Can Chocolate be Good for You? The Dark and Light Side of the Force

By Jesica Levingston Mac leod, PhD

It is this time of the year again: San Valentin (aka Valentine’s Day) –  the best excuse to give and more importantly to EAT a lot of chocolate. But, maybe a better gift that receiving chocolate,  is to know that eating chocolate might be good for your health.

In the beginning chocolate was “created” as a medicine –  a healthy beverage –  around 1900 BC by Mesoamerican people. The Aztecs and Mayas gave it the name of “xocolatl”, it means bitter water, as the early preparations of the cacao seeds had an intense bitter taste. Almost one year ago, a longitudinal study, done in the US East Coast, connected eating chocolate with better cognitive function. Yay! Great news, right? The scientists gathered information over a period of 30 years (starting in 1976) from 968 subjects (aged 23-98 years) in the Syracuse-Maine area. The results showed that more frequent chocolate consumption was meaningfully associated with better performance on the global composite score, visual-spatial memory and organization, working memory, scanning and tracking, abstract reasoning, and the mini-mental state examination. Importantly, they pointed out that with the exception of working memory, these relations were not attenuated with statistical control for cardiovascular, lifestyle and dietary factors across the participants.

More good news arrived last summer: an Italian research team announced that flavanol-rich chocolate improves arterial function and working memory performance counteracting the effects of sleep deprivation. The researchers investigated the effect of flavanol-rich chocolate consumption on cognitive skills and cardiovascular parameters after sleep deprivation in 32 healthy participants, who underwent two baseline sessions after one night of undisturbed sleep and two experimental sessions after one night of total sleep deprivation. Two hours before each testing session, participants were assigned to consume high or poor flavanol chocolate bars. During the tests the participants were evaluated by the psychomotor vigilance task and a working memory task, systolic blood pressure (SBP) and diastolic blood pressure (DBP), flow-mediated dilation and pulse-wave velocity. As you might know, sleep deprivation increased SBP/DBP. The result was that SBP/DBP and pulse pressure were lower after flavanol-rich treatment respect to flavanol-poor treatment sleep deprivation impaired flow-mediated dilation, flavanol-rich, but not flavanol-poor chocolate counteracted this alteration. Flavanol-rich chocolate mitigated the pulse-wave velocity increase. Also, flavanol-rich chocolate preserved working memory accuracy in women after sleep deprivation. Flow-mediated dilation correlated with working memory performance accuracy in the sleep condition.

The European Food Safety Authority accepted the following statement for cocoa products containing 200 mg of flavanols: “cocoa flavanols help maintain the elasticity of blood vessels, which contributes to normal blood flow”. This statement means that flavanol-rich chocolate counteracted vascular impairment after sleep deprivation and restored working memory performance. In another study led by Columbia University Medical Center scientists,  dietary cocoa flavanols—naturally occurring bioactives found in cocoa—reversed age-related memory decline in healthy older adults. One possibility is that the improvement in cognitive performance could be due to the effects of cocoa flavonoids on blood pressure and peripheral and central blood flow. Following on this other chocolate attribute, it was shown than weekly chocolate intake may be beneficial to arterial stiffness.

But, there are some bad news!  A review of 13 scientific articles on this topic, provided evidence that dark chocolate did not reduce blood pressure. However, the reviewers claimed that there was an association with increased flow-mediated vasodilatation (FMD) and moderate for an improvement in blood glucose and lipid metabolism. Specifically, their analysis showed that chocolates containing around 100 mg epicatechin can reliably increase FMD, and that cocoa flavanol doses of around 900 mg or above may decrease blood pressure if consumed over longer periods: “Out of 32 cocoa product samples analyzed, the two food supplements delivered 900 mg of total flavanols and 100 mg epicatechin in doses of 7 g and 20 g and 3 and 8 g, respectively. To achieve these doses with chocolate, you will need to consume  100 to 500 g (for 900 mg flavanols) and 50 to 200 g (for 100 mg epicatechin). Chocolate products marketed for their purported health benefits should therefore declare the amounts of total flavanols and epicatechin”.  The method of manufacturing dark chocolate retains epicatechin, whereas milk chocolate does not contain substantial amounts of epicatechin.

