The sweet potatoes in this pie originated in the New World. Photo: paul goyette.

As you fill your grocery cart with food for Thanksgiving, pause for a minute and think about where that food came from. I don’t mean is it local or organic or hormone/pesticide /gluten-free—I mean is it Old World or New World? On what continent did that food evolve?

During the age of exploration, Europe was called the Old World, along with its continental neighbors in the Eastern Hemisphere, Africa and Asia. The Americas, North and South, were the New World. Australia is sometimes lumped with the New World, too. This is a geographical and historical division. But the Old World/New World distinction also speaks to the biology of the regions. Organisms that originated on one continent are different from those that evolved halfway around the world. And for the most part, living things—animals, plants, microbes—didn’t travel from one hemisphere to the other without human help.

The sweet potato/yam mash-up is my favorite example of an Old World/New World confusion. Sweet potatoes originated in Central or South America, and are the starch-filled roots of plants related to morning glories. Yams, however, are completely different. They originated in Africa, and are actually the stem tissue of a monocot plant. Most of what we see labeled as “yams” in our grocery stores are actually sweet potatoes. The common name confusion started centuries ago, when African slaves brought the name—but not the vegetable—to the Americas with them. Yams don’t grow in temperate North America; they need a tropical climate, like Africa, Asia, or the Caribbean (where they’ve been imported).

So let’s go through your grocery cart. Your soon-to-be-mashed potatoes? New World—they originated in South America. (And the Irish Potato Famine occurred long after potatoes were imported to Europe.) The corn in your cornmeal stuffing originated in the New World, too. Your turkey is from the New World, but the soy in your tofurkey is native to Asia. And the apple in your apple pie is not at all American—it originated in Europe.

Many foods have moved across the ocean. This mixing of culinary components and cultures is definitely something to be thankful for. (Invasive plants and animals—and diseases—that have crisscrossed continents are something else entirely.) This Thanksgiving weekend, I plan to read the book 1493: Uncovering the New World Columbus Created. Author Charles C. Mann writes about the Columbian Exchange—the movement of plants, animals, and people from one hemisphere to the other. I’ll read it while enjoying a cup of coffee (Old World—Africa) and some leftover pecan pie (New World—North America).

Stem cells in the gut of Drosophila divide in response to food. Photo courtesy of John Tann

Researchers investigated how stem cells in the gut of the fruit fly respond when different amounts of food are present. They found that when food is abundant, stem cells in the gut divide more rapidly, increasing the size of the gut as long as food continues to be available. When food is removed, the cells stop dividing and the gut shrinks down again.

“The real surprise was that the fruit fly intestine is capable of secreting its own insulin,” said principle investigator David Bilder in a press release. “This intestinal insulin spikes immediately after feeding and talks directly to stem cells, so the intestine controls its own adaptation.”

Insulin is also the primary signaling molecule for converting blood sugar into usable energy in muscles, and storing it as fat.

What the current findings mean for human physiology or chronic overeating is still unknown, but it raises many new questions regarding the role of intestinal stem cells and metabolism.

Photo courtesy of robad0b

In his latest article titled, "How Change Is Going to Come in the Food System", published in The Nation, Pollan argues that while a cultural revolution has taken place in American’s perception of what and why we eat, little real change has taken place at the level of policy.

“The food movement has discovered that persuading the media, and even the president, that you are right on the merits does not necessarily translate into change, not when the forces arrayed against change are so strong,” says Pollan.

However, the food movement can take a page from the fight against tobacco in recruiting a powerful ally: the insurance industry. With the passing of Obama’s Patient Protection Act and Affordable Care Act, insurance and government agencies can no longer neglect individuals with preventable, diet-related chronic diseases.

“No longer allowed to cherry-pick the patients they’re willing to cover, or to toss overboard people with chronic diseases, the insurance industry will soon find itself on the hook for the cost of the American diet too,” writes Pollan.

Until now local, grassroots movements to improve food economies haven’t been able to compete with the lobbying efforts of the largest industry in America. But “as soon as the healthcare industry begins to focus on the fact that the government is subsidizing precisely the sort of meal for which the industry (and the government) will have to pick up the long-term tab, eloquent advocates of food system reform will suddenly appear in the unlikeliest places—like the agriculture committees of Congress," writes Pollan.

Wouldn’t that be a welcome change in season.

How do we make healthy eating cool? Image courtesy of f_mafra.

