Marks Daily Apple
Serving up health and fitness insights (daily, of course) with a side of irreverence.
29 May

Does Your Blood Type Determine Your Optimal Diet?

bloodcellsI get a lot of emails about the “Eat Right For Your Type” diet, also known as the blood type diet, which asserts that specific optimal diets exist for each blood type. In this post, I’ll take a look at whether there’s anything to this idea, and whether you should change the way you’re eating based on whether you’re Type O, A, B or AB.

The proposed diets all tend to be pretty decent, whole foods-based ways of eating, and they’re all better than the standard American diet of industrial processed junk, but differences do exist. Here’s the basic breakdown of all four blood type diets:

Type O (PDF): The “original” blood type and the oldest one, proponents claim it evolved among hunter-gatherers in response to their (Primal) diet of animals and plants. People with this blood type do best on meat, fish, and certain fruits and vegetables while limiting starches and omitting grains (especially wheat), beans, legumes, and dairy. It’s pretty much a strict paleo approach.

Type A (PDF): The agricultural blood type, proponents claim it arose after the advent of agriculture. People with this blood type do best on vegetables, fruits, grains, beans, legumes, and limited fish. They should avoid meat, wheat, and dairy. It’s basically a vegetarian diet.

Type B (PDF): The “nomad” type, proponents claim it arose amongst pastoralists raising animals for meat and milk. People with this blood type do best with lamb, mutton, rabbit, and most other meats (except for chicken and pork), dairy, beans, and vegetables. They should avoid wheat, olives, tomatoes, and corn.

Type AB (PDF): The “generalist” blood type. People with this blood type can eat many meats, some seafood, dairy, beans, grains, and fruit, but they should limit kidney beans, lima beans, seeds, corn, beef, chicken, and buckwheat.

I see a few things wrong with their reasoning:

First, they’ve got the anthropology all mixed up. Type O blood isn’t the oldest blood type, nor was it formed by human dietary patterns. The most recent research has found that Types A, B, and O arose almost 20 million years ago in a far-off ancestor common to humans and other primates – long before humans hunted, gathered, farmed, domesticated animals, or even existed. In fact, if anything, it’s type A blood that’s the oldest.

Second, if type A blood arose in response to agriculture, why would the Australian aboriginal diet of meat, marrow, and foraged plant foods, or the Sami diet of reindeer blood, meat, and milk and fatty fish both give rise to a preponderance of type A blood carriers? Type A is supposed to be founded on agriculture – grains, beans, with very little animal products. If a high-animal foods diet selects against type A blood, why does it flourish in these populations?

Third, the justification given for eliminating certain foods from these diets is that the lectins found in them trigger agglutination (clumping) of the red blood cells when consumed by someone with the wrong blood type. So, lectins found in olives are supposed to cause agglutination in Type As, lectins found in grains are supposed to cause agglutination in Type Os, and so on. Proponents claim that specific lectins are selective in their tendency to agglutinate – they interact differently with the various blood types. This supposed selective agglutination is the proximate arbiter of whether a food belongs in a particular blood type’s ideal diet or not, but it doesn’t even exist. The actual research suggests that lectin agglutination is non-selective with regard to blood type. If a particular lectin agglutinates, it generally agglutinates across all blood types. If a lectin is harmful to one blood type, it’s harmful to all.

That said, the blood type diet folks do highlight an interesting observation: the individual blood types are often associated with different rates of certain diseases.

Type Os have a curious relationship to certain infectious diseases. While those with type O blood are more resistant to contracting cholera infections, if they actually get infected, they’re more likely to have an extremely severe reaction. It protects you until you get cholera, after which it leaves you extremely vulnerable. The extreme virulence of cholera to this blood type may even explain the relative paucity of type Os in areas where cholera is common.

Type Os also are far more susceptible to ulcer, now known to be caused by infections from H. pylori bacteria. This is likely explained by the greater preponderance of “H. pylori receptors” in the guts of type O individuals.

Against other diseases, however, type O seems to be somewhat protective:

When compared to other blood types, type O is associated with lower rates of heart disease. The studies (comprising roughly 90,000 people) determined that 6.27% of the cardiovascular disease cases could be attributed to having a non-type O blood type.