The first epidemiological “indication” for beneficial health effects of chocolate were found in Kuna natives in Panama with low prevalence of atherosclerosis, type 2 diabetes, and hypertension. This fact correlated with their daily intake of a homemade cocoa. These traits disappear after migration to urban and changes in diet.


There are many  claims about the potential health benefits of chocolate, including anti-oxidative effect by polyphenols, anti-depressant effect by high serotonin levels, inhibition of platelet aggregation and prevention of obesity-dependent insulin resistance. Chocolate contains quercetin, a powerful antioxidant that protects cells against damage from free-radicals. Chocolate also contains theobromine and caffeine, which are central nervous system stimulants, diuretics and smooth muscle relaxants, and valeric acid, which is a stress reducer. However, chocolate also contains sugar and other additives in some chocolate products that might not be so good for your health.


Oh well, maybe the love of chocolate is like any other romantic affair: blind and passionate. Apparently, the beneficial dosage is 10 g of dark chocolate per day (>70% cocoa), so enjoy it as long as the serotonin boost for rewarding yourself with a new treat last.


Happy Valentine’s Day!



Spend Valentine’s Day Under the Stars


By Knicole Colon

What’s more romantic than spending a night with that special someone under the stars?  If you really want to romance someone, you could tell them the story behind some of the constellations.  Cassiopeia is a “W”-shaped constellation that is easily recognizable in the northern night sky.  It was named after a queen in Greek mythology, who was extremely vain and constantly bragged about how beautiful she and her daughter, Andromeda, were.  As a punishment for her boasting, she was placed in the sky to cling to her throne for the rest of time.  While you’re with your honey and telling them this story, be sure to say how much more beautiful or handsome they are than Cassiopeia.  That should win you some brownie points for sure.

Andromeda, Cassiopeia’s daughter, also has a constellation named after her.  The constellation is located in the sky right next to Cassiopeia.  There’s also a galaxy named after her that is visible with binoculars or a small telescope (though it just looks like a faint smudge, it really is an entire galaxy containing billions of stars!).  In mythology, Andromeda was bound to a rock as prey for a huge sea monster that had been sent to attack her kingdom.  Poseidon, god of the sea, had sent the monster as punishment for the queen’s boasting.  Luckily, Andromeda ended up being saved by (and then marrying) Perseus, a hero in Greek mythology.

Cassiopeia. Credit: Chaouki (Flickr).
Cassiopeia. Credit: Chaouki (Flickr).

Perseus also has a constellation named after him that is located right next to Andromeda and Cassiopeia.  He killed the dangerous creature Medusa and used her head to turn the sea monster to stone, thereby saving Andromeda and making it pretty clear that he deserved permanent recognition in the sky.  It’s probably a good idea for you to assure your loved one that you would gladly save them if they were ever in peril of being eaten by a sea monster.

The movie Clash of the Titans (both the original 1981 version and the recent remake) is one famous version of the story of Cassiopeia, Andromeda, and Perseus.  So, if it happens to be cloudy on Valentine’s Day, you still have the option of watching the movie and proudly declaring that you know a little something about the constellations that are named for characters in the movie.

Songs of Love


by Sally Burn


If music be the food of love, play on” said the lovesick Orsino in Shakespeare’s Twelfth Night. Music is intimately entwined with romance; from a lovelorn John Cusack holding aloft his boombox in Say Anything, to One Direction breaking teenage hearts with their love paens, to tear-stained mixtapes littering a breakup. However, love songs aren’t just for humans. Mice are another species that use the power of song to attract mates. Male mice are quite the warblers, emitting ultrasonic “songs” when they meet a female or encounter female urinary pheromones.  A number of previous studies have shown that female mice are attracted by male songs. Now a team of researchers from Japan have discovered that not just any old song will do: females demonstrate song preferences, more specifically they prefer the songs of males unrelated to them. This, the authors propose, helps to prevent inbreeding and is therefore beneficial for maintaining genetic heterogeneity.

It was already known that male songs vary between different strains of mice. The researchers therefore played female mice from two different strains the songs of males from both these strains. The songs were played in separate cage compartments, which also contained the scent of the corresponding male. Females could recognize strain-specific songs and sought out songs from a different strain, indicating that they would seek to mate with a less-related male. Song preference showed links to sexual reproduction as it was modulated by the female’s reproductive status (increased preference for different strain when in diestrus) and by the male pheromones (these further enhanced the preference for a different strain’s song). However, the most influential factor was the song itself.

