If you've ever bitten into a raw cranberry, you know it's as bitter as a lime. Native Americans embraced that acidity to fight infection, and pilgrims believed there was something in the red skin of cranberries that fought scurvy.
Scientists today are investigating dozens of health-promoting compounds found in cranberries, and they're finding that there's a lot of truth to the lore of centuries past.
The 'Pick Me!' Berry
When the pilgrims first arrived in the New World, they wouldn't have been able to miss the vibrant red bogs of the indigenous cranberry. Like the Native Americans, they came to think of cranberries as medicine, says Kathleen Wall, culinary historian at Plymouth Plantation.
Pilgrims and other early settlers ate the berries to fight off scurvy, unaware that it was the vitamin C inside that made the berries good medicine.
"They thought that sour things would take salt out of their body," says Wall, "and they thought salt was causing scurvy. So even if they had the wrong reason, there was something to it."
There was also something to the Native American practice of grinding up cranberries and using the paste to fight wound infections.
"What it did was sort of form a barrier so the skin and wound could heal underneath, and there was some truth to it," says Wall. "They wouldn't keep doing it if it didn't work."
Centuries later, the medicinal lore holds up. Researcher Diane McKay of Tufts University says cranberries contain compounds that help prevent bacteria like E. coli and staph from sticking to our cells. So there's some truth to the old wives' tale that drinking cranberry juice can help prevent urinary tract infections. But it's not quite a primitive antibiotic, says McKay.
"It kind of prevented the infection," she says, but "I don't think it would be able to treat it."
At the USDA's Food Composition and Methods Development Lab in Beltsville, Md., food chemists are using liquid chromatography and mass spectrometry to detect what exactly is inside a cranberry. They're even finding compounds scientists didn't know about 20 years ago.
The lab has helped develop a comprehensive method to detect and measure the thousands of plant-based compounds found in fruits and veggies.
Finding a way to detect and measure these compounds is important because while we know that people who eat lots of fruits and vegetables tend to be healthier, it's not always clear how these compounds work or which are most beneficial.
Jim Harnly, the lab's research leader, knows from past experiments that cranberries and other berries are loaded with polyphenols, which are known to have an antioxidant effect. While oxygen is the stuff of life, it can also naturally break down living tissues, i.e. aging. Antioxidants are compounds that prevent or slow oxidation in the body -- that's why you sometimes hear antioxidants called "anti-aging" compounds.
Scientists have proven the polyphenols in berries do have an antioxidant effect -- but only in the test tube. They haven't yet been able to determine how much these antioxidants work in the body.
Red Is Key
Harnly runs a test on some cranberries I brought to his lab, and shows me a list of 18 compounds found in my berries. On the list are anthocyanins. "That's giving you the color in a cranberry," Harnly explains.
And perhaps much of the cranberry's health benefit, too. After I left the lab, I called Jeffrey Blumberg at Tufts University to help me make sense of these anthocyanins.
"Yes, anthocyanins from berries may in fact contribute importantly to promoting our health." Blumberg says the interesting thing about anthocyanins is that they seem to work in more than one way in our bodies. They have antioxidant power, fighting against cell damage. But there's another way, too.
"It seems small amounts of these phytochemicals find their way from plant foods, like cranberries, into our cells, and then direct cells to reduce our inflammatory reactions."
Basically, these compounds fight against inflammation. "And inflammation is not only something we see with infectious disease, but chronic low levels [of inflammation] now appear to be an important risk factor for both cardiovascular disease and cancer," Blumberg adds.
Beyond Cranberry Sauce
Now that we know why cranberries are good for us, let's get back to the fun part. How do we get more of them into our diet? Susan Stamberg's famous cranberry relish is one way.
Gina Chersevani has a different approach. "Everybody assumes you have to cook cranberries and boil away with sugar, right? They're so bitter and acidic."
But she doesn't cook them. Her forte is liquid; she's a mixologist at PS 7's restaurant in Washington, D.C.
She shows me how to make a low-calorie, non-alcoholic cocktail, starring cranberries. She juices fresh berries with pears, strains out the seeds, and then adds some quince and honey simple syrup.
The result? A regal and refreshing drink that captures everything that's good about cranberries, perfect for your Thanksgiving table.
Before You Go
There's an explosion of research on the cranberry's summer cousin, the blueberry. Like cranberries, these native North American berries are also loaded with polyphenols.
Researchers at the University of Cincinnati are investigating blueberries' effects on patients with mild cognitive impairment -- a precursor to dementia. In one small study, patients who drank 2 1/2 cups of blueberry juice per day for three months were able to improve scores on memory tests such as word recall lists and paired associative learning tasks (for instance, I say "north," and you respond "south"). The study was published in the Journal of Agriculture and Food Chemistry.
"I don't believe we're reversing the aging effect," says lead researcher Robert Krikorian. But it's possible that blueberry consumption can help slow the damage that leads to memory loss.
Krikorian doesn't know which compounds in the blueberries may be responsible for the effect, but he suspects it's the anthocyanins found in the pigment of the fruit. "They have potent inflammatory effects, and that, I would guess, is an important factor given the importance of inflammation in neurodegeneration"
One big caveat: This is one of the first human trials of blueberries, so clearly these findings are preliminary.
