MS. DIANE REHMThanks for joining us. I'm Diane Rehm. Omega-3 fatty acids are linked with any number of health benefits: lowered blood pressure, reduced inflammation and increased mental acuity. But it's hard to know how much is enough. And recent studies pose new questions about health benefits. Joining me to talk about what omega-3s may or may not do for us: Dr. Majid Fotuhi of the Neurology Institute for Brain Health and Fitness, Paul Coates of the Office of Dietary Supplements at the National Institutes of Health and Thomas Sherman of the Georgetown University Medical Center.

MS. DIANE REHMI invite you to be part of the program. Call us on 800-433-8850. Send your email to drshow@wamu.org. Follow us on Facebook or Twitter. Good morning, gentlemen. Thanks for joining us.

DR. MAJID FOTUHIGood morning.

MR. PAUL COATESGood morning, Diane.

PROF. THOMAS SHERMANGood morning.

FOTUHIDr. Fotuhi, I'll start with you. You've said that omega-3s are the building blocks of the brain. Explain what they are and exactly how they operate within the brain.

FOTUHII, first, want to thank you for having me on your show. I am very much interested in omega-3 fatty acids and have done research in this area and have found very strong benefits of omega-3 fatty acids for brain function, among other things. So I have looked into what they actually do, and I just summarize it for you. Omega-3 fatty acids are these chains of molecules which are anywhere between 16 or 22 carbon molecules attached together in a chain, and that's what we call omega-3 fatty acids.

FOTUHIAnd the three or six refer to the structure of double bonds which is a minor issue anyway. But these compounds in the brain do three things: number one, they reduce inflammation, number two, they increase blood flow, and, number three, they are very important for the structure of the membranes which are the surroundings of cells and make those things and are important for reduction of proteins associated with Alzheimer's disease. So the three things are: increase blood flow, reduce inflammation and structure of the membranes which are important for integrity of the brain cells.

REHMI gather you get these omega-3s primarily in food. But if not in food, some people take supplements for them.

FOTUHIThat's right. Just like many other vitamins, there are molecules that our bodies cannot make, and omega-3 fatty acids are examples of such molecules. An excellent source of omega-3 fatty acids, such as DHA, is fish, and the fish get it from algae. There are other sources, but they're not as good sources. Now, these include meat or egg or flax seed, walnuts. But the best sources are really algae and fish and some specific type of fish, such as salmon.

REHMDr. Majid Fotuhi, he's chair of the Neurology Institute for Brain Health and Fitness, assistant professor of neurology at Johns Hopkins University School of Medicine. And turning to you, Paul Coates, at the National Institutes of Health, I gather there have been some recent studies that raise questions about some of these benefits. Talk about that research.

COATESThe research, I think, you're referring to is a series of what are called systematic reviews with meta-analyses that have tried to understand the full body of evidence relating these omega-3 fatty acids to putative health benefits. And I think what you're referring to is that they raised questions about whether or not omega-3 fatty acids really do have the benefits that had been seen in smaller studies in ecologic sort of epidemiologic studies. And they do give us a pause to think about what it is we are looking at here.

COATESAre -- is it the omega-3s themselves that are providing benefits in certain kinds of studies? Are there confounding factors in those studies that make it seem as though we're losing the benefit of omega-3 fatty acids? We don't necessarily do studies the same way now as we did maybe 10 or 15 years ago. Our office actually sponsored a series of these systematic reviews about 10 years ago and discovered that for most of the putative health benefits, really, the data were not there.

COATESThere were some promising leads, but that the data were not there. Well, that doesn't mean that there isn't an effect. What it meant to me was that more research needed to be done. And so we've tried to enhance that research effort at the NIH.

REHMYou know, it's interesting. I gather it is -- it arises out of this question of why the Eskimos seem to be without heart disease and tend to eat lots of salmon and other fatty fishes.

COATESThis was a very exciting discovery and something that we really paid a lot of attention to. That was the whole research community, and there definitely had been studies that have indicated that there are benefits, cardiovascular disease benefits associated with increased omega-3 fatty acid intake usually from fish. Is it only the omega-3s from fish? Or is it something -- is it the broader array of things that are associated with eating fish that afford the benefit? And, to be honest with you, I don't think we know all of those answers yet.

