All about fruitarianism with a long-term fruitarian, Lena

Those experiencing pernicious anemia (an auto-immune reaction to either the parietal cells or intrinsic factor) go on to develop vitamin B12 deficiency through malabsorption if untreated. Deficiency could develop within 1–3 years in those experiencing malabsorption. 

Patients having surgical alteration of the distal ileum, Crohn’s disease, and using metformin are also at an increased risk for malabsorption.

Herbert (1994) estimates that deficiency could take as long as 20–30 years to develop in persons having normal absorption/reabsorption and suddenly ceasing to include substantial amounts of vitamin B12 in their diet during adulthood. This is due to the large amount of vitamin B12 that can be stored in the body and recycled through enterohepatic reabsorption. 

The prevalence of vitamin B12 deficiency increases with age and is associated with a number of conditions and treatments.

The main causes of vitamin B12 deficiency are

  • poor dietary intake (as in vegetarianism),
  • poor absorption (occurring in achlorhydria, pernicious anemia, Helicobacter pylori (H. pylori) infection, Crohn’s disease, and metformin use),
  • poor distribution (genetic predisposition for aberrant proteins that are inefficient in transport or cellular uptake of vitamin