People who immigrate to the United States from traditionally healthy cultures usually develop Western disease patterns within one or two generations. Since genetic changes cannot occur this rapidly, environmental factors, particularly diet, are considered to be primary the reason for the shift.

While it has been proposed that dietary changes are the result of having access to less healthy foods, new research suggests that poor food choices are often made not from preference but from pressure to fit in as an American.

In a new study to be published in the upcoming issue of Psychological Science, researchers from Stanford and UC Berkeley explored the eating choices made by Asian-American and white college students when put in situations that threaten their American identity.

The first part of the experiment asked students to write down their favorite foods, but first prefaced some of the students with the question, "Do you speak English?" All the students could speak fluent English, but of the Asian-American students that were asked the question 75% included a stereotypical American food in their food preferences, compared to 25% who had not been asked the question. There was no difference in preferences of white students with or without the question.

To test if cultural pressure affects eating habits directly, researchers performed a similar experiment but offered students dishes from typical American and Asian restaurants. Before the experiment, however, some students were told, "Actually, you have to be American to be in this experiment."

Asian-American students who were asked the question were more likely to choose the American food options than the students who were not asked the question. Subsequently their choices were less healthy and they ate an extra 182 calories in the meal.

Attitudes about food and social pressure can greatly impact eating habits, and this study is consistent previous findings that overweight people tend to have overweight friends. Bad eating habits aren't just individual choices, but reflect societal pressures and group psychology.

But the question remains, how do we make healthy eating cool?

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"Minuscule" amounts of iodine-131 was found in milk from Washington state. Image courtesy of stevoarnold.

Reuters reports that trace amounts (0.8 pCi/L) of radioactive iodine-131 was found in milk from cows in Washington state, though officials stress this is nothing to be alarmed about.

"These types of findings are to be expected in the coming days and are far below levels of public health concern, including for infants and children," said the Food and Drug Administration and the Environmental Protection Agency in a joint statement.

Though the levels found in the US are 5,000 times below the FDA's standard, this particular isotope of iodine is not normally present in milk. When milk is contaminated, iodine-131 can accumulate in the thyroid and lead to cancer.

US officials have been monitoring radiation levels in milk and drinking water since the radiation leak at Japan's Fukushima Daiichi nuclear plant after the March 11 earthquake.

Fortunately the half life of iodine-131 is quite short, only 8 days, meaning the vast majority of the dangerous isotope should be degraded in 2 weeks time so long as there is not additional exposure.

US citizens are at extremely low risk of radiation exposure due to the events in Japan, but officials will continue to monitor the situation.

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Who knew that 95 percent of what we think is taste is actually smell?

I love producing QUEST stories because there’s so much I learn in the process. Who knew that 95 percent of what we think is taste is actually smell? Or that flavor is really a complex combination of all the senses mixed with our feelings and perceptions?

One element of the story that especially resonates for me is the piece about smell memories. I’ve always found smell to be very evocative, and so I asked our experts about smell and memory and emotion. Hildegard Heymann, the UC Davis sensory scientist who we feature in the piece had wonderful things to say about smell memories and why they can be so powerful. Our favorite smells may not be pleasant in the typical sense, but they can have a true therapeutic effect.

For example, one of Dr. Heymann’s favorite smells is the odor of skunk. In her interview she described it this way: “For me, the smell of skunks makes me intensely happy. I know, intellectually, exactly what is happening, but even though I know that, emotionally it never ceases to work. My husband will literally drive around to try and find the smell of skunk when I’m depressed. He gets me in the car and takes me there. Because it immediately makes me happy. Why? I grew up in South Africa where going to the beach at Christmas time, which is in the middle of the summer, we had to cross the sand dunes. And they had these little plants that when you break them, smell like skunk. So to me, skunk means Christmas, happy, vacation—all those things. And even 35, 40, 50 years later, it still works that way. So we all have them. You just need to figure out what your aromatherapy odorants are, and then hopefully they’re purchasable. Skunks aren’t!”

Personally. I love the smell of Italian delicatessens. My father had a passion for salty Italian meats, cheeses and olives, and I have distinct childhood memories of deli cases full of colorful antipasti, burlap sacks full of dried beans, and shelves lined with bottles of wine. My odor memory is a wonderful blend of ripe gorgonzola, fat rounds of parmesan, salty prosciutto, briny olives. This mélange also probably contains hints of burlap, cardboard, oil and vinegar infused wood floor, wine cork, and who knows what else. It’s a pretty pungent aroma, but I find it enormously comforting, not unlike Hildegard Heymann’s skunk.
On a final, flavorful note I want to share a wonderful poem by Chilean poet Pablo Neruda. I found it in a book of food poems called O Taste and See. Even if you’re don’t like tomatoes, I think you’ll enjoy this evocative, colorful, delicious poem.

