I'm not making it easier for you with this picture

In my last post I wrote about how children think junk food is tastier when there’s a cartoon on the package. As adults, we may be wiser to such blatant marketing schemes, but we still love our junk food, Shrek or no Shrek. Take pop for example: as of 2006, the production value for carbonated soft drinks in Canada was $2 billion. We also like our donuts: one of the biggest sources of added sugars in our diet is bakery goods. While it’s sometimes nearly impossible to resist the enticing aroma of fresh cinnamon buns baking at the coffee shop, think twice before you splurge: a new study suggests that added sugars in the form of fructose is positively linked to high blood pressure.

High blood pressure, or hypertension, affects over 5 million Canadians, and is increasingly affecting teenagers. It’s a direct risk factor for many nasty conditions, like heart failure and stroke. Interestingly, the increase in the prevalence of hypertension mirrors the increase in our consumption of fructose. And while technically, fructose is a type of sugar found in fruits, it is not thought that the increase in fructose consumption is due to eating more apples. The culprits are sweetened drinks, processed foods and those deadly cinnamon buns.

To address this question directly, American researchers analyzed the data from the very, very large (>4500 participants) National Health and Nutrition Examination Survey. Not surprisingly, the more fructose you consume, the higher your risk of hypertension. This fructose intake/high blood pressure relationship holds even when you control for a number of other factors, including demographics, physical activity, other diseases, calorie intake, alcohol intake, salt intake, and others.

This study highlights what we call an “independent association”, which is not to be confused with a cause-and-effect relationship. There is not enough data to say that eating a lot of fructose leads to hypertension, only that those two things seem to occur together. However, the study has some strong features, namely that it is looking at a very large sample of people, and that it controls for many possibly confounding factors (an important one being salt intake, as it can lead to hypertension).

On the plus side, it’s very easy to limit your fructose consumption by decreasing the amount of pop you drink and the amount of processed foods you eat. On the downside, cinnamon buns are oh-so-very-tasty...

Reference: Increased fructose associates with elevated blood pressure. (2010) Jalal DI et al. J Am Soc Nephrol [Epub ahead of print].

Is Scooby-Doo to blame?

In this age of pre-prepared processed meals and endless hours on Facebook, it’s no wonder kids are getting fatter. In the US, obesity rates have doubled for preschoolers (2-5 years old) and more than tripled for children 6-11 years old. To explain this alarming obesity trend, many blame the accessibility and affordability of fast food. As a graduate student I often relied on cheap take-out to sustain myself. Luckily I quickly discovered that in Vancouver, sushi costs less than a McDonald’s meal, offering an interesting alternative. If my rent didn’t force me to live below the poverty line (hey, this PhD’s got to be worth something, right?), I would have thought this was heaven. In any case, I’m digressing. Cheap fast food is one part of the equation, kids drooling, lifeless, in front of the computer and the television is probably another part. Interestingly, a recent study suggests that another contributor to the obesity crisis is no other than… Scooby-Doo. And Dora. And Shrek.

The researchers were interested in finding out if putting the image of a popular character on the packaging of a product (this marketing ploy is called “character licensing”) is an effective way to sell food to kids. To test this, the researchers studied three foods: graham crackers, gummy bears and baby carrots. The participants in the study, children aged 4 to 6 years old, were presented with two packages of the same food item (for example, graham crackers). The only difference was that one of the packages had a sticker of a cartoon character (Scooby-Doo, Dora or Shrek) on it. The kids were then asked to say if one of the two foods tasted better, and if so, which one. They were also asked which food they would prefer to have for a snack.

So, does it work? Are children that oblivious to this obvious and dubious marketing trick (Scientific Chick challenge: Write a sentence with more than 3 words ending in -ious)? Absolutely. Overall, children perceived the food items with the cartoon on them to taste better than the ones in the plain packaging. This finding was statistically significant for the “junk” food (the crackers and the gummy bears). Not surprisingly, the children also indicated they would prefer the snacks with the characters on the packaging. As it turns out, character licensing is especially effective in children because they lack the ability to understand that the advertisement is meant to be persuasive.

You would think that all you would have to do to solve the obesity crisis is to slap Elmo’s face on broccoli and apples, but the fact that the character licensing experiment didn’t work as well with the carrots suggests this wouldn’t necessarily do the trick. The researchers only studied 40 children, a relatively small sample size to draw out any solid conclusions, but it’s still an interesting finding. I find it a little worrying that cartoon characters can lead to a more positive perception of the taste of junk food. I find it very worrying that food and beverage companies spend more than $1.6 billion per year on advertising for kids. I guess Ramen advertises for grad students and nobody gets worked up about that.

Reference: Influence of licensed characters on children’s taste and snack preferences. (2010) Roberto et al. Pediatrics, 126(1):88-93.

