Livin' on the MDedge

Teen junk-food rebels, 3-D printed hearts, and strategic java stockpiles


Sticking it to the (junk-food) man

Fight the power – the power, in this case, being Ronald McDonald and his brethren.


In a new effort to convince teens to reject junk food and make healthier choices, researchers found that one surefire way to achieve this was to play on the natural teen desire to reject authority and rebel. Parents of teens across the country don’t know whether to rejoice or groan.

The study, published this week, found that an effective way to combat junk food marketing was to frame companies as corporate overlords and figures of authority who take advantage of vulnerable populations (so, the truth). The teens, who value social justice and autonomy from adults, responded well to this reframing. Instead of snacking on Doritos at lunch, the study subjects chose to really stick it to the man and make healthy food choices instead.

Researchers reported that boys in particular responded positively to the idea of rejecting authority. Which will surprise no one who has ever known a teenage boy.

I heart 3-D printing

Fifty-two years ago, a South African surgeon named Dr. Christiaan Barnard took a heart from one (deceased) human and successfully transplanted it into another (live) human. Now, Israeli researchers could relegate Dr. Barnard’s recycled-cardiac-parts approach to the medical history museum’s hall of obsolete approaches, next to the leeches and the wax barber-surgeon.

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In a claimed first, Tel Aviv University scientists have “printed” a fully vascularized, engineered human heart. The organ is crafted from a cellular slurry of a patient’s own fat cells turned into pluripotent stem cells. With collagen and glycoproteins as structural printing “ink,” the researchers mixed in the stem cells and printed their 3-D heart. The cells differentiated into cardiac and endothelial cells, complete with a medical first: vascularized and perfusable heart tissue.

Unlike Barnard’s allogeneic approach, building from a patient’s own cellular material can eliminate the risk of organ rejection, the heart’s creators say.

Next on the heart-printers’ punch list: getting the cells to contract in unison to form a pumping unit. Then testing it in animals. Oh, and creating something a bit larger than their initial rabbit-sized heart.

And then? Who knows? Perhaps even Dorothy’s friend the Tin Man can finally get an autologous, printed replacement for that allogeneic, heart-shaped clock.

Larger portions of food for thought

In the world of nutrition science, there’s a concept known as self-regulation, which suggests that people have an innate ability to consume only as many calories as they need. Studies have shown that, in adults anyway, self-regulation can be circumvented by something known as the portion-size effect, which is the tendency to eat more when larger portions are served.


But is the same thing true for small children? Let’s find out.

Researchers provided a group of 3- to 5-year-old children with all their meals and snacks for two 5-day periods. During one of the periods, the portions were 50% larger than the other period. The children were allowed to eat as much of each meal/snack as they wanted, and any leftovers were weighed to determine actual calorie intake.

The data showed that the children ate 16% more food and consumed 18% more calories when they were given the larger portions.

So, we already knew that if you give adults more food, they’ll eat more. And now we know that if you give children more food, they’ll eat more. Could this be the end of self-regulation?

Maybe it would work if you gave the little tykes something besides food. Maybe you could give them … money. Round up a few hundred children, put them together in a big room, and throw money at them.

Oh, right, that experiment is already underway. It’s called Congress.

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