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Are There Foods that Could Help Prevent Cancer?

Epidemilogist Susan Oliveria is an expert on the link between nutrition and cancer. She is one of the authors of the new book, "The Strang Cookbook for Cancer Prevention: A Complete Nutrition and Lifestyle Plan to Dramatically Lower Your Cancer Risk" (Dutton). The book includes recipes from gourmet chefs. Oliveria teaches at the Strang Cancer Prevention Center, Cornell University Medical College, and Memorial Sloan-Kettering Cancer Center.




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Other segments from the episode on May 5, 1998

Fresh Air with Terry Gross, May 5, 1998: Interview with Michael Osterholm; Interview with Susan Oliveria.


Date: MAY 05, 1998
Time: 12:00
Tran: 050501np.217
Head: Food-Borne Illness
Sect: News; Domestic
Time: 12:06

TERRY GROSS, HOST: This is FRESH AIR. I'm Terry Gross.

Some of our foods are poisoning us -- infecting us with bacteria, parasites and viruses. Some of these microorganisms are lurking in undercooked hamburgers, raw chicken and produce. In fact, that recent stomach flu you thought you had, may have been food poisoning.

To help us understand why food-borne illness seems to be on the rise, we invited an expert on the subject, Michael Osterholm. He's state epidemiologist with the Minnesota Department of Health. He's also principal investigator for the CDC Emerging Infections Program.

He says that in his state, food-borne illness was the number one reason for emergency room visits last year. I asked him why more bugs seem to be ending up on our plates, and he told me that, ironically, it relates to our emphasis on a healthy diet.

MICHAEL OSTERHOLM, STATE EPIDEMIOLOGIST, HEAD, ACUTE DISEASE EPIDEMIOLOGY SECTION, MINNESOTA DEPARTMENT OF HEALTH: In the last generation, we have developed the heart-healthy diet in this country, which everyone would agree has been very kind to the cardiovascular system. It's been very good for cancer prevention. But it's also meant that from the gastrointestinal tract standpoint, we've had some real problems.

We've had major increases in our consumption of fresh produce, for example. Much of that today is actually coming from developing world countries. In a grocery store today, you'll have 400 different produce items on the shelf 365 days a year. Much of that's coming from the developing world.

We, in turn, also, even for that product grown here in the United States, recognize that much of the produce that we get today has very susceptible points in its production -- a whole line of delivery -- that makes it possible for it to get contaminated, and we can't eventually decontaminate it through washing and so forth.

So, that change has been very important. We're eating a lot more poultry today. That's a big change from 20 years ago, when the amount of meat -- red meat consumed in this country was almost three times higher than that of poultry. Today, it's almost equal.

We know that poultry is a very major source today of a number of infectious agents. And with the work done here in Minnesota, we're actually demonstrating not only are we getting more infectious agents, now we're starting to see antibiotic-resistant infectious agents coming through there.

So if you just continue to look at that whole diet change, that alone has been very important in getting the kind of infectious agents from around the world here into our kitchens.

GROSS: I want to hear more about the fruits and vegetables that we're eating here that are actually imported from other countries. Is there any way of knowing when you buy produce where it's from?

OSTERHOLM: Well first of all, as much as we're concerned about the international produce issues, and I think the outbreaks that occurred over the past several years with raspberries and a parasite called cyclospora with the raspberries coming from Guatemala. We've heard more recently about lettuce outbreaks from products in Central America and so forth.

I have to say at the outset that we can't just tell you that one country's production is safe and another's isn't. The United States- produced produce also has some real problems associated with it. And it's just that the domestic produce probably doesn't have the same exotic bugs necessarily that we might find in a developing world country.

So, one of the things that's always difficult when you're in a public health setting is: how do you advise the consumer about the safety of produce? Number one, I have to tell them that yes, there may be different risk with foreign produce. I can't say that it's higher than it is with domestic produce.

The second issue comes up is: what do we do about it? And we would like to be able to tell consumers that, like cooking your red meat or your chicken, what do you do about produce? And unfortunately, we can't. And what I mean by that is we've actually been involved with the studies trying to decontaminate produce items -- washing them. What else can you -- what kind of rinses can you use? And quite frankly, you can remove some of the bugs, but it's very difficult to remove all the bugs.

And for that reason, unfortunately today consumers are really at kind of a loss as to what they can do to really guarantee that their produce isn't carrying some agent that can cause a serious food-borne outbreak.

GROSS: Are there more germs on produce today than there used to be? Or, are we just eating more produce and therefore increasing our odds of getting sick?

OSTERHOLM: That's the million-dollar question. I don't think anyone can really tell you because produce, as a likely food-borne-related product, really wasn't recognized as being important until the last several years.

In Minnesota for example, a state that has probably had one of the most active food-borne disease surveillance programs of anywhere in the country, today produce accounts fully for over 30 percent of all of our outbreaks of food-borne disease.

And we believe that that's just still the tip of the iceberg. So, the question is: is it we're just eating more? That's probably part of it, without a doubt, but also we do believe that a generation ago, if you went into any grocery store, supermarket in the United States, you would find seasonal product from very localized delivery areas, meaning that if you were from the East Coast, you might get product that came up and down from the East Coast, but it was rare you'd get it from the West Coast and you clearly didn't get it from an international source.

