The Effects of Choline and DHA in Pregnancy
OmegaMatters: Episode 42
Hosts: Drs. Bill Harris & Kristina Harris Jackson
Guest: Dr. Kevin Klatt
About this episode: In this episode Drs. Harris & Jackson talk to Dr. Kevin Klatt, an assistant research scientist and instructor in the Department of Nutrition Sciences and Toxicology at UC Berkeley. He received his PhD in molecular nutrition from Cornell University and completed his dietetic internship at the NIH Clinical Center. Kevin has experience from the lab bench to human clinical trials to clinical practice. For more information on OmegaMatters, visit: https://omegaquant.com/omegamatters-broadcasts/
SHOW TRANSCRIPT
Dr. Kristina Harris Jackson: Hello, welcome to OmegaMatters, where we talk all things omegas. I’m Kristina Jackson, this is Bill Harris. And today, we have a great guest, Dr. Kevin Klatt. Kevin is an assistant research scientist and instructor in the Department of Nutrition Sciences and Toxicology at UC Berkeley. He received his PhD in molecular nutrition from Cornell University and completed his dietetic internship at the NIH Clinical Center. He’s also the inaugural Dennis M. Bier Young Career Editor for the American Journal of Clinical Nutrition and hosts the AJCN podcast called AJCN In Press. Kevin has experience from the lab bench to human clinical trials to clinical practice, and we are very excited to talk with him about his work in the Omega-3 space. So thank you for joining us today, Kevin.
Dr. Kevin Klatt: Thank you so much for having me.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: Unfortunately, I’m no longer young, so they kicked me out of the Young Career Editor position and I’m just an associate editor.
Dr. Kristina Harris Jackson: Well, congratulations still. AJCN is the big dog in nutrition.
Dr. Bill Harris: At least, they didn’t kick you out completely. Yeah.
Dr. Kristina Harris Jackson: Yeah. Can you take us through a little bit of your career journey? How did you get into nutrition in the first place and how’d you get to where you are now? I know it’s a lot, but, yeah.
Dr. Kevin Klatt: Yeah, I mean, that’s taken you back. I actually wasn’t really into nutrition until … I guess early in college, I got into it. I had lost some weight in high school, and any of that exposes you to the whole world of what’s the best diet, yada, yada, yada. But I went to an undergrad that didn’t have a nutrition program and I had a scholarship there, so I didn’t want to leave. So I did a relatively long and winding path as a biological anthropology major, which I think is a great undergraduate major. I think understanding human variation and human adaptability is super important context in nutrition, especially where things get dogmatic and prescriptive really fast. But I did all the classes I could that would get both the dietetic and the nutrition science background. I did a quick year at Drexel University. I’m from Philadelphia, went to undergrad there, so I did some of the dietetics coursework there and I was just really eager at that point to get into research.
My honors undergrad thesis advisor or just advisor always told me, she’s like, “You’re going to be a researcher.” And I was like, “No, I want to be a clinician and practice.” She’s like, “All you do is ask questions about how we think we know this and how do we get better at knowing it.” And I was so vehement that I wasn’t going to be a researcher. I sent her an email a few years ago being like, “Oh, you were very right.”
Dr. Kristina Harris Jackson: Yep.
Dr. Kevin Klatt: Listen to your undergraduate advisors. They know you better than you know yourself.
Dr. Kristina Harris Jackson: Oh, yeah.
Dr. Kevin Klatt: I was eager to get into research, but I also wanted to finish the RD. And so I just applied to a couple programs where I could. I have two DPD classes left that I needed to finish and I was too eager to get into the full research track and things. So I did my PhD at Cornell in Marie Cawdell’s lab and she’s who I went there to work with. And this is so 2013 coded of me, but I was really interested in epigenetics at the time, particularly just the idea that the methyl donors in the diet and the amount of them could influence histone post-translational modifications in CPG, methylation state, and influence gene expression was just this like wow. And I look back on it being like, “Oh my gosh, we have so little molecular tools both at the cellular and in vivo level to really say anything too causal.” And there’s a bit of naivety I look back on, but I’m still fascinated by that idea of what you eat during pregnancy is structurally building a fetus. It is laying out what their metabolic state is going to be in some ways for the rest of their life.
And so Marie had done a little bit of work in that epigenetic space, but choline was also interesting to me, particularly in pregnancy, because the power and potential promise of epigenetic programming, whatever, and then you look at the DRIs and they’re like, “Oh, a study done in men was used to estimate the requirements in non-pregnant women and then they adjusted the non-pregnant women to get the pregnancy value.” And you’re like, “Okay, you don’t have to be a feminist to say maybe pregnancy don’t have to come from studies done in men.”
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: So there’s a lot of work that needed to be done, clearly. And Marie was doing a lot of that work. She and Steve Zeisel were the two big folks in the field. And Marie had the PhD RD training. And so I very much looked up to her from afar and was fortunate to get to work in her lab.
And so I ended up doing … When I was with Marie, one of my big career goals was to … I think what I found most frustrating, people are like, “What’d you go into your PhD to do?” And I just wanted to build a toolkit. I didn’t really … As much as choline seemed like an opportunistic nutrient, but I didn’t want to be a single nutrient person. At the time, the vitamin D wars were going on and people are screaming at each other at conferences about vitamin D recommendations. And I was like, “I just don’t care about any nutrients to go scream about at the conference.”
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: And I was just very interested in … I was reading papers, I was frustrated if I read a cell culture paper or I read an animal paper. I could get it, but I didn’t know how to critique it. And I think you really have to do the work to understand all the nuances of critiquing it. So I set out really just to try and get as many skill sets under my belt as I could. And Marie’s lab was really great for that because she very much encouraged her students to go work in another lab for a year and do some … Some of the students that were doing a whole-body human metabolism, vitamin D also went and did some work in a cell culture lab where they were studying vitamin D and a placental cell line there. And so that was really great. And so I ended up having a co-mentor, a reproductive biology co-mentor, Mark Roberson, and spent a bunch of time in his lab. So I got the full gamut of he was doing cell culture and primary cells and knockout mice. And then Marie was the whole-body human physiology, isotope tracing LC-MS lab. And it was a lot of hours of work to be across two labs, but it got me that goal of really wanting to work across the translational spectrum.