REHMPaul Coates, he is director of the Office of Dietary Supplements at the National Institutes of Health. Tom Sherman, as associate professor of pharmacology at Georgetown University, you've said that these studies raise some red flags for you. Tell me about that.

SHERMANYou know, these studies seemingly contradict a lot of earlier studies that were seemingly very, very positive, and I think it just highlights a lot of changes that have happened in the American diet and in the way we administer health care for cardiovascular disease in the last 20 or 30 years. You know, when these studies were originally done back in -- started in the '60s and up through the '90s, our diets were different than they are today. You know, it's not just the fact that we're eating less fish oil.

SHERMANWe're eating less and fewer fruits and vegetables. We're eating way more carbohydrates. We're eating a lot more processed sugars. And I think other components of our diet are affecting the impact maybe, as Paul says, that these fish oils would be having on our health.

REHMCould it also possibly be that the foods themselves are changing the amounts of fish oil, for example, within salmon, the amount of omega-3 within walnuts? Could it be that something in the environment itself is changing?

SHERMANCertainly, the levels would be changing, and we learned that in the early days of fish farming that, you know, just like industry is trying to raise a population on corn in this country, we tried to raise populations of fish when we started fish farming on corn and realized that they will not survive. And fish, probably surprising to many people, don't make their own omega-3 fatty acids but derive them, as Dr. Fotuhi said, from algae, from marine dinoflagellates, which are shockingly rich in omega-3 fatty acids.

SHERMANBut -- and so we had to start feeding them these essential fats in order for them to survive. And certainly, many farm-raised fished, depending on where they're made, are very poor in omega-3 fatty acids. Tilapia, which is the chicken of the seafood realm right now, is very poor in omega-3 fatty acids, and that's what most Americans like to eat: a bland, white fish.

REHMSo do we have to take food supplements in order to achieve a healthy body balance of omega-3s, Dr. Fotuhi?

FOTUHIThe answer is yes. And I appreciate that Paul and Tom raised the issue of doing a systematic review and really figure out what is going on with this. Some people say it's good, sometimes not good. It's like vitamin E, you know, for a few years, it's good. In a few years, it's not so good. So what is the consumer to think of these things? And this is something that I read every day. And I keep up with the literature, so let me give you the bottom line. The problem is, as Paul mentioned, there are different outcomes that people measure.

FOTUHIIn one study, for example, people measure memory. In another study, people measure executive function. So how do you compare that? In one study, they put 300 milligram. In the other study, put 600 milligram. In one study, they have mostly African Americans, and the other study are mostly white people from Scandinavia, for example. So what have you got to do with this, and how are you going to make sense of these things? Well, I'll tell you.

FOTUHII published a paper, a systematic review of literature in Nature Clinical Practice Medicine along with a professor of neurology and psychiatry in UCSF, Dr. Yaffe, and we concluded that, overall, there seems to be a strong association with taking this DHA at about 900 milligram or 1,000 milligram and reduced risk for Alzheimer's disease.

REHMIn pill form.

FOTUHIYes. Many of them suggest that whether it's from pill or whether it's from strong diet with a lot of fish in it, that seems to be the amount. But that's an association, and that association does not mean causal. So then a study was published called MIDAS, which was a study, a double-blind, placebo-controlled. That's the gold standard of the studies.

FOTUHII mean, in that study, they took people which were 55 -- who were 55 years and older. And one group received placebo, and the other group received 900 milligrams of algal DHA, the very pure form of DHA from algae. And they found out that people who took that performed better in memory tests as if they were three to seven years younger.

REHMInteresting. All of it is very interesting. I hope our listeners will join us with their own questions, comments. Stay with us.

REHMAnd welcome back. We're talking about omega-3 that we get from both foods and food supplements. There have been some recent studies that have raised questions in people's minds. This most recent study, I gather, included -- incorporated some 70,000 people which, in and of itself, could contain a huge variability. But I want to ask you specifically, Dr. Fotuhi, and then get the others to chime in. What about this relationship between omega-3s and Alzheimer's?

