufacturers state that their drinks contain vitamins, and this is where the energy boost actually comes from. But, basic nutrition tells us this makes no sense. Vitamins do not provide any usable energy; that comes from the calories in carbohydrates, fats, and even some proteins. Some have tried to backpedal and say their vitamins assist the metabolism of energy. This is basically true, but your body's normal supply of Vitamin B is more than enough to do this job, and supplementation is usually just wasted excess. This claim is risky ground for them to tread; if it were true, they'd basically be advising you to take a 5-cent vitamin pill instead of their overpriced drink.

Hi, this is Alex, a grad student from Arizona State University. I was wondering if any of the purported dangers of sunscreen are true. I've heard that some fail to actually protect from the UV light that causes cancer or that sunscreen itself is a carcinogen and causes health problems that outweigh the benefits.

You've raised two important questions that have been asked a lot in recent years: First, is sunscreen itself unhealthy or even carcinogenic; and second, are sunscreen SPF ratings actually true and reliable? Fortunately, the United States FDA issued new rules in June 2011 that answer both.

The first question is simple enough. There is no evidence that the ingredients in any commercially available sunscreen product have ever given anyone cancer or caused anyone to go blind, nor is there any plausible reason to suspect they might, when used as directed. Neither have any victims ever surfaced. This appears to be nothing more than your garden-variety Internet myth.

Manufacturers have a year from the date of the new ruling to comply with labeling rules that the consumer will finally be able to rely on. The FDA will basically allow two types of sunscreen labeling: "Broad spectrum" sunscreen, which provides protection against both UV-A and UV-B ultraviolet light, will be permitted to show an SPF of 15 or higher and will be labeled "broad spectrum". They will also carry labeling that states that when used as directed with other sun protection measures, they can reduce the risk of skin cancer and early skin aging. Other sunscreen products, with SPF of 14 or lower, will only be permitted to say that they have been shown only to help prevent sunburn, not skin cancer or early skin aging.

So look for sunscreen marked 15 or higher and that says Broad Spectrum, and you'll get the protection you expect, without fear of getting skin cancer directly from the lotion.

Hi Brian, my name's Lachlan McGowan and I study geology and law at the University of Newcastle, Australia. In my online battles with young-earth creationist trolls, I've noticed a new trend for them to use the word "information" to describe DNA. They talk about it being impossible to create new information, or about DNA losing information over time. However, I can't get a definition of "information" out of them, and the only places I can find the word "information" used in science outside of its conventional sense is in the deep physics of black holes and subatomic particles. Is the argument from information even vaguely valid, or is it equivalent to a homeopath's use of the word "quantum"?

Basically what they're doing here is misusing scientific sounding terminology that they've heard but don't properly understand. So to answer your final question, yes, it's exactly like New Agers throwing around the term "quantum" as if the word is an explanation supporting whatever they feel like claiming.

Classical information, like words printed in a book or the arrangement of proteins in DNA, can easily be created and destroyed all day long. One famous example is writing a book to create information, then burning it to destroy it. This does not violate entropy or thermodynamics or anything else, because quantum laws apply only in the quantum world, not in the classical world. Information in that sense refers to the quantum state of particles, which is not changed at all when a book is written or burned, or when a baby is conceived then dies and decomposes. So the reason you can't get a definition of "information" out of them is that they have no idea what kind of information the laws of thermodynamics refer to.

Their claimed paradox of DNA losing information over time is exactly analogous to taking their Bible and occasionally tearing a page out of it. There's no reason you can't do this, and doing so proves nothing. The quantum state of the particles in amino acids is not changed by the degradation of DNA, and the quantum state of the particles in the discarded Bible pages is not lost either.

Hi Brian, this is Michelle from Sydney Australia. I would like to know if you are aware of the group called "Health Sciences Institute" of Baltimore. They help themselves to my mother's bank account to the tune of about $80 a year I think and for this fee they share with her a monthy email about "secret" discoveries such as "A secret cure for cancer" which they say comes from an Amazonian tree called Graviola. I cant wait to hear what you have to say about this and their many other exposes of real but "secret" health cures. Thanks Brian!

