Ask the RD: Probiotic Timing and the Blood Type Diet

This week in our Ask the RD podcast, we’re answering not one but two separate questions! We sincerely appreciate everyone submitting their great questions. Laura and Kelsey will be addressing the following topics in this podcast:

  1. Should I take probiotics on an empty stomach or with a meal?
  2. What do you think about the “eating for your blood type” diet?

Links discussed:


Thanks to Noelle Kahne for volunteering to transcribe this week’s podcast.

LAURA: Hi everyone, welcome to this week’s episode of Ask the RD. I’m Laura; I’m a graduate student at UNC Chapel Hill studying public health and nutrition and I’ll have my RD at the end of 2013.

KELSEY: And I’m Kelsey, a registered dietitian specializing in whole food, ancestral diets, and I’m working on my master’s in nutrition and functional medicine.

LAURA: Thanks for joining us for this week’s Ask the RD podcast. We’re excited to be here and we hope that you’ll enjoy learning about nutrition-related topics. Remember to submit your nutrition-related questions through the online submission form, which we’ve linked to on Chris’s site. We’ll be answering your questions on the show, so feel free to submit as many as you want. As a reminder to everyone this is just general advice and should NOT be used in place of medical advice from a licensed professional. So let’s get started with our podcast. Kelsey, I think the first question that we have is for you.

KELSEY: All right.

LAURA: Should I take probiotics on an empty stomach, or with food?

KELSEY: Excellent question. So first, I just want to talk a little bit about probiotic supplements in general and then move on to the crux of the question because I think a little bit of background information is useful here.

First, it’s really important to think about probiotics in terms of what strains you’re introducing. And when I say strain I don’t just mean Lactobacillus acidophilus, I mean Lactobacillus acidophilus LA-5. That third letter number or name is really important. Just saying Lactobacillus acidophilus is just like saying ‘dog’, but what we’re looking for is the particular breed of dog, which would be equivalent to that strain of bacteria. And, the point being that we’re looking for something more specific. So once you know the actual strain of bacteria, you can look at research on it to see it’s survival in the gut, and it’s specific effects on body systems.

The reason I bring this up is because if you buy a supplement that doesn’t specify that strain of bacteria, you really have no idea what the supplement is going to do because different strains have completely different effects on the body and completely different survival through the gastro-intestinal tract. So I really only recommend supplement companies that are willing to disclose which strains their products contain, because that means that they did the research, saw that those are really good strains to be using, that they’ve survived through the GI tract, and they’re being used for a particular purpose, and put them in a product. So if a supplement company doesn’t disclose that information, to me that means that either they don’t know that strain is important, or they know it’s important and they don’t put the best strain in or most researched strain in order to keep the price down. So they’ll use just a general lactobacillus acidophilus strain that they don’t even know what it is because it’s cheaper than lactobacillus acidophilus LA-5 or some well-researched strain. Either way, you know, whether they don’t know it’s important or they know it’s important and choose not to put it in there, it’s not a company I want to buy from.

So I just want to preface this conversation with that information, because usually the strains they’ll put in a supplement are going to be the ones we know survive well in the GI-tract and actually get where they’re supposed to go, which is important when we’re talking about when to take these supplements. If it’s a good strain and it’s known to be acid-resistant and bile-resistant, then it shouldn’t matter too too much when you take it, but we’ll talk about what can kind of give you an edge when you’re talking about when to take a particular probiotic supplement.

So, another thing to just keep in mind too is some of these companies will use general strains where they don’t tell you the strain and they might try to convince you that their enteric coating will help them to survive through the GI-tract, but it’s usually just because they’ll do something like that which is an expensive process to not only drive up the price but also to go around the fact that they’re not using a well-researched strain that’s known to be able to survive stomach acid and bile very well. So I want you to keep that all in mind as we’re talking about this. And you definitely want to know that the probiotics you’re taking have been studied and been shown to survive the long journey through the GI-tract very well.

