The results of an earlier study suggested that people belonging to the A, B, or AB blood groups have an increased risk of coronary heart disease.Ī 2019 study in Croatia also found an association between the AB blood type and the risk of psychiatric disorders. A large genetic study from 2019, for example, found that people with type A and AB blood have an increased risk of gastric cancer. Share on Pinterest A person on a O blood type diet can eat most types of vegetables.ĭifferent blood types may make people more or less susceptible to certain conditions.