Foods That Heal, Foods That Kill—Part 2, Optimal Diet

Part 1: Foods That Heal, Foods That Kill—Blood Types and Lectins

by Heidi Stevenson

30 June 2009

The Roman poet Lucretius said, "One man's meat is another man's poison." It's a basic truth of food and the reason that no diet claiming to serve everyone should be trusted. The previous article discusses two seemingly disparate subjects, lectins and a history of blood types. These are, though, the keys to understanding what sort of diet is best for you, a unique person like no other on earth.

History of Blood Type Development in Humans

The first modern humans, usually called Cro-Magnons, were hunter-gatherers. Their diets consisted primarily of meat from animals they killed—or perhaps stole or scavenged—and vegetable materials they gathered. Grains were a fadingly small portion of what they ate, since they were hard to gather and prepare. They all had the same blood type, O.

As they became more successful and populous, people moved to an agrarian type of life, probably between 25,000 and 15,000 CE, most likely focused around the middle east. It became practical to eat grains, since they could be grown easily and in abundance, and the increasing population meant that people could specialize in different tasks, allowing some to become millers and others bakers. However, the O blood type contains antibodies to the lectins in most grains and to wheat in particular, making it less than healthy.

On balance though, the ability to mass produce food in the form of grains allowed more people to survive, though many must have died young and others would not have made it through childhood. This helped select for a new blood type, A, which wasn't as sensitive to some grains as type O, but it's not the whole story.

Blood type A's receptors are just like those of type O's, except for the addition of a single molecule, making it more difficult for microbes to match and fool the immune system. So, as human population centers became more crowded, those with type A blood were more likely to fight off the disease epidemics brought about by close proximity—yet another reason for the survival of those with type A blood.

Somewhere between 10,000 and 15,000 CE, for reasons less well understood, blood type B arose in the highlands of the Himalayas, where modern-day Pakistan and northern India lie. The people of that area did well and moved across the face of Asia and into Europe. Their culture was focused more on herding and domesticating animals, and their diets were centered on meats and dairy. The B blood type is well suited to such a diet. It is also better suited to screening out unwanted microbes because of another refinement to its antigens, the addition of yet another molecule.

Type AB blood did not exist until about 1,000 years ago. It is literally a combination of types A and B, with red blood cell surfaces containing antigens of both types, thus giving people an improved ability to respond to infections. It also helps protect from allergies and autoimmune diseases, though it does make them more susceptible to cancer. Type AB blood sees anything that's similar to A or B antigens as self, so it is less likely to make antibodies against them. Therefore, cancer cells, which are naturally similar to one's normal cells, are less likely to be recognized as diseased.

It should be understood that for every benefit gained from a blood change mutation, something has been lost. Type AB's ability to resist allergies and autoimmune diseases is balanced against a great risk from cancer. Don't think that people with more recently-developed blood types are more advanced. They simply have somewhat different responses to diseases and diet.

What Do Lectins and Blood Type Mean in Terms of Diet and Nutrition?

Each blood type is sensitive to different lectins, though there are similarities among all of them. For this reason alone, no single diet can possibly be good for everyone. Of course, though of central importance to diet, lectins are not the only factors. However, they do form a basis from which a person can identify a good diet. So, let's focus on how blood type affects one's ideal diet.

• If you're a type O, then a pure vegetarian diet will likely leave you feeling listless. With the blood type that comes directly from paleolithic hunter-gatherers, the focus needs to be on meats in balance with fish, fruit, and veggies. Grains of all kinds should be kept to a minimum, and wheat, corn, and soy should be eliminated. Likewise with most beans, though black beans and black-eyed peas can generally be tolerated well.
• Type A's diet is the result of agriculture, which means a greater focus on vegetables. These are the true vegetarians of the world, the people who should avoid meat and dairy of all kinds. Though not particularly good for them, type A people can tolerate grains and beans better than type O.
• Type B's descend from herders and nomads. If this is your type, then you're a true omnivore, a person who should eat a wide variety of foods, though chicken is not good for you. Have you ever heard of a chicken herder? However, all other meats are fine. You can generally eat beans, though it's important to know how best to cook them—and avoid prepared beans, as they are rarely properly prepared. Though you can tolerate grains, they are not particularly beneficial. Veggies and fruits are, of course, good, but are needed in lower amounts than other types.
• Type AB does well on a mixed diet, but should generally avoid red meat. As a combination of types A and B—of agricultural and nomadic peoples—there's less logic in what should and shouldn't be eaten. Of course, as with other types, wheat is not beneficial, though it's tolerated better than it is in type Os. You maintain type A's ability to eat chicken. In general, beans and grains can be tolerated, though like others, there are negatives in eating them.

These are very general guides. In fact, there are many other considerations in determining a good diet. Although one's blood type may be O, it's possible to have a heritage that includes others. This sort of variation is likely to modify one's ideal diet. Issues like organic versus conventional foods are certainly a factor, as well as genetically modified foods. Speaking of which, that brings us back to the subject of lectins.

The Genetically Modified Foods Connection

Some genetic modification is done by splicing lectins from one plant or animal to another. This is how pest resistance is transferred, by splicing a lectin from a pesticide-resistant species into one that isn't. Naturally, lectins chosen for this purpose are toxic; they're chosen for that characteristic. It's also entirely possible that a lectin you're sensitive to could be transferred to a food plant that's normally healthy for you. Obviously, the risk of eating plants with unknown lectins is significant.

Which Diet?

Obviously, choosing a diet by reading a book isn't likely to be a suitable method for most people. Certainly, a few will have good results for a lifetime—a very few.

The current craze of no-carb diets will help many people lose weight, but ultimately, these diets don't satisfy most people, so they drop out and their weight bounces back—usually worse than before. All these diets stem from observations of the hunter-gatherer diet, whether they're named the Zone Diet, the Atkins Diet, the Paleolithic Diet, or any other. Every single one of them misses or ignores a significant fact: The hunter-gatherer's diet included carbohydrates. They were often, in fact, high in carbs. Plant roots, which were often foraged, as can be seen with modern-day Bushmen, were staples.

Diets based on the genetics of blood type are a good way to start. In fact, such diets start from a basis of what Paleolithic people ate, but take into account genetic changes that happened throughout human history. These, though, tend to miss the fact that we're too individual to determine how to eat based on only four categories.

Nonetheless, blood type diets are a great place to start. Basing your eating on blood type will almost certainly bring about significant benefits, including weight loss. This article gives only the broad outlines of such diets, but there is no better starting point to determine what diet is best for you: an individual like no other in the world.