So, moving on to whether or not we should take probiotics with food or without – it’s important to think about our ancestors here, because if you think about them, our ancestors would have always had their probiotics with food, because that’s where the probiotics came from. They didn’t have these nice supplement companies to isolate probiotics and put them in a little pill for us to take every day, it’s just not how it works in nature. So I want to point that out first because there’s not a ton of research on this topic, so you’ve got to kind of think about the context behind this and another thing to consider with our ancestors is things like sauerkraut or kim chi they were usually used as condiments, so they were eaten with a meal, usually. It’s not like you would just eat kim chi on it’s own, it was part of a meal. So, think about that context as we start to talk about some of the research behind this as well.

So, what you’ll hear very often, in blogs and you know if you just Googled ‘should I take probiotics on an empty stomach or not’, people will tell you to take probiotics on an empty stomach, which is not something that I necessarily agree with. I think there might be some strains that survive just fine without a meal, but for the most part research has shown that probiotics are better absorbed, either about 30 minutes before a meal, or with meals. So ones that I looked at used a multi-strain product and used an in-vitro model of the digestive system and compared different timings of meals and different meal types to the survival of the probiotics through the GI-tract. And what they found, was that the survival of the probiotics, like I said, was best about 30 minutes before or with the meal. And there were less bacteria that survived if the probiotics were given 30 minutes after the meal. They also compared the probiotic survival to which meal the digestive simulator was given, and the options were apple juice, water, or oatmeal with 1% milk. And what they found was that the survival was significantly better with the oatmeal and the authors actually related that to the fat content, but I think that it’s also important to note that oatmeal has some fiber and resistant starch, which would have helped survival as well. So, I think that’s important to think about when we’re deciding when to take our probiotics.

Like I said, if you have a really well-researched strain that’s been known to survive really well with stomach acid and bile, which are the two main killers of probiotic bacteria, then usually it can survive even if you do take it on an empty stomach, you might get a little bit less than you would if you took it with a meal, but overall it should be OK. What you want to think about here is that also, when you’re eating with a meal, you’re usually getting some kind of prebiotic with your meal, so if you had something with you know a starch, like we said, that study showed the oatmeal was particularly helpful, and of course oatmeal is not part of our usual diet on a Paleo diet but if you had something like a sweet potato or a potato, that would give you some of those prebiotic components with your probiotics to enhance survival.

In a study on rats they tested a few different strains of probiotics and the effect of different prebiotics on their survival and found that the different prebiotics actually helped different strains survive better, so some particular strains of probiotics did better with FOS, which is fructo-oligo-saccharide, some did better with inulin, etc.

LAURA: Are some probiotic supplements, are they packaged with the prebiotics as well?

KELSEY: Right, yes that’s called a symbiotic when they have some prebiotic component in there. So I think that can be a good idea. I don’t know how much more significantly it gives you an edge because with prebiotics usually the biggest difference is shown in the gram levels of taking probiotics. So for example FOS – that has been shown to be the most significant, getting the most significant benefits at about 10grams. So that’s not what you’re going to get in a supplement that’s also packaged with probiotics. You’re not going to get anywhere near there.

But that’s not to say that it won’t help to get those probiotic that are in there to where they’re supposed to go and survive better. So I definitely don’t think it’s a bad idea, for sure. And I would probably suggest that, over something that’s just plain probiotics. But the issue with that is that sometimes a lot of the really good companies that are using really well-researched strains, I find that they don’t tend to package them together because some people are really sensitive to prebiotics, so if you’re FODMAP intolerant you won’t usually do well with FOS, though the amount they would normally put in a symbiotic you might be able to tolerate just fine. So I think they usually will sell them separately, in some cases just because of that. But if you’re someone who’s taking a prebiotic as well as your probiotics, it’s just a good idea to take them together, because it will help the probiotics to survive, certainly. And if you can tolerate prebiotics than definitely, you know, consider a symbiotic product as long as you know that the probiotic strains are well researched. Does that make sense?