And as a result of that, you would have five, 10, 15 items in the shelf space in a given season, but you didn't have the availability of 400 different items 365 days a year.

Well, with those additional items and where they come from, we now also raise the concern about exotic bugs. Cyclospora, the parasite I mentioned earlier, which caused that disease over the past several springs with Guatemalan raspberries, was a bug that we had not seen before in this country.

Is that because there was some unique risk of this getting contaminated in Guatemala with something that -- as a traveler going to that country, we'd be worried about -- with traveler's diarrhea, but we wouldn't think of in this country. And that's probably true. So, I think that the extension of the produce market into the developing world countries, as we chase the sun around the world to keep produce on our shelves 365 days a year has also added to the problem.

And so therefore, it's probably not just we're eating more of it, but we're also getting different bugs which causing the kinds of diseases that we didn't see a generation ago.

GROSS: Is there any difference between eating fresh fruit and vegetables from a salad bar than it is if you're at home and you're cutting it up fresh and, you know, preparing it in your own kitchen?

OSTERHOLM: Well, we've obviously equalized out the risk here in terms of either the commercial establishment or the home in terms of the product coming in, because if it's contaminated, it's going to likely be contaminated at either location from the actual growing process, handling kind of situation.

But once it gets into the kitchen, there can and often is additional risks that occur with the contamination of that produce. For example, in the commercial establishment side today, we find that the food handler often introduces additional bacterial or viral agents into the food.

And while we don't like to think about it today, it's true that if you look at who's behind the scenes in many of our restaurants, these are individuals who are paid minimum wage. They have no health benefits. And in many cases, they're actually of foreign origin.

And while that may seem upfront to say: well, why should that matter? We find that these individuals often don't speak English, and educational programs on hand-washing and appropriate hygiene in food preparation are lacking.

Second point to that, I mentioned in my initial comment that they often don't have health insurance as part of their job. If you look in the food service industry today, this is one of the most underinsured groups of employed people in the country. That's important to me as a public health practitioner, because these people don't go seek medical care often when they are sick.

We've had outbreaks here in Minnesota going on where management was not even aware of the fact that half the individuals had diarrhea, and none of them had health care, so they didn't leave. They just kept working.

Well, if you put that together with the produce and the fact that it's easily contaminated wet, cold produce -- if you handle it at all, it makes for a bigger problem. So, that doesn't happen in the home as much. You know, you can't infect yourself with a bug you're already infected with, in a sense. So, you don't have a chance for a new-introduced bug.

So, clearly eating out with produce is a bigger problem.

GROSS: Is that the only problem with salad bars -- the introduction of germs because of the food handlers? Or, are there other problems when produce is sitting around for a while?

OSTERHOLM: Actually, it's a whole chain of events. As you've just alluded to, we mention now that it may come in contaminated. The food handler may contaminate it. Then a third and fourth component, very quickly to that, is one is that many salad bars are not held at appropriate temperatures.

We oftentimes can go into restaurants and find that the temperature is too warm for where this material is sitting, so that it makes for a very nice growth medium. It grows up very nicely. Whereas if it were appropriately refrigerated on the salad bar line, that wouldn't happen.

And finally, the fourth thing is the consumers themselves coming in. We find that they will rummage through salad bars, introducing their own infectious agents. And if you put that all together, that can make for a real problem in terms of salad bars as a source of infectious diseases.

GROSS: Now, we've been reading a lot about irradiation, and the FDA has approved irradiation for some foods. And why don't you describe what irradiation is.

OSTERHOLM: Well, irradiation to a certain degree is one of the most misunderstood technologies in the country today. Just very briefly, the term "radiation" means any kind energy that moves anywhere. Sunlight is irradiate -- is radiation.

Unfortunately, the term "irradiation" has -- comes to encompass three types of energy: X-rays, gamma-rays, and high voltage electrons that can be beamed on any number of things to kill the bacterial and parasitic agents on the food. It has nothing to do with the kind of radiation you think of in a nuclear plant of some kind. It has nothing to do with that.

Today, we can use this kind of technology, which by the way has been the most extensively studied food preservative -- food safety technology in the world -- by far, much more than canning, microwaving, cooking, freezing -- all of them. And has been found to be a very, very safe way to basically eliminate these infectious agents from food without cooking it.

An irradiated piece of meat is a piece of meat you cannot distinguish from one that was non-irradiated. So in fact, you could eat your red meat undercooked today and not be concerned about it. But, it's clearly a technology who we believe whose time has come and we think will be in the marketplace in the near future.

GROSS: Would irradiation be effective in dealing with fresh fruit and vegetables?

OSTERHOLM: Today, we know irradiation can be used very effectively in red meat and poultry without changing the chemical composition or the flavor in any way. The problem with produce is is that for some of the produce items, because they actually require a certain maturation from the time that they're picked until the time that they actually are consumed, it may cause some chemical changes in a way that doesn't allow them to ripen or it doesn't allow them to stay firm.

But a lot of work is being done on that very process to better package these materials and do it in such a way that will not change the chemical or the flavor composition of the product. This would be much akin to what happened with microwaving a decade ago.