And then after I did my PhD in Marie’s group … I was in Marie’s group, I was doing a big RCT that we’ll talk about the results of today. And then in Mark’s group, I had my hands in a number of projects, but I had a spin-off in nutrients influencing some of the nuclear receptors, which are transcription factors that regulate gene expression and hunting down a potential ligand. And that’s some of the work I continue to do today in addition to the human clinical trial stuff for nutrition. And so after I left Cornell, I went and wrapped up the dietetic internship, which was nice. I highly recommend people take a break from research, especially after your PhD, you’re a little burnout. I did my clinical training and then did a postdoc down at Baylor, following up on the more nuclear receptor stuff. But I have the clinical trial data coming in from working with Marie and the fatty acid analysis that we did together and we’ll dive into.
So I’ve tried to stratify this both a little bit of human trials and a little bit of basic science for most of my career, I guess my entire academic career at this point, which is increasingly hard to do. But, yeah, that’s me in a nutshell. I’ve covered different nutrients from choline, did a little bit of B12 work and continue to do that. And then different fatty acids, both. Some of the saturate. There are shorter saturates like lauric that are fun and interesting. And then some of the omega-3 work as well.
Dr. Kristina Harris Jackson: You have always been someone who I think just blows me away with you know more about more things than I can even speak about. And I’ve been out of grad school for long enough where … And in one lane where I’m starting to feel like, “Oh, I can’t talk about anything else besides fatty acids,” because I haven’t been keeping up at all.
Dr. Kristina Harris Jackson: But it’s always fun to hear you at conferences, just come up and just bring that little bit of a more holistic type of view when we get too narrow and focused in on things. And that’s where I do think where your work with the choline and the DHA in this RCT you did at Cornell, it’s one of the first that we’ve seen where omega-3 levels get affected by another nutrient in a very specific timeframe, which is the caveat. So I would love to dive into this part of the talk. So let’s go into the science, go into these two studies that were run. I don’t know how much you want to talk about both, but the paper, for everyone that wants to check it out, is the one that your lead author on is prenatal choline supplementation improves biomarkers of maternal docosahexaenoic acid status among pregnant participants consuming supplemental DHA, a randomized controlled trial that is AJCN in 2022. Is that the primary one? Sometimes there’s several. Okay. So can you set the scene and tell us what you did?
Dr. Kevin Klatt: For sure. Yeah, yeah. So I was always eager to not be a single nutrient person. So this was the perfect topic. And Marie was very interested in the choline omega-3 fatty acid interactions and the rationale for it, which gets a little metabolic biochemistry right up Bill’s angle, for sure. So supplemental DHA in the diet, it can come in in various forms. We don’t really eat the free fatty acid form. You get typically triglycerides, you can eat these phosphatidylcholine forms, but for the most part, it gets deconstructed in the intestine absorbed and the body is repackaging it to the way that it needs it. And you can find it in circulation esterified in different forms within lipoproteins or circulating as a free fatty acid bound to albumin or as a lysine phosphatidylcholine bound to albumin as the primary ways it’s getting around. And so there’s lots of debates in the literature about what circulating form, particularly in pregnancy, is there for the fetus. For the adult human brain, there’s all these big debates right now about whether the free fatty acid form is sufficient or how much these LPC-DHAs supply the adult human brain.
But within pregnancy, one of the things that’s really interesting that there’s a link choline and omega-3s is phospholipid synthesis is dramatically increased. And so normally, we think about DHA getting incorporated into phospholipids, particularly phosphatidylcholine. And in pregnancy, there is this … The gene that produces phosphatidylcholine de novo that gets dramatically upregulated in pregnancy, it’s called PEMT or the Phosphatidylethanolamine N-methyltransferase pathway. But it’s taking … So we’ll call that PEMT, but it takes phosphatidylethanolamine, another phospholipid, puts three methyl groups on it to make phosphatidylcholine. And early work back into the ’90s and then the knockout mouse for the PEMT gene in the 2000s really identified this link that the PEMT pathway produces the phosphatidylcholine that’s particularly rich in omega-3s like DHA. And so that starts to form the linkage between choline metabolism and omega-3 fatty acid metabolism.
And so when you knock out PEMT in mice, when you do fatty acid profiling of their plasma, DHA has dramatically reduced the knockout mice relative to the wild type. So we think … And PEMT, I should say, is very highly expressed in the liver and not really anywhere else. And so we think that this is a liver-specific pathway for synthesizing phosphatidylcholine in general, this major way that the liver exports omega-3s. And in the pregnancy … Oh, yeah, go for it.
Dr. Kristina Harris Jackson: Can I see if I’m tracking this? So we consume omega-3, body breaks down, absorbs the fatty acids, the liver remakes it, and most of the fatty acids that would go to the placenta are the specific kind of phospholipid, phosphatidylcholine, that is attached to albumin. Or is it within other-
Dr. Kevin Klatt: Phosphatidylcholine will be more in the lipoproteins.
Dr. Kristina Harris Jackson: Okay. And so people are tracking that specific … Because there are lots of … So when we talk about omega-3s, we’re talking about red cells, but red cells, those are phospholipids as well, just all different kinds. And so this is a specific kind of phospholipid that seems to be the one that is getting across the placenta … That’s the one that goes in the placenta or does it …
Dr. Kevin Klatt: We think it’s really important for getting from the liver into circulation and then the circulation, it’s going to go to all other tissues including the fetal compartment.
Dr. Kristina Harris Jackson: Okay.
Dr. Kevin Klatt: So in just the general adult, though, this pathway of producing phosphatidylcholines enriched in DHA, this gene, the protein PEMT, is really important for getting that out. And the pregnancy link comes in that there’s … Molecular biology speak, there’s a promoter in front of the gene where estrogen is able to bind and upregulate the expression of the gene. And we know across pregnancy there’s a tenfold increase in estrogen.