Upon reviewing twelve separate studies, researchers determined that type O blood confers protection against pancreatic cancer. Type B was most strongly associated with pancreatic cancer, followed by types AB and A, respectively. Despite the results, “the mechanism by which these SNPs influence risk is unknown.” It could be that “these SNPs may act as markers of allelic variants in nearby genes, and the ABO antigens may not be directly involved in” the development of pancreatic cancer at all. Then, once a person has pancreatic cancer, type O confers a significant survival benefit over the other blood types. This may be explained by the observation in animal studies that the immune systems of types A and B seem to have a harder time at “noticing” and “destroying” cancer cells.

Type Os are also less likely to get gastric cancer, despite their increased susceptibility to H. pylori infections (usually a risk factor for gastric cancer).

These connections are worth looking into and deserve further study, certainly, but they have nothing to say about what diets work best with each blood type.

Obviously, I agree that certain kinds of dietary lectins are problematic, especially if they make it past the gut and into the blood stream. They’re a big reason why I avoid most grains, beans, and legumes – not only do they contain large numbers of lectins, but the lectins they have tend to be particularly proficient at disrupting and navigating the gut barrier. And yes, some people seem more sensitive to dietary lectins than others, but I see no evidence that a person’s lectin sensitivity – and thus ideal dietary composition – is determined by their blood type. It’s an attractive idea, the notion that we can determine someone’s optimal diet and offer them perfect health and protection from disease simply by checking their blood type. It’s just not a realistic one, according to the available evidence.

In the end – and this might be the most important part of this whole thing – the blood type diet “works” because it eliminates processed food regardless of blood type, removes wheat from the diets of people with blood types A, B, and O (which takes care of the vast majority of the population of the world), and recommends that most people (type O is the most common blood type) eat a diet based on meat and plants with little to no grains, beans, sugar,and legumes. I’m honestly not all surprised that so many people get great results.

What about you? Have you tried the blood type diet? Do you know anyone who’s tried it and had success – or failure? If so, what type were they?

Thanks for reading, folks!

You want comments? We got comments:

Imagine you’re George Clooney. Take a moment to admire your grooming and wit. Okay, now imagine someone walks up to you and asks, “What’s your name?” You say, “I’m George Clooney.” Or maybe you say, “I’m the Clooninator!” You don’t say “I’m George of George Clooney Sells Movies Blog” and you certainly don’t say, “I’m Clooney Weight Loss Plan”. So while spam is technically meat, it ain’t anywhere near Primal. Please nickname yourself something your friends would call you.

  1. I feel better on the type A diet.
    Chalk it up to whatever you like.
    I’m happy with it though.

    Matthew wrote on November 19th, 2013
  2. Friend of mine has been on this diet for 15 years. He suggested I look into it and I found my way here. Personally I was very skeptical when I heard about and my research has bore out to my satisfaction my doubt.
    As for my friend,he said it turned out he was sensitive to wheat. He stopped eating wheat and followed the diet and got better. Not really the blood type diet that made him well, but it did help him find out what making him sick and get him well.

    James Quarello wrote on November 22nd, 2013
  3. Aaarrggh! No meats and proteins for Type A??

    Stefan wrote on November 25th, 2013
    • Actually his more recent work (Genotype Diet) has As eating alot of fish, turkey.

      mims wrote on December 10th, 2013
    • That’s not true. A’s can have small amounts of chicken and turkey along with plenty of fish options. Tofu (soy) is super beneficial for most A’s.

      Tom Martens wrote on December 12th, 2013
  4. I completely swear by the blood type diet. I have severe IBS and its the only things, including pills and medication, that relieves my symptoms!

    Kari wrote on November 25th, 2013
  5. Bloodtypes, Bodytypes, and You by Joseph Christiano is another great book on this subject. I had never heard of Dr.D’Adamo. I got it all from Joseph Christiano.

    Richard wrote on December 10th, 2013
  6. I am surprised no one seems to be talking about the rh factor of the blood and how that effects the body’s reaction to different nutrients. All blood cells are not the same so I am not sure how so many people arrived at the conclusion that blood type has no/very little effect of how the body absorbes nutrients. Certain foods are treated almost like an allergic reaction by certain blood types and rh factors. It seems most people here recognize that they have to “listen to their body” to see what works week with them in fine tuning a paleo diet. Really all they are doing is observing their body’s reaction to certain foods – what make’s their body react differently to certain foods – blood type and rh factor. That is my thought on all this.