The researchers hypothesized that song choice is a form of sexual imprinting, given that it promotes outbreeding. Sexual imprinting is an evolutionarily important phenomenon that facilitates kin recognition and thus avoidance of inbreeding. The researchers showed that song preference is indeed imprinted in females during their upbringing. Song preference was reversed if they raised females of one strain with foster parents from a second strain: the females now preferred the songs of males of their own strain. More specifically, imprinting relied on exposure to the father’s song. When female pups were raised without a father they lost preference for any strain-specific song. This study shows for the first time that male songs are a socially-programmed form of kin recognition in mammals. It also adds weight to the argument that ladies should really not date someone who sings like their dad…

’Til Death Do Us Part – The Science of Love and Attachment


By Robert Thorn

As Valentine’s Day approaches, excitement starts to fill the air in anticipation of Cupid’s visit. The key to the potency and strength of love has been a mystery to scientists for some time. It may surprise you to know that the key to unlocking the secrets of love came from studies of common prairie voles. Prairie voles are unique in the fact that when they get together during mating season they generally mate with one partner and this connection lasts for life. This is in stark contrast to the prairie vole’s evolutionary cousin, the montane vole which is a more promiscuous species of vole. By comparing the different between these monogamous and promiscuous voles, scientists were able to get an idea of what hormones and brain regions may be involved in pair bonding, or as we humans call it, relationships!


Two hormones that were identified in early studies of the prairie and montane voles are oxytocin and vasopressin. If you have heard of these before, it is probably because they are important hormones in different human systems. Oxytocin is used primarily during childbirth, acting to start muscle contractions during birth, as well as being involved in lactation during breastfeeding. Vasopressin is important for a healthy functioning cardiovascular system, as well as maintaining blood pressure by helping to regulating the amount of water filtered out in the kidney. While both of these hormones seem unrelated to each other, and definitely unrelated to love, they were thought to be important for pair bonding because compared to the montane voles, prairie voles have more oxytocin and vasopressin receptors in their brains.


Once two prairie voles mate, vasopressin and oxytocin are released and pair bonding occurs. To show the importance of these two hormones, scientists manipulated the action of one or the other in prairie and montane voles. When the action of either vasopressin or oxytocin was blocked, prairie voles began displaying more promiscuous behaviors, similar to those seen in montane voles. On the other hand, when scientists increase the activity of vasopressin in the brains of montane voles, by increasing the number of vasopressin receptors located in the brain, they began to adopt a more monogamous relationship with their mating partners.


To further examine the role of these hormones in pair bonding, the location of their receptors were mapped to different areas of the brain. Oxytocin receptors were seen in areas of the brain that are involved in dopamine reward system (nucleus accumbens) and emotional memory formation (amygdaloid complex). Vasopressin is seen in different areas of the brain that are involved in motivation and the dopamine reward system (ventral palladium). The role of the dopamine reward system in pair bonding was further confirmed by experiments, which showed that blocking dopamine blocks pair bonding, and adding extra dopamine artificially creates pair bonding without mating (i.e. without the release of oxytocin).


It is interesting to note that the dopamine reward system has been implicated in the addictive nature of some drugs. Keep this in mind if you get struck by one of Cupid’s arrows this Valentine’s Day – You might just get hooked on love.

The Sweet Smell of Love


By Sally Burn

When you’re in love you want to share every experience and let the whole world know you’re together. But your Facebook declarations of affection have nothing on lemur love statements.  A new study from Duke University has shown that loved up lemurs share the same scent, letting the whole lemur world know that they’re a couple.

The study’s authors, Lydia Greene and Christine Drea, collected scent secretions from the genital glands of 15 lemurs living at the Duke Lemur Center (more specifically, Coquerel’s sifakas). These secretions take the form of sticky goo, released from glands on the animals’ genitals and throats. Secretions are left behind on trees, allowing the animals to mark their territory. Gas chromatography and mass spectrometry revealed that the secretions contain over 250 compounds, including hydrocarbons, alcohols, and squalene. Significant sex differences existed in the abundance of certain compounds.

