IRA FLATOW, HOST:
This is SCIENCE FRIDAY. I'm Ira Flatow. Hope you had a good Thanksgiving, this being the day after. One of the best parts of Thanksgiving is, I think, the leftovers. Don't they always taste better? Well, my next guest is here to tell us how we can get the most flavor and nutrition out of those leftovers and our food all year round.
She says we've been breeding the nutrition out of our food for years, but if you choose the right variety of fruits and vegetables, and you prepare them correctly, you can reclaim the minerals and the taste. Like, did you know that crushing garlic is more nutritious than leaving it whole? And what about the heirloom varieties? Are they any better for you?
Journalist Jo Robinson is author of "Eating on the Wild Side." Thanks for joining us.
JO ROBINSON: Good to talk with you, Ira.
FLATOW: We won't be taking your calls this hour, but for more information about what we're talking about, go to sciencefriday.com. I like to grow heirloom veggies in my garden and we think the heirloom varieties has more natural form and more flavorful, and you say that we have to go way further back than just a generation to regain those nutrients that we lost.
ROBINSON: The research shows that we've been breeding nutrients out of our plants since we first became farmers 10,000 years ago. We didn't mean to. Basically we were modifying wild plants to make them better tasting and easier to produce and easier to prepare, and it's only been in maybe the last 15 or 20 years that we're understanding the consequences of those early choices.
FLATOW: So give me an idea of a plant that would be totally different looking and tasting 1,000 years ago.
ROBINSON: Well, corn is an excellent example. We've modified it to the extent that we wouldn't even recognize wild corn as corn. Wild corn has maybe, I think it's five to twelve kernels per little spindly cob. They're encased in hard shells, as hard as an acorn shell, and they're very starchy, not sweet at all. But they're essentially about two percent sugar, but they're twenty percent protein.
And so what we have in the store today, these huge, super sweet varieties that are between two and four percent protein and up to forty percent sugar.
FLATOW: That's like eating a candy bar, right?
ROBINSON: It is. It's candy corn.
FLATOW: And it's most of the corn, just about all the sweet corn we eat today is that super sweet variety?
ROBINSON: Yes, 95 percent of the corn in the supermarkets is ultra sweet.
FLATOW: Wow. Most people though don't like - in America they don't like the bitter taste. That is just an American palate?
ROBINSON: Well, all of us are highly adverse to very bitter flavors because we're programmed that way because many poisonous plants are very bitter or astringent or very sour, and so we wouldn't be here if we loved really bitter flavors. But there's a big difference in how much bitterness people like according to which country you live in. And it looks like we're the world wimps when it comes to bitterness.
You know, our light beer is, like I think on the bitterness scale, is a four, and there's some German pilsners that are 100. So yes, for a combination of reasons we have really bred the bitterness and, now we know, these important compounds called phytonutrients out of our food.
FLATOW: They're in the bitterness, they're in the bitter part of it?
ROBINSON: Yeah, many of the most important phytonutrients are slightly bitter, and we've gone overboard. We have gotten rid of most of the bitterness from most of our plants and we're left with ones that have really diminished health benefits for us.
FLATOW: So how can we recapture that? How can we choose wisely the plants we should be buying, and where can we find them?
ROBINSON: There's a big difference among different varieties of the same kind of fruit or vegetable - apples or blueberries or pears or grapes - in that some of the, unbeknownst to us, have five, 10, 20 times more of these phytonutrients than others. We can't always see which ones they are, just like you can't look at a fruit and know how much Vitamin C is in it.
We have to go by a list and this is also true of phytonutrients, although there are some general rules that I like to give people.
FLATOW: Give us those rules, yeah.
ROBINSON: Yeah, okay. One of them is if it's purple, red, blue or black, eat it.
FLATOW: Purple, which would be - what kind of purple? Like an eggplant?
ROBINSON: An eggplant, purple plums, purple grapes, purple berries of all kinds. Red, as in red grapefruits, and all of the red berries. Blue is not all that common in this culture, but it used to be. We used to have blue corn and in the Andes they have lots of different blue potatoes.
FLATOW: Blueberries? Would blueberries be there?
ROBINSON: Blueberries are on that list, absolutely. And so why are these better for us? It's because they have one of the most well researched and beneficial phytonutrients that we know, which are anthocyanins, and I'm just really impressed by the new studies showing what they can do for our health. This is a very new science, but now test-tube studies and animal studies and finally small human studies are all beginning to line up in the same direction, showing that anthocyanins have the potential to reduce most deadly and chronic diseases.