And so Marie’s previous study had shown that with stable isotope tracing, that PEMT activity was really increased across pregnancy. And that fits. You want to be able to produce a lot of phosphatidylcholine to build this baby with all its cell membranes. And what’s interesting is that during the third trimester pregnancy of lots of brain development and eye development where you’re depositing these PUFAs, and that’s also the time at which estrogen peaks the highest. So you can form this all axis where estrogen is increasing so that the maternal liver produces a ton of phosphatidylcholine and a ton of PUFA gets them out to support fetal brain development and just development in general.
But one of the things that we questioned was PEMT, it’s a methyltransferase that uses tons of methyl groups and it’s known to be one of the largest consumers. You have hundreds of transferase in the body, but quantitatively, as far as it goes for methyl group consumption, it is one of the major ones and it’s probably the major one in the pregnant body. And so it needs a lot of methyl groups. And we wondered whether that reaction was potentially limited by the fact that coincidentally choline is the major methyl donor within the diet and choline itself becomes so important. It’s really concentrated within the fetal compartment. And what Marie had seen in her previous study is that of all the metabolic fates of choline, it seemed like when you have lower choline intakes, there was less oxidation to betaine. And that is the committed step for using choline as a methyl donor. So there was a shunting away from its use as a methyl donor so that you could concentrate choline within the fetal compartment and support other phospholipid synthesis pathways.
So at this time, when you have the most consumption of methyl groups, you have a less utilization of choline as a methyl donor. And so we wondered whether giving choline back would supply those methyl groups to basically fuel the maximal activity of PEMT. And so whether it was essentially rate limited by not having enough dietary methyl donors because metabolically you’re so stressed with choline during pregnancy, it’s being reprioritized away from that methyl metabolic fate and utilization. So I guess at a high level, we’re thinking that the PEMT activity is important for just getting out phosphatidylcholine enriched in DHA into circulation in general in all humans. But in pregnancy, that pathway is dramatically upregulated at a time when you’re also using choline less for generating methyl groups, it’s required for the PEMT activity.
And so we just ask simply if you supplement with choline back, which I think has independent benefits on its own, particularly for fetal development, that the choline supplementation would be beneficial. And Marie had seen that in a previous study that you might also have these metabolic benefits and enhance the utilization of DHA. So we designed a study where everybody got their prenatal on both arms. Everybody got their standard of care at 200 milligrams of DHA, but then one group got a small amount of choline in just the form of a stable isotope tracers of 25 milligrams per day. And then we also gave … The other group got 550 milligrams of choline, 500 from a supplement and then 50 milligrams of the stable isotope tracer. So this mirrored very much what Marie had previously seen in her controlled feeding study she did before that high doses of choline just independently improved fetal cognition. So we’re still doing … Or sorry, infant cognition. So we’re still doing the postnatal follow-up with Rick Canfield and Barb Strep do that.
But basically, we do all the pregnancy and metabolic element of that and then we pass off the infants to our human development colleagues who then assess these really important, I think, somewhat clinical outcomes of cognitive development. So we try and have a … These are tons of work to do these studies, so we try and get all the outcomes that we can that are relevant to choline, but our primary outcome for this was really looking at this choline DHA metabolic interaction.
Dr. Bill Harris: Does choline do anything to enhance the synthesis of DHA from ALA?
Dr. Kevin Klatt: There’s not really any data on that that I’m aware of.
Dr. Bill Harris: Okay.
Dr. Kevin Klatt: I guess it’s … Well, the metabolic theory, I think, is lacking on it, but nobody’s ever lifting, giving an ALA tracer alongside different doses of choline and seeing if you enhance DHA synthesis. But I don’t know of … I’m trying to think of any data that would exist to even imply that. Most of it’s been this context of … Steve Zeisel has done some work where in choline deficiency in pre-menopausal women, they also see reductions in circulating phosphatidylcholine DHA just outside of the pregnancy state. So most have looked at if you compromise omega-3, or sorry, choline and methyl donor availability in individuals that have really high PEMT activity, then you might limit DHA availability that’s out there.
Dr. Kristina Harris Jackson: Right.
Dr. Bill Harris: Okay.
Dr. Kristina Harris Jackson: We have seen estrogen does affect the pathway to increase DHA like they’ve given, but is that at all connected to the choline story, if that’s also how we end up measuring it? I don’t really know if there’s a separation of the two, if that makes any sense.
Dr. Kevin Klatt: Right now, it’s like estrogen influences ALA to DHA and then estrogen influences choline production through the PEMT pathway, whether they synergize in some way that’s not fully known, but we think they’re relatively independent effects. So the estrogens, that’s basically prioritizing the de novo synthesis of both of these really important nutrients.
Dr. Kristina Harris Jackson: Which is so cool, that pregnancy is taking care of that in some ways.
Dr. Bill Harris: Yeah.
Dr. Kristina Harris Jackson: It’s cool.
Dr. Bill Harris: How much PC do we eat?
Dr. Kristina Harris Jackson: Yeah, that was my question.
Dr. Bill Harris: Oh, okay.
Dr. Kristina Harris Jackson: Just choline.
Dr. Bill Harris: Well, if phosphatidylcholine cause the lipid, we need to make more than we eat, apparently, even of PC.
Dr. Kevin Klatt: Yeah, we make a ton of PC. So for a while, people didn’t even think choline was a essential nutrient because this pathway exists. So you can use other dietary methyl donors like methionine or betaine to fuel the PEMT activity, and you take phosphatidylethanolamine and make phosphatidylcholine and you have phospholipases that can cleave that choline head group off. So there’s … It’s somewhat akin to vitamin Ds as an example, not obviously the same, but you can make some. And it took proving that we’re totally removing choline from the diet while keeping the intakes of folate, B12, methionine all still high that facilitate the rest of those methyl transferase activities to show that there’s still some clinical consequence of this, so you need to eat some amount of it. The exact amount is still not known. So there were seminal studies that Steve Zeisel did, basically giving everybody a run-in diet with around, it’s like 7 mgs of choline per kilogram. So it ended up being about 550 milligrams that folks got and then really depleting to less than 50 milligrams and watching for whether folks get signs of fatty liver. And it also appears that there’s a muscle damage phenotype thing can occur in some individuals and then repleting them back.
