"Peter D'Adamo has either made a very significant contribution to the study of human dietetics, or he has revolutionized the field of nutritional medicine."

-Jonathan Wright, M.D.

The Significance of Secretor Status

In general being a non-secretor results in several disadvantages with regard to metabolism and immune function. However, understanding your succeptibilities gives you better control over them.


Data suggest the non-secretor type is associated with insulin resistance syndrome or "Syndrome X". The data was especially significant with men, including a tendency to a 'prothrombic' metabolism and higher levels of triglycerides and fasting levels of serum insulin and plasma glucose. While also positive, these same relationships are not as strong for women. This link to a metabolic function associated with carbohydrate intolerance is especially interesting in light of several well-conducted studies linking non-secretor status with alcoholism. Certain immune functions in diabetic non-secretors are also known to be depressed when compared with secretors and findings suggest that an increased proportion of non-secretors are found among patients with diabetes, particularly of the insulin-dependent diabetes type.


The activity of intestinal and serum alkaline phosphatase is strongly correlated with secretor phenotypes. Non-secretors, independent of their ABO blood groups (as your remember type O's have the highest alkaline phosphatase activity and type A's the least), have lower alkaline phosphatase activity. Intestinal alkaline phosphatase is associated with the breakdown of certain types of dietary fat and the ability to assimilate calcium. It has been estimated that the serum alkaline phosphatase activity of non-secretors is only about 20% of the activity in the secretor groups.


Evidence suggests that non-secretors have lower levels of the antibodies IgG and IgA. The lower levels of IgA are especially significant and may help explain why non-secretors tend to have more frequent problems with heart valve disturbance thought to be the result of infection of the bloodstream due to dental work. One of the innate defences against superficial infections by Candida species appears to be the ability of an individual to secrete the water-soluble form of his ABO blood group antigens into body fluids. Since they cannot do this, it is not surprising to find that non-secretors also carry more Candida organisms in their mouth and digestive tract than secretors. Non-secretors appear to have an increase in the prevalence of a variety of autoimmune diseases including ankylosing spondylitis, reactive arthritis, psoriatic arthropathy, Sjogren's syndrome, multiple sclerosis, and Grave's disease. Non-secretors appear to be at extra risk for recurrent urinary tract infections.


Non-secretors are reported to have shorter bleeding times (thicker blood) and a tendency towards higher factor VIII. Data allows the conclusion that non-secretors are at a higher risk for myocardial infarction and even more so among men than women. Of surprising interest is the trend towards a protective effect of alcohol in reducing the risk of heart disease among certain elements of the non-secretor population.


In all blood groups, the average amount of cavities is lower for secretors than for non-secretors. This difference is most significant for smooth surface areas of the teeth. And, secretors of blood group mucin A had the lowest numbers of cavities. A higher intensity of oral disease is found among non-secretors. So it is not surprising that when it comes to precancerous, or cancerous changes to tissue of the mouth and esophagus, non-secretors seem to fair worse than secretors. This oral disease susceptibility is reflected in the occurrence of epithelial dysplasia (pre-malignant changes) which is found almost exclusively in the non-secretor group. Being a non-secretor also offers a slight increase risk for having a problem with habitual snoring.


Duodenal ulcer patients are more likely to be non-secretors, and being a non-secretor acts to multiply the activity of a separate gene for the excessive production of the enzyme pepsin. Thus non-secretors have a harder time turning off many of their digestive enzymes and because of this have a higher risk of duodenal ulcer. If you are a non-secretor, your immune response against H. pylori appears to be lower and H. pylori appears to attach with higher aggressiveness and cause more inflammation. If you are a non-secretor and have a duodenal ulcer the odds are very high (maybe even 100%) that it is associated with an H.pylori infection. In the intestines, non-secretors are at an increased risk for development of coeliac disease Since your secretor status dictates the presence of A, B, and H blood group antigens in the gut the inability of non-secretors to secrete their blood type antigens into the mucus in the intestines impacts how some of the bacteria that are capable of taking up local residence.