Author Archives: Jenn_Labrie

Sea lampreys help scientists fill in gaps in our evolutionary history

A group of researchers at the University of British Columbia recently found that sea lampreys, an ancient species of jawless fish, appear to respond to stress much more differently than scientists originally thought.

Many species of lampreys are parasitic. Sea lampreys lack jaws and have suction-cup-like mouths that are lined with teeth, which they use to latch onto fish and suck their blood.
Source: Shutterstock.

The paper, which was published in General and Comparative Endocrinology in 2013, detailed a two-year-long experiment that culminated in some unexpected results. The researchers were attempting to determine whether previous assumptions about stress regulation in lampreys were true. By injecting lampreys with certain chemicals, called hormones, that are turned into “stress hormones” in other vertebrates, the researchers checked the lampreys’ blood levels for these “precursors” and for the stress hormone, cortisol, to see whether lampreys also turned each of these precursors into cortisol.

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Simplified diagram of the classic stress response seen in many vertebrates.
Source: Jenny Labrie.

For years scientists had assumed that lampreys, like other fish, had a stress response that involved the same three types of hormones – corticotropin-releasing hormone (CRH), adrenocorticotropin (ACTH), and cortisol – that are seen in humans and other animals. These three hormones and their involvement in the stress pathway is discussed in the video below, as well as what is already thought to be true about the evolution of the stress pathway.

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The researchers found that, similar to other animals and to fish, lampreys do respond to CRH with increased levels of stress. CRH is a precursor to stress hormones in different species; in humans it is cortisol, which has been popularised over the past few decades as the concept of “stress” has received increasing amounts of attention – both from academia and the popular media. The lampreys injected with CRH displayed increases in their own type of cortisol, indicating that they were indeed experiencing stress in response, just as humans would.

Unexpectedly, the lampreys did not respond to several types of ACTH that they were injected with. In both humans and other fish, ACTH is the hormone that is released in response to CRH and eventually stimulates cortisol release, which causes classic signs of an activated stress response (e.g., increased heart rate).

What does this mean? Well, yes, scientists were once again mistaken; lampreys are not just like every other fish. But why should this matter? Who cares about this 505-million-year-old fish?

Click image to enlarge.
Source: Wikimedia Commons. Originally illustrated by Ernst Haeckel, and published in ‘Generelle Morphologie der Organismen’ (1866).

As it turns out, we all should. Contrary to popular opinion, scientists don’t know everything there is to know about human evolution, but we can fill in some of our knowledge gaps by studying lampreys. A better understanding of stress regulation in lampreys helps us better understand how this system has evolved since the time of these early vertebrates. Humans diverged from lampreys 500 million years ago, and we are related to them – as uncomfortable a thought that may be for some people. This link means that lampreys may be key to understanding the origins of biology in many higher vertebrates – including humans!

Perhaps for this reason alone it is worthwhile to strive to conserve lamprey species, and this research does also have implications for protection of certain lampreys, as discussed in the podcast below.

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Some have hailed the sea lamprey as an up-and-coming “evolutionary developmental model of choice.” Clearly, even blood-sucking parasites have their place in nature’s plan.

Text, video, and podcast by Jenny Labrie, Kelly Liu, Rubina Lo, and Kathy Tran.


Close, D.A.; Yun, S-S.; Roberts, B.W.; Didier, W.; Rai, S.; Johnson, N.S.; and Libants, S. (2013). Regulation of a putative corticosteroid, 17,21-dihydroxypregn-4-ene,3,20-one, in sea lamprey, Petromyzon marinus. General and Comparative Endocrinology, 196: 17-25.

Kimura, M. (1969). The rate of molecular evolution considered from the standpoint of population genetics. Proceedings of the National Academy of Sciences of the USA, 63(4): 1181-1188.

Nikitina, N.; Bronner-Fraser, M.; and Sauka-Spengler, T. (2009). The sea lamprey Petromyzon marinas: a model for evolutionary and developmental biology. In K. Behringer (Ed.), Emerging model organisms: a laboratory manual (pp. 405-421). Cold Spring Harbor, NY: CSHL Press.

Further reading

The hormone, cortisol

The sea lamprey and its cousin the Pacific lamprey

The stress response

Lampreys in the news

Scientists find genes linked to human neurological disorders in sea lamprey genome

Sea lampreys provide a unique solution to gene regulation

Lamprey research sheds light on nerve regeneration following spinal cord injury

Lampreys give clues to evolution of immune system

What’s wrong with microwaves?

In A Dissertation Upon Roast Pig, British writer Charles Lamb tells how mankind discovered cooking after “seventy thousand ages [of] eating meat raw”. With tongue firmly in cheek, Lamb relays how the son of a swineherd in ancient China accidentally burnt down a cottage full of pigs. After the fire dies, the boy pokes a pig and burns his fingers. He instinctively places them in his mouth and – Eureka! – bacon was discovered.

We may chuckle at this comical tale (which ends with all the villagers burning down huts filled with pigs so that they may taste the oh-so-magical bacon), but it’s true that for thousands of years humans have had to build fires whenever they wanted to cook. Nowadays, we cook using electricity. Burning fuel to generate heat, steam, and eventually electricity has been outsourced to powerplants, which send our electrical energy to us without our ever having to light a match. It’s rare to find someone who doesn’t prepare a meal without turning on an oven, stove, blender, food processer, rice cooker, slow cooker, etc.

It wasn’t until 1947 that Percy Spencer invented the first microwave oven (often shortened to “microwave”). This new, fireless method of cooking works on a principle that few people understand, and for that reason many people fear it. Many pseudoscientists (a.k.a. “scienticians”) encourage others to shun the microwave, claiming it chemically alters your food and is killing you. This is the naturalistic fallacy at its best, and some investigation quickly dismantles these myths.