FOTUHIThere seems to be an association between taking omega-3 fatty acids and a reduced risk for Alzheimer's. But you need to keep in mind that Alzheimer's is a complex disease that has many different factors. So it's really difficult to say that any one factor would significantly abolish the risk for Alzheimer's.

REHMSo there's no way of proving that taking supplements or eating foods containing omega-3s is actually going to mitigate or indeed reduce the incidence of Alzheimer's? Paul Coates.

COATESYes, there are ways to do it. But what we've discovered in trying to do them is that they are difficult studies to do.

REHMWhy? Tell me why.

COATESThere are a lot of confounding factors that we don't always take account of. Background diet in people who are enrolled in these clinical trials can be quite variable. You referred to that when you mentioned 70,000 people in the systematic review of cardiovascular disease. And that can be confounding issue. We also don't know very much about the individuals who are included in these clinical trials.

COATESLet me give you a hypothetical: supposed we knew at the beginning that there were people who were responsive and then people who are not responsive, then maybe we would -- instead of seeing an average effect, we'd be able to articulate the effect in people whom we believe were responsive. Sounds really good, but it's very difficult to identify people who could -- to enroll in a trial like that.

REHMOf course, the other issue becomes we now seem to be able to at least begin to identify people who are susceptible or who might develop Alzheimer's disease. So if you've got that as something that's in your family history, would you, as individuals who've been studying this, recommend to those individuals that they take omega-3 supplements and increase the fatty acids in their diet? Tom Sherman.

SHERMANI would definitely recommend a diet or a Mediterranean-style diet that was rich in polyunsaturated fats and low on carbohydrate. But I wouldn't necessarily recommend supplements for fish oil because, I think, the associations, while sometimes there, are actually much stronger with staying lean, staying active, staying mentally fit, eating low, you know, keeping sugar levels low. Those associations and risks with Alzheimer's disease, I think, are stronger than the results that have been observed with fish oils. But it's certainly, certainly part of a really good diet.

REHMPaul Coates, a number of people have asked about the difference between omega-3s and omega-6s? Can you help us understand that?

COATESI can try, and I'm sure the others have opportunity to weigh in as well. Both omega-3 fatty acids and omega-6 fatty acids are classes. There's not a single one of either kind. They're all essential. They are not made by most individuals, and so we do need them. Omega-6s have tended to be looked at as the bad guys, and omega-3s...

REHMWhy? Why?

COATESBecause they end up being the starting point for synthesis of fatty -- of factors that maybe problematic later on.

REHMTo put it simply, weight gain?

COATESHmm, no.

REHMNo.

SHERMANProbably more inflammation.

COATESYeah. So our -- but they are both very important. Is the ratio between them as important? We don't really -- I don't really know that. But there is certainly plenty of evidence to suggest that omega-3s are less important or less seen in our diets now than are omega-6s.

REHMAll right. And joining us now by phone from Westchester County, N.Y., Susan Allport, she is the author of a book titled "The Queen of Fats: Why Omega-3s Were Removed from the Western Diet and What We Can Do to Replace Them." Good morning to, Susan. Thanks for joining us.

MS. SUSAN ALLPORTThank you, Diane.

REHMTalk about how omega-3s were removed from our diets and nutritional thinking. How did that happen?

ALLPORTWell, omega-3s and omega-6s are both the central fats, as was pointed out, but they compete with each other for positions in our cell membranes, such that if you have a diet that's very, very rich in the omega-6s, your membranes are going to be full of those fats even if you eat large amounts of fish. You have to eat very large amounts of fish or take large amounts of fish oils in order to counteract a diet that's very rich in those omega-6s. So...

REHMAnd what are the foods that contain these omega-6s that are problematic?

ALLPORTWell, seed oils tend to be very much richer in omega-6s than omega-3. So as we replace the butter and lard in our diet with these seed oils from corn and from soy, we very much increase the amount of 6s in our diet.

