This article originally appeared on Live in the Now.
In the first installment of this series, we discussed some basic concepts and misconceptions about the Blood Type Diet. Now we’re going to explore the scientific foundation that makes each blood type unique, and why each requires specific dietary attention.
Before I was introduced to the science behind the Blood Type Diet, and to naturopathic medicine for that matter, I was a vegan. I ate foods like tofu and tofurkey, believing I was making a health choice that would prevent disease, give me energy and keep me slim. Unfortunately, being vegan was the worst possible dietary decision I could have ever made — because my blood type is O.
What Makes Type O Blood Unique
Making up 44% of the U.S. population, type O blood is the most common blood type found here in America. There are three main characteristics that set those with type O blood apart:
1. Blood cell characteristic: Blood type O has no antigens, which is why it is revered as the universal donor blood type.
2. More stomach acid: People with type O blood tend to have a higher level of hydrochloric acid in their stomachs, making it easier for them to digest specific types of food.
3. Higher levels of IAP: Type Os also possess a higher amount of an enzyme called intestinal alkaline phosphatase, or IAP. In fact, those with type O blood have almost three times the amount of this enzyme than those with any other blood type.
These biological differences, however, also make those with blood type O more prone to certain conditions. For example, if one with type O blood is not eating properly, the increased level of stomach acid (hydrochloric acid) makes a type O individual more prone to stomach ulcers.
Type Os are more susceptible to insulin resistance, sluggish thyroid activity and other metabolic issues. As a result, many with type O blood battle fatigue and depression and can have difficulty losing weight.
The Very First Blood Type
Genetically speaking, blood type O is believed to be the oldest of the blood types and to have served as the platform from which the other three types developed. Understanding this helps to understand the type of foods best tolerated by people with this blood type.
The earliest populations were “hunter-gatherers” and, as such, they did not harvest grains or consume dairy products. They did, however, hunt animals and forest for plants and seeds.
The blood type O individuals of these early populations would not fare well in today’s world of processed foods, harvested grains and dairy products because that is not what their bodies were designed to use as fuel. Because of this, the basic dietary rule for a type O person is to eat protein, protein and more protein — with plenty of type-O-friendly vegetables on the side of course!
And since those with blood type O have a higher level of hydrochloric acid in their stomachs, in addition to three times as much IAP, they can digest meat proteins and lipids significantly easier than those with other blood types.
In fact, the enzyme IAP is responsible for splitting dietary cholesterol structures — a process which ultimately helps the body breakdown and excrete cholesterol. The other important fact to know about IAP is that it is activated when the individual ingests protein. Bottom line here is that type O individuals who eat high-quality (organic and hormone-free, please) animal protein stand to actually lower their cholesterol.
So What Should One With Type O Eat?
The short answer is that one with type O blood should focus on proteins in addition to foods that are alkalizing to the body such as berries and plums.
Remember lectins? Lectins in certain foods can aggravate the sluggish thyroid and reduce overall metabolic function in type Os. But don’t worry, that sluggish metabolism can be kicked into high gear by eating high quality protein and vegetables.
Foods to eat: Type O individuals can enjoy foods such as beef, buffalo, lamb, venison, cod, halibut, herring, mackerel, pike, rainbow trout, red snapper, salmon, sardines, shad, snapper, sole, yellowtail, kale, spinach, broccoli, artichokes, sea kelp, seaweed, okra and sweet potatoes.
Foods to avoid: Some of the “bad lectin” containing foods that are likely to slow your metabolism include wheat, barley, corn, potatoes, cauliflower, lentils, cabbage, navy beans and kidney beans. It is highly recommended that people with type O blood avoid gluten.
Here is an excellent, comprehensive chart from Blood Type Diet expert Dr. Michael Lam.
Exercise and Stress Reduction
These two go hand in hand with type O individuals. Consistent exercise is the number one most important thing for managing stress in type Os, and the word “vigorous” sums up the type of exercise needed. Anything that gets blood pumping and the body sweating is a good place to start. Most Os benefit from running, hiking, weight training and aerobics. Doing any of these activities 3-4 times per week will not only help with stress reduction and weight loss but will also help type Os balance their neurotransmitter levels which is important for warding off depression, anxiety and sleep issues.
Earlier we learned that type Os have a higher amount of stomach acid. While this is great for breaking down proteins, unfortunately this also means they are more susceptible to ulcers, which is another reason to eat foods that are type O friendly and to stick to a vigorous workout schedule to reduce overall stress.
“Blood Types in the U.S” Bloodcenter.stanford.edu. 2008-06-20. Retrieved 2012-12-14.
Shreffler, D.C. American Journal of Human Genetics. 1965 January; 17(1): 71–86.
Genetic Studies of Blood Group-Associated Variations in a Human Serum Alkaline Phosphatase