Are microwaves radioactive? Arguably, yes; microwaves are radiations, but so are the radiations on television that provide reality TV. Which ones are worse is anybody’s guess. Microwaves are shorter in wavelength than radio waves, and higher in energy. Light is also comprised of electromagnetic waves, but they’re shorter than microwaves and even higher in energy. Still, you can’t cook food with light or read by microwaves.

Meet Magnetron – not just a cool superhero name.
(Source: Wikimedia Commons)

Microwaves can be generated by magnetrons, which spit them into your oven; the microwaves bounce around as long as the magnetron is operating. Some of the molecules in food – especially water molecules – are polar and line up with an electric field that reverses its direction nearly five billion times per second. The water molecules flip their orientations manically to keep up; in their agitation, they knock around other molecules, which also become fast-moving and excited. Fast molecules are hot molecules, and so the microwave-induced flipping spreads heat in your food.

(Not an entirely accurate representation of excited water molecules!)

What about microwaves “chemically altering” food? Is that true? Of course! This not-so-magical process is cooking. The essence of food is chemical, and all cooking methods cause chemical changes in foods.

And claims that microwaves destroy nutrients? Also true, but not unique to microwaves. Some vitamins (namely vitamin C) are destroyed by heat, so any cooking method will “destroy” some of the food’s vitamin C.

“But my microwave makes carrots and broccoli give off sparks!” Relax. There isn’t metal in your veggies. Some vegetables that are cut with sharp knives have sharp edges as a result. Those carbonized, sharp edges can act like lightning rods and develop concentrated electric field gradients, which generate sparks.

Your microwave isn’t the devil in disguise, I swear.

Text and illustrations by Jenny Labrie.



Hoffman, C.J., and Zabik, M.E. (1985). Effects of microwave cooking/reheating on nutrients and food systems: A review of recent studies. Journal of the American Dietetic Association, 85(8): 922-926.

Osepchuk, J.M. (1978). A review of microwave oven safety. Journal of Microwave Power, 13(1): 3-26.

Stone, M.A., and Taylor, L.T.  (2003). Feasibility of enhancing high-performance liquid chromatography using microwave radiation. Journal of Chromatographic Science, 41(4): 187-189.

Multivitamins: Helpful, harmful, or just harmless?

Although the idea of vitamins (initially “vitamine” from “vital amine”* (1)) was conceived in the early 1900s, it wasn’t until the 1930s that scientists discovered that they could be artificially synthesised (2). Twenty years later, multivitamins and multimineral complexes (called MVMMs) would be widely consumed based on the belief that they were beneficial for one’s health (3).

Nowadays almost everyone takes MVMMs, and the nutraceutical market has grown into a multibillion-dollar industry. Despite their popularity, MVMMs have received a significant amount of flak in the past year due to the documented inefficacy in healthy individuals. There are several research papers documenting MVMMs ineffectiveness, and some recent findings indicate that MVMMs can be harmful (4, 5, 6, 7, 8, 9, 10, 11).

It’s not unexpected that high doses of some vitamins are harmful; after all, “the dose makes the poison” and anything – including water – in a high enough dose can kill. However it is unexpected that taking moderate doses of certain vitamins can be harmful. Some ingredients in MVMMs that can harm more than help are vitamin A, folic acid, iron with vitamin D, and possibly vitamin D.

The negative effects of beta-carotene (a precursor to vitamin A) on smokers has been known for two decades, and gave scientists the first inkling that vitamin supplements could be harmful. There is a well-established correlation in the scientific literature between beta-carotene supplementation (by smokers) and lung cancer (12). Most non-smokers ignore this, but this finding was only the beginning.

Folic acid, the synthesised form of B9, is well-known by women who are trying to conceive or pregnant. After the finding in 1964 that folic acid supplementation reduced neural tube defects, the pill became widely prescribed to pregnant women (and mandatorily added to food) (13, 14, 15).

Despite its supposed benefit, an increased susceptibility to multiple cancers has been associated with folic acid in recent years. Excessive folic acid – especially when it is unmetabolised, as happens often with synthetic B9 – can stimulate tumour growth (16, 17, 18, 19, 20). Some researchers chalk this up to folic acid being inherently different from the naturally occurring form in food, tetrahydrofolate.  The research is still unclear, but it’s probably a good idea to avoid MVMMs with folic acid (unless you’re pregnant).

Regular doses of vitamin D have recently been correlated with increasing the severity of cardiovascular disease (21, 22, 23). The proposed mechanism involves   vitamin D increasing calcium levels (which can contribute to plaque calcification) (24). (Excess can build up after taking a low dose of vitamin D over the long term**.)

Perhaps the most surprising finding on the harmfulness of some vitamins was on vitamin C and iron. Vitamin C is believed to increase the absorption and uptake of iron in the gastrointestinal tract, so many doctors will advise iron deficient patients to take a hefty dose of vitamin C alongside iron supplements. Apparently, this has been linked to a drastic increase in risk of cancers in the GI tract (25, 26, 27).

If you’re a relatively healthy individual, it’s best to avoid supplementation of a number of vitamins and/or minerals. Some people consider MVMMs “health insurance”, although there is clearly a dark side to some complexes.

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(Don’t take MVMMs; if you’re going to supplement, it should be targeted.)

*The “e” on “vitamine” was dropped when scientists realised that not all vitamins contain amines.

**The “long term” is apparently “three months or more”.

– Jennifer Labrie