Cancer, cardiovascular disease, Alzheimer's, diabetes.
ROBINSON: So we need to find - we need to eat more of them and find ways to bring more of these purple, black, red and blue foods back into the American diet.
FLATOW: So if you can't remember that, then just look for the most colorful foods that you can get, because that would...
ROBINSON: Well, not the most colorful. That's one of the new foods rules that actually this new science is contradicting. It's those particular cues that are full of anthocyanins. And then there are some fruits and vegetables that are pretty colorless that are excellent for us, and this is a surprise for many people. One of the most nutritious vegetables in the store is the artichoke.
ROBINSON: It's not red, blue, purple or black, and it's not bright green or, you know, or any of these other colors we've been told to look for. It's this kind of drab army green, but it is one of the most antioxidant rich vegetables in the store. There are other colorless phytonutrients. They're in onions, for example, and in apples, and in teas, so you know, the idea of shop by color is a half-truth.
Really what we need is a shopping list. We need a shopping list based on science that tells us which one of these varieties are going to be restoring nutrients to our diet we've bred out for 10,000 years.
FLATOW: You say that the shallot is the superstar of nutrition. What do you mean by that?
ROBINSON: Right. Yeah, in the allium family, which includes onions and garlic, it is one of the most nutritious, and we see them more and more in the supermarket. It used to be used by chefs and, you know, really, you know, dedicated cooks, but now you can find shallots and scallions, you know, pretty much everywhere. Little more expensive, but they're much better for us, and so I'm encouraging people to use more shallots in particular.
FLATOW: What about, we hear all the time about garlic. Does that deserve the praise it's gotten over the years?
ROBINSON: It really does. It looks now that garlic is one of the most potent cancer fighting fruits or vegetables known, but we learned in 2001 that it matters a great deal how we prepare garlic, and if we don't do it right, all we get is the flavor and none of those cancer-fighting properties. The problem is, is that the medicine - I call it the medicine in garlic - is a compound called allisum.
And in a fresh clove of garlic, there's actually no allisum. There's just the two ingredients that have to be combined to make allisum and if we take that garlic and immediately slice it or press it and throw it in hot oil, one of those ingredients required to make allisum, which is an enzyme, is destroyed immediately. So we don't have the allisum.
But these same study showed us what goes wrong with conventional ways to cook it showed us what to do. Next time you use garlic, I advise that you press it, slice it, and set it aside for about ten minutes before you put it into anything hot. And during that time, those two ingredients, an enzyme and a protein, work together and create maximum amounts of allisum, which itself is tolerant to heat.
So now you can throw it in that shimmering hot oil and you get all the benefits.
FLATOW: Is that the same thing with onions? Your eyes don't tear until you actually slice the onion, 'cause it's combining two chemicals, right? Is that the same thing going on in an onion?
ROBINSON: Not exactly, because the main phytonutrient in onions is something called quercetin and that's not enzyme-dependent, so you can take onions and slice them and dice them and put them in hot oil, and you will get their benefits. In fact, quercetin increases as you cook onions, so you don't have to have, you know, such a fussy attitude towards onions.
FLATOW: And cooking itself frees up more nutrients than eating raw vegetables?
ROBINSON: Sometimes yes and sometimes no. I mean, unfortunately the science is very complex and one of the things it's telling us is that we really can't have blanket rules about how to prepare things. Some people swear that eating things raw is the best way to go. Others point to the fact that things increase in health benefits as you cook them, and it's really dependent upon the fruit or vegetable.
Tomatoes become much richer in a phytonutrient called lycopene, which is linked with a lower risk of heart attack and stroke, the longer you cook it. So those long simmered Italian pasta sauces are excellent for us.
FLATOW: Tell us more about what other vegetables we should be looking for. What should we do to get back to...
ROBINSON: Yeah, I think another rule that I have besides eating those blue, red, purple and black vegetables, I think we should be eating between three and four servings from the cabbage family every week. They're showing, again, like garlic and onions, really good anti-cancer properties. There's this one study at the University of Washington that showed that men who eat these three to four servings from the cabbage family a week have a 60 percent reduction in the risk of prostate cancer.