REHMThat's very interesting. And I gather that you experimented to see what changed when you tried to alter the balance between the omega-3s and omega-6s in your own body. What did you do?

ALLPORTI did do that. But a little a background is that we store omega-6s in our fat cells, whereas we don't store very much omega-3s. We either use them in our membranes, or we, you know, metabolize them. So we don't have large amounts of stored 6s hanging around. So when a person who -- on the normal American diet, has plenty of extra fat around, let's say, 20 pounds, a huge amount of that is going to be these omega-6s.

ALLPORTAnd when they go on fish oil, you're not going to see that fish oil showing up in their membranes for a long time because it's competing with those stored omega-6s. So I thought to myself, well, here I've been on a high-omega-3 diet for -- since 2004, since then, when I started researching this book, and I have fairly good levels of omega-3s in my body. Let me see if I go on what's recommended, to have fish twice a week but I'm going to change just the oils in my diet to be those oils that are very rich in omega-6. So I had a very healthy diet by most people's standards.

ALLPORTBut instead of my peanut butter with flax oil, which has a good balance of these 3s and the 6s, I switched to just peanut butter instead of my usual salad dressing of olive oil and canola, which happens to be a seed that has some omega-3s in it. I switched to salad dressings made with safflower or sunflower and corn oil. And I just made that change for a month, and the omega-3s in my tissues dropped by half. The DHA, which is so vital for brain function, also dropped by about a half.

REHMAnd what happened to your weight?

ALLPORTAnd I thought my weight -- I felt really heavy after this. But my weight went up just half a pound and not very much and -- which was the reason this article had been commissioned by Oprah Magazine. But they didn't run it because they thought, well, half a pound of weight after a month, who's going to think there's anything significant about that? But my resting metabolic rate also dropped, and that could've accounted for that gain in weight.

REHMAll right. And finally, you write that when it comes to diet trends, the public usually focuses on just one bad guy or a good guy at a time. What's to say that the current fixation with omega-3s isn't just another in a long line of fixations?

ALLPORTIf that's question for me, it's because there are all these clear biological mechanisms linking omega-3s to better health, and chief among those are the reduced inflammation, the increased blood flow and the better structure of membranes because those omega-3s are faster fats, and they get in there and create membranes where enzymes can do their jobs much more readily.

REHMSusan Allport, she's the author of "The Queen of Fats: Why Omega-3s Were Removed from the Western Diet and What We Can Do to Replace Them." Thank you so much for joining us.

ALLPORTThank you.

REHMGood luck with your eating habits.

ALLPORTThank you very much.

REHMAll right. We've got lots of callers waiting. I'm going to open the phones now. Our listeners are always a very important part of the program. Let's hear their questions. First, we'll go to Indianapolis and to Dan. Good morning to you.

DANGood morning, ma'am. I have been a vegetarian since the age of 18, and as I've progressed, I'm now practicing medical doctor psychiatrist and searched for sort of vegetarian options of omega-3s as most foods that are supplemented include fish oil, and a lot of flaxseed pills are in gel caps. And that has led me to looking at various things like, for instance, milk. And I was wanting to know if your guests could comment on the content of omega-3s in milk and sort of the effects of the fat-free dairy movement and the removal of the omega-3s via that process.

REHMInteresting. Dr. Fotuhi.

FOTUHIYes. The amount of omega-3 fatty acids -- and I must specify is that DHA, that's the most critical. As Paul mentions, omega-3 fatty acids are a group of compounds, not just one. There are probably 10 of them. And the most important one and the one that seems to be most critical for brain function, for brain development, for prevention of cognitive impairment with aging seems to be DHA.

FOTUHISo let's focus on the amount of DHA in various foods that we can -- we eat. So salmon, let's say, has anywhere between 700 milligram or 1,000 milligram, whereas meat or poultry or walnut or all of these other ones have in the magnitude of one or two milligrams per serving. So there's a huge difference in the amounts that we get from, let's say, salmon versus other sources.