LAURA: Yeah, I guess at that point it might just be easier to get the probiotic strain that you know is good and then just add your own prebiotic to the mix.

KELSEY: Right, right. Exactly. So if your probiotic mixture that you have already, as long as it’s telling you the strains, of course, if it has some prebiotic in there – go for it. I think that’s an excellent idea. It might not do a ton to help, but it’s certainly not going to hurt anything. And then the other thing to think about in terms of prebiotics and starch and everything is just to eat something, I would say it’s a good idea if you eat starch on a regular basis, to just take your probiotic when you’re eating something starchy. So if that tends to be breakfast for you, or after working out, I would say that’s a good time to take your probiotic supplement because it will help that survival.

All said, I don’t think it’s the end of the world, if for some reason you can’t take your probiotics near when you eat food. Like I said as long as it’s a type, a strain, of probiotics that’s been shown to be bile- and acid-resistant, you should still get most of that probiotic benefit all the way into the intestine. but, most of us have the ability to eat or take our probiotics when we’re going to eat. I think that if we can do that then it’s beneficial to do so and especially if it’s a starchy meal. again, you should take your probiotics sometime within that half hour before you eat because that’s been shown to have the best survival of probiotics to where we want them to get. and of course, if you’re taking a prebiotic, that’s an excellent time to take it as well because it will help all those nice probiotics to survive. So does that all make sense? I know it’s a little bit, kind of complicated.

LAURA: I think it’s pretty simple in my opinion, whether you take it on an empty stomach or not. I think you’ve explained to our listeners that whoever is telling them to take it on an empty stomach is probably not accurate.

I’m actually not even sure what the idea behind taking it on an empty stomach is, because it almost sounds like the food combination discussion we had, where it’s like ‘oh if you take it on an empty stomach there’s not going to be acid or bile’ and, well that stuff ‘s still going to be there, it just won’t you know, be buffered by any food.

KELSEY: Right and that’s actually exactly the point. You want it be buffered by food, so that the bacteria survive better. You know, if they’re just exposed to plain stomach acid that’s going to do a lot to kill them. So you want it to be buffered by food, which is part of why this makes sense.

LAURA: Yeah and like you said before, just looking at it from an ancestral perspective, people were not eating probiotic like anything on it’s own, they were eating food that had been fermented or you know even if you go back farther it’s probably that they were eating food that had dirt on it or something. But they weren’t just eating the dirt you know,

So there’s really no natural situation where somebody would be taking in a lot of probiotics without there being some kind of food.


LAURA: I just think it’s a little strange that people would recommend it if there’s really no instance where that would be happening in nature.

KELSEY: Yeah, and I tried to find why people say that. And what I found on most sites was that they say to take it with a glass of water because it gets to the intestines more quickly, which maybe that’s true, but the fact that it’s then exposed to plain stomach acid, you know, that’s not helpful either. You want it to be buffered by the food. So a lot of the sites were just like… ‘it helps it to survive better’ which clearly is not the case, so I think the reasoning is a little bit vague, even to the people who are recommending to take them that way, which is definitely problematic. So you should know always, why you’re recommending someone take something a certain way and it sounds like for a lot of people they are either just you know taking the word of someone else and maybe don’t really understand the reasoning behind it, or they think that because it goes through quicker, it’s better, which is not the case because then it’s just, it’s not buffered by food, like we’ve talked about.

LAURA: Right, and  it could also be that people … you know how you’re supposed to take antibiotics on an empty stomach, well some people might say ‘well if you need antibiotics on an empty stomach then maybe probiotics need to be on an empty stomach too’ and they’re such different actions that they can’t be compared. So …

KELSEY: Right. Yeah, so I think what I wanted to mention with this is really just that you should be making sure you’re getting good probiotic strains to begin with, because if it’s not a good probiotic strain, you have no idea whether it’s going to survive well at all because there’s been very little research on it. And the types of strains that good supplement companies will put in their products, they’ve been shown to be able to survive well the stomach acid and the bile. So in that case, it shouldn’t make too much of a difference whether you take it with food or without food, but you probably even then still get a little bit of benefit from taking it with your food.