And so in later studies beyond when we had the DRIs in America set, there was more of a stepwise reintroduction of dosages to identify at what point do we meet the needs of like 50% of the population. But the DRI is really based on that 550 value that they did in the depletion-repletion studies. And so, yeah, you basically … It’s recommended, the AI that is given for the DRI value is 550 milligrams for men and then a body weight based adjustment for women, it’s a little bit less, and a small additive increment of 25 milligrams for pregnancy back onto the women of reproductive age values. And so it is a big guessing game, and in DRI speak for folks who don’t know, the AI, it means adequate intake, but I teach it to students, I would say when you hear adequate intake, you need to think inadequate data because it means it wasn’t dose response data available to estimate the average requirement of a person and then go two standard deviations out to set an RDA.
So there’s a lot of uncertainty here, but you eat essentially a few hundred milligrams of choline on average a day, and egg intake is a really rich source of phosphatidylcholine. So most of the choline you’re eating, like 75% of it in the diet, comes in as PC. About 20% comes in through other forms. So when we say dietary choline, it’s like it’s not a single compound. It’s actually several choline containing compounds. And in our trials, we use … What’s that again?
Dr. Bill Harris: It’s not free choline, it’s not free choline, it’s always a esterified to something.
Dr. Kevin Klatt: Very low … No, there’s a little bit of free choline that you’ll absorb in the diet, but it’s pretty minimal. We use choline salts, which will come in predominantly as a free choline, in our supplementation. So that’s a big caveat where it’s really hard to back translate from supplements to what it means for food with choline because we’re not giving the form that is mostly found in food, and that’s largely because a phosphatidylcholine is only like 12% choline by a weight. And so when you do an intervention study, you’ve got to ask … And this has happened in pregnancy studies where you’ve got to ask women to take an extra seven or eight horse pill sized things on top of their prenatal, on top of the DHA. And so you always worry about compliance and burden just on the participants. And it also scientifically becomes an issue of which form of phosphatidylcholine do you give because you start to give meaningful amounts of the fatty acids that are on the phosphatidylcholine molecule.
And so you’re co-intervening not only with choline but the linoleic acid that comes in with the soybean oil phosphatidylcholine. And so it’s a design nightmare. And so giving the phosphatidylcholine is much easier to work around. They do taste gross. I have sat at a bottle of kitchen test tasting. When you put 500 milligrams of choline, it turns out black tea actually really masks a lot of the bitter and sour taste of the choline salt. We gave it in a small juice cocktail. We made 15 mil Eppendorf tubes and people just took a shot of choline. Make it easy for folks. But, yeah, there’s so much dietetic angles on this that could go down a whole rabbit hole, how you translate this into population level recommendations. And I should say the metabolic fate is probably reasonably different between a choline salt, which is water-soluble, comes into the portal vein, hits the liver. A lot of it looks like it gets oxidized to be tamed because that’s what the liver does when it gets tons of choline at once, whereas phosphatidylcholine is going to come in and largely gets repackaged into column microns and goes through that route where a lot of extra hepatic tissues are going to see at first before it makes its way back to the liver.
And so there’s a little bit of isotope tracing data saying that the initial metabolic fates are different. Whether that has long-term consequences, we don’t really have great data in humans comparing head-to-head different forms of choline, but there’s enough biochemical rationale that I’m very reticent to be like, “Yeah, our 550 milligrams of choline supplement,” you can back translate back to eggs or whatever, which would be like five eggs, a few more eggs a day. So it’s not like I go around recommending that either, but our supplements, I really encourage people to interpret it as the effect of the supplement and not back translate to food so much.
Dr. Kristina Harris Jackson: Yeah. But most prenatal supplements do not contain choline because they’re so big because it’s so much … Is that true?
Dr. Kevin Klatt: Yeah. So choline … A lot of our micronutrients are in microgram or low milligram amounts, so we’re giving 550 milligrams. And so that is … If you’ve seen a calcium pill, it’s quite similar in size to that, so you’d have to double the size of the … A calcium with prenatals is often pretty low. It’s only 150 milligrams because it’s taking up so much weight in that pill size, so you have to have a whole second pill, basically.
Dr. Kristina Harris Jackson: Same with the DHA.
Dr. Kevin Klatt: Yeah.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: It’s so funny. I always think about there’s no amazing studies for manganese in pregnancy, but we throw it in there because it can fit. But because these nutrients are … They’re metabolically so much more important during pregnancy, but because they’re so big, you have to have this super high level of evidence to ever tell somebody to take a supplement with the DRI level of them, whereas selenium is not really killing it on the RCT front.
Dr. Kristina Harris Jackson: No. Yeah, it’s where … It’s very, very frustrating. I think there’s one supplement I saw that it’s like eight pills a day to get as much closer to what they think the actual needs are in missing nutrients was a choline and omega-3 would be major aspects of that. And that’s eight pills a day, like you said. And when with pregnancy you’re already a little bit nauseous, there are a lot of issues.
Dr. Kevin Klatt: Yeah. I was in a dose response histidine study at Cornell and I had to take, I think it was 18 pills or something crazy. I was so tired of it.
Dr. Kristina Harris Jackson: It’s the worst.
Dr. Kevin Klatt: Pregnant women in the studies are so motivated. They want to do I’m so grateful for our participants because they’re just so motivated to the cause of improving our knowledge of pregnancy nutrition requirements. So I’m pretty sure they would do almost anything we ask them. You obviously want to make it as easy as possible and it’s got to be something translatable. Your pregnancy research participants might be super motivated, but when you go to a … If it’s going to inform a population public health recommendation around supplementation, it can’t be take eight phosphatidylcholine supplements a day and there’s too much equipoise about whether PC is really the same as a choline salt, so you got to use the form that would be most reasonable.
