November | 2014 | Forgotten Physiology

We need sweetness. Yeah, you heard me (well you hear me in your head). I’m not here to bore you with another article about why sugar is bad for you. We get it. As an information saturated society we know more about nutrition today than any other time in the unabridged history of the human race. Yes, sugar is bad for you BUT we still need to sweeten things from time to time. We have evolved taste buds on our tongues for sweet things. Every culture on the planet, from the bleakest deserts to the darkest rain forests, eats sweets. So when sugar is no longer lead singer on the sweetener stage who do we turn to?

Let’s get artificial!

The term “Artificial sweetener” has always bothered me for some reason. It just makes it seem as though we are lying to our tastebuds but the only lie is in thinking that sugar is the basis of our perception of sweetness. Sweetness is in the brain. To understand sweetness think about locksmiths. Yes, every lock needs the right key to open it. A chemical doesn’t have to be table sugar ( C₁₂H₂₂O_{11 )}to have the right molecular structure to unlock our taste buds.

Taste buds, making flavors known for more than 165 million years

A word or two about taste receptors…

The many protruding papillae structures on the surface of our tongue contain receptors that constitute our infamous taste buds. All of these protrusions create a massive amount of surface area around the tongue, providing many points of contact for the foods entering our mouths to make their flavors known. These taste bud receptors have a direct line to the gustatory (feeding related) areas of the brain where we interpret and experience those tastes. Just like sight and smell, taste is largely in the brain. This is why the smell or taste of fresh baked cookies or whatever can conjure up vivid memories of a time and place (rolls from the oven make me think of Grandma’s house).

Humans have big ole brains and those brains are powered by calories. Yes it takes calories to power the brain (roughly 20% of our total intake at rest) just like any other organ in the body. Sweet things tend to have a lot of calories. So it would make a lot of sense that, calorically speaking, sweet things would be so appealing (I see you over there cinnamon roll. How you doing?) What if the pleasure we get from two scoops of ice cream is really a deeply rooted feeling of security that we’ve met our body’s caloric demands?

Saccharin how do you do it?

C₇H₅NO₃S or Miss Jackson if you’re nasty…

When I say “artificial sweetener” do you think of little, bright pink packets? It’s ok, we all do. Saccharin (commercially known as Sweet n Low) has been cluttering breakfast tables like confetti for decades but has been in use for more than a century. Of course saccharin meets and greets the same taste receptors on our tongue as table sugar but it’s 300x sweeter per serving. Where does it get its mutant flavor powers?It’s not fully understood but part of the answer is solubility my friends.

In order for us to taste anything, some portion of that substance needs to dissolve in water so that a sample of it’s molecules can shake hands (on the molecular level) with our taste buds. Saccharin in the form of a salt (sodium saccharin) dissolves in water like a champion and thanks to it’s shape, the molecule has a high affinity for the taste receptors on the tongue. I mean where sugar shakes hands with our taste buds saccharin goes in for the long, awkward hug.

Yeah…Saccharin is “that guy.”

BUT…. is it safe?

You just had to ask that question didn’t you? To be honest (always) the topic of saccharin toxicity is a murky one. It has been investigated more than some organized crime bosses. There are definitely concerns about sodium saccharin’s toxicity. In some laboratory trials high doses of saccharin have been linked to bladder cancer in test rats. Now please keep in mind that they were testing lab rats and not humans. We are yet to find definitive proof that saccharin causes cancer in humans. It was for this reason that saccharin was removed from the U.S. National Toxicity Program’s Report on Carcinogens in 2000 where it had been listed since 1981. Also, the rats in those studies received high concentrations of sodium saccharin. They weren’t casually sipping Crystal Light after working in a few laps on the hamster wheel. For the sake of a toxicity study researchers are looking for toxic effects. So they test and test and test until they find some. A researcher measures those effects at different concentrations under a variety of conditions. In contrast, the amount of saccharin in your packet of sweetener was only intended to make that cup of old, burned coffee easier to drink while you wait for your car at the Jiffy Lube.

So no, I’m not here to defend the little pink packets (though I will accept cash or personal checks if they would like me to.) You will simply have to use your own judgement. However, I will leave you with this thought…

Can a substance that contains no calories or nutritional value still be considered food, and if not, why are we putting it in our mouths?

Stay curious, stay classy, and never stop learning my friends 🙂

One day I will grow the Soul Train afro of my dreams.

Pre-season’s greetings my fellow information seekers! No no, I’ve missed you more. We’re shining this week’s E-Hollywood spotlight on the “hypnic jerk”. While it may sound like a funky, dance from the 70’s, it describes a far more psychedelic physiological phenomenon. Can you dig it? I knew you could.