LAURA: Yeah and unfortunately the ones that are research-supported are typically more expensive. and I’ve had patients before that don’t want to spend the extra money on their probiotics so they’ll end up just getting one of those little Culturelle or whatever, and…

KELSEY: Culturelle actually is a researched strain, I will tell you that.

LAURA: Well, anyway. So, you know, as opposed to the VSL-3 or something like that …

KELSEY: Right.

LAURA: … that has shown benefits for specific conditions, or they just go out and buy Activia yogurt or something and think that that’s going to do the trick, but, I do think that it’s worth spending a little more money on the ones that are more researched and also… I think Culturelle’s what, one type of bacteria?

KELSEY: Yeah I think it’s Lactobacillus Rhamnosus GG if I remember correctly.

LAURA: I wouldn’t know, I’m not a probiotic expert the way you are, but I think that one of the things about probiotics that is helpful is to have a variety of strains. So you know, if you’re only taking the Culturelle, and that’s it, then you’re not going to be getting the different types of strains that have different purposes, so I think that if you’re going to go the route of taking a probiotic, then it’s worth spending maybe a little more money than just getting even like a Brand X at Walmart or something.

KELSEY: Mh, hmm. Yeah, I will say that, in general for healthy people who are just trying to keep up the good bacteria in their gut, yes a broad-spectrum product is probably a good idea that has a few different strains, but the reason some of the products have only one strain is because they’re used for particular things. So Florastor for example, that’s…

LAURA: Saccharomyces boulardii.

KELSEY: … that’s uh, yes and boulardi lyo is the strain. So Saccharomyces boulardii lyo is the full name. And that’s a particular strain that’s been shown to, you know, help get rid of other bad guys in the gut. So it’s used particularly for that. And also for c-diff and other infections like that.

LAURA: So S. boulardii’s actually, I’m sure you know, but for our listeners, it’s a yeast and not a bacteria, so, you know, in that case, that’s completely different than a single-strain bacteria.

KELSEY: Right, so even things like the Culturelle product with the Lactobacillus rhamnosus GG, or Align, which I’m forgetting the actual bacteria in there, but it’s again a one-strain product, they’re used for different, they’re used for different things. So, they’re better for particular conditions than other strains are. So, that’s the reason for sometimes having a single-strain product. They can certainly put it in with other strains, but for whatever reason they tend not to, so you kind of have to take it separately, unless you can find a product with that particular strain, that’s packaged with a few other strains. But, at least for the one in Culturelle, GG, I don’t know if they make a product that has more than just that strain. But I’ll have to look into that. But, that’s the reason why. Sometimes you just want one particular strain for particular purpose. And that’s when it’s useful to use one of those because you’re looking for that particular strain and a lot of other commercial products maybe won’t have it.

LAURA: So, for when you’re recommending probiotics to your patients… Do you normally do the one strain or do you normally do one that’s multi-strain?

KELSEY: It depends. For someone who maybe just has dysbiosis and we’re just trying to fix that I’ll usually do one with a few different strains. But if we’re doing something in particular like trying to deal with a particular condition, I have a whole chart of what strains are useful for what conditions …

LAURA: Oh wow.

KELSEY: … so then, yeah, I’ll use that determine a particular probiotic if I think it will be useful in that particular case.

LAURA: Interesting. I might need you to send me that.

KELSEY: Yeah, it’s a good little chart. I got it from school, actually.

LAURA: Unfortunately this is one of those things we don’t talk about in normal dietetic programs, which is a shame because it’s obviously something that could be very helpful for people. I was always under the impression that the more variety, the better, just because you’re getting, you know, the different strains that would normally be found in a probiotic food, but I’ll need to …

KELSEY: Right, and in general for healthy people that does make more sense. but when you’re trying to deal with a specific condition, just to get extra benefit you want to use particular strains that have been researched to be useful against those conditions.