So Marie’s lab is always just the choline salts, but you can find this is a huge problem of the field where you’re doing meta-analyses with choline supplementation of pregnancy. There’s only a few trials as it is and you have to split between who used PC and who used choline salt.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: The data gets noisy and messy and is different in so many other angles. So if there are funders listening, please fund more studies on choline so we can have recommendations that are solid. Although this might be a foregone issue, we can get into it if you want, but the companies are already coming out based on the couple studies out of Cornell that have shown positive cognitive benefits. I think recruiting women, it’s very much like a same issue for DHA, recruiting people into the study population who want to be in a placebo arm and are okay with it when all their friends are taking the supplemental dose already, you can’t really get a low exposed group. So I think we’re approaching that time and Ritual has a choline supplement, Nature Made has one as well. And so choline’s on the obstetrics beat right now. I think it’d be very hard to recruit in America to have that low choline arm, unfortunately.
Dr. Kristina Harris Jackson: Yeah. Yeah, I totally … There’s so many similarities in the DHA front at this point. Is there a good biomarker for choline or does it move around? Is it too metabolized in too many ways where it’s like …
Dr. Kevin Klatt: Yeah, it’s very metabolized. It’s like you can measure the concentration biomarker of just serum choline levels, but that is a composite of not only what you’re eating and absorbing, but then what is Genova synthesized and then what issues are uptaking? And so what you see across pregnancy is actually choline, even in Marie’s controlled feeding study with the low choline arm, and you see it in ours with the true placebo arm where they’re eating habitual choline intake for even lower than Marie’s lowest arm, the controlled feeding study. Choline is increasing across pregnancy and that’s because the liver is just doing what it can to produce a bunch of it so that the placenta can start it up and concentrate it in the fetal compartment. But it’s the perfect example of just seeing higher levels of a nutrient and blood don’t tell you anything about what’s happening at the tissue level because the choline is increasing across pregnancy in the maternal serum, but that’s because it’s accruing in the fetal compartment and the maternal liver is actually really stressed.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: And you see this in rodent data better where at the end of pregnancy, the hepatic choline levels and the dams or the moms are much depleted at the end of pregnancy on just like the standard child otherwise provides the essential requirement. And so we think that the maternal liver is getting exhausted and that’s part of why supplemental choline is helpful just to replete moms the hepatic stores of it and the amount of choline that’s there to do all the activities that choline should be doing. And that’s what our data supports is that supplement it, which I guess we didn’t get into the results of that.
Dr. Kristina Harris Jackson: We haven’t yet. We can go back. Yeah.
Dr. Kevin Klatt: Yeah. No, you go read the paper, but choline implementation dramatically … I will tell you, I was a doubter. I was doing this study, I wanted the pregnancy stuff, but I did not think there was going to be a huge choline DHA effect.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: I’m always preparing myself for the null and happy if it’s not, but the choline supplementation had a substantial effect on DHA status in a way that was quite shocking. And so we saw in the placebo arm that just got the 200 milligrams standard of care that those individuals started about 6% RBC DHA, which is already high, and I think it speaks to … We’re recruiting women from Ithaca, New York where there’s a lot of interest in nutrition already, and then they went up to about 7% by the end of pregnancy. We’re talking about red blood cell DHA level, so they felt like a one percentage point increase and choline supplementation on top of that same dose of DHA took them from around that 6% baseline to around 8% at the study end.
And so if I double the relative effect, which … I’ve shown that data to a lot of DHA experts besides yourselves. And there’s a lot of four-letter words that come about like, “Wow, that’s huge effect.” And I think it has a lot of … Makes you think a lot about that nutrient-nutrient interaction and how you think about past DHA done in pregnancy where it’s all done in this choline stressed environment that to really [full effects of omega-3s, do you need to add choline, but I think our study is very much internally we look at it as like this is an important nutrient-nutrient interaction through this PEMT access that you can get. We don’t have isotope tracing with DHA to say, “Was it just more getting out? Was it less being oxidized?” But from all the data, we can see that plasma levels of total DHA and PCDHA are up. With our isotope tracing data, we see increased evidence of that activity of the PEMT pathway being fueled. In our placental tissue and our fetal red blood cells, we see that DHA tracked up, so it’s like mom seems to have exported more and the fetus has taken it up, which is good. It would’ve been awful if mom had more plasma and then fetus is down.
Dr. Kristina Harris Jackson: Yeah. Yeah.
Dr. Kevin Klatt: Everything went in the direction we want. And so we think it’s very much … At least one of the mechanisms that choline is increasing DHA status is by increasing the activity that PEMT pathway and that export, which I think implies … Maybe, Bill, you have thoughts on this that some percentage of the supplemental DHA that we’re giving is getting oxidized in the liver because it’s not able to get out and we’d need an isotope tracer to confirm that. But the question is where … If we’re not giving any extra DHA, but choline’s increasing all the status markers, it means in the placebo arm, some of that DHA is getting inefficiently used and probably oxidized instead of exported and incorporated into membranes.
And so I suspect that that fat trapping, to some degree, in the liver from that low PEMT activity is leading to a metabolic rate that we don’t want. What you’d see increased if you get it as an isotope, you’d see that enrichment in the exhaled CO2.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: But that’s another study.
Dr. Bill Harris: That’s another study.
Dr. Kristina Harris Jackson: So I have several thoughts. So one thing, is it possible … So this was really in the second trimester pregnancy.
Dr. Kevin Klatt: No, it’s not going to end third trimester that.
Dr. Kristina Harris Jackson: Second and third. In the first study you did-
Dr. Kevin Klatt: So we got them right after you cleared the fetal demise window. We were worried about something bad happening, and rolled up and then went all the way through to we have placentas collected at the time of parturition or giving birth.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: The previous study was just third trimester only.
Dr. Kristina Harris Jackson: And they didn’t see the effect in the third trimester, so they were like, “We think this is actually happening earlier.” Is that right? Is that part of the design?
Dr. Kevin Klatt: Yeah, there was a choline DHA interaction effect that Marie saw in the previous controlled feeding study in the non-pregnant group. And then in the pregnant group where they went in the third trimester when estrogen is already really high and upregulated, we think of that as probably already a pretty … We intervened late in the choline stress of it all and at a time when PEMT is already pretty high in its activity. So we wanted to go earlier, intervene when you’re metabolically and hormonally more like the non-pregnant state where we saw that effect, and that seemed to be true that we’re going earlier. So it’s not that there’s not benefit. Marie saw benefit from choline supplementation in that third trimester for infant cognition. So choline has independent benefit. We just didn’t observe in pregnancy the nutrient-nutrient interaction, but going sooner, we saw it quite clearly.