And in order for men to get that same reduction, they would have to eat 10 servings of other kinds of fruits and vegetables a day. So it's three or four servings a week of the cabbage family, or eight to ten servings of fruits and vegetables a day. The cabbage family is a very big family, you know. There's mustard greens and cabbage and broccoli and kale, horseradish, wasabi, you know, a very long list.
FLATOW: I didn't know horseradish was in the cabbage family.
ROBINSON: Yes, it is.
FLATOW: Wow. We have to take a break and when we come back, lots more tips about eating on the wild side, with Jo Robinson.
This is SCIENCE FRIDAY from NPR.
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FLATOW: This is SCIENCE FRIDAY. I'm Ira Flatow. We're talking this hour about how to get the most nutrients out of your fruits and vegetables with Jo Robinson, author of "Eating On the Wild Side." What about carrots, the color of carrots? How the carrots have changed over the years? Talk about that, if you will.
ROBINSON: Yeah. This is another example of how unwittingly we've worked against our health benefits by the way we've bred fruits and vegetables. So originally, carrots were purple, red or in some cases yellow, and about 400 years ago in the Netherlands, this group of really patriotic plant breeders decided that they wanted to honor this political house called the House of Orange that had protected the Netherlands from Spanish marauders.
And so they crossed a red carrot with a yellow carrot from Africa that was actually a mutant carrot to come up with orange. And they were such great promoters of carrots, as they were of tulip bulbs, that it wasn't long before people the world over were eating primarily orange carrots. And only now do we know that those original purple carrots have 16 times more antioxidants than the orange ones in the store.
So it's so fascinating to me, is that - yeah. It's like, it's our very latest science which is giving us insight into what we did for a very, very long time. And we're poised - this is what excites me the most - to start making different choices, you know, to start - yeah.
FLATOW: No, go ahead. I was just wondering if it's possible to find any seed or carrot seed left from that original carrot and get it going again.
ROBINSON: Well, I actually grow three kinds of purple carrots.
FLATOW: You do?
ROBINSON: In my own garden. Yes. Look in a seed catalog and you will find them. And they're not only gorgeous, they're sweeter than orange carrots, so they're better for you and sweeter.
FLATOW: What about all these baby carrots that we see all the time? Are they just carrots that are cut down to little size?
ROBINSON: Yeah, that's what they are. And so someone came up with a way to not have to throw away or feed to animals all these broken, misshapen carrots and so they just put them on these mandrels and whittled them down to these tiny little stubs and sell them. And we think that when we eat them we're getting the same benefits we get from carrots, but almost always the most phytonutrients in plants are in the outer levels, especially the skin.
FLATOW: So that's true then? When we were growing up, it said eat the skin, the potatoes, whatever.
FLATOW: Just not an old wives tale. Your mom was right.
ROBINSON: It's not. Eat the skin. An old rule that still works. Like, if you were take a carrot and you were just to peel it and put the peels on one side and the rest of the carrot on the other, the peels would give you as many health benefits as the whole rest of the carrot. And underneath the peel it's more nutritious than the layer - as you go towards the core, the less nutritious it becomes.
So these baby carrots have almost all of the health benefits whittled away and thrown away.
ROBINSON: And so we munch happily on these raw baby carrots and, you know, they're better for us than Hostess Twinkies and potato chips, but they don't give us the health benefits that we assume they do.
FLATOW: So is it safe to eat - is it better to not peel the carrot, just wash it?
ROBINSON: Absolutely. Yeah. I would never peel a carrot, but I just scrub them very well and I also buy organic carrots, which, you know, I won't have to worry about the pesticide contamination.
FLATOW: Let's talk about how you can boost our post-Thanksgiving meals. Let's set up a menu. What should we do?
ROBINSON: Okay. So are we relying on what we had for Thanksgiving yesterday?
FLATOW: Yes. We have leftovers. What's the best way to make nutritious value out of that?
ROBINSON: Well, make sure you eat all the cranberries. They're almost a wild berry, extremely rich in antioxidants and anthocyanins, so fight for the cranberries more than the stuffing.
FLATOW: It's not the jelly stuff that comes out of the can that we're talking about here, right?
ROBINSON: Well, actually even cooked cranberries are good for you. Sometimes canned food is better for you than fresh, but I won't go into that.
ROBINSON: For that wonderful turkey sandwich, if you've got some rye bread on hand, put it on rye bread because rye bread has more phytonutrients than wheat bread and it gives it just, you know, a richer flavor. Instead of putting lettuce on that sandwich, got any spinach? That's far better for you than the lettuce and people find they like it just as much on sandwiches as, you know, the less nutritious lettuces.