Remember those first horrible microwave meals you got? Where when you put them in the microwave and you cooked them, it just didn't taste good and it was uneven cooking? We've come a long ways that way in technology with our use of our microwave. And we believe that the same will be true with irradiation.

And this will be the one opportunity where we won't have to cook it. We won't have to freeze it. That we will be able to basically kill the infectious agents in it and still make it that kind -- type of delightful food that we want that's fresh and does not have any evidence of having treated it in any way.

GROSS: Irradiation is still a controversial process, and there are consumer groups who are opposed to it, unsure of what the long-term health risks might be. You're not worried about that yourself?

OSTERHOLM: There are basically, I think, two myths that come up around the issue of irradiation. One is that consumers are really fearful of this. We have extensive data now collected with focus groups and household surveys -- random household surveys, much like the Gallup Poll-type survey around the country, where consumers are becoming much more educated. They understand the safety around this, and they also understand the lack of safety around their food in terms of infectious agents.

And if it comes to what you're going to feed your child today, would you rather feed them irradiated food and know of its safety status or not? And those data are available. So I think that one of the problems we've had has been to a certain degree, the media has continued to foster this issue. We've got to have a balanced report here. Some people are afraid of irradiation; some are not. So we'll do a 50/50 kind of split here in terms of what the comments will be in this particular media piece, and that reflects the reality.

And that's just not the case. That would be equivalent to saying if the world were flat today, you got half the people to say it was; half to say it's not, and now it's balanced. I am the one that in the back end of it has to deal with all these illnesses. I'm the one that has to watch these children die in intensive care units with hemolitic uremic (ph) syndrome. I see what happens when we don't have a safe food supply.

And from the standpoint of risk with irradiation, I mean, we've been feeding this stuff to our astronauts for four decades and as maybe one would say: if it's good enough for them, it might be good enough for the rest of us. And we know we could do a great deal to eliminate a lot of unnecessary disease in this country if it were irradiated.

And again, I go back to the fact that the World Health Organization has strongly endorsed the use of irradiation in a food safety standpoint. I could list hundreds of groups that have done the same thing. But most importantly is that people don't realize, is that irradiation has been studied since the late 1800s as a possible use for improving the quality of food. It is, again, the most-studied technology in terms of all the safety issues.

And there isn't even a concern at this point. The World Health Organization has allowed the use of irradiation at very, very high levels in this country -- well beyond what we'll use for food -- and basically with no possible human side effects concern.

GROSS: Michael Osterholm is my guest. He's state epidemiologist with the Minnesota Department of Health. Let's take a short break and then we'll talk some more.

This is FRESH AIR.

Michael Osterholm is my guest. He's the state epidemiologist for the Minnesota Department of Health.

When I bring raw chicken home, I kind of act as if I'm dealing with toxic waste in my kitchen. I try to be so careful. I run around washing my hands and washing everything as if I'm going to really contaminate myself. I don't remember my mother having to be that careful when I was growing up and she was making chicken. Is chicken more dangerous than it used to be?

OSTERHOLM: Well, there really is kind of a middle answer here. Your mother should have been more concerned, and you don't have to worry: it's not toxic waste.


So, it's somewhere in-between. Clearly today, we have the data to show that chicken is one of the most contaminated commodities that we produce in this country. How does it compare to a generation ago is unclear. We didn't have some of the testing technologies that we have today, or for that matter we didn't know about some of the infectious agents that are a problem.

One of the areas that we're very concerned about in our studies here is related to a disease called campylobacter infection. Campylobacter is a bacteria that can cause a quite severe diarrhea. It's the leading cause of recognized bacterial food-borne disease in this country. And today, campylobacter is an infectious agent that's very commonly found in chicken as they grow.

It doesn't cause disease in the chicken, but it's there in their gastrointestinal tract. In studies that we've done here in Minnesota, we have found that well over 80 percent of all chicken you buy on the store shelf is loaded with campylobacter. When I say "loaded," we're talking about in many cases very, very high levels.

What's even more concerning to us recently has been the fact that chicken around the world, even here in the United States, have been fed antibiotics that help them fight off other infectious agents, but the kind of antibiotic they most commonly use -- one called lefloraquinalone (ph) is an antibiotic that's very important to us in human medicine. And it's used widely. Ironically, it's even used to treat campylobacter infection.

It turns out that as this is used in chicken, they very quickly develop campylobacter-resistant bacteria -- campylobacter bacteria that are resistant to the antibiotics, I should say. And in that case, we now are also seeing that a quarter of all of our chicken in the country are now actually not only contaminated with campylobacter, but highly drug-resistant campylobacter. That's of real concern.

GROSS: How does the campylobacter from the chicken's gastrointestinal tract get it into say the breast meat that we're eating?

OSTERHOLM: When a chicken is processed, even under the best of conditions, you have almost an invisible film of contamination that gets throughout the bird. It's no longer just inside the carcass. It's on the outside. It's not typically in deep inside the meat. So, that's not a problem. But it's all over the outside.