    Richard wrote on December 10th, 2013
    • The rh factor isn’t nearly as important as Secretor Status. For the 20% of us that are non secretors it pre-disposes us to more cardio vascular issues, diabetes, dental, auto-immune problems, blood viscosity and stomach acid levels. It also changes the foods we can eat.

      Tom Martens wrote on December 12th, 2013
  7. PubMed agrees with Dr. D’Adamo and his take on Blood Type history.

    Quoted Text:

    Analysis of a Larger SNP Dataset from the HapMap Project Confirmed That the Modern Human A Allele of the ABO Blood Group Genes Is a Descendant of a Recombinant between B and O Alleles.

    From:

    http://www.ncbi.nlm.nih.gov/pubmed/24288652

    Quoted Text:
    The result indicated that the A allele, possibly once extinct in the human lineage a long time ago, was resurrected by a recombination between B and O alleles less than 300,000 years ago.

    From:

    http://www.ncbi.nlm.nih.gov/pubmed/22319172

    Tom Martens wrote on December 12th, 2013
  8. I am an AB+ and really wanted to believe this book, but after gaining weight, feeling awful, and having gut issues, all while eating my perfect blood type diet, I had to look at the facts!!! THIS DOES NOT WORK!!! Grains made me sick, the bread he suggests, make me sick and fat and miserable feeling…I went full tilt Paleo when out of desperation I started on the HCG diet, and shots. People it worked because it is Paleo! I did not adhere to the starvation 500 calorie diet they propose, I just cut out all carbs, ate Paleo, and lost 60 lbs. got rid of all my gut issues, and had an “AH HA!” moment. DING DING!!!! I am now feeling great, maintaining my perfect body weight, my skin is no longer dry, inflammation is gone, gut issues evaporated, and have so much more energy.

    If this blood type stuff works, it is because he does propose a pretty good diet of lots of veggies, meats, fruits, and exercise. Just like HCG, it works because it cuts out the carbs. Across the board, diets that work, all pretty much propose the same things, just written a bit different.

    Donna wrote on December 26th, 2013
  9. I just really enjoyed this and I hope to stumble on many more topics like this. Many thanks for your online contribution.

    Stanley Berg wrote on January 12th, 2014
  10. I am from Scandinavia, blood type A+, and eating according to my blood type is the best thing ever, naturally get slimmer and feel GREAT!
    I started to eat the right way by intuition before I read the book, so that adds trust on the whole thing. Love it.

    Anne wrote on January 16th, 2014
  11. In the mid 90’s I was diagnosed with celiac disease and also found to be casein intolerant. Soon after being diagnosed I read “Neanderthin” by Ray Audette and Peter D’Adamo’s first book “Eat Right for your Type”. I am a blood type A-. I basically combined the two diets, eating a paleo diet that consisted of turkey, chicken, eggs,and ghee, and blood compatible fruits and veggies. It made sense to me as I have disliked red meat immensely as a child, it just felt “right”. I felt great, life was good! About 6 years ago I decided to widen my diet based on my readings on the paleo/primal movement. I started to decrease my poultry (because it is difficult to get it truly pastured, they are fed grain and soy) and started to eat grass-fed beef, bacon, coconut oil, bone broth, etc. Last year I incorporated Kruse’s epi-paleo diet and started to incorporate a lot of shell fish, fish, and offal. Theoretically speaking, paleo and epi-paleo are brilliant. I wanted these diets to work for me! But they didn’t…to be honest, I never felt worse! Bloated, tired, weight gain. I went back to my type A/paleo diet and never felt better. Last year I read D’Adamo’s new book on the genotype diet. I decided to spend some money and go to his clinic in Wilton CT. and be evaluated. It was a fascinating experience. I learned that I am an Explorer Genotype…I had a “swami” done for my genotype and blood type together, and I’ll be damned but every “avoid” food on my list has always given me problems, such as beef, pork, dairy, coconut, olives…the list is pretty long. I can tolerate poultry and lamb (which is the ONLY red meat I ever liked as a child) and some mild white fish. Unfortunately shell fish and crustaceans are also avoids for me (I so dislike anyway!) but I know they are packed with nutrients. No bacon, no coconut…but yes to ghee and lots of veggies and some fruits. The personality profile of my genotype fits me to a “T”, as well as my exercise tolerances (no cross-fit for me…I have only done hiking/yoga/pilate anyway my whole life), and health and lifestyle preferences as well. His writings on the genotypes are extremely interesting. So, I’m back to my Type A paleo lifestyle and feel so much better. I also started the Leptin Reset again using poultry and find it so much easier this time around using blood type friendly proteins…