LAURA: Interesting. Well now I’m glad we talked about it because I actually wasn’t aware of that.

KELSEY: Yeah, it’s an interesting topic.

LAURA: I knew Florastor was effective against c-diff. and you know, I actually have recommended that multiple times in the hospital I worked at, but you know we don’t usually get to even recommend specific types of probiotics, so you know it’s very limited in the hospital environment or even in a typical medical environment that you can actually get that level of detail about what strains you’re using.

KELSEY: And I think that’s part of the issue is because most people just don’t realize that probiotics and their effects are absolutely strain-specific. And that’s just such an important thing to remember when you’re deciding what strains to take because one strain might be totally useless for you, while another one could be really, really beneficial.

LAURA: I was always under the impression that it was just more about amount of CFUs, so colony forming units, and then a greater variety, so…

KELSEY: Right. And the colony forming units, those are important too. There’s a certain number you need to take in order for it to be beneficial. So if you’re taking a low amount, then, yeah, it’s not, even if it’s been shown to be useful for a certain condition, if you’re not taking the required dose, then it’s not going to be useful for you, either. So that is important to consider. And when you’re healthy, that’s why, you know things like yogurt or other fermented foods, there’s tons of different bacteria in there, and that’s useful for healthy people just to continue getting probiotics on a regular basis because as you know, they don’t really colonize for a long time in the gut, they’re very transient, but still very useful. So, in that case for healthy people, yeah, a big amount of bacteria is a good idea, different types of strains.

LAURA: Cool. Well, maybe we’ll have to do a whole show on the different strains of probiotics you recommend for different conditions. I feel like that would be really helpful for some people, including me, who I feel a little silly that I didn’t know that there was information about specific bacterial types for specific conditions.

KELSEY: I think people don’t talk about it enough, honestly. That’s why a lot of people don’t know that, because we just think that ‘OK as long as I’m getting a bunch of bacteria, a bunch of different strains then I should be OK’. Which is correct for most healthy people, but when you’re dealing with sick people with particular conditions that you want to be working with, then yeah that’s when the strains become important.

LAURA: All right, well, I don’t want to run this too long, we’ll definitely have to do a show on bacterial strains as I’m sure there’ll be a lot of interest after this show. But I guess we should move on to the next question so that we have enough time to get through both of them.

KELSEY: Yes, all right. And this is for you, LAURA.

LAURA: Okay.

KELSEY: What do you think about the eating for your blood type diet?

LAURA: Okay, so before I share my opinion on the blood type diet, I’m going to describe what the diet is, since I’m sure some of our listeners may not actually be familiar with the diet. The blood type diet is based on the premise that we all have different ABO blood types that effect what our bodies recognize as self vs otherthrough the presentation of antigens to the to the immune system. So we generally all know our own blood type or at least we should know our own blood type, and our blood type mainly determines the type of blood we can accept from transfusions, based on the antigens present on our blood cells. So there are two types of antigens; A and B. Our bodies produce antibodies against any of the antigens that are not present on our blood cells. So if you have type A blood that means you have type A antigens and anti-B antibodies. If you have type O blood that means you have no antigens and you have both anti-A and anti-B antibodies. But if you have type AB like I do, you have both types of antigens and no antibodies in your blood. So the reason why this is important during blood transfusions is because you can only accept blood types that do not have the antigen for which you have an antibody. So A types can only take type A and type O; AB types can take any of the blood, so A, B, AB, and O; and type O can actually only take O blood.

And the positive and negative refer to the RH protein which effects whether you can take the blood as well. So if you get the wrong type of blood, your immune system attacks the new blood cells and lyses them, which causes rapid destruction of the donor red blood cells and can either lead to acute renal failure or even death in some conditions.

So this is why type AB+ blood is known as the universal acceptor and type O- is the universal donor since AB+ can take any type of blood and O- can be used as blood for anyone.