REHMNow, I have in front of me a Wall Street Journal report on this study that was recently done, which says that a serving of salmon can contain anywhere from 1,200 to 2,400 milligrams per 4-ounce serving. And that's a salmon steak I'm looking at, which tends to be the fattier portion of salmon. And then a look at walnuts would indicate that you get 2,300 milligrams from a quarter of a cup of walnuts. That puts them pretty much on the same level, doesn't it?

FOTUHIWell, I need to look at the sources before...

SHERMANThey're probably not making a distinction between DHA and alpha-linolenic acid...

REHMOh, my goodness.

SHERMAN...which is the essential fatty acid that we need.

REHMI see.

SHERMANIt's actually a very interesting difference. I mean, all plants, leafy green vegetables, walnuts, things like that can be very rich sources of omega-3s, but it's the essential fatty acid that we then process and extend to make DHA. And that -- we do that slowly, but we do do that.

REHMAnd you're listening to "The Diane Rehm Show." I want to go back to our caller who talked about her own experiment, Susan Allport. From a physician's perspective, Majid, what is your thought on her experiment with trying to change the balance between the omega-3s and the omega-6s?

FOTUHII think she was absolutely right. One way to think of the omega-3 and omega-6 fatty acids is to compare them to LDL and HDL. We know that LDL is a bad cholesterol, HDL is a good cholesterol. So, same way, omega-3 fatty acids and, again, DHA seems to be the good omega-3 fatty acid, the good guy, and omega-6 fatty acid seems to be the one that are not so good, and they're associated with increased risk of inflammation.

REHMYou're smiling, Tom Sherman.

SHERMANI mean, it's true. I mean, it is true. It's just that this competition between omega-3s and omega-6s is very seductive biochemically because we know that these two pathways compete for enzymes that take these essential fatty acids and make them into arachidonic acid or DHA. It's very seductive, but we've actually never seen good studies that have confirmed that. And so we -- it makes sense.

SHERMANIt seems like it should be that way, but the studies have never actually been particularly strong in that regard. And so I'm always sort of waiting to see who's going to design the experiment that sort of decides this question.

REHMSo you're saying it's going to be awfully hard to do.

SHERMANIt is hard. You know, Susan is right, and Dr. Majid is right, too, I mean, that omega-6s have dominated our diet and omega-3s are more rare. And it's -- and we really can't implicate it or associate it with all of these things. It's just that it's an association, and...

REHMPaul, what do you think?

COATESYeah. And I mentioned a little earlier that these studies need doing. They are not easy to design, but I think we are obliged to be able to do them. If we're going to be able to say that A causes B, then we have to figure out a way to go beyond just association between the potential intervention and the health effect. We need to show that, and it has not been easy to do that.

REHMMajid.

FOTUHIYes. So I think that what we need are double-blind, placebo-controlled studies, and more of them are getting published these days. One was just published recently and showed that children ages 7 and 9 who took DHA performed better in the reading versus children who received placebo. It was a placebo-controlled study. The MIDAS study in which people took 900 milligram of algal DHA was a placebo-controlled study.

REHMSo it's also indicated that omega-3s may help with ADHD in some children?

FOTUHIYes. And, again, as Paul and Tom mentioned, it's really difficult to have good outcomes that everybody agrees on and uses the same thing. So the challenge is doing the right studies.

REHMDr. Majid Fotuhi, he's chair of the Neurology Institute for Brain Health and Fitness. Short break here. We'll be right back.

REHMAnd welcome back. We're talking about omega-3s. Some have raised questions about some recent studies involving some 70,000 people to try to determine exactly what the benefits are and what the benefits may not be from either eating omega-3-filled foods or taking omega-3 supplements. Here's an email from Linda, who says, "Does canned salmon have the same benefit as wild salmon? Also, is fish oil better than cod liver oil?" Tom Sherman.

SHERMANCanned foods -- so, actually, back -- actually, Susan Allport could have answered this question well, too, that the reason omega-3s many times are removed from processed foods is that they shorten shelf life, that it's when they oxidize, they contribute to the rancidity of food. So if canned salmon is rancid, then not only is it not edible, but its levels of omega-3 are going to be lower. But if it's edible and it's good, then it's going to simply reflect the amount of omega-3s in that fish when it was canned. The second question was?