Then, the chicken is submerged into basically a chiller at the very end of the process. A chiller is a big bath of very, very cold water to help cool down the chicken quickly. And while the chiller is -- has chlorine in the water system, we know that this still can produce levels of bacteria in the chiller that help disseminate it throughout the chicken.

When that chicken then comes into your kitchen, not only has the bacteria been moved around the chicken -- kind of made more into almost a soup, you might way -- but in addition to that, the chicken has absorbed some of that water, and that's been an issue that many people have raised over the years is that, you know: am I really getting my true value here, 'cause I'm paying for some of this water in the poundage that I'm paying for in my chicken when I go through the checkout line?

Well, that water is important to us, not really so much from a value standpoint of whether you're paying for water in what you buy in your chicken, but because when you thaw that chicken out, what happens with that water? It thaws out. And if you ever noticed when you thaw out your chicken on the counter top -- which you shouldn't do, you should do it inside the refrigerator -- but even still inside the refrigerator, you get this pooling of fluid underneath the chicken.

Well, that is loaded with the bacteria. That's where you should get concerned in your chicken, because it's that fluid that's loaded with the bacteria that then gets on the cutting board. It gets on the knives and the forks. It gets on the dishrags. It gets on your hands. It gets on the counter top.

Now, you have a cross-contamination problem. So anything else you prepare, that might not be cooked again if it comes in contact with that, is not contaminated.

GROSS: What precautions do you take at home and that you recommend we take when we're preparing chicken?

OSTERHOLM: Well, first of all, I love chicken, so I have to say right up front, as much as I know about this, a properly prepared chicken is very good to eat. It can be a very safe product to eat. But one has to be very careful about the issues of cross-contamination. That's kind of the invisible problem that we have. We don't often think of that.

You know, we take the knife. We cut it through the chicken. We might even quickly run it under water and appear to get all the visible contamination off of it, yet we know it's still there. So then I take that same knife and I go and cut up the cantaloupe that I'm going to serve with it. And now I've just taken that bacteria and put it right into the meat of the cantaloupe.

I don't wash my hands. Or if I do, I do that very quick once under the water, barely get it wet kind of hand-wash. And now, my hands are very potent weapons in that kitchen in terms of contaminating another item. So, wash hands often.

And then, in terms of how do you decontaminate your kitchen? You know, you don't need to call in some kind of special crew of high-risk toxic waste people to do it.


It's just good common sensed with a lot of soap. Don't have to go out and buy these expensive anti-bacterial soaps. They're basically useless. And that's very strong words, I realize, but I'm very concerned about the continued use of this anti-microbial soaps out there in terms of developing resistance with some of these bugs to the soaps. But in addition to that, it's that they're basically not needed.

If you just use a good detergent with warm water, that will remove all this material off the item. And that's enough. If you do that, you're going to do a lot to avoid any problems with food-borne disease as it relates to chicken or any other item that might come into the kitchen contaminated.

GROSS: Michael Osterholm is state epidemiologist at the Minnesota Department of Health. He'll be back in the second half of the show.

I'm Terry Gross and this is FRESH AIR.

This is FRESH AIR. I'm Terry Gross.

Back with Michael Osterholm, an expert on food-borne illness. He's state epidemiologist at the Minnesota Department of Health.

Let's talk about this new strain of E. coli that has been infecting some foods. It's been a problem I think in some fruit juices and some hamburger meat. Why is there this new strain of E. coli?

OSTERHOLM: Well actually, this is one of those times when we can actually say it is new. Many of the recent infectious agents that we find new really probably have been around a long time. We've just discovered them, meaning that we for the first time have been able to identify them.

This one is -- the agent you're referring to is a bacteria known as E. coli 0157H7, which just basically is a designation for a type of E. coli. And there are many, many kinds of E. coli in the world. But this particular strain of E-coli appears to have evolved in the late '60s and early '70s, particularly here in the United States.

And what it did is it picked up a certain piece of genetic material that allows it to produce a poison or a toxin that when in the body does two things: one is it causes a number of us to get this severe bloody diarrhea. And the second thing it does, in a select group of people, primarily those who are very, very young -- under three to five years of age -- it can trigger a series of events leading to a condition known as hemolitic uremic syndrome -- HUS.

This is the very severe condition that children will die from when they're -- when this outbreak of this kind of infection occurs. And most notably in the Jack In The Box outbreak in the Northwest a few years ago; last summer with the Hudson Meat problem -- those were the cases we were concerned about was HUS.

This particular bacteria is not unique, though. We know that there are other kinds of E. coli that also are on the horizon that have the same possible mechanism of this toxin or poison. So while this is a new one, we have to be aware that there are other ones coming down the pike that are just like it.

GROSS: Why has this E. coli been a particular problem in chopped meat?

OSTERHOLM: Well, one has to understand that hamburger is not just your "typical red meat." When you take a cow, a pig, a chicken -- any kind of food animal into the processing plant, they have the kinds of contamination in their gut systems, their entrails, basically that can cause food-borne disease.

Imagine in a processing plant, if you're trying to basically cut open a 900-pound steer and remove its entrails, and you're trying to do it as antiseptically as possible so you don't contaminate any other part of the carcass, how difficult that's going to be.