    christine wrote on January 26th, 2014
  12. and just an addendum to the above, other “super foods” for me are cod, sardines, snails, squab, and ostrich meat all which I really love and have an affinity for, much more than beef or pork…there are about 10 other fish that are considered super foods for me but I haven’t tried them yet! I think that the people that just brush off the blood type diet as nonsense are behaving similar to the people who used to same the same thing about the paleo/primal diet! I think Peter D’Adamo is actually quite brilliant…I use some of his supplements also for my blood and genotype and they are probably the first supplements that I’ve ever used where I actually felt an effect. God, when I think of all of those years that I tried to down the Green Pasture fermented Cod Liver oil (a big “avoid” for me)…ugh, what a waste of time and money.
    It’s sort of a no-brainer for me now in terms of herbs and supplements etc…

    christine wrote on January 26th, 2014
  13. Say Mark Sisson, what’s your blood type? Sounds like you’re an O to me. ;)

    priest wrote on February 7th, 2014
  14. I’ve been following the blood type diet for quite a while now and I have had huge success. Apart from the obvious weight loss, I am healthier than ever before. Even my allergies are gone. It’s just amazing how your body can react if you eat the right foods. I don’t follow any specific “plan”, I just make sure that I only eat from foods that are neutral and beneficial for my blood type. You can avoid so many health issues that people deem “normal with age” so I cannot imagine why people won’t want to benefit from this :)

    Lorien wrote on February 15th, 2014
  15. About five years ago I was diagnosed with gastritis(which means I am painfully gassy in part) and meniers disease (a buildup of fluid in the inner ear)which causes vertigo, and along with vertigo, which lasted 3-5 days during my attacks, I also couldn’t eat anything from the constant vomiting. These two combined really messed up my world. Once I was diagnosed I was told to go on a low sodium diet and to cut out chocolate, caffiene, and meats as much as I could. I admit I am a chocolate freak, and I really love my coffee, SOOOOO i still partake from time to time, BUT meat…the big one. I love my filet, but it doesn’t love me. I cut out salt initially with a vengence and my vertigo came less and less. It wasn’t as hard as I thought it would be but let me tell you EVERYTHING has salt in it, even my drinks, processed of course. Once I got control on the sodium in everything…I noticed that I didn’t want to eat red meat. My stomach would cramp any time that I ate even a little bit, so I slowly began cutting it out and eating fish, chicken, turkey, and beans as a substitute. Now I have completely removed red meat and I don’t remember the last time my gut hurt. I began eating for my blood type about two years ago, A- agrarian, and I feel SOOOO much better. I don’t follow the diet as law, but I try to stick to it as much as I can and want. If I want chocolate I eat it, but not a whole bar, just a bite or two and I am good, it feels good to have control over my food issues.
    I began this journey of excercise and eating right about 12 years ago at 190 lbs. I am a 5’3″ woman with a medium frame and that was TOOOOOOO much. I am now at a comfortable 127 lbs and plan to stay there, following these restrictions may not be exactly suitable for everyone, BUT someone posted a question, why keep eating things that don’t make you happy? My response is I eat things that make me happy and keep my body happy too. I may love to eat a nice rare filet and mashed taters with gravy and a fat ear of corn, but really a piece of cod and a salad makes my day much more productive and feel good for me. SO don’t fuel your hybrid with diesel…

    paula cher maestas wrote on March 15th, 2014
  16. Thanks james.you read and practice more

    punom wrote on April 22nd, 2014
  17. I tried the blood type diet long before I switched to paleo — I did this as an experiment while at an artists’ retreat in a rural, very cold area where I knew I wouldn’t be doing my own cooking or exercising that much, but where the food served was ‘clean’ and where ingredients at the cafeteria meals were clearly marked for those with food allergies, and where there was a salad bar at lunch and dinner daily with oil/vinegar dressing as an option. I more or less ate a modified paleo diet — I’m a blood type O and have tested with my doctor for wheat/dairy/soy sensitivity, so that puts me on the paleo path anyway, the only real change being an edit of my gluten-free carb choices.