REHMWell, the second question was in terms of fish oil and cod liver oil.

SHERMANOh, so fatty fishes: the mackerels, the sardines, the salmons, they're fatty fishes because the fat is in their flesh where lean fishes keep the fat in their livers. And so it seems like a good idea to eat cod liver oil because that is where all the oils are, and they do have lots of omega-3s. But they also have very high levels of vitamin A, which can be problematic for people who take too high levels of vitamin A in terms of bone health, in terms of some cancer risks, so...

REHMSo you would say that fish oil is better than cod liver oil?

SHERMANOh, definitely. Definitely.

REHMDefinitely. OK. Here is an email from Gloria, who says, "I was taking fish oil supplements until my doctor recommended krill oil as a better option. What's the difference? And is it really better?" Paul Coates.

COATESI think krill is one of those microorganisms.

SHERMANIt's the little crustacean.

FOTUHIYeah.

COATESIt's the little -- oh, it is. So it's not...

SHERMANIt's the -- it's -- I mean, it's a good source of omega-3s, but, yeah.

COATESBut is it -- it's not the vegetarian source that you might think algae are.

SHERMANYou know, that's a good question.

COATESYou know, they are little micro-crustaceans.

REHMI love the fact that doctors themselves are not quite, quite sure.

COATESYou know, the point there, though, is that the lower you get into the food chain, the cleaner your omega-3 fatty acids are going to be, and so the lower...

REHMThe lower you get in the food chain.

COATESAnd so as you eat -- so as you go from dinoflagellates and algae and krill, to anchovies and sardines up to salmon, the bigger the fish, the more fat they store, but the more that they accumulate these toxins, heavy metals...

REHMInteresting.

COATES...pesticides in the water. So...

REHMYeah. Well -- and you've got these warnings, for example, about swordfish and mercury. So how do you balance? Is swordfish not one of the fish that you gentlemen would recommend?

SHERMANSwordfish doesn't -- is not a big source of omega-3 fatty acids to my knowledge.

REHMGotcha. OK.

SHERMANBut in the -- just so you know, when fish oil supplements are manufactured, very often, the manufacturing process itself eliminates a lot of those toxins. That's not guarantee that they're not there, but they're considerably less in supplements, ironically, than there might have been in some of the native fish.

REHMOK. I do want our listeners to know, because I realize that there are great many people online with questions, that our three doctors have agreed to be online to respond to your questions. After the program, they'll do it by virtue of answering questions that come in on the Web. I hope I'm saying that correctly. If I'm not, somebody's going to call me and say, Diane, you didn't say that right. OK. Let's take a caller in Gainesville, Fla. Good morning, Bill. You're on the air.

BILLGood morning. Yeah. I take Lovaza because my doctor says I would not get enough of the omegas I need from fish and flaxseed and walnuts for my purposes. Can you speak to any research showing that omegas help with depression? And is there any harm in taking Lovaza? I'd -- I haven't had any side effects. Thank you.

REHMPaul Coates.

COATESI'd be happy to try to answer that. Lovaza -- or is the prescription drug version of omega-3 fatty acids. And it has a fairly specific clinical indication, and that's to reduce the level of triglycerides in blood. I'm not aware -- maybe one of my colleagues is -- about the use of this drug for depression or other...

REHMMajid.

FOTUHIYes. To my knowledge, this study -- this drug has not been tested in clinical trials for depression, though I'm not -- I wouldn't be surprised if there are ongoing clinical trials.

REHMInteresting.

FOTUHII think the best source, in my opinion, is to take algal DHA. As Tom mentioned, algal is the most pure form, and algal DHA is a supplement that people can take. And a clinical trial that was done was done with algal DHA 900 milligrams. So that's makes it easy for me. That's what I take myself. And, you know, we're talking about children with ADHD. I do -- I give it to my two daughters, who are five and seven. It's like a desert after dinner. We have our little DHA supplement. They have smaller amounts, obviously, than I do.

REHMInteresting. Seven and nine.

FOTUHIFive and seven, yeah.