Blueberries For Blood Sugar
Several studies have shown that diets rich in the colorful pigments found in blueberries can help lower the risk of cardiovascular disease and metabolic syndrome. Now, there's some evidence that berries may also help regulate blood sugar and stave off Type 2 diabetes.
A small study published in the Journal of Nutrition found that participants who drank two blueberry shakes daily for six weeks experienced a 22 percent change in insulin sensitivity. This is a good thing. It means they needed less of the hormone insulin to process sugar from the foods they were eating. The study included patients who had pre-diabetes.
None of the patients in the double-blinded study knew if they were eating a blueberry shake with artificial flavoring, or if it was the real thing loaded with polyphenol compounds. "Overall, the blueberry group had a significant increase in their insulin efficiency, whereas the placebo group did not," says William Cefalu of Louisiana State University.
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RENEE MONTAGNE, host:
This is MORNING EDITION, from NPR News. I'm Renee Montagne.
Eat a raw cranberry and you will wince. That's because they taste as bitter as limes, but they are the berry of Thanksgiving. Today in Your Health, NPR's Allison Aubrey looks at how this fruit earned a place at the harvest festival, and how early settlers believed - as scientists do today - that cranberries help keep us healthy.
Allison begins the story in Plymouth, Massachusetts.
ALLISON AUBREY: It's still possible to climb aboard the Mayflower docked near Plymouth Rock - or at least a reproduction of the ship. Kathleen Wall knows the way.
Ms. KATHLEEN WALL (Plymouth Plantation): So, hello. Welcome to Plymouth Plantation. On our colonial site, it's the year 1627, so you've had a little travel back in time. We're standing in one of the recreated gardens.
AUBREY: Wall is the plantation's culinary historian. And she says though she can't see a cranberry bog from where she's standing now, there are still plenty of them nearby. She grew up with them.
Ms. WALL: We had cranberry bogs right across the street. And so we waited for ice to harden up, and we'd go skating there all the time. We loved it, the beautiful, beautiful landscape of blue water and red cranberries.
AUBREY: The vibrant color must have stood out to the pilgrims and early settlers, too. They came to think of cranberries as medicine. They ate them to fight off scurvy, not knowing that it was all the Vitamin C�in cranberries that that made this work.
Ms. WALL: They thought that sour things would take the salt out of your body, and they thought the salt was causing scurvy. So, you know, even if they had the wrong reason, you know, there was something to it.
AUBREY: There was also something to the Native Americans' practice of grinding up cranberries and using the paste to fight wound infections.�
Mr. WALL: What it did was sort of form a barrier so that the skin and the wound could heal underneath. You know, there was some truth to it. They didn't keep doing it if it didn't work.
AUBREY: But does this medicinal lore really hold up to today's science? Researcher Diane McKay of Tufts University says cranberries do contain compounds that help block bacteria like E-coli and staph from sticking to our cells. That's why people drink cranberry juice to prevent urinary tract infections. So could you think of the berry as a sort of primitive anti-biotic?�
Dr. DIANE MCKAY (Tufts University): Well, it kind of prevented the infection. I don't think it would necessarily be able to treat it.
AUBREY: Scientists are studying cranberries for lots of different reasons.
SUSAN STAMBERG: Excuse me. You're talking about cranberries and not including me?
AUBREY: Hello. NPR's Susan Stamberg just walked into the studio.
STAMBERG: A.K.A. Ms. Cranberry. Or actually, daughter-in-law of Mama Stamberg.
AUBREY: That is right.
STAMBERG: Whose cranberry recipe I give out every - interminably - single Thanksgiving on NPR.
AUBREY: And I am not trying to steal your thunder here.
(Soundbite of laughter)
STAMBERG: Of course not.
AUBREY: This close to Thanksgiving, we cannot talk about cranberries on MORNING EDITION without expecting to hear that recipe. But we're probably a little early yet.
STAMBERG: Yeah. I'll do it, with any luck, the Friday before Thanksgiving so people can do their weekend marketing.
AUBREY: Got it. OK. We are just talking about health benefits here.
AUBREY: And is this something that comes up? And when people ask for your relish recipe, are they looking for the health-promoting qualities of cranberries?
STAMBERG: No. Usually, they're looking to get away from the table, or they're exercising their eyes because the brilliant, shocking pink color. But I know it's good for us. It's got lots of Vitamin C, right?
AUBREY: That's right. But there's actually something a little more interesting, at least to scientists. There are polyphenols, anthocyanins - all kinds of plant compounds.
STAMBERG: It sounds like mouthwash.
(Soundbite of laughter)
AUBREY: It gets really confusing. But you know what? In order to sort of peer inside the berry, I�visited a lab at the U.S. Department of Agriculture, where they have these fancy techniques, from liquid chromatography to mass spectrometry. They can actually detect bio-active compounds in cranberries that scientist didn't even know about 20 years ago.
