There are four main blood types that determine who you can donate blood to and receive blood from. Some people also believe your blood type is important for other aspects of your health. These people think you should eat right for your blood type in order to stay healthy.
Blood Types, Health and Nutrition
Humans have four main blood types: O, A, B and AB. Within these blood types, you also have rhesus positive and negative groups (aka, Rh positive and Rh negative) .
The prevalence of blood type varies by region and country, because this trait is genetically determined. According to the Stanford School of Medicine Blood Center:
- 37.4 percent of Americans have O-positive blood
- 35.7 percent of Americans have A-positive blood
- 8.5 percent of Americans have B-positive blood
- 6.6 percent of Americans have O-negative blood
- 6.3 percent of Americans have A-negative blood
- 3.4 percent of Americans have AB-positive blood
- 1.5 percent of Americans have B-negative blood
- 0.6 percent of Americans have AB-negative blood
Your blood type is extremely important in terms of donating blood or needing a transfusion, as well as tissue and organ transplantation. Not all blood types are compatible with one another, and receiving the wrong type can negatively affect your immune system. If you were to receive the incorrect type of blood, you could become sick and even die.
However, some people believe that blood type plays a role in other aspects of health. In particular, some people believe that you need to eat right for your blood type. The "blood type" diet advocates eating certain foods based on your blood group, which is supposedly reflective of your ancestors' dietary habits.
The Blood Type Diet
The blood type diet is based on the book "Eat Right for Your Type," by Dr. Peter J. D'Adamo, which was originally published in 1996 and was republished in 2016.
- People with AB type blood consuming dairy, tofu, lamb, fish, grains, fruit and vegetables.
- People with B type blood consuming a diet that incorporates meat, fruit, dairy, seafood and grains.
- People with A type blood consuming fruit, vegetables, tofu, seafood, turkey and whole grains. They should otherwise avoid meat products.
- People with O type blood consuming a lot of protein-rich foods, especially large amount of meat and fish. They should avoid grains, beans and legumes but should consume vegetables and fruits.
In addition to these, there are also specific foods you should try to consume if you're trying to lose weight. For example, a blood type B meal plan for weight loss would involve foods like leafy greens, eggs, liver and licorice tea. This meal plan would have you avoid foods like chicken, corn, peanuts and wheat.
These specific diets were each created with the idea that they're the foods your ancestors consumed. People with O type blood were meant to be hunter-gatherers, while those with A type blood were meant to be farmers. People with B type blood were meant to be nomadic and consume dairy, while those with AB type blood were the progeny of people with blood types A and B.
Each diet is meant to go hand in hand with specific types of exercise that are also meant to be complementary to blood type.
Validity of Blood Type Diets
Harvard Health Publishing, the Journal of Nutrition study and a July 2013 study in the American Journal of Clinical Nutrition all state that there is no validity to the idea of a blood-type diet. A January 2014 study in the journal PLOS One found that certain recommendations that were part of the "blood type" diet could be healthy. However, these health benefits were completely unrelated to people's blood types.
There's currently no proven connection between blood type and gastrointestinal health or weight. However, your blood type may be able to influence your gut microbiome and can affect your health in other ways. The Journal of Nutrition states that blood groups have been associated with the risk for diseases and conditions like:
- Venous thrombosis
- Cancer (specifically skin, gastric, pancreatic and ovarian cancers)
Several studies — including a March 2015 study in the Diabetologia Journal, a January 2016 study in the European Review for Medical and Pharmacological Sciences and a May 2016 study in the Integrative Obesity and Diabetes Journal — all found that people with blood type O have the most resistance to Type 2 diabetes, while people with blood type B have the least resistance.
There is a well-established relationship between unhealthy food consumption, weight gain, obesity, inactivity and diabetes. However, this only means that you might want to keep an eye on your diet and your body's ability to process insulin if you have a B blood type. If you're otherwise active and healthy, you likely have nothing to worry about.
Healthy Diets and Good Nutrition
A variety of the principles that are advocated for as part of the "blood-type" diet are healthy. Whether they are for weight loss or just everyday consumption, these diets typically promote the ingestion of plant-based foods and recommend the avoidance of processed and junk foods. These are also recommendations that are in line with the Dietary Guidelines for Americans.
However, the Dietary Guidelines for Americans recommends obtaining all your nutrients from the foods you consume, whereas the "blood-type" diet recommends the consumption of supplements for optimal health. If you're consuming the FDA-recommended amounts of macronutrients (roughly 65 grams of fat, 50 grams of protein and 300 grams of carbohydrates per 2,000 calories in a day), you shouldn't have issues getting all of your recommended vitamins and minerals.
If you do feel like the standard dietary recommendations aren't suited to you and your health, there are other healthy diets you can try. Low-carb diets, high-fat diets, high-protein diets and plant-based diets are all alternatives that have well-established health benefits. Talk with your doctor or dietitian to figure out what dietary plan would work best for you.
- Food and Drug Administration: "Total Carbohydrate"
- Food and Drug Administration: "Protein"
- Food and Drug Administration: "Total Fat"
- Health.gov: "Dietary Guidelines for Americans, 2015-2020"
- Mayo Clinic: "Type 2 Diabetes"
- Integrative Obesity and Diabetes Journal: "Distribution of ABO and Rhesus (Rh) Blood Group Antigens in Male Type 2 Diabetes Mellitus Patients in Hail Region of Saudi Arabia: High Incidence of Diabetes Mellitus in Males With B+ Blood Type"
- European Review for Medical and Pharmacological Sciences: "Association of ABO and Rh Blood Groups With Type 2 Diabetes Mellitus"
- Diabetologia: "ABO and Rhesus Blood Groups and Risk of Type 2 Diabetes: Evidence From the Large E3N Cohort Study"
- PLOS One: "ABO Genotype, ‘Blood-Type’ Diet and Cardiometabolic Risk Factors"
- American Journal of Clinical Nutrition: "Blood Type Diets Lack Supporting Evidence: A Systematic Review"
- Harvard Health Publishing: "Diet Not Working? Maybe It’s Not Your Type"
- Journal of Nutrition: "ABO Genotype Does Not Modify the Association Between the 'Blood-Type' Diet and Biomarkers of Cardiometabolic Disease in Overweight Adults"
- American Red Cross: "Facts About Blood and Blood Types"
- Stanford School of Medicine Blood Center: "Blood Types in the U.S."