So you inherit your blood type from your parents. Each parent has two copies of the gene and give one each to you. So in my case, I believe my mom is type A and my dad is type B, so they each gave me one of their A and B genes, and that’s how I ended up being an AB.

So the theory behind this diet is that each blood type can be traced back to a certain type of ancestral background. The guy who came up with this diet is named Dr. Peter d’Adamo. I’m actually not sure how to pronounce his last name, but we’ll go with D’Adamo. And he groups each blood type into a common ancestry with a specific diet recommendation. So the book that he has written is called Eat Right 4 Your Type and the four is a number four, and the claim here is that each ABO blood type processes food differently, and following a diet specific to you’re A, B, or O blood type may improve your health, general well-being, energy levels, and reduce your risk of developing chronic diseases like cancer and cardiovascular disease.

So the book is based on a theory that each blood type contains the genetic message of the diets and behaviors of our ancestors and that these traits still have an impact on us today. And blood type O is described by D’Adamo as a Hunter. He recommends that those of this blood type eat a higher protein diet. Blood type A is called the Agrarian or Cultivator, and is recommended to eat a diet which emphasizes vegetables and is actually free of red meat, which is a diet that’s more closely vegetarian. Blood type B is called the Nomad and Dr. D’Adamo said that this type is associated with a strong immune system and a flexible digestive system and that people of blood type B are the only people that can thrive on dairy products. And he calls blood type AB The Enigma, which is, you know, apparently I’m an enigma so that’s interesting, but this group’s diet is actually a mix between type A and type B.

So now that I’ve described the basics of this diet theory, we can actually talk about the evidence for the diet or the lack thereof. There’s some evidence to suggest that different blood types have different susceptibility to certain diseases like heart attacks, pancreatic cancer, and stroke. But as far as the diet goes, there’s really no concrete evidence that the diet works the way D’Adamo says it does. And there was actually a really good study that came out in May that searched for blood type diet studies that fit a list of criteria for legitimacy, such as only using in-vivo human studies, which means you know actually experimenting with human subjects. And they actually didn’t find one single study that met their criteria and showed an association between ABO blood type diets and health-related outcomes. There’s really only one study that even met all the criteria and it didn’t show any health benefits. Yeah, so I’ll link to this study in the show notes so that people can read it for themselves, but unfortunately it shows that there is really no evidence to support this diet theory.

Now I know lack of evidence isn’t evidence against, but I really think this concept is silly if you think about it. Blood types are distributed amongst the different countries of the world and are not really associated with one type of eating pattern. So to suggest that a person would benefit in any way from eating in a way that has been somewhat arbitrarily assigned to their blood type, it doesn’t really make any sense to me from a scientific standpoint.

KELSEY: Yeah plus if you think about families in general, wouldn’t you all have to be eating different types of diets.

LAURA: Well yeah that’s a really good point because as I mentioned before my mom is a type A and my dad is a type B and I’m type AB. So in Dr. D’Adamo’s perspective we all three should be eating different diets.

KELSEY: Like completely different diets.

LAURA: Yeah. Well at least my parents should be eating completely different diets, and mine, being the enigma and all, I could eat a combination of what my parents eat.

KELSEY: Interesting.

LAURA: As far as like ethnicity goes, my parents’ ethnicity is similar. My whole family’s from like the German or Germany, Austria, Hungry, and Ireland areas of Europe so it’s not like one of my parents is Chinese and one of them is like, you know, English.

KELSEY: Right.

LAURA: You know, they’re very similar in ethnicity and they have different blood types, so I just feel it doesn’t really make sense that we would be eating differently in any normal situation in life.

KELSEY: Right.

LAURA: And this book came out, in I think 1996, so I feel like at this point if it was a valid diet that there should be some amount of research conducted to back it up. Really at the end of the day I feel like personal experience is going to tell you way more about a diet’s appropriateness for you than something like a blood type assignment. And for me, it’s really hard for me to know if any of these blood type diets would be helpful because being an AB, it really doesn’t even give me any explanation as to what I should be eating.