REHMFive and seven. All right. Here's an email from Michelle: "If algae is the source of the omega-3s in fish, can we just eat seaweed to get the same benefits? I realize this might not be a popular suggestion, but it sure would be cheaper." Any comment?

COATESI mean, yes, you can do that. It actually be -- the seaweed is typically commercially available, isn't particularly rich in omega-3 fatty acids. But probably, more importantly, when somebody eats seaweed, they actually don't eat very much seaweed. And so -- I mean, yes, it would be part of a good diet and -- but it is -- it wouldn't necessarily be a replacement.

REHMAll right. To San Antonio, Texas. Good morning, Philip.

PHILIPGood morning. Yes, I'm a forager, and a lot of people don't realize in this country that we don't market purslane very well in this country. It's a wild succulent that just grows in my yard, in anybody's yard. And you could probably buy it at Home Depot potted in a plant, and that's the only way we market it in this country. We do not real -- it's higher in omegas than spinach, and nobody even realizes it.

REHMPaul Coates.

COATESYou're right. And sometimes we have these unexpected treasures even in our own backyards.

FOTUHIYeah. It isn't the best tasting we've known, but...

REHMWell, it do sound that way.

FOTUHI...Susan Allport tells a good story in her book, "The Queen of Fats," about how free-range chickens will eat purslane and insects and that the high levels of omega-3 in those plants lead to eggs that are just so rich in omega-3s that they compete with many fish and are delicious.

REHMAll right. Here is an email from Kate, who says, "This topic is great. Could your guests go out on a limb to help an overwhelmed mother and prescribe a source of omegas for my family: one husband, almost 40, 6-year-old boy, 4-year-old girl, 18-month-old boy and me, a 35-year-old woman. In case it matters, I am white, and I live in Ontario." Majid.

FOTUHIYes. I'll tell you what I take. I'm actually on the same age group as what's mentioned. And my wife and myself and our daughters are the same age. So I usually take 900 milligram of algal DHA and my wife does the same. And our daughters take 100 milligram each.

REHMSo a different milligram counts depending on the age. How do you feel about that, Paul?

COATESI'm not quite as excited about that possibility. I would very much like to see people consider taking omega-3 fatty acids. But if they're taking them in relatively high amounts -- and I'm not saying that 100 milligrams is high for a child -- I would probably be a little more comfortable if I saw this being done under the supervision of a health care professional.

REHMOf a physician. And what do you say, Tom Sherman?

SHERMANWell, I'm the proud father of three beautiful daughters, including a 2-year-old and 4 1/2-year old, and we take more of a dietary approach. And we -- our daughters have grown up eating fish, eating green vegetables, eating nuts and my granola. And I think developing these kinds of eating habits is going to serve them well for their whole lives.

REHMOf course, I adore walnuts, so I'm with you. Let's go to Boston, Mass. Good morning, Heather.

HEATHERHi. Thank you for having me on the show.

REHMSure.

HEATHERI wanted to bring up the idea of chia seeds which are antioxidant rich, so they don't spoil and then rich in omegas. And then also after that, coconut milk as a DHA alternative as I'm raising a vegan son.

SHERMANWell, chia seeds are very rich in DHA which -- I mean, in alpha-linolenic acid. It's, you know, given my growing up with Chia Pets, I've always thought that was entertaining. I don't think there is DHA in coconuts, but they are a very rich source of short-chain fatty acids which have their own benefits. But, yeah, chia seeds, they're small, so they really have to be ground. Our teeth are really designed for grinding those really small seeds.

REHMAll right. To Detroit, Mich. Hi there, Chuck.

CHUCKGood morning.

REHMMorning, sir.

CHUCKYes. I just wanted to provide an endorsement of fish oil and the omega-3s. I lost my health insurance about in the mid-'90s and started taking a nutritional regimen and -- including, you know, lots of supplements, including large quantities of fish oil. And I discovered some of my other ailments, such as Crohn's disease, reversed. My depression went away. And I was taking fairly large quantities, and I still do.

REHMInteresting. Dr. Fotuhi.

