The Blood Type diet is one of the most controversial diets known. Many people in the medical community believe that the diet has no scientific basis, but many more people say it has improved their health tremendously. Peter D’Adamo author of the Blood Type Diet books believes that following the diet is the key to health.

Blood groups

In his teachings, D’Adamo has 8 different ways to approach diet. The four blood types, A, B, AB, and O secretors, and A, B, AB, O non-secretors.  RH factor is not taken into consideration but could be important. It is unknown if RH makes a difference in the foods we tolerate or resist on a cellular basis. Every blood type has subgroups that set them apart according to sugars and proteins on their cell surfaces. For instance, an A-type person can be A1 or A2 blood type due to enzyme differences. There are 4 blood types but 33 blood groups. The diet can still work for most people, others may find that blood subgroups may also help determine foods that are best for them. (1) (2)

Can we react to the foods we eat according to our blood type?

Scientists have known for decades that certain foods create reactions according to our blood type. In 1945 at the Boston School of Medicine it was discovered that lima beans caused cells to agglutinate or clump together, only in people with A blood type, but not in B’s or O’s. Since that discovery, other foods, as well as bacteria and viruses, were studied and found to react to, or bind to, a certain blood type but not to other types.

 

How does this happen?

On the surface of the cells lining our GI tract are sugars and antigens that are specific according to our blood type. If you are for instance blood type O, you have antigens that protect you that only people with O blood type have. (See illustration below). The sugars (called oligosaccharides) play a role in cell recognition and reaction. An important function of these distinct sugars or carbohydrate chains is their ability to respond to lectins. Lectins are a type of protein in the foods we eat. The reactions between our cells and lectins determine our ability to tolerate, digest, and metabolize certain foods. When we eat foods that are incompatible for our type lectins can bind to our intestinal lining and cause inflammation and damage our ability to digest certain foods. Reactions on cell surfaces can influence our health in many ways. Those same sugars and antigens can also bind bacteria and viruses in some blood types but repel those same organisms in other blood types.

Each blood type has a different set and sequence of sugars on its cells surface making them react differently to foods and pathogens we come in contact with.

Another thing to consider is that certain blood types have more enzymes for digestion than other blood types. For instance, the enzyme alkaline phosphatase helps break down proteins. Some blood types like O have higher levels in their blood, but Type A has lower levels in their blood. This may be a good reason that type 0’s do well eating higher amounts of meat, but type A’s don’t do as well. If you are a non-secretor you most likely have even lower levels of this important enzyme working for you. Newer research has found that low levels cause increased inflammation in your body. This may enhance the negative effects of some of the foods you eat.

Problematic lectins vary by blood type but foods to watch out for are wheat gluten and other grains, beans, corn, soy, especially genetically modified foods. If you are a nonsecretor you are even more sensitive to the effects of these foods.

Where is the proof?

Very few studies have been performed to prove if the diet really works, but when studies were done health conditions, like cardiovascular disease and cholesterol levels, did improve while participants were on the diet. Some questions remain unanswered:

* Since the study used only healthy young people, how can you determine much improvement? It seems that the diet works best for those with health problems. For instance, an O blood type person with skin eruptions from gluten or dairy may see obvious relief where a healthy person with no obvious problems would not see any difference.

* How strict was the diet that they followed? If O blood type people followed the diet for a month, did they eliminate all gluten and dairy? I ask this because I cannot have either gluten or dairy and it takes a lot of effort to completely eliminate those two foods from your diet. You absolutely have to read labels and some ingredients are hidden in other ingredients. Dairy and gluten are in so many things. For those who are very sensitive, even small amounts can make a big difference, especially in foods you eat often.

* Even though all participants in the study were healthy, the study findings still reported improvement in the cardiovascular health of the individuals following the diet. With heart disease being the leading cause of death in the United States, that says a lot.

Read any blog or remark pertaining to the diet and you will see many comments from people reporting that the diet changed their health for the better. Most of the people that saw positive changes suffered from chronic health conditions.

So, can the Blood Type diet work for you?

If the quote “Let food be thy medicine and medicine be thy food” is true, then we should all pay attention to the way our bodies react to the foods we eat. I am a firm believer that food can make a huge difference in our health. We just have to make the right choices. The Blood Type diet is worth a try, if only for a few weeks to see if it works for you.

Click here to visit the Blood Type Diet official site.

References:

(1) Mitra, R, Mishra, N, Rath, G, 2014, Blood groups systems, Indian Journal of Anesthesia, 2014 Sep-Oct; 58(5): 524–528.

(2) Essays, UK. (November 2018). Secretors and Non-secretors Disease Susceptibility. Retrieved from https://www.ukessays.com/essays/biology/disease-susceptibility-among-secretors-and-non-secretors.php?vref