KELSEY: Right, you can kind of eat whatever you want.

LAURA: Right, except for I guess with AB, lacto-vegetarian would be ideal, but I don’t necessarily think that’s right.

KELSEY: I’m B, so which type would that be.

LAURA: The Nomad. So you have a flexible digestive system and you would thrive on dairy products.

KELSEY: Hm, well OK that’s interesting because I don’t do well on dairy products. I can eat some but like fluid milk, or even yogurt gives me issues. So, interesting.

LAURA: So there you go, just based on your experience, it’s not necessarily an accurate description.

It’s ironic because I think type O tends to be a more rare blood type and this one is the one that more closely resembles a Paleo diet. (CORRECTION: Type O is actually the most common blood type world wide, with type A being a close second.) So I don’t know, I just feel like the fact that most people that go Paleo tend to do better than they were doing on say, vegetarian diet; I doubt that these are all people that are type O blood types. Maybe I’m wrong, I don’t know; we could take a poll.

KELSEY: Yeah, we need to do a poll apparently.

LAURA: Yeah, and see like what people’s blood types are.

(This section of the transcript has been deleted due to speaker error. Sorry about that folks! :-) )


LAURA: So anyway I’m open to hearing if anyone has evidence to support this diet. I didn’t find any and this one study that was conducted just in the last six months didn’t find any. So yeah I think that most of the evidence is coming from D’Adamo having clinical evidence or anecdotal evidence that his patients do well. But honestly a lot of this could just be that they’re paying attention to their diet when they might not have been doing so before.

KELSEY: Right. If you’re come from a Standard American Diet and going to vegetarian or lacto-vegetarian, you’re probably going to be doing a lot better than you were before.

LAURA: Yeah, and that’s usually the reason why vegetarianism is associated with things like lower BMI and just healthier outcomes is because people who are vegetarian, compared to the average omnivore, they’re focusing on eating a certain way.

So there’s evidence that just paying attention to your diet for any reason is enough to make you healthier than someone who doesn’t care what they’re eating.

KELSEY: Exactly, that’s a really good point.

LAURA: So, I feel like this blood type thing, I would think, and this is just my theory, but I would think that a big part of it is just that people go from eating whatever they want to eating a way that they think is healthier for them.

KELSEY: There’s something to be said for the placebo effect. If you’re eating a diet that you think is better for you, you’re probably going to feel better than if you’re eating a way that you think is bad.

LAURA: Right.

KELSEY: And usually when people are changing their diet they’re changing other lifestyle factors as well to make themselves healthier. Maybe they’re getting more sleep, they’re exercising more, so there’s a lot of other healthy behaviors that go along with changing your diet to ‘be healthier’ in whatever way you’re choosing.

LAURA: Right, so Kelsey and I would always agree with Chris, in that people need to figure out what diet works for them. And there’s really no better way to do it than self-experimentation. Fortunately Chris’s book which is coming out in December is going to focus very closely on this strategy. So figuring out how to eat in a way which makes you feel the best. Really you need to be doing personal experimentation and not just arbitrarily saying ‘Oh I’m a type B, so that means I should eat a lot of dairy products’. Like you said, you don’t do so well on tons of dairy, so if you were just following this blood type diet you might actually do worse.

KELSEY: Right. I would imagine I would do a lot worse.

LAURA: So that’s my opinion on the blood type diet, I think Kelsey you would agree with me?

KELSEY: Yeah, first of all like you said there’s not a lot of research to back it up. And like you said, doesn’t mean it doesn’t work, but I think there are some other factors that we discussed like just paying attention to what you’re eating and other lifestyle factors – coming from a Standard American Diet you’re certainly going to feel better. So that’s probably where that anecdotal clinical experience is coming from for this doctor that wrote the book.

