Blood type brouhaha. (Letters From Our Readers).

I read the letters to the editor [about the vegetarian cover story] posted on the E website. Some of the people have not had good experiences with vegetarian or vegan diets. Without knowing more, some of the problems sound like B12 deficiencies, which can be easily solved in most cases by taking a B12 supplement. Some other nutrients also need attention in vegan diets.

There are some popular books that say people should eat according to their blood type. One book says people with Type O blood should not be vegetarian. The theory is that different humans evolved eating different foods, and that a person's blood type corresponds with the humans from whom he/she descended.

Actually, the ABO blood types existed long before humans evolved, according to Stephen Bailey, Ph.D., a nutritional anthropologist at Tufts University. In fact, blood types do not vary as much between races of people as within the same race. Both the Tufts University Health & Nutrition Letter and the UC Berkeley Wellness Letter have criticized the blood type diet as unscientific. Additionally, there is no published research backing up the theory that some blood types have a worse time as vegetarians.

I did a survey of vegetarians and vegans. Out of 76 people, 39 were Type O, their experiences were mostly positive, and there were no detectable differences in experiences between the various blood types. I'm also a Type O, healthy, athletic, 13-year vegan.

Jack Norris, Registered Dietitian
Director, Vegan Outreach
Davis, CA