Dr. Kristina Harris Jackson: Right. Having a higher or more sufficient choline intake improves your ability to uptake DHA where it needs to be. Is that … And it’s most dramatic in pregnancy. Do you think that could potentially also be happening in a non-pregnant population and affecting whatever we think of as bioavailability? It’s like that next step of, well, if you’re not having any choline, maybe that’s part of that interpersonal variation where some people have great response to supplementation and some people don’t. Is that maybe even another layer?
Dr. Kevin Klatt: Yeah, I would love to look more in the non-pregnant women of reproductive age who’s high estrogen. This gets complicated to look at with controlling for cyclicity and oral contraceptives and all these sorts of things. But Steve Zeisel’s work, where they were doing … They followed up from the data that informed the DRI was really just men. Later on, he did data in women both of reproductive age and also post-menopausal women in efficiency type study designs and non-pregnant women who are placed on a deficient diet see a reduction in the amount of PCs that contain DHA and circulation.
And so we think that this choline DHA interaction is relevant, but we only know from the non-pregnant state that it’s like make the diet super, super, super deficient, you compromise DHA export in a inverse way of what we’re looking at in pregnancy. But asking whether choline insufficiency across a more normal intake range, not in a deficiency diet setting and non-pregnant women might be a determinant of DHA status, I think, is a really valid question. And you could do with everything from just getting dietary reports and associating DHA or choline intake with DHA status potentially in an observational way or in a controlled trial type setting.
But I suspect it would be … It’s this complex interaction of your methyl donor requirements with your methyl donor need, your estrogen status, and PEMT activity, and you add into that. Then the other determinants of DHA status, like your baseline DHA, I think it’d be a pretty ample size to consider here. I think pregnancy is so metabolically stressful and there’s such this massive upregulation in estrogen driving that PEMT gene expression and activity of the enzyme. It’s such a stress state for most people that the choline supplementation effect revealed itself relatively well, though choline DHA link in the non-pregnant state, I think in Steve Zeisel’s work revealed itself because you place them in our extreme choline deficiency.
Dr. Kristina Harris Jackson: Right.
Dr. Kevin Klatt: But I think teasing it out in the general population is going to be a much more subtle effect. And so you need a big sample size. And because there’s not a choline status biomarker yet, it makes it hard to say use that as an objective measure, because with self-reported diet choline, it’s tough because a lot of processed foods use like lecithin as an emulsifier PC. And so that’s not captured in a lot of the food nutrient composition databases all that well. And it’s not captured, obviously, when you give a self-report, even if you have a really strong 24-hour recall with a dietitian led probing. I guess if you do that with an eye towards choline and we’re reviewing nutrition facts labels to see the emulsifier amounts or whether there’s emulsifier use on the product, you get a little bit better, but we think that there’s an underestimation of choline intake in a lot of the American diet because you’re just not capturing well that emulsifier use.
Dr. Kristina Harris Jackson: Okay.
Dr. Kevin Klatt: It’s ironic. It’s like if you don’t eat a lot of processed foods, you’re probably not eating as much choline unless you’re eating a lot of eggs. And so it’s hard to, I think … All self-reported dietary data has its issues, for sure, and it’s good on some nutrients and not so good on others. And with choline, we don’t think it’s particularly amazing, but the validation studies aren’t well done for that.
Dr. Kristina Harris Jackson: Yeah. I mean, I’m thinking of vegans right now because they’ll come and they’ll usually have pretty low levels of DHA and then go on to an algal DHA supplement, but if they’re totally vegan, are they getting … I mean, eggs seem to be the main source of choline, but also seafood and meats are pretty major sources. And so if they’re just getting DHA without choline, is that potentially a stress state for them?
Dr. Kevin Klatt: I think that would be the population you’d want to intervene and then study. There’s a caveat here. So we talked about choline being oxidized to betaine and used as a methyl donor, and that is an important metabolic fate. You eat a lot of dietary betaine. And so choline itself and more plant foods, but betaine is … Or sorry, choline itself has been more animal foods because the animal cell membrane contains phosphatidylcholine, but you eat a lot of betaine particularly in plant foods like dark leafy greens and grains. And so it’s known from animal work. We cannot put a number on this, but it’s known from animal work that betaine can, to some degree, fulfill what we think of as the choline requirement. And so vegetarians and vegans, whether they’re all walking around super choline deficient, they may be partially meeting their requirement through betaine.
Dr. Kristina Harris Jackson: Nice.
Dr. Kevin Klatt: And so the degree to which that all maps out is that we can’t really put a number on it.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: Vegetarians are still eating at least a couple hundred milligrams of choline per day. The deficiency symptoms for choline are so nonspecific. Fatty liver infiltration, slight increases in ALP, AST, and a bit more dramatic muscle CPK damage marker in the deficiency state. But as a clinician, for you to say like, “Oh, you have a choline deficiency based on your biomarkers,” it’s not really there. So, yeah, it’s really tough to say much about dietary choline adequacy and whether specific populations are going to be super high risk or not because there’s not really good national monitoring of this. We’re worried about our self-reported dietary intake measures. That’s why a lot of what we’ve done is we’ve gone in states where we know metabolically there’s a big demand for choline. We basically doubled choline intake, give or take, whatever the normal variation is. So you’ll see the biggest effects there, but whether the NIH is ever going to fund choline feeding studies in these populations, not holding my breath for that one, unfortunately.
Dr. Kristina Harris Jackson: No. I’m also thinking about one of Susan Carlson’s older studies, they did DHA-enriched eggs, was the intervention in their pregnancy population. I can’t remember the name. Was it KUDOS? I don’t remember. But it was like 600 milligrams of DHA, they had a huge effect in those women. And they’re also usually low omega-3 intake. And I just think for pregnancy, eggs are a lot more palatable and a lot less scary than fish for a lot of people, but there’s also just really strong data on seafood intake and cognitive outcomes for kids, and that’s choline and omega-3 and a lot of other great stuff.