LAURA: And if you just look at the recommendations… So if you’re type O and they say ‘Oh eat more protein’ well you’re probably going to do better anyway because we know that most people do better on a somewhat higher protein diet, just because, you know, of the way that most people are eating normally. They’re not necessarily eating a good amount of protein, and protein enhances satiety and helps build lean muscle, and all that. So people that switch to the O diet are probably going to do better than they were doing before. And then even looking at blood type A, which is the sort of vegetarian and red meat-avoidance diet, that one is recommending more vegetables. So eating more vegetables is probably going to be an improvement in diet compared to the way a lot of normal people eat. And then, the dairy thing. You know, some people do actually thrive on dairy products so …

KELSEY: Yeah Chris is an example, he always talks about that.

LAURA: Right, so I think some of these diets might just be general improvements over what people are normally eating. You know eating more protein or eating more vegetables or eating good quality dairy products. Like I don’t think anyone would argue that this is not a good way to improve your diet. The fact that it’s blood group based I think is a little hokey.

KELSEY: Right, and maybe just a little arbitrary. It doesn’t really matter as long as you’re paying attention and eating more vegetables or more dairy if that’s great for you, or more protein. You’re probably going to be eating a lot better than you were before.

LAURA: Like I said, if anyone knows of research to support this diet, then please feel free to share it in the comments.

KELSEY: Yeah we’re all ears.

LAURA: But as far as what I could find, and apparently what these researchers could find on any actual evidence to support this diet, there really isn’t any. So, yeah that’s pretty much what I would like to say about the blood type diet. Who knows, maybe in five years we’ll have some really great study that’s actually tested it and shows that it’s got a benefit to it. But as of right now I can’t find any reason to follow it in a way that’s, you know, too strict or anything like that.

KELSEY: Again, personal experience is going to trump any of that, these just blanket diets even if it is somewhat based on different factors like blood type or any other kind of diet that’s for a particular kind of person. Personal experience is always going to be best because it’s based on you.

LAURA: And this even goes for just like strict Paleo. I don’t think a lot of people necessarily feel great doing what they would consider to be “strict” Paleo.

KELSEY: For a long period of time.

LAURA: Right. I don’t know, I really feel like personal experimentation at this point is the only way to know for sure whether a diet is good for you.

KELSEY: Absolutely.

LAURA: Maybe in like twenty years we’ll have some kind of blood test that you can get done that will tell you exactly what you should eat. But, as of right now, we don’t.

KELSEY: Right, got to just experiment.

LAURA: And I know it’s not usually what people want to hear, but unfortunately that’s the way things are. If somebody wants to invent that blood test, they’ll probably be a millionaire, but as of right now we don’t have it. Anyway, that’s all I wanted to talk about with the blood type diet. Did you want to add anything?

KELSEY: No. I think you brought up all the important points there, and at the end of the day, it’s about experimentation.

LAURA: Right. Okay, well that’s all the questions we have for this week everyone. So thanks again for joining us on this episode of Ask the RD. We hope you enjoyed the show and we’d love any feedback you have on how we can make our podcasts even better. And as a reminder you can submit your nutrition- related questions through the link that we’ve provided on Chris’s website. And who knows, we might answer your question on the next show. So have a great week everyone and we’ll see you next time.

KELSEY: All right, take care Laura.

LAURA: You too, Kelsey.


This podcast is not designed to and does not provide medical advice, professional diagnosis, opinion, treatment or services to you or to any other individual. Through this site and linkages to other sites, Laura Schoenfeld and Kelsey Marksteiner provide general information for educational purposes only. The information provided in this podcast, or through linkages to other sites, is not a substitute for medical or professional care, and you should not use the information in place of a visit, call consultation or the advice of your physician or other healthcare provider. Laura and Kelsey are not liable or responsible for any advice, course of treatment, diagnosis or any other information, services or product you obtain through this site.

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Welcome to The Ancestral RDs Podcast!

Laura Schoenfeld and Kelsey Marksteiner, your favorite Ancestral Registered Dietitians, will teach you everything you need to know about ancestral nutrition and lifestyle to optimize your health - without stress or unnecessary restrictions!


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