So now take that and even if there's no visual contamination -- you don't see anything there. So it looks like you did a good job of, you know, basically gutting this animal. We know that there is this invisible film of microbes that are there.

It doesn't mean you have visual contamination with what people call, you know, this feces veneer. It's not like it's something really gross and terrible that some consumer advocates would have you believe that the plants just don't care and they let cow manure get all over the carcass. That's not the case.

But when that carcass is cut up, every time you draw a knife through the carcass, what was ever on the outside gets drawn into the inside. Now, if you go and have your steak, that's not a problem if you have it medium- rare because remember every place the knife cut was on the outside of the steak. And that is all cooked, because even if we have medium-rare steak, the outside is seared.

But hamburger is very different from any chopped meat, because the inside of the chopped meat is no different than the outside. So now we want that same kind of red location in the inside of the product, but it's the very same as if it were on the outside and it's just as contaminated.

So the problem we have with hamburger, uniquely, or chopped pork for that matter or chopped -- grilled chopped turkey, the same thing -- is that the inside is not adequately cooked and that's still contaminated with what was ever on the outside.

GROSS: So your recommendation is if you're eating any kind of chopped meat, make sure the inside is well-cooked.

OSTERHOLM: Right. That's going to be critical because that's where many of the problems with E. coli 0157H7 come from. People are feeding undercooked hamburgers, for example, to children. If you do that, you have to realize today that you have a real risk there of transmitting a life-threatening, infectious disease.

And most people don't take that seriously. So that, you know, the parent who is about to grill those hamburgers out there, and they make it nice and thick and juicy and it's red in the inside and feed that to their child, I have said, and while it may sound melodramatic I think it's actually -- it's not necessarily that far off the mark -- that would be like putting your child in the front seat of your car without a seatbelt or a car seat and driving 60 miles an hour through red lights.

They -- parents have to understand that that's that kind of important situation in terms of -- particularly with the issue of hemolitic uremic syndrome today.

GROSS: Do you eat out a lot? Are there foods that you won't eat when you're eating out?

OSTERHOLM: Yeah, I eat out. I'm on the road a lot. I have no choice. And I think I do pick my foods probably more carefully than most people. And I think I'm very fortunate that I've had very, very few episodes of diarrheal disease. But that's a situation where, yeah, I don't eat a lot of the foods that probably other people routinely eat.

GROSS: What are some of the foods that you try to stay away from, especially when you're eating out?

OSTERHOLM: I have been in too many outbreak situations in too many restaurants to know how much of our cold food today ends up being basically a soup in which the food handler of the day washed their hands in it. And I have a hard time with a lot of cold foods. You can say that I'm over-cautious that way possibly, but I think a number of my colleagues would agree in the same light.

When you get that nice cold salad sitting in front of you; or you get that nice pita bread sandwich with all that cold seafood stuffing inside of that that looks wonderful, do you have any idea who prepared that? How they prepared it? And what they did to prepare themselves to prepare it? Did they wash their hands? Did they not?

That is a bit more difficult. And today, our love affair with the cold deli-type food items clearly has increased our risk of food-borne disease in this country.

GROSS: A lot of times, if you have a stomach upset, you just consider "well, it's just one of those things." And you'll be over it. And you don't go to a doctor and, you know, maybe you'll take a diarrhea medication or maybe you just won't eat for a few hours. Do you think it's important to find out if it's a food-borne illness that you have? I mean, does it -- if you're not terribly sick, does it matter if you get a real diagnosis or not?

OSTERHOLM: Probably for the average American today who is otherwise healthy, you know, the 24- to 36-hour, as they would call it, flu bug, which is not -- is probably not a reason to see a physician at all. That's not going to help us a lot in terms of changing the safety of the food supply.

But for a lot of people today who are immuno-compromised; who are older, where a food-borne problem can actually be a life-threatening infection; or who have either bloody diarrhea or diarrhea that lasts for more than two and a half to three days, then they should see a physician.

And we should know about that because those are the kind of life-threatening or potentially life-threatening situations that we need to deal with quickly. And if we just could get those kind of infections diagnosed appropriately, we could do a lot in this country to begin to improve on the safety of the food supply by identifying the real problem areas.

GROSS: Michael Osterholm, I want to thank you very much for talking with us.

OSTERHOLM: Thank you.

GROSS: At least I think I want to thank you for talking with us.


You've left me more worried than I was before.


OSTERHOLM: Well, and we didn't get into a lot of the areas. I think that the susceptible population today, we're seeing with cancer patients increasing dramatically 'cause of the aging population; HIV -- things like that. We see a lot more serious outcome of food-borne disease than we did a decade ago.

More and more people are dying. It's really very serious. I think in that sense, people don't realize that when you're in those conditions, and the aging population's going to be a real classic one. People over age 55 and food-borne disease is very different than a young healthy strapping 21-year-old.

GROSS: So, you have to be more careful about food.


GROSS: Michael Osterholm is state epidemiologist at the Minnesota Department of Health.

Coming up, foods that may help prevent cancer.

This is FRESH AIR.

This is a rush transcript. This copy may not
be in its final form and may be updated.