Dr. Kristina Harris Jackson: And so the reduction in fish intake due to the potential methylmercury toxicity has just a lot of effects if that was such an amazing nutrient source of all these nutrients that are pretty stressed in pregnancy and pretty needed. So there’s a lot around … I mean, the DHA train is really pushing that right now, I think, to get that reversed, but it just comes along with so many other good knock-on effects, I hope.
Dr. Kevin Klatt: Yeah. Yeah. I think if you’re increasing animal foods, you’re going to get a solid amount of choline coming in or it’s going to be a decent source of choline. I always highlight for folks, though, that in our studies, where we’re clearly seeing cognitive benefits, it’s from a supplemental dose, which is itself a biochemical form of choline, and it’s like whether people are going to be eating four, five, six eggs a day is pretty questionable. So until we … I would love to do a food-based choline intervention study to see, does it supply the biomarkers in the same way that we see, does it influence cognitive outcomes in a similar way? Obviously, you won’t be able to attribute all to choline, but there’s a big need for … I could go out, I have some papers on this I can send you if you guys want to link in the show notes, but our dietary data or our dietary intervention studies in pregnancy are so limited.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: We have a few of these supplemental studies that exist on really important nutrients like folate, and choline, and DHA, but translating that back to food-based recommendations is really tough. There’s only a few controlled feedings that he’s ever done in pregnancy or even food delivery studies, and we think a lot about this is such an important time but also a vulnerable time. And I think there’s a big push, particularly from bioethicists, saying pregnant folks need to benefit from research, not be protected from research, because that in the long run that we don’t have data on them. And so if there are, again, funders listening, please fund. This is such an important physiological state that we really are guessing at a lot of our nutrient requirements and back translating data from supplements into food. And it’s a bit of a mess.
As you pointed out, foods are rich in many nutrients and many bioactive components that the effects may be bigger than we predict based on nutrients alone. So we’re coming off finishing a control feeding study in Tanzania because it was easier to build a metabolic kitchen there and do a control feeding study there than it was to do a control feeding study in America.
Dr. Kristina Harris Jackson: Wow.
Dr. Kevin Klatt: The infrastructure and the funding here is just so awful. And so I’m always on this social media being like, “Please, everybody cares about making America healthy and all this stuff,” I’m like, “Well, you got to fund the research to actually know what is helpful.”
Dr. Kristina Harris Jackson: Yeah. Okay. That’s a perfect transition because I wanted to talk … Sorry, do you want to go ahead?
Dr. Bill Harris: No, no, I think that’s a great point. Very timely point.
Dr. Kristina Harris Jackson: Yes. And also … So you have this deep research knowledge. You also interact with the public. You go on Instagram and you talk to this level, this depth of detail about things, which I just love it. And you also have the AJCN In Press podcast as well. So you are translating, you’re translating research, and you’re also coming up against misinformation. What’s the motivation to do that for you and how is it going?
Dr. Kevin Klatt: I will say a lot of this is just for my own mental sanity where you’re in lab all day running, balancing, I’m going to go to the mouse house and I got to go to sales and I got this question while running and LTMS, I got to go down to this other building to get that, and I was Marie Cawdell’s last PhD student and also PhD student in Mark’s lab. And so I was … Particularly at the end, I was alone a lot of the time. And you can only do so many podcasts and audiobooks that I would just … I always liked tweeting and things like that and doing Instagram and whatnot. But a lot of … It’s just when you’re sitting there alone with your thoughts and you’re reading the science and you’re frustrated about it, I usually was just tweeting out whatever I thought.
So I wouldn’t say my translation of science is all that strategic. I guess I want to be clear, I’m not trying to talk … People always say like, “Oh, you’re talking at too high of a level for the public.” I’m like, “I know, I am just tweeting my populations.” And I think a lot of it … I think of what my role is, is breaking it down for clinicians who are informed and want to learn more that it’s an economy of scale thing. I could try and be the expert for the public or I could try and be somebody who’s breaking things down for every RD nurse, PA, physician out there that knows enough that they want to break through the nuance and make sure they’re giving people accurate information.
Clinicians, as well as journalists, are who I have really geared my messaging more towards to get the right information out there because I’ve realized this a while ago. I could tweet into the void about all this terrible study on Splenda or whatever, and even if you get a thousand people who like your tweet or whatever at that time, I was like, “If I can inform a journalist who writes a New York Times article about it or Washington Post article about it, and that lives for forever and as a top hit in Google, that’s the economy of scale and impact that I’m more one more fit to do and have the energy to do, and I think also has the lasting impact.”
And that’s not to knock on anybody. There are a lot of dieters out there who give great information directly to the public, and I think you need all people walking in all different lanes. But mine, my approach has always been like, how do we get a high impact article that cuts through the meat? Because the way you see after you’ve been in these spaces for 10 years is that the stories repeat over time, the same limitations of the same study designs come up over and over, and as you just say, ad nauseam. And I think a lot about how do we try, and I don’t think I’m doing a good job at it necessarily, but how do we address these things in the long run so that there’s at least accurate information out there for folks to get at.
I think a lot of it, too, is I got into nutrition, I didn’t go to medical school, I didn’t want to write prescriptions so much. A lot of nutrition is about the flexibility of things and the nuance of all the study designs and whether it applies to that person that’s sitting in front of you at that point is what you’re clinically thinking about. And a lot of study designs have no relevance to your patients because it’s a totally different population, totally different dietary background, et cetera. But a lot of what is out there in the media and what people profit off of is this relatively dogmatic, highly prescriptive dietary programs, which is ruining the fun of nutrition clinically in my standpoint.
So over time, I’ve increasingly just focused on, let’s talk about a nuance and poke holes in this because it’s not a prescription. Diet is so complex and has so many reasons even beyond the science, too, why people eat what they eat. But dietary study designs are just a snapshot of a single context and it’s not the same as a statin versus a placebo that, I think, leads to a more deterministic prescription for folks. And so getting people to embrace that nuance, let that take away some of the anxiety about I need to eat perfectly or whatever, whatever people are telling perfect because we’re at a point now where everything from carnivore to vegan is the ideal human diet and everything in between, and it’s just created a mess of misinformation for folks and stress about eating that should otherwise be.