    So, long story short, I was at a cold windy writing retreat for 3 weeks and lost 2 lbs — without exercising, and the occasional wine — by following recommendations for Type O. I attribute the success not to the blood type diet recommendations but to this diet’s similarity to paleo. I more or less ate paleo with some non-paleo gluten-free choices (zing bars for breakfast on days I couldn’t have eggs, occasional Lara bars, rice with curry dishes or steamed chicken/broccoli from local chinese place on days I couldn’t have the cafeteria offerings), occasional peanut butter, and sometimes had some paleo choices that could’ve been better replaced with other options (sometimes for snacks I had pumpkin seeds and a few prunes).

    I think this diet, as the article outlines, helped more b/c it advocates clean food for the various blood types. The varying lists of fruits and veggies and meat choices felt a bit random, but you do get all the food groups. Paleo is simpler and more logical to pick up (and to follow, even among non-paleo folks), in my view.

    Jane wrote on May 18th, 2014
  18. I’m O negative and followed the O blood type off and on for a few years. The biggest thing it highlighted for me was how awful gluten is on my system. But I always did pretty well with some of the softer, non-aged cheeses, and terribly with the few hard ones mentioned as neutrals on the original diet.

    Then the Genotype diet came out. My choices were between the Hunter diet (a classic blood type O diet that heals a sensitive gut) or Explorer (usually Rh negative folks who tend to be sensitive to chemicals and drugs and who tolerate a big more grains and beans and dairy than the classic Hunter/O diet). Given my history of chemical sensitivity and bad reactions to drugs, I started playing around with both lists. I found that when I eat the beneficials and totally avoid the avoids on the Explorer list, I feel amazing.

    Two years ago, I tried a paleo diet. I felt amazing for a few weeks then started getting migraines. I couldn’t figure it out because I was eating more greens and veggies than I ever had in my life. About three months in to hard core paleo, I threw in the towel due to migraines every other day, and back pain and fibro so bad I was crying every other night. Went back to my Explorer diet, and was so much better a week later. I tried paleo again a few months ago, after seeing Chris Kresser talk at a book signing. Asked him why I was getting migraines on paleo. He said it could be histamine or salicylates and to give paleo another go. I tried eliminating the foods that would be causing those symptoms. It didn’t matter. Same deal. The migraines were crippling. Once I was eating brown rice and beans again, on a regular basis, they were gone.

    In hindsight, I know now that I have an MTHFR mutation (which tends to cause chemical sensitivity), but the Explorer diet takes that into account and emphasizes high folate and magnesium rich foods (critical if you have an MTHFR gene). I also know the Explorer diet tends to be lower in histamine and salicylate (but if a food is incredibly beneficial, even if it contains more than other foods, it’s included).

    Dr. D’Adamo’s philosophy is that if you take everything away that makes you sick, you won’t get sicker. But if you add things in that are crucial to your health, you’ll thrive. Such was the case for me with rice and beans. I still love the principles of paleo, but I get too sick on the diet to stick with it. Big huge fan of Dr. D’Adamo!

    misspudding wrote on June 12th, 2014
  19. I began my foray into dietary elimination after reading D’Adamo’s “Eat Right 4 Your Type.” Coming from a background that was solidly entrenched in western medicine, the FDA diet, etc, etc, it wasn’t entirely believable to me. What kept me researching was the word “lectin.” I had some biochem background, but I’d never heard of them, so I kept researching. To this day, I still do, everyday – because there is so much information in the field of lectinology that one person cannot ever retain all of it.

    In this respect, the concept of a blood type diet can change lives: the book – or just the idea that it presents – is an arrow. Some people just take it or leave it. Others start with the statement that is presented and turn that into a list of questions that must be answered, but will (more than likely) lead to more questions. The sum of the acquisition of knowledge is the exponential increase of knowledge. Questions asked now are answers that were too complex for me to ask before my current knowledge base.

    Eberhardt Kalmar Huhn wrote on July 17th, 2014
  20. I believe that even the best diet systems are never 100%. Some closer than other. I am blood type A and have tried the paleo diet for a few years but have not felt great on it at all. Even though I thing Dr. Dadamo’s historical reasoning should be left out, actually takes away from things, I think on the basis of science, results, and my own experience I love it. It does work for me! No system works perfectly but if it works for you than you need to go with it. I am glad for those who truelly benefit from the primal diet but I can’t do it – have had a lot of physical problems from it. I will definitely myself opt for the bloo type diet.

    Ray wrote on October 30th, 2014

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