Dateline: Terry Gross, Philadelphia
Guest: Michael Osterholm
High: Epidemiologist Michael Osterholm is a leading expert on food-borne illnesses, like E. coli and toxoplasmosis. Some illnesses are less serious resulting in diarrhea, and stomach and abdominal pain. Food-borne illness is on the rise, partly because of the increased consumption of fruits and vegetables in this country, and their importation from developing countries. Osterholm is State Epidemiologist and Chief, Acute Disease Epidemiology Section, of the Minnesota Department of Health.
Spec: Health and Medicine; Disease; Food-Borne Illnesses
Please note, this is not the final feed of record
Copy: Content and programming copyright 1998 WHYY, Inc. All rights reserved. Transcribed by FDCH, Inc. under license from WHYY, Inc. Formatting copyright 1998 FDCH, Inc. All rights reserved. No quotes from the materials contained herein may be used in any media without attribution to WHYY, Inc. This transcript may not be reproduced in whole or in part without prior written permission.
End-Story: Food-Borne Illness
Date: MAY 05, 1998
Time: 12:00
Tran: 050502np.217
Head: Cookbook for Cancer Prevention
Sect: News; Domestic
Time: 12:40

TERRY GROSS, HOST: There's been plenty of bad news about foods that may cause cancer. But there's also some potential good news -- some foods may help prevent cancer.

Susan Oliveria is an epidemiologist at the Strang Cancer Prevention Center, which is affiliated with Cornell University where she teaches. She focuses on the link between nutrition and cancer. Oliveria is the co-author of "The Strang Cookbook for Cancer Prevention." She says that cancer researchers are studying phytochemicals -- substances found in fruits and vegetables which may have the ability to block or suppress carcinogens.

SUSAN OLIVERIA, EPIDEMIOLOGIST, INSTRUCTOR, STRANG CANCER PREVENTION CENTER, CORNELL UNIVERSITY MEDICAL COLLEGE, MEMORIAL SLOAN-KETTERING CANCER CENTER, CO-AUTHOR, "THE STRANG COOKBOOK FOR CANCER PREVENTION": The ways in which we think that they act is to detoxify particular carcinogens that might be in our body, and to help block any carcinogenic changes.

Also, as what we call "tumor suppressors" -- to actually suppress carcinogenic changes, so maybe there's some genetic alterations going on and these phytochemicals actually will help to suppress these.

And then there's other ancillary roles that think these phytochemicals will play, such as increasing immune function, acting as anti-oxidants and reducing what we call cell proliferation, or cell growth.

GROSS: So, what foods can we find these phytochemicals in?

OLIVERIA: Well, it really goes back to -- to what we've heard probably all our lives -- the good old fruits and vegetables are where we find the predominant amount of these phytochemicals. But we're also finding phytochemicals in things such a soy, which is from a soybean. Some of us know it as tofu. And there's many soy products that are available right now, such as soy milk, soy cheese.

And in soy, for instance, the particular phytochemical is called "isoflavones." And these, again, act, as I had mentioned, to suppress carcinogenic changes. And all this stuff is very, very new, but we believe and feel comfortable that this is -- is really what's going on because we've known for a long time that fruits and vegetables and some of these other foods actually reduce cancer.

So, it makes sense that when we get down on more of a molecular/biological level, we can actually see some of these substances. So, what we're purporting here is not anything that is not backed up by scientific and medical consensus.

GROSS: I think that there are attempts now to put phytochemicals into pill forms that you could just take phytochemical supplements. What do you know about that and how effective is ingesting these substances through pill form?

OLIVERIA: Well, that's an excellent point and I think a really good question that needs to be addressed, because the American public really generally looks for the quick fix. They look for the pill that they can take. They look for the vitamin that they can take. You know, they don't want to work at changing their diet or their nutrition on a daily basis.

And what we know about is very little about these new phytochemicals that are coming out in pill form that you have seen in the health food stores. And it's a very dangerous area to be moving into -- taking phytochemical pills per se, because they're synthetic and we really don't know in the quantities that they're made in, or the quantities that people are taking them in, in interaction with other things, how they're going to react.

So you're really better off to go back to basics and get these phytochemicals from your fruits and vegetables, and to stay away from the pill forms because we just don't know enough about them.

GROSS: There's some researchers showing that there are certain fish oils that could be very beneficial in -- in what? -- in preventing cancer?

OLIVERIA: Yes. The omega-threes is what they are called. And they are actually also classified as one of the phytochemicals. They sort of classify them under that grouping. And we have known that omega-threes found in the fatty fishes, such as swordfish and tuna and salmon, can reduce some forms of cancer.

And that's the interesting thing here. Not all of these foods or not all of these substances act on all cancers. They work on some cancers, so that you have to be careful in -- in what you're eating and why you're eating it. The best approach is to really eat moderately and eat lots of different things.

With respect to the omega-threes, we do know that when people have a higher intake of these, they have reduced risk for cancers.

GROSS: Now, you don't recommend trying to take omega-three oils in pill form. Why not?

OLIVERIA: Right. Definitely, that should only be undertaken under a physician's consultation. They do have, and can have serious side effects such as hemorrhaging and stroke and can increase -- actually increase cholesterol levels. So, that that really needs to be done under a physician's care and should not be -- there should be no form of self-medicating with the fish oil capsules.