Quack miracle health cures have always been, and will probably always continue to be, just about the most marketable products on the planet. 150 years ago, street corner Victorian pitchmen sold snake oil, and the promise of miracles was so perfect then that it hasn't had to be updated in any meaningful way. Throughout their history, the pitches for these cons have had three basic points:

  1. Make up, or read about, virtually any substance and call it a miracle cure for any condition you want.
  2. Give a testimonial from someone, real or invented makes no difference.
  3. Suggest that it's "secret" or suppressed by some conspiracy of the medical establishment; something "they" don't want you to know.

Your example hits all three points pretty squarely. No, I have not heard of your particular institute or their particular miracle cancer cure, but just Google "secret cancer cure" to see how innumerable these are (24 million results for the search I did just now). Why so popular? Consider your example; for $80 a year it's probably one guy who has to do nothing more than write one email a month. If he has 1,000 customers he's making a living. There will always be people desperate for a miracle (I'd love to have one myself), so there will always be someone happy to take their money to promise it.

Hi Brian, my name's Scott from the University of Melbourne. I've been brought up to think that I shouldn't drink hot water from the tap. Can I please get your thoughts on this?

This is an interesting case because the reasons for it are sound, and there is actually a risk; but the reality is that the risk is probably negligible. Tap water is not pure water, obviously. Even the cleanest and safest contains contaminants — chemical, mineral, and organic. Hot water dissolves contaminants more quickly than does cold water. The hot water pipes in your home (those between the water heater and your tap) are probably more corroded than the cold water pipes. Those corroded minerals, including lead from solder, end up in your glass when you fill it with hot tap water.

But consider the actual risk. Imagine a pile of all those corroded minerals on your desk after 20 years. It's probably not a very big pile, perhaps the size of a grapefruit or a melon, as a rough estimate. Consider that nearly all of it went through the bathtub, shower drain, dishwasher, or clothes washing machines. The tiny percentage of that total that went into your coffee mug, over 20 years, can probably be scooped up on your fingernail. That's it. It pales in comparison to what everyone gets environmentally just by existing on Earth. So, is it a real risk? Yes. Should you drink hot water from the tap? Not if you have an alternative. Do you need to worry about it? Probably not.

Infection by Legionella bacteria is another risk that's been discussed. Legionella can cause a potentially fatal infection. However, Legionella grows best in warm water, below 140 degrees, and most home hot water heaters are set to higher, which will kill it. In addition, the infection is transmitted by breathing in water vapor, not by drinking; so if you're going to catch Legionnaires' disease at home, it will be in the shower, not from drinking a glass of hot tap water.

By Brian Dunning

Please contact us with any corrections or feedback.


Cite this article:
Dunning, B. "Student Questions: Energy Shots and Sunscreen." Skeptoid Podcast. Skeptoid Media, 26 Jul 2011. Web. 27 Nov 2015. <>


References & Further Reading

Baldwin, R. "Information Theory and Creationism." TalkOrigins Archive., 14 Jul. 2005. Web. 22 Jul. 2011. <>

Barrett, S. "Questionable Cancer Therapies." Quackwatch. Stephen Barrett, MD, 4 Apr. 1997. Web. 22 Jul. 2011. <>

CDC. "Water." Lead. Centers for Disease Control and Prevention, 1 Jun. 2009. Web. 22 Jul. 2011. <>

FDA. FDA Sheds Light on Sunscreens. Washington, DC: US Food & Drug Administration, 2011.

Foster, J., Kallmyer, T. "Caffeine Content of Drinks." Energy Fiend., 13 Jan. 2006. Web. 22 Jul. 2011. <>

Park, J., Band, W. "Rigorous information-theoretic derivation of quantum-statistical thermodynamics." Foundations of Physics. 1 Jan. 1976, Volume 7: 233.


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