Diet is powerful. But my example for folks, though, is that look at the DASH diet, it’s like 10 things that combined they make of pharmacological effect on blood pressure, but any one thing is not … It’s important that we have public health guidance on sodium and people think eat less sodium, but the sodium effect on that blood pressure lowering is pretty small. The potassium effects is pretty small, the calcium effects is pretty small. The nitrates are pretty small. I think reorienting folks to it is a lot of little things add up to a big thing. And when you sustain that over time, it’s meaningful. But we are in the era where every little thing is apparently make or break.
Dr. Kristina Harris Jackson: Yeah. And that leads to so much stress. I mean, we’re pretty focused on fatty acids, we’re expanding a little beyond omega-3s now in our research, but you study that and then you understand this becomes a part of a diet. You have to get deep. There’s still so much … We think of omega-3s as one of the cleanest, easiest nutrients to study because it has a biomarker, because it has too much data, still tons we don’t know about it. And it enters the field of normal people’s lives and their diet, and how do you not stress them out but also be like, “This is helpful.” This is where pregnancy really to me becomes … I want to talk to clinicians, too, because pregnant women get bombarded with wanting to do everything you possibly can, but also everything becomes heightened and it’s so stressful and you don’t know which way to go.
And so if a doctor can help take some of that stress off and see, can we really ramp up nutrients in an easy way, in a way that we know a little bit, we know something, but there’s still so … We don’t know everything. But this has been my soapbox for a long time, and looking at being more in the omega-3 pregnancy space versus just a general adult wellness, it’s a totally different game in my mind, especially having been pregnant twice and being able to have a doctor see … We are at a point now where we think we have blood levels that will allow a doctor to prescribe a higher or low dose of DHA and that have a meaningful effect on preterm birth rates.
And I want that because the fish story is so stressful to women, a lot of women, not all women, it’s getting better. The doctor doesn’t have time to talk about the ins and outs of fish with the patient because it becomes an argument. So that’s where I want a targeted nutrition, single nutrient like clean story, but it’s also within the context of the entire diet is important. And at the same time, the body’s super flexible. We can handle vegan. We can handle carnivore. I mean, you start to push things and things happen, but that’s why studying nutrition is fascinating and the most frustrating thing in the whole world because there’s just every variable in the world is affecting it.
Dr. Kevin Klatt: Yeah. And we talked about my organs and biological anthropology briefly, but I fall back on that so much of thinking about the adaptability of the human species across so many environments. And I’m not saying adaptability doesn’t always mean optimal, and that’s a lot of what we’re thinking about, is that that added little benefit of doing … The amount of DHA, the amount of saturated through eating, whatever it is, these are all optimizing, but not doing it wouldn’t lead to a catastrophic effect, which I think is what I try to emphasize. I still see patients and a lot of come to me and I’m like, “First, let’s talk about foodborne illness.” They think I’m going to spend all the time talking about, what’s your experience been? I’m like, no, there’s some big high impact things that are really worrisome.
Dr. Kristina Harris Jackson: Yeah.
Dr. Kevin Klatt: And then we’ll get into the two IQ points for your child stuff down the road, but it was really about that triaging and that prioritization of the goals and making sure people are oriented correctly. But, yeah, they’re not worried about the low amounts of methylmercury and the fish and talking about the high impact of the omega-3s and the iodine and all these things, … communicating all that is really, really difficult on the one-on-one level. So I do not envy, I think, a lot of clinicians out there, especially obstetricians and gynecologists who are frontline on this, who want a sound bite to tell people who are in passing because they’ve got 40 other things that they need to talk about in their visit.
Dr. Kristina Harris Jackson: Yeah, that’s exactly … When we’ve talked to clinicians, the biggest issue is time. And like you just said, they are so much more oriented to reducing risk versus the other stuff because they’ve seen the worst that could happen when you don’t do that. And, of course, that’s the main thing that they’re going to spend their time on. So there’s a big disconnect with research and what clinicians have time for and how they communicate with their patients that, I think, is really important to bridge that gap.
Dr. Kevin Klatt: Well, I have two dieticians here. I think we could be nepotistic and say there needs to be expanded insurance coverage for pregnant folks to see a dietician because we’re asking the physicians and PAs and nurses to do something that they’re not fully trained in and don’t have the time for and don’t get reimbursed for.
Dr. Kristina Harris Jackson: Yes.
Dr. Kevin Klatt: And we have a totally unused clinician population of RDs that I have … Patients have to pay basically out of pocket and resubmit insurance trying to get coverage, and I know oftentimes they don’t just to get … It’s crazy to me that just even a one-time visit to talk about what’s the high priority food safety things, what are the nutrient thing, but even later on in pregnancy, I’ve seen patients that are having GI side effects from the iron and just wanting to think about different dietary strategies. And I’m like, “It’s so sad that that is” … We have all these dieticians out there not being effectively utilized and we have all these patients who could be benefiting from that, but our insurance model and coverage model doesn’t really allow for it. So there is a medical restriction therapy act sitting before Congress…
Dr. Kristina Harris Jackson: Oh, really?
Dr. Kevin Klatt: Yes. It was introduced in 2020 right before the pandemic.
Dr. Kristina Harris Jackson: Perfect.
Dr. Kevin Klatt: It still has not seen much action. And so there’s a lot of hype nowadays about improving the nutrition of Americans. And it’s like, well, we, still for the most part, have to wait until you have a disease to get your insurance to cover seeing a dietitian. And if we really care about prevention, you need to massively expand the access to dietitians.
Dr. Kristina Harris Jackson: Yeah. Amen. We can finish there. I love that we just went way deep and also pulled way out and that’s always a conversation with Kevin Klatt lands in that zone, which is great. So thank you so much, Kevin. You’re great. This was a really interesting conversation and we’re excited to see where you go next.
Dr. Kevin Klatt: Thanks for having me on. I can’t wait to put OmegaMatters on my CV.
Dr. Kristina Harris Jackson: That’s right. Thanks. All right.
Dr. Kevin Klatt: Awesome.