GROSS: Let's look at anti-oxidants. You hear a lot of talk about them now. I don't really understand what they are.

OLIVERIA: Well, "anti-oxidant" is a term that is sort of a catch-all term used to describe many types of foods, vitamins, even phytochemicals are sometimes described as anti-oxidants. So that's more of an adjective -- more of a descriptor.

And it just basically means that this food or this vitamin has the property of being able to stop the oxidation process and to stop the potential DNA repair -- DNA damage that can occur because of this process that we all go under called oxidations.

It's a little bit complicated, but we -- during our metabolism, we actually have oxidation that goes on. And these free radicals, these little unstable molecules float around in our body. And what our body does generally is to suppress these little free radicals. They sort of act as scavengers and sort of suppress them.

If they're not suppressed, they can actually go on to do damage to the cells. And so, any type of vitamin or food that actually works to -- against this -- we describe as an anti-oxidant. So for instance, some of the vitamins -- vitamin A, vitamin C, vitamin E -- they've been shown to have these anti-oxidant properties. Vitamin C is another one. Also, many of these phytochemicals that we talked about also have these properties of being anti-oxidants.

And it's good to have these in your diet because they do counter-balance some of the effects of the -- this oxidation or these free radicals.

GROSS: Now, you've recommended certain things not be taken in pill form, such as omega-three oils, phytochemicals -- we don't know enough about that yet, you say, to take it in pill form. But what about anti-oxidants, because a lot of vitamin supplements now are coming with anti-oxidants in them.

OLIVERIA: Yes. Generally, the -- the big picture is that try to get all your -- what you need from food. That's really what we recommend. But in some instances, you feel like you need a little bit more insurance. And we went through and actually, basically said which vitamins we felt comfortable with. Vitamin C -- we felt if a person wanted to supplement with that, as long as they kept it under 400 milligrams, that would be fine.

Generally, if you just take a multi-vitamin, that's going to do the trick, and try not to supplement with individual vitamins, because that's when you start with what we call "megadosing" and you just don't know how all these extra doses of vitamins are going to interact with your body. You can actually be doing yourself some harm.

GROSS: Now, what kind of harm can you do with vitamins?

OLIVERIA: Well, you can -- if they're a vitamin that is actually stored in your body -- some of the vitamins are what we call "fat soluble," so they actually can be stored in your fat. You can actually build up toxic levels. And depending on the vitamin and depending on the interaction with other vitamins, there can be many different side effects.

So, you have to be very careful of what you're supplementing with, and that actually also goes into some of the new herbal -- they're not called vitamins -- but the herbal types of remedies that are out there. You have to be very careful with that. And our book really didn't address the whole idea of herbals because that's an area that is just so preliminary at this point and it just -- there's no science to really back that up -- that we did not move into that area.

GROSS: Now, some supplements say that they have selenium in it, and selenium is one of the anti-oxidants. It's I think for many of us a new word in the nutritional vocabulary. Can you tell us a little bit about what selenium is? Whether it enters the picture in cancer prevention and what you think of selenium supplements?

OLIVERIA: Yes. Selenium has been for a long time really thought of as this might be the key; this might be the magic bullet. It looked as though it was going to have cancer-fighting properties. So far to date, the research has given some evidence and some suggestion that for certain cancers. But the disadvantage of selenium is that it can be highly toxic. And so, you have to be very careful.

And our recommendation is that it can be taken, but in a very small amount and we give the amount for that. I think the research is still ongoing with selenium. I would not recommend supplementing with selenium supplements per se. You'll get some in a multi-vitamin.

And just to clarify, when I say a "supplement," I mean an individual pill that you would buy in a bottle that says "selenium" versus your multi-vitamin that has a little bit of everything in it.

GROSS: My guest is Susan Oliveria, epidemiologist at the Strang Cancer Prevention Center, which is affiliated with Cornell University where she teaches. We'll talk more after a break.

This is FRESH AIR.

If you're just joining us, my guest is Dr. Susan Oliveria. She's co-author of the Strang Cookbook for Cancer Prevention. She's director of epidemiology at the Strang Cancer Prevention Center, which is affiliated with Cornell University.

In discussing foods that might be bad for you, you really divide them into two categories. One is carcinogens and the other is cancer-promoters. What's the difference between those two categories?

OLIVERIA: What we think happens with the cancer cycle is that we think there's two phases to it. There's a promotion -- an initiation -- where a cell sort of gets primed for cancer. It doesn't mean you have cancer. And this actually can be due to certain environmental factors -- smoking is what we would call an initiator; air pollution is what we call an initiator.

To date, there aren't any foods that we think actually initiate cancer. OK? So you're sort of -- you're setting the stage in your body.

The next phase is called "promotion." This is a very simplistic model, but we think this is how it works. And this promotion phase is when a lot of the lifestyle things that we do actually can increase our risk and sort of take those initiated cells and sort of turn them into cancer. And this is where fatty foods will come into play. If you don't have foods that are high in cancer-fighting substances like the fruits and vegetables, they may come into play.

And again, this is a hypothesis, so this is what we think happens. We're not 100 percent sure, but it's the best guess that we have right now.

