Blood Type Diets (BTD) and Aging: An Overview

Abstract

It has recently been proposed that glycans, being the third alphabet of life, interact intricately with endogenous biomolecules to modulate tolerance, immune and inflammatory responses. Specifically, food glycans could impact health and be a source of inflammation and age-related diseases. These special carbohydrates are present as glycoconjugates (glycoproteins or glycolipids) in and on the surface of all the cells (glycocalyx) of all organisms or are found in free form in biological fluids. Recent advances in glycobiology and glycochemistry have shown how glycans bind with naturally present human proteins (lectins), through protein-carbohydrate interactions (or PCI), but also how oligosaccharides can interact with other glycans, present throughout the human body (through carbohydrate-carbohydrate interactions, or CCI). Oligosaccharides present in food sources, which go beyond the definition of normal fibers, once ingested are then either absorbed in the bloodstream, where they are recognized by the immune system, or interact with the surface of GI epithelial cells, thus generating appropriate biochemical cascades that induce a tolerance or immune/inflammatory response. Because the ABO epitopes have been encountered on all human cells, not just erythrocytes and based on the different biotypology (A, AB, B, and O) impose morphic changes in the distribution of the glycans on the glycocalyx (lipid rafts and clustered saccharide patches), their CCI with food and microbe glycans will be different, thus, eliciting contrasting responses. This can explain the epidemiological data for blood type diets (BTD). Through continuous consumption of the wrong types of glycans, processes of chronic inflammation could be initiated and progress to accelerated aging. Four basic modes of action have been identified showing how glycans can trigger inflamm-aging. Since glycobiology is a young science, further studies with newer technologies are warranted for advancement in this field.