The researchers found that courting lemurs exhibited similar patterns of olfactory behavior. When one of a pair sniffed or deposited secretions, so then did the other partner. Smitten lemurs in the earlier stages of their relationship (i.e.: without offspring) spent a great deal of time sniffing each other’s scents, allowing them to get to know one other and for the male to figure out the female’s reproductive cycles. Lemurs who had parented offspring together shared less olfactory behavior patterns than those who had not, but shared a much more similar scent. Sharing offspring seems to be the key to scent mirroring as the similarity was greater in recently paired lemurs with offspring than in long-term partners without children.

The authors propose that the purpose of scent synchronicity may be to mark the couple’s territory more strongly, hopefully leading to a safer environment in which to raise their offspring. Scent mirroring may also be a way for lemur lovers to update their relationship status to “paired up with kids” and warn off potential suitors who may seek to break up their partnership.

Sexy Science: How Aphrodisiacs Work


By Chris Spencer

This Valentine’s Day, you may find a stunningly beautiful person staring at you with the piercing gaze that only comes from a feeling of pure, unadulterated lust. You then may notice that person’s look of longing slowly morph into a visage of confusion and dismay. The reason they look so dejected is that you clearly aren’t mentally undressing them. You’re lost in thought, trying to work out exactly what it is about oysters that seems to get everyone going. If I were you, I’d satiate my scientific curiosity now, and focus on a different form of satisfaction on Valentine’s Day.


Using studies in rats, nutmeg has been proven to enhance sexual desire. In fact, reading the study lead me to one of my favourite scientific phrases; “feeding nutmeg increased mountings onto females.” It is as clear cut as that ladies and gents. The probable mechanism nutmeg more than likely stems from its nerve stimulating properties, so grate some onto your risotto on the big night.

Spanish Fly (Lytta vesicatoria)

If like me, you’re a fan of the 1987 Beastie Boys classic “Brass Monkey,” then you’ll be aware of the aphrodisiac potency of the Spanish fly. The beetle secretes cantharidin when threatened – a toxin which is toxic to humans in high enough doses. Despite this, people have been grinding Spanish fly up and putting it in peoples’ drinks for at least 2000 years. The toxin inhibits phosphodiesterase and protein phosphatase activity and stimulates a mild urethral irritation that can lead to priapism (a sustained erection of the penis or clitoris). This one seems to be a difficult one to administer safely, so maybe give it a wide berth. I certainly don’t condone spiking anybody’s drink with it.

Red Wine

That leads me neatly onto alcoholic beverages, specifically red wine. Red wine is a double whammy in terms of getting you in the mood. The high concentration of phenolic compounds such as resveratrol and tannins are present in numerous traditional aphrodisiacs, and they have been shown to increase blood flow to your danger zone. This is another compound which has been shown to make rats mount other rats under experimental conditions. The other side of the coin with red wine is alcohol. Of course alcohol relaxes you, and if you’re with someone new (or trying something a bit new) – that feeling of relaxation may well be vital. Don’t get carried away though, or you gentlemen might find that priapism won’t feature on your list of problems.

Chilli Peppers

The erotic component of hot chillies is capsaicin, a molecule which fools our thermoreceptors into thinking it’s hot. Capsaicin works in two ways: not only does it release endorphins to stimulate a mild euphoria, but it increases circulation and speeds up metabolism, which are similar responses to those experienced during sex.

This one comes with a caveat. If you’re preparing any spicy dishes yourself, take it from me, you’ll probably want to wear gloves while you’re chopping the chillies. There are a couple of rather intimate mucosa that you probably don’t want to get capsaicin anywhere near. “Burning loins” are just a figure of speech, you should endeavour to keep it that way.


That is right, chocolate has done it again. The pharmacologically active substances in chocolate are phenylethylamine, which reportedly enhances pleasurable sensations in the brain and affects serotonin and endorphin levels, and N-acylethanolamines, which may activate cannabinoid receptors to increase tactile sensitivity. Pass the dessert.

Symbolic Aphrodisiacs

A fair number of reported aphrodisiacs don’t actually have a proven mechanism of action. Examples such as the avocado (avocado comes from the Aztec word for testicle tree) and the banana are pretty much just phallic symbols. Oysters are used primarily because of their association with the Aphrodite herself.

That’s not to say that these foods won’t get you going of course. If you and your partner sit down to a candlelit dinner of oysters, then I’d imagine you’ll both know it’s on.