AUBREY: Yeah, it's pretty cool. So here's what happened. About a week ago, I arrived at the lab, and I was looking for the director.
Dr. JIM HARNLY (U.S. Department of Agriculture): I'm Jim Harnly, the research leader for the food composition and method development lab.
AUBREY: The lab is set up in an old building that just sort of blends into the farm landscape here at the USDA's Human Nutrition Research Center in Beltsville, Maryland.�From the outside, you'd never guess that researchers here are on the cutting edge of food science. They've helped develop a comprehensive method to measure anti-oxidants and loads of other plant-based compounds.�
It's important because we know that people who eat lot of fruits and vegetables tend to be healthier. This technique will help scientists figure out which compounds or groups of compounds may be most beneficial.
I arrived with a bag of fresh cranberries. And Harnly told me that the first steps to figure out what's going on inside is to chop them, dry them and grind them up. He's�got an industrial-sized coffee grinder.
(Soundbite of grinding)
Dr. HARNLY: Push down on the lever, and you grind the sample.
AUBREY: And what you've got is pulverized cranberry.
Dr. HARNLY: Absolutely right - dried pulverized cranberry in this case.
AUBREY: And you're telling me there's a way to figure out exactly what's inside this cranberry?
Dr. HARNLY: Yes.
AUBREY: Harnly takes the pulverized cranberry and puts it in a vial. He leads me over to a wall of machinery designed to detect plant compounds. There, a robotic arm equipped with a needle pierces the vial, extracts some of the cranberry and within a few minutes, starts to graph results on a computer screen.
So what are we seeing now? Is this the actual chromatogram?
Dr. HARNLY: Yes. You will see the series of peaks coming off and we can see a series of one, two, three, four peaks.
AUBREY: Each peak represents one compound, or polyphenol. And Harnley knows from past experiments that cranberries and other berries are loaded with these compounds.
Dr. HARNLY: What we have here, we've listed 18 different compounds that we've found and these are either anthocyanins...
AUBREY: Oh anthocyanins, those are those compounds that make them really colorful, right?
Dr. HARNLY: Yeah. That's what's giving you the color in your cranberry. That's right.
AUBREY: And perhaps much of the benefit too. After I left the lab, I called Jeffrey Blumberg at Tufts University to help me make sense of these anthocyanins.
Dr. JEFFREY BLUMBERG (Tufts University): Yes, anthocyanins from cranberries and other berry fruit, too, may in fact contribute importantly to promoting our health.
AUBREY: Blumberg says the interesting thing about anthocyanins is that they seem to work in more than one way in our bodies. They have antioxidant power, fighting against the damage of our cells. And there's another way, too.
Dr. BLUMBERG: It seems that small amounts of these phytochemicals find their way from plant foods like cranberries into our cells and then they direct our cells to reduce our inflammatory reactions.
AUBREY: So actually fight against inflammation?
Dr. BLUMBERG: Exactly. And, of course, inflammation is not only something that we see with infectious diseases, but inflammation, chronic low levels of inflammation, now appear very clear to be an important risk factor for both cardiovascular disease and cancer.
AUBREY: So now we know why cranberries are good for us. But let's get back to the fun part. How do we get more of them into our diet? Well, cranberry relish is one way, right, Susan Stamberg?
STAMBERG: Sure. We have it at Thanksgiving dinner, of course, and we have it for breakfast the next morning, lunch, dinner, and this goes on. And with leftovers it's terrific, also very good with roast beef and nice in juice.
AUBREY: And I've heard you say that your recipe sounds terrible but tastes terrific.
STAMBERG: Tastes terrific, girl.
AUBREY: Are you sure that everyone agrees with you?
STAMBERG: Not a bit.
AUBREY: And, you know, the sour cream is the thing that's always made me a little frightened.
STAMBERG: That could be your next scientific experiment.
(Soundbite of laughter)
STAMBERG: That, the onions, the...
AUBREY: Well maybe. But let's get back to cranberries. So if relish isn't going to do it for you, let me introduce you to mixologist Gina Chersevani. She's got a different approach to cranberries.
Ms. GINA CHERSEVANI (Mixologist, PS7's): Everybody always assumes you have to cook cranberries and boil them away with sugar.
AUBREY: Right, they're so bitter...
Ms. CHERSEVANI: Yeah, and acidic.
AUBREY: But she doesn't cook them. Her forte is liquid. She runs the bar here at this trendy and cavernous restaurant called PS7's, just a stone's throw from NPR headquarters.
Ms. CHERSEVANI: We're going to actually juice our cranberries in a juicer. We're going to put a little bit...
AUBREY: In the go the berries, some strained pear juice and a simple syrup made from honey, water and quince.
(Soundbite of juicer)
AUBREY: And then she pours us each a glass.
Ms. CHERSEVANI: It's so much better.
AUBREY: It's so gorgeous. It's like regal. Wow.
If you want the recipe for this drink and a bunch more, or want to learn more about the super powers of blueberries, check out my video series, Tiny Desk Kitchen. That's at npr.org/health.
I'm Allison Aubrey. Transcript provided by NPR, Copyright NPR.