Some studies suggest people with Type O may have:

• Lower risk of blood clots

• Lower risk of certain cardiovascular conditions

But they may also have:

• Higher risk of bleeding disorders

• Slightly increased susceptibility to certain stomach ulcers caused by Helicobacter pylori

These are population-level observations, not guarantees for individuals.

Blood Type A

Research has suggested possible associations between Type A and:

• Slightly higher risk of stomach cancer

• Higher risk of certain cardiovascular diseases

Again, many other factors—such as smoking, diet, exercise, and genetics—play a much larger role.

Blood Type B

Some studies have explored links between Type B and:

• Certain metabolic conditions

• Infectious diseases

The findings are mixed and often inconsistent.

Blood Type AB

Type AB is the least common ABO blood group.

Some research has suggested possible associations with:

• Cardiovascular disease

• Blood clotting

• Cognitive decline later in life

These findings require further study and should not be interpreted as predictions for any individual.

Your Genes Matter More Than Your Blood Type

Nutrition science has become much more sophisticated over the past two decades.

Researchers now recognize that many factors influence how people respond to food.

These include:

• Genetics

• Gut microbiome

• Age

• Physical activity

• Sleep

• Stress

• Medical conditions

• Medications

Blood type represents only a tiny fraction of your genetic makeup.

It is unlikely to determine your nutritional needs by itself.

What About the Gut Microbiome?

Your digestive tract contains trillions of microorganisms collectively known as the gut microbiome.

Research suggests the microbiome may influence:

• Digestion

• Immune function

• Metabolism

• Responses to certain foods

Interestingly, some studies suggest blood type may have a small influence on gut bacteria.

However, this research is still developing and does not currently support blood type-specific diets.

Can Blood Type Affect Digestion?

There is no strong evidence that people with different blood types digest protein, carbohydrates, or fats in fundamentally different ways.

Digestive enzymes are influenced by many factors, but blood type is not considered a major determinant.

The Role of Lectins

One key idea behind blood type diets involves substances called lectins.

Lectins are proteins naturally found in many foods, including:

• Beans

• Whole grains

• Tomatoes

• Potatoes

• Peanuts

The blood type diet proposes that lectins interact differently with different blood types.

However, current scientific evidence has not supported this theory in everyday eating.

Most lectins are significantly reduced through normal cooking.

Foods containing lectins—such as beans and whole grains—are consistently associated with positive health outcomes in many populations.

Healthy Eating Patterns Supported by Research

Rather than focusing on blood type, experts generally recommend dietary patterns supported by decades of research.

These include:

Mediterranean Diet

Emphasizes:

• Vegetables

• Fruits

• Whole grains

• Beans

• Olive oil

• Fish

• Nuts

Associated with improved heart health and lower risk of several chronic diseases.

DASH Diet

Originally developed to help manage blood pressure.

Focuses on:

• Fruits

• Vegetables

• Low-fat dairy

• Whole grains

• Lean proteins

• Limited sodium

Plant-Forward Eating

Does not necessarily eliminate meat but encourages:

• More legumes

• More vegetables

• More whole grains

• More nuts and seeds

Research consistently supports these eating patterns across many populations.

Individual Differences Matter