Science for Foodies

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“Transpoosion” is this week’s word—perhaps you’ve heard of it. It is precisely as it sounds, a fecal transplant that replaces one person’s poo with another’s. It’s had remarkable success in restoring desirable microbes to a sick person who can’t kick a disease.

I’d never heard of transpoosions before spending a week at MIT in the Knight Science Journalism Food Boot Camp. The discussion of fecal matter stemmed from a lecture on the good microbes without which we as human beings couldn’t exist (see more below). Not everything at Boot Camp centered on excreta; we had four full days of obesity, child nutrition, packaging and processing, fast food, foodborne illness, the evolution of E. coli, the philosophy of agriculture, food marketing and the environmental costs of meat. Heavy stuff—some of it downright depressing, but all of it tempered with the luscious arrays of colorful salads, sweet fruits, fresh fish, grilled veggies, soups, noodles, stews and enchiladas served for lunch.

Amid all that were a few scientific lectures that dug deep into the human brain, our mouths and guts to explain what goes on at the molecular level when we smell, taste and eat. Fascinating! I love that stuff. So without further ado, I give you a few snippets from my week as a science geek-wanna-be at MIT:

1. Microbes are our friends.

So says Roberto Kolter, professor of microbiology and molecular genetics at Harvard Medical School. Microbes get a bum rap, but the truth is: we couldn’t live without them.  And they’re everywhere: in the soil, and interlaced through all living things. Microbes allow legumes to fix the nitrogen that plants need to grow. Microbes allow ruminants (cows, goats, sheep, elk and other animals that become burgers and steaks on our plates) to digest grass.  Microbes give our gardens that sweet, summery smell; they lend our vegetables rustic, earthy flavors.

We are, in fact, “born in a sea of microbes,” Kolter says. Every inch of our bodies is chock full of the little microscopic bits that make us who we are. Ninety percent of the cells in a human body are microbial. Each of us has a unique microbiota that determines how we react to the world around us and the foods we eat. “Different people will have different responses to different foods.” For the most part, we’re stuck with our microbes through geriatric age—unless, of course, something goes drastically awry and we require “stool infusion therapy” to restore order to our internal flora.

I really enjoyed Kolter’s talk—he was one of few speakers to exhibit enormous passion for EATING FOOD (I had expected more at a food conference). He showed us photos of braised lamb, bread, wine and cheese; and then he explained how microbes played a part in everything on the table. I admire his food philosophy, too: “I think food should taste great and you should love eating it. And don’t eat too much of it…. And that’s basically it.”

2. Brain dopamine.

Bet you can’t resist that piece of chocolate. You know why? Your brain is wired to want it. When we as animals eat something desirable (basically anything with sugar, fat and  salt), dopamine levels in the brain increase. The more we eat, the more we want, the more we eat—and each time the cycle repeats, we strengthen the neural circuits that make it happen. The behavior becomes self-sustaining, says former FDA Commissioner David Kessler, author of The End of Overeating. Furthermore, he says, it’s not just the chocolate itself that gets us mentally salivating; it’s any sort of sensory cue that reminds us of the rewarding benefits we get from eating that chocolate. Drive by your favorite restaurant, Kessler says, and the juices in your brain start flowing long before those in your mouth. That’s some powerful wiring.

The problem is, our culture bombards us with salient stimuli. In the last few decades, we’ve removed the boundaries between acceptable and unacceptable eating times. “We’re constantly being cued,” Kessler says. Yet not everyone suffers this problem. The cover of his book depicts a carrot and a piece of carrot cake. Most eyes focus straight on that cake, but 15 percent of people feel no deep need for the sweets. “They’re the ones I really want to study,” he says.

Getting at the brainwork behind eating is critical in these times of rising obesity and disease rates. (By 2030, diabetes rates in the United States are expected to be 36.5 percent higher than they were in 2000; for more on this subject, check out Kelly Brownell’s work at the Rudd Center for Food Policy and Obesity.) As Kessler says, if we can understand what drives over-eating, we might unlock the answers to a whole harvest of questions.

3. Taste receptors.

One day several years ago, Gary Beauchamp participated in a Sicilian olive oil tasting. When he drank the oil (like a glass of wine) he noticed a familiar burning sensation in his throat. It was precisely the same sensation created when he swallowed ibuprofen. Ding! The discovery eventually led Beauchamp’s team at Monell Chemical Senses Center in Philadelphia to isolate a compound in olive oil now known as oleocanthal.

Beauchamp, director of the Monell Center, suspected olive oil might harbor some of the same anti-inflammatory properties as ibuprofen—and he was right. In addition, oleocanthal shows promise in protecting against Alzheimer’s disease and cancers.

This is but one of Monell’s many fascinating studies in the arena of taste reception, which, in my mind, provoke equally intriguing questions about cultural adaptations to flavor. Studies show that American consumers dislike the olive oil throat burn, but southern Europeans prefer it. “This burn is a sign of excellence,” Beauchamp says. Why? Do people perceive sensations differently? That’s possible, Beauchamp says. But more likely, people develop a preference.

Take bitterness, for example. Most humans eschew bitter flavors. “Things that are bitter tend to be poison and we’re built to avoid those,” Beauchamp says.

But after many years in Southeast Asia, I’ve come to enjoy bitter herbs and leafy greens, often eaten for their medicinal properties (sometimes what’s toxic at a high dose can be beneficial at a low dose). I asked Beauchamp about that and he figures people have learned to overcome their bitter aversions. “Early flavor experiences alter flavor preferences,” he says.

Infants whose bodies have trouble digesting protein often are fed an easily digestible type of formula that tastes horribly bitter. “It’s really foul,” Beauchamp says. But babies younger than 4 months accept the formula despite its wretched taste. “It’s not that they don’t detect it, they just don’t mind it.” Not so for the older babes, who flat-out reject the bottle.

Here’s something else: we have bitter taste receptors in the lungs and upper nose. It’s thought, perhaps, they somehow protect against bacterial infection through detection of harmful microorganisms.

Turns out, we have taste and smell receptors all over our bodies, in places I’d never suspected (lungs, stomach, even sperm cells). All of this leads to a slew of sciency philosophical questions: what is taste, really? Must it involve food? Do we really taste with our mouths? Or do we taste with our brains?

Photography by Jerry Redfern.

 

Originally posted on The Faster Times

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