So therefore, you can see that it's a long process, generally 10 to 30 years before a cancer develops. And that if you do make changes in your lifestyle, you really can make chances in your -- changes in your cancer risk and reduce your risk of cancer.

GROSS: In your book, you write that diet contributes to 20 to 40 percent of all cancer. That's a lot. In what way does diet contribute to it?

OLIVERIA: Well, the way that those numbers have been estimated is, researchers got together and they looked at all the different exposures or environmental things that happen to us, whether that be smoking, air pollution, what we eat, what we drink, how active we are. And they tried to come up, using advanced statistical techniques, of sort of like a model that sort of broke it up, if you think of a pie chart and sort of what portion of the pie can be attributed to diet.

And they basically came up with some numbers that, again, are guesstimates of where we think certain environmental factors play out. And this is important because it can sort of tell us what's important.

So for instance, you know, food additives -- people think that those are a huge cause of cancer, but when you look at this pie, they actually account for probably less than 1 percent of all cancers. Then you go and you look at diet, and that accounts for a huge slice of the pie -- probably around 30 -- you know, anywhere from 20 to 40 percent.

And this is just a ballpark figure to give people an idea of what changes would really make an impact. And also, for people who are in public health -- if we really want to focus on changing people's behavior, where's the best bang for our buck here?

GROSS: You seem pretty confident that certain foods can have a positive impact on preventing cancer. Do you think that most oncologists would agree? Do you think most oncologists give the kind of information that you would like to see them give about food?

OLIVERIA: Yeah, the reason that I'm so confident about this is that when -- in writing this book, there's -- the section that I was predominantly responsible for was the science and the medical aspects of it. And basically, I did all of the research. I went out and I pulled every article. All of the articles are peer-reviewed. They're all from reputable scientific journals.

So, I feel very comfortable with interpreting this data and with making these recommendations. There's other institutions in the country that have seen this and also agree. This is -- you know, this is very much mainline. This is where we need to be with it.

I think the problem arises when you get into more the clinical end of it; where people are actually treating individual patients. A lot -- many of the physicians -- many of the oncologists -- they do not have the same background and training in nutrition, so therefore they have more of a broad-brushstroke. They may not be able to get to all this information and may not have it.

And I think sometimes, just by virtue of trying to treat, say, the cancer patient -- you know, you've got a cancer. You've got to work on that first before you work on somebody's diet. So, things take priority.

What I think is really important is down -- with the primary care physicians and the internists and the family practitioners -- I think it's really important to get this information to them.

GROSS: Dr. Oliveria, have you changed your diet in the past few years as more research is conducted on the relationship of food and cancer?

OLIVERIA: Well, it's interesting. This has always sort of been a hobby of mine, ever since I've been in my early 20s, and I actually changed a career that I had to go into this when I was in my mid-20s. So, I've actually been a -- been on the bandwagon for a while.

What I am thinking about now on a personal level is I'm expecting my first child and it's very important to me to start instilling some of these behaviors and some of these nutritional guidelines in my child, with the idea that kids don't want to eat this stuff. So, that's my big challenge that will be coming forward for me.

And that's where I really want to be able to take this because we do know from research that shows that children adopt eating habits early in life, and then they track -- which means if you eat poorly as a child, you're more likely to eat poorly as an adult. So, your really best chance to make an impact is at a young age.

On the other hand, it's never too late for any of us to change our diet, and most of the research that has been done has been done in adults, so that we know the reduced risk from eating this healthy diet can make an effect late in life as well as early in life.

GROSS: Well, good luck in getting your child to eat fruits and vegetables.


OLIVERIA: Thank you.

GROSS: Susan Oliveria is the co-author of The Strang Cookbook for Cancer Prevention. The Strang Cancer Prevention Center is affiliated with Cornell University, where she teaches.

This is a rush transcript. This copy may not
be in its final form and may be updated.

Dateline: Terry Gross, Philadelphia
Guest: Susan Oliveria
High: Epidemiologist Susan Oliveria is an expert on the link between nutrition and cancer. She is one of the authors of the new book, "The Strang Cookbook for Cancer Prevention: A Complete Nutrition and Lifestyle Plan to Dramatically Lower Your Cancer Risk." The book includes recipes from gourmet chefs. Oliveria teaches at the Strang Cancer Prevention Center, Cornell University Medical College, and Memorial Sloan-Kettering Cancer Center.
Spec: Health and Medicine; Cancer; Food; Nutrition; Strang Cookbook for Cancer Prevention
Please note, this is not the final feed of record
Copy: Content and programming copyright 1998 WHYY, Inc. All rights reserved. Transcribed by FDCH, Inc. under license from WHYY, Inc. Formatting copyright 1998 FDCH, Inc. All rights reserved. No quotes from the materials contained herein may be used in any media without attribution to WHYY, Inc. This transcript may not be reproduced in whole or in part without prior written permission.
End-Story: Cookbook for Cancer Prevention
Transcripts are created on a rush deadline, and accuracy and availability may vary. This text may not be in its final form and may be updated or revised in the future. Please be aware that the authoritative record of Fresh Air interviews and reviews are the audio recordings of each segment.

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