By Dr Ananya Mandal, MD
What is the blood type diet?
In 1996, naturopathic physician Dr Peter D’Adamo released his work “Eat Right 4 Your Type”. He proposed that the ideal diet for good and optimum health was not universal but is one that fits a person according to his or her blood type.
He claimed that blood type determined how food benefits the chemistry and the immune system of the body.
The fad diets based on blood type caught on with many claiming that they lost weight, felt fitter and healthier after choosing diets tailored to their individual blood type.
It was further endorsed by celebrities who swore by it including Elizabeth Hurley, Courtney Cox-Arquette, Martine McCutcheon etc. the book sold millions of copies over the next decade in nearly 50 languages and was also followed up by related books like – “Allergies: Fight Them With the Blood Type Diet”, “Cook Right 4 Your Type” etc.
What are the different blood types?
There are four different blood groups O, A, B and AB. The differences between them are due to chemical markers called antigens on the surfaces of red blood cells. These antigens recognise specific foreign substances and when they do, they release antibodies to deal with the invaders.
ABO blood type antigens consist of a ‘base’ antigen along with a carbohydrate chain of molecules called fucose.
Type A includes another sugar on the fucose, N-acetylgalactosamine while Type B includes D-galactosamine on the fucose. In type AB, both sugars are present while in type O none are present.
According to D’Adamo, Type O is the most common blood type at present and is the original blood type present in the Africa-based Neanderthal and Cro-Magnon ancestors around 50,000 years ago.
Since our ancestors ate mostly meats along with plants, leaves, nuts, roots, fruit and seeds, a similar diet suits type O persons.
D’Adamo says that type A blood developed in the Middle East around 20,000 years ago when cultivation was developing. Thus these individuals purportedly tolerate various cultivated grains.
Type B developed around 10,000 years earlier in the Himalayas and this type benefits from meats and dairy.
Type AB appeared around 1,000 years ago and has blends of both types A and B.
Controversies regarding the blood type diet
The controversies regarding this diet plan according to blood type are many but the foremost is how exactly did D’Adamo find which food a particular person should consume in quantity, in moderation or completely avoid?
Furthermore studies have shown no real benefits from these diets. There is no evidence that these diets help patients with chronic long term conditions including fibromyalgia.
In fact following these diets blindly could even leave some people deficient in key nutrients especially with such diet restrictions.
Further diet also becomes tedious and monotonous. Eating excess amounts of meat for example in type O could also make them more susceptible to heart disease.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)