When I first heard about the “hypnic jerk” I was…

17 years old or so, nodding off in statistics class to that dream where I’m giving my Nobel Prize speech and no one in the audience is laughing at my jokes because I’m not wearing any pants. Anyway, in the dream the floor of the stage suddenly collapsed and I fell into this bottomless pit of my subconscious. At that very moment I was in fact sliding out of my desk. My arms and legs flailed wildly, like a cat trying not to take a bath, knocking my textbooks onto the floor and waking me from my pants-less slumber. What I didn’t know then was that this phenomenon is actually experienced by many people (the falling feeling, not the no pants thing).

Hypnic Jerk

The Mayo Clinic recommends not taking naps near the Jacuzzi.

In the movie “Inception” (kick-ass movie btw) they refer to it as “the kick,” that moment while asleep when the sudden sensation of falling jolts you awake. Most of us have experienced this at some point and the feeling is anything but pleasant. What I experienced that day in high school was actually a rare scenario of dream incorporation.

The funny thing about R.E.M. is…

You may not know this but during the surprisingly brief stage of R.E.M sleep, where all of our dreaming takes place, your body is temporarily paralyzed. It’s quite normal, and when you think about it, evolutionarily advantageous not to be able to act out your dreams. Otherwise, we would be jumping out the window every time we’re chased by zombie hordes in our sleep. In fact the only motor function that doesn’t seem to be impaired during this stage of sleep is our eye movement. This is how the R.E.M. stage or rapid eye movement gets its name.

Of course, the line separating the dream state from the waking state is notoriously blurry and it is proposed that the hypnic jerk phenomenon occurs during that awkward intermediate stage where the region of our (brain beneath the cortex) most active when we are awake intrudes on our sleepy-time region of the brain (ventrolateral preoptic nucleus, or VLPO) that manipulates our sleep. I will affectionately refer to this region of the brain as “Vilpo” that’s right,…Vilpo Baggins.

Stay with me this gets interesting…

The VLPO region of the brain is practically next door neighbors with the optic nerve (anterior of the hypothalamus). Why so close? The theory is that during the day Vilpo is busy collecting information from our eyes about light levels (time of day) and it uses this solar sense of time to direct our sleep cycle. Yeah..sounds good, but more importantly it is neurotransmitters like serotonin and adenosine that activate the VLPO. These crafty neurotransmitters accumulate throughout the day until they reach a concentration that causes us to turn in for the night. While we sleep the VLPO releases it’s own neurotransmitters that inhibit the neurons that are most active and frisky when we’re awake so that we can stop being so frisky and get some rest. So neurotransmitters encourage sleep and neurotransmitters keep us asleep.

Sleep is not passive. To sleep and to wake means that there is always some element that must actively be kept under control.

While we are awake the VLPO is inhibited by opposing neurotransmitters. When we are awake our reticular activating system, R.A.S is awake. This region of the brain is BFF’s with the cortex, hypothalamus, and cerebellum which control basically every conscious and semi-conscious thing we do (walking, eating, SEX, etc.). So one cluster of neurons inhibits another cluster of neurons in a daily battle of sleep and wakefulness where both sides win and both sides lose.

So here’s the deal…

Hypnic jerks seem to occur as a kind of involuntary hiccup of motor control during the crossing over phase into sleep paralysis. The mechanism behind this is still poorly understood but it is the last gasp of waking motor function. It is a paradoxical, involuntary muscle reflex (Myoclonus) and it is pretty common in healthy people. We do know that these episodes can be triggered by persistent stress and anxiety, which is never good. It is also indicated that strenuous activity throughout the day can trigger an episode. It may sound paradoxical but you can actually be “too tired” to get a good night’s sleep and you can cheat your body out of its natural progression into the stages of sleep by being either too exhausted or too wired before you cut out the lights.

Let’s say you let 6 hours of YouTube videos play on your laptop while you typed up a research paper, opened 20 website browsers, and then shut your computer without shutting anything down. It may sound like a lousy way to treat your computer but we do it to our brains all the time…we don’t “go to bed” we just slam our laptops shut without “shutting down” first.

Hypnic Jerks seem to serve as a haunting reminder of the gaps in our understanding of the mechanism of sleep.

Human beings make straight lines and sharp angles. Our buildings have perfect triangles, solid walls, and mathematically proportional rectangles and squares. We believe in boundary lines and cut off points but the human brain itself, with its mosaic of soft tissue and blood vessels, is not confined by the same boundaries. You have to consider that perhaps no one portion of the brain is designated strictly to sleeping or waking but that these two states of consciousness are far more intimately connected, perhaps even dependent on each other. The phenomenon of sleep could be nothing less than an infinitely complex culmination of subtle details and relationships within the vast landscape of the brain.

Stay curious, stay classy, and never stop learning my friends 🙂