FOTUHIYes. I think that 1,000 milligram -- roughly 1,000 milligrams seems to be a good dose, but sometimes people take 2,000 or 3,000 milligram a day. And I think when you get to that range, then, if you're taking Coumadin or some blood thinners, you may be at risk for harmful issues. But at the range of 1,000-plus or minus, you know, 500, I think, people are safe. And again, the distinction is between fish oil, omega-3 fatty acids and DHA. DHA is a form of omega-3 fatty acids, and fish oil have a lot more than omega-3 fatty acids.

FOTUHISo I personally prefer DHA because DHA has been associated with reduced blood pressure, better HDL, better brain function. And I have seen in some studies that I feel there is plenty compelling evidence that I would take it myself.

REHMI have the feeling there is going to be a run on this across the country. Are you, Paul Coates, comfortable with what Majid Fotuhi is saying without talking with your own physician?

COATESNo.

REHMYou are not?

COATESThat's the easy answer.

REHMYeah.

COATESBut there's a lot behind it. And the fact is that associations are really very important in helping us to discover whether something will have a benefit in a particular setting. Since I make decisions that are intended to effect the public health rather than the clinical decision making that goes on between a patient and the health care provider, I have to worry about things like, are there side effects that we don't know about? They have not been completely studied.

COATESI'm not saying that omega-3s have a dangerous safety profile. They certainly do not. But there are some things that we don't know. And if I'm going to be making recommendations across a population, I feel I need to have a higher bar for evidence.

REHMPaul Coates is director of the Office of Dietary Supplements at the National Institutes of Health, and you're listening to "The Diane Rehm Show." Let's go to Crystal Lake, Ill. Good morning, Yvonne.

YVONNEGood morning. Thanks for taking my call.

REHMSurely.

YVONNEI'm a physician, and I've done quite a bit of research in the last year on how to best help my patients. And I've been recommending fish oil capsules. And my question is, because I've been researching the krill oil also and I know someone else called with this question, the difference that they market for the krill oil is that it's in the fast lipid form so it's supposed to be better absorbed.

YVONNEHowever, the dosage of the DHA that's in each capsule of krill oil is only 62.5 milligrams, whereas, you know, I used a omega-3 that has 200 milligrams per capsule. And I know you can get the higher DHA capsule that have much more. But I wonder if there's any comment from the people on your show today regarding whether the fast lipid form is that much better absorbed to warrant the much lower dose in the krill oil capsule.

REHMTom Sherman.

SHERMANNo, I don't believe so. I mean, fats -- unless you have a malabsorption disorder, fats are going to be well-absorbed no matter what.

REHMAnd here is a tweet: "So many vendors are offering vitamin supplements, particularly for omega-3-type supplements, what is the pertinent criteria when choosing?"

SHERMANActually, Paul could probably answer that one best.

COATESJust to distinguish, vitamins are not the same as omega-3s, but they are all in the category of dietary supplements. And I think the overarching issue that we should be concerned about is the quality of the products that are made and be able to identify reasonably well that the contents are what they say they are on the label.

REHMMajid.

FOTUHIYes, I agree. But also, just following up the conversation we had just before this question is, why doesn't NIH support the recommendation of the DHA for use for brain health? There are double-blind, placebo-controlled studies. Another one is published. How much more do we need to say that it is at least good?

COATESDo all of the studies that you're aware of point to -- in the same direction?

FOTUHIYes.

COATESI'm not aware that they all point in the same direction. And that's probably where the tension lies, that there may well be some evidence of benefit. And that usually should be a good clue for moving forward with research.

REHMPaul Coates, he is director of the Office of Dietary Supplements at NIH. Dr. Majid Fotuhi, he is an assistant professor of neurology at Johns Hopkins University School of Medicine. Tom Sherman is associate professor of pharmacology at Georgetown University Medical Center.

REHMWe know we can't get to all of your questions, could not get to all your questions during this segment, so, please, submit your questions for this panel via email, Facebook or Twitter. We'll post as many answers as we can on our website drshow.org by tomorrow. Thank you, all. And thanks for listening. I'm Diane Rehm.