ROBINSON: You've got parsley left. I mean, people think of parsley as a garnish, but actually it's far more nutritious than most of the things in the produce aisles. So I like to chop up parsley and put it in lots of different things, and I would put it in that sandwich.
FLATOW: Well, I have to have it mixed in with something, 'cause I'm not a fan of parsley. So if it's mixed in, I think I can lose it.
FLATOW: You have to have mashed potatoes, right? Somebody has to have it, it's lying around. What's the most nutritious way of having mashed potatoes?
ROBINSON: OK, let's suppose that you've done it with white potatoes, which are the least nutritious potatoes in the store. If you didn't make garlic potatoes, add garlic to the leftovers and heat them up and you'll get all the benefits of garlic, so that would be a good step.
FLATOW: If you're thinking of making another pie - it went real fast yesterday at the Thanksgiving dinner - what's the best pie suggestion, the filling, I guess, what would you put in it?
ROBINSON: Oh, I think a berry pie would be superb. Actually, berries become more nutritious as you cook them, so...
FLATOW: Oh, is that right?
ROBINSON: Yes. That berry pie is an excellent choice for dessert.
FLATOW: Any kind of berry?
ROBINSON: Yes, almost all berries. I can't think of a berry actually that isn't excellent for us.
FLATOW: But if you're going to use an apple pie, make the apple, you're saying, because of the rule about there's good stuff still in the skin, leave the skin on the apple if you're making...
ROBINSON: Right. And also there's a tremendous difference in phytonutrients between different varieties of apples, so make it from a Granny Smith, for example, which is by far the most nutritious apple in most supermarkets. Honey Crisp is actually a good one too and it's much sweeter, so if you don't like tart apples, go for the Honey Crisp.
In my book I list, you know, all of the most nutritious varieties that you can find. I wanted to make this information, which can be very complex, easy for, you know, consumers to take advantage of.
FLATOW: And speaking of your book, it's called "Eating On the Wild Side." I'm talking with Jo Robinson on SCIENCE FRIDAY from NPR. Let's talk about wine. Everybody can have some wine and leftover wine. Or it's the holiday season; you're going to go out and buy wine anyhow.
ROBINSON: Right. I think a lot of people know that the red wines have more health benefits than the white ones and the reason is anthocyanins again. Red wine is fermented along with the seeds and grapes for varying amounts of time and during all that time it's fermenting the anthocyanins, which are primarily in the skin, mix in with the juice and are much better for us.
And also there's a compound called resveratrol, which is in red grapes but not white ones - not many white ones - that get into that wine, so definitely a red wine. And here's a trick I use. The denser the color of that red wine, the more phytonutrients it will contain, so the very dark Cabernet Sauvignon or a Merlot or Shiraz, basically a red wine that you can hold up to the light and you can't see through it is going to be your most nutritious choice.
FLATOW: Some people say that there's resveratrol in grape juice. Is that correct?
ROBINSON: It is true.
ROBINSON: But it's purple grape juice, not white grape juice.
FLATOW: So if you're not into the alcohol part and you want to have grape juice, you can still get that benefit.
ROBINSON: Yeah, and one of the best sources is Welch's grape juice. The concord - it's made from concord grapes, which is basically a wild American grape, and it is - it's been shown to have really remarkable health benefits. It's increased the cognition and memory of older people that are showing the first signs of memory loss. It has reduced blood pressure, so it's a very cheap source of anthocyanins and universal.
FLATOW: What about the sweet wine, like Manischewitz and all those other sweet red concord wines? Will they get the job done?
ROBINSON: They will. And interestingly, anthocyanins can kind of counteract the negative effects of the sugar in our food.
FLATOW: No kidding.
ROBINSON: They - yeah. They could help keep our blood sugar lower and our insulin - more effective insulin, so we wouldn't have high insulin. So drink those if you like sweet wine.
FLATOW: Just a couple of really great tips. We could go on forever. Talking with journalist Jo Robinson. She is author of "Eating on the Wild Side." There are some great tips in this book. And thank you for writing it because it adds to the growing volume of good eating habits and the ways to eat healthy. Thank you very much for being our guest today.
ROBINSON: It was my pleasure. Thank you.
FLATOW: You're welcome.
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