The little-known benefits of pumping iron

At the risk of sounding like a broken record, exercise is good for you and your brain. That being said, most studies looking at exercise and cognitive function evaluate aerobic exercise (the kind that gets your heartbeat going). The other kind of exercise, resistance training (strength training with weights), has not been of much interest, perhaps due to the old stereotype that has been plaguing bodybuilders forever: big biceps, small IQ (although big biceps never stopped anyone from becoming governor of California). Switch the young lads for older women, though, and a recent study from a team of researchers at the University of British Columbia (represent!) suggests that gaining muscle can translate into a better brain.

The study looked at 135 women between the ages of 65 and 75 over the course of a year. The women were assigned one of three groups: group one took a one-hour resistance training class once a week, group two took a one-hour resistance training class twice a week, and group three, the control group, took a one-hour balance and stretching class twice a week. The women were all evaluated for a range of cognitive functions at the start of the study, at the six-month point, and at the end of the study (at the 12-month point).

The bad news is that strength training for six months, whether once or twice a week, didn’t lead to any changes. The good news is that if you stick to it for a year, you only need to train once a week to see an effect. After 12 months, the researchers found that all the women who underwent strength training showed a significant improvement in attention. The researchers evaluated attention using the well-established Stroop test (see image below), where the names of colors are written in an ink of a different color (for example, the word blue is written in red ink). To assess attention, the participants were asked to name the color of the ink (and not the word) as fast as they could (try it!). The once-a-week and the twice-a-week resistance training groups significantly improved on this task, while the performance of the balance and stretching group slightly deteriorated.

This improvement in cognitive function didn’t come without a price. The women in the once-a-week resistance training group complained of joint and muscle pains more than the women in the two other groups. It seems that the sweet spot for both an improvement in cognition and a lower risk of pain is to train twice a week (at least). This makes sense to me: the more frequently I exercise, the more my body gets used to the motions. It is also worth noting that the researchers tested other cognitive tasks such as memory and these didn’t show any change with resistance training.

Overall, though, I think this study is great news. I know that many older adults shy away from rigorous aerobic exercise (even young adults… *cough cough*), so this could be an easier alternative to help with brain health. And even if the “brain benefits” of resistance training could be a little more impressive (like by curing Alzheimer’s disease, while we’re at it), on the plus side, strength training also improves gait speed (your natural walking speed), and an improved gait speed is associated with a significant reduction in mortality. So if you don’t exercise for your brain, do it for your lifespan.
Reference: Resistance training and executive function: A 12-month randomized control trial. (2010) Liu-Ambrose T. et al. Arch Intern Med 170(2):170-8.

If I only had a (better) brain

Scarecrow, from the Wizard of Oz, desperately wanted a brain. Given the financial success of the brain training industry, it seems he’s not the only one hoping for cognitive enhancement. “Brain training” refers to the improvement of cognitive function by the regular use of computer exercises. Recently, it’s popped up everywhere, targeting kids through video games like “Big Brain Academy” to older adults through iPhone apps like “Lumosity”. While brain training companies are stuffing their pockets, the question remains: does it work?

A team of researchers from the UK set out to test how well brain training works. They teamed up with a popular science show on television and recruited over 11,000 healthy participants. The participants completed a general initial assessment of cognitive function (the “benchmarking” assessment), then started a regimen of 10-minute training session three times a week for six weeks. The online training sessions tested a broad range of cognitive functions: short-term memory, attention, math skills, and so on. These tests were designed to be similar to those found in commercial brain training programs. The researchers followed the progress of the participants over the six weeks of training and concluded the study with a final general benchmarking test similar to the initial one.

The good news is that the researchers saw a significant improvement on the specific tasks the participants trained on. The bad news is that this improvement did not extend to general cognitive function. These results mean that while you can improve at, say, a specific memory game that involves remembering the items in a scene, this won’t necessarily translate to better memory in your everyday life (where did I put my keys again?).

As can be expected, the study was criticized, especially by individuals with a commercial interest in brain training. Some suggested that the participants didn’t train long enough or often enough to see an improvement in general cognition. Others said that it’s not because these researchers didn’t observe an improvement that it’s impossible to achieve cognitive enhancement through computer games. However, it’s important to keep in mind that the study also scores some good points: the researchers looked at a very, very large number of participants, and the games used for brain training mimicked those that are commercially available.

Personally, the last thing I need is a reason to spend more time in front of the computer, and I like to think that fresh air is a terrific cognitive enhancer. What do you use to maximize your brain power? Coffee? Naps? Share in the comments!

Reference: Putting brain training to the test. (2010) Owen, AM et al. Nature 465:775-8.

Light at night

At the end of June, I will once more ride my bike from Vancouver to Seattle as part of the Ride to Conquer Cancer. In the weeks leading to this event, I log many, many kilometers on the saddle and inevitably my thoughts wander to cancer biology (and sometimes to the excruciating pain emanating from my behind). What triggers cancer? How can cancer be prevented? Why are some cancers like breast cancer more prevalent in industrialized countries? While researching the question, I came across a most unsuspected potential risk factor. I’m especially excited about this piece of relevant science because for once I won’t be writing about how eating healthy and sleeping more can cure all your ailments.

In the study, researchers took groups of female rats and exposed each group to different intensities of white light during the dark phase of their daily cycle (typical lab rats live in a programmed 12-hour light/12-hour dark cycle). After two weeks of this night cycle disruption, the researchers implanted a tumor (derived from human breast cancer tumors) in the female rats, and continued on with the night cycle disruption for many weeks. By the end of the experiment, the rats that had been exposed to the strongest intensity of light showed a marked increase in tumor growth rates. The brighter the light at night, the bigger the tumor.

Ok, light at night makes tumors grow faster, but can too much light be the cause for cancer? To answer this question, it’s best to turn to studies in humans. There is convincing evidence that women who work night shifts have a significantly higher risk of breast cancer. As well, women with the brightest bedrooms also have a higher risk of breast cancer. Scientists believe the reason for these correlations is a molecule called melatonin. At night, in the dark, your body produces melatonin, which is a very effective anti-cancer molecule. Several studies have looked at this link in more detail and have shown that melatonin can block the development and the growth of tumors in non-human models of breast cancer.

The light-cancer link is gaining interest, and researchers even started sprucing things up by using a catchy acronym, LAN (for light-at-night), so it’s something to keep in mind. Based on this research, I’ve decided to break my habit of flicking on the lights for my midnight nature calls. Would this habit necessarily give me cancer? No. But flicking on the lights does interrupt my production of melatonin, and on top of being an anti-cancer molecule, it’s also a powerful antioxidant. So I’m just trying to put all the chances on my side. That being said, I’m running into a different problem, which is waking up everyone in the building when I stub my big toe on the door frame. Nobody said staying healthy was easy…

Training for the ride, thinking about cancer

Reference: Circadian stage-dependent inhibition of human breast cancer metabolism and growth by the nocturnal melatonin signal: consequences of its disruption by light at night in rats and women. (2010) Blask D.E. et al. Integrative Cancer Therapies, 8(4):347-353

Another quality science headline

My friend David just alerted me to a quality headline for an article based on the diet and Alzheimer's disease study:

"Salad dressing good for the brain, new study shows"

Wow. Excellent interpretation of the take-home message of the study! Forget orange juice: doctors now recommend a cup of creamy ranch dressing to kick-start your morning. It's good for your brain!

Seriously, headlines like this make me cringe.

Creating life from scratch... Or not.

There’s quite a bit of hullabaloo (I can’t believe I just used that word) surrounding the recent creation of the first “man-made” synthetic cell. Genomics, the study of DNA sequences of entire organisms, has come a long way in a very short time: after all, Watson and Crick discovered the structure of DNA less than 60 years ago, and already we’re toying with the thing like it’s silly putty.

DNA can be thought of as the recipe book to make an organism. In your DNA, there is all the information necessary to make every single part of your body. Strangely enough, DNA is only made out of four units: A, C, T and G (remember the movie “Gattaca”? That’s a play on a DNA sequence). The sequence of these units determines your genes (small chunks of DNA), your chromosomes (larger chunks of DNA comprised of many genes), and your genome (the sum of all your DNA). To create the synthetic cell, the researchers started with the genome of one bacteria (let’s call it “donor”). They mapped out the genome of the donor into a computer file, and then edited the code, adding a few specific chunks here and there. These added chunks (the “watermarks”) would later serve as markers to confirm that the resulting organism only hosts the synthetic code. Once the researchers had a DNA sequence they were happy with, they fed the code into a machine that spurts out the As, Cs, Ts and Gs in the correct order and generates small pieces of synthetic DNA. The researchers then used elaborate techniques to stitch together the small pieces into a complete genome. Finally, the researchers transplanted this synthetic genome into a different bacteria (the “recipient”) previously emptied of its own genome. Shazam! Synthetic “life”.

At this point, I don’t think we can call this breakthrough “artificial life”. Life was not created from scratch. What we have here is a functioning cell (and that includes the ability to replicate) with a synthetic genome. This synthetic genome, even though it was created from a computer, only includes genes found in nature (and the watermarks, but they don’t code for anything). And while it’s fun to imagine that we’re only days away from reviving the woolly mammoth, it’s important to keep in mind that this synthetic cell has a very tiny genome. What’s more, the genome of the synthetic cell had some mistakes in it: it wasn’t exactly as the researchers had intended.

Still, I think there is cause for concern, both in terms of ethics and biodiversity. If we had already cracked open Pandora’s box with transgenic animals and plants, this represents a rip-the-lid-off-and-break-the-hinges advance. Especially considering that current legislation allows the patenting of such organisms (a subject for a later post, perhaps). However, with all the bad comes some hope: like stem cells and gene therapy, this technique may represent a new hope to cure diseases.

What’s your take on this new breakthrough? A step closer to mastering life and curing diseases, or a scary slide down a slippery slope?

Reference: Creation of a bacterial cell controlled by a chemically synthesized genome. (2010) Gibson DG et al. Science, May 20 [Epub ahead of print]