Ode to The Tomato

The street filled up with tomatoes, noon, summer, the light splits in two tomato halves and the juice runs down the streets. In December the tomato breaks loose, invading kitchens, stealing into lunches, lounging on sideboards and in between glasses, butter dishes, blue salt-shakers. It has its own light, benign majesty. We must, unfortunately, murder it: the knife sinks into its living flesh, it’s a red viscera, a cool sun, deep, limitless, it fills the salads of Chile, marrying happily the bright onion, and to celebrate, we let oil, child and essence of the olive, pour down over its open hemispheres, pepper adds its fragrance, salt its magnetism: these are the weddings of the day, parsley raises its flags, potatoes boil vigorously, roasting meat bangs on the door with its aroma, it’s time! let’s eat! and on the table, on the waist of summer the tomato, astro of the earth, fertile, ever multiplying star, reveals to us its orbits, its canals, the distinguished plenitude and boneless, heartless, armorless abundance, brings to us the gift of its fiery color and the integrity of its freshness.

Watch The Science Of Taste tv story online.

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In America, it has taken several documentaries, books and expert nutritional advice to help me choose healthy food – unlike cheeseburgers – to enjoy.

I just finished reading Omnivore’s Dilemma. It mysteriously appeared on my desk a few months ago; someone who still is anonymous thought I should read it. I remember my friends singing it praises a year ago and now I can see why. It also cleared up a confusion I had about some weight loss in England. When I was twenty-two, I lived in England for a year. I only changed one thing in my diet when I went abroad; I ate multi-grain bread instead of white. Yet I dropped two dress sizes all the while enjoying pints and chips covered in malt vinegar and wrapped in newspaper. Until this day, it was always a mystery to me how I could have lost weight on English fare.

But American fare and our way of eating is much more insidious. Corn is in everything manufactured. I didn’t believe this assertion in Omnivore’s Dilemma until I started reading labels. It’s in pasta, soda, yogurt and even ketchup. Surplus corn is synthesized into a variety of ingredients; for example high fructose corn syrup sweetens almost every soda and corn is synthesized into emulsifiers found in an assortment of frozen foods. We also do not have a culture of food, like the English, French, or Greeks. In England, Sunday constituted a big Sunday dinner. Either my flat mate or myself would cook and we would cook for about twenty friends. It was social, leisurely and incredibly enjoyable. Looking back on the year, we didn’t eat out very often. There were many shared dinners and meals were hardly ever rushed. I found it odd at the time but every meal and social engagement included some sort of tea. Even stranger, eggs and milk were left in the cupboard rather than fridge and people shopped on a daily rather than weekly basis. Canned and processed food did not list undistinguishable ingredients. I was tickled to find out that chocolate contained cacao, sugar and cream rather than the incomprehensible list of things found in Hershey bar.

It seemed the reason I lost weight in England was lack of highly processed corn in my diet. Since the weight came back fairly readily when I returned, it seemed the most obvious culprit. It wasn’t just Omnivore’s Dilemma that has educated me and made me a fan of European food and eating habits. Reading Superfoods has made me familiar with fourteen foods that can boost health. Watching the documentaries, Food Inc. and Obesity in America cemented in my mind that food doesn’t fit neatly into an industrialized or global definition. It is best when local. I have seen family members get diagnosed with diabetes and cancer; these ailments have always been coupled red flags in their food choices. I have also gone back to reading Andrew Weil and agreeing with him about his caveat that health is intimately linked to nutrition. My first time heralding this claim was when I changed my food in college. I was diagnosed with ADD at sixteen. In college, I went off meds and cut out simple sugars and carbohydrates in my diet. My ADD actually improved dramatically with the dietary change.

So my food has changed once again in response to my research on the normal American diet. I started shopping at farmer’s markets rather than Safeway. I buy fruits and vegetables in season that are locally grown. I look at ingredients, if there is more than five I put it back on the shelf. I look for meat and eggs that haven’t come off an assembly line or are corn fed but rather comes from a local farm. What’s so funny is when I was in England, this is exactly how I shopped but I didn’t know it at the time. In America, it has taken several documentaries, books and expert nutritional advice to help me choose food healthy enough to enjoy. But the experience has opened me up to a world of taste and enjoyment that was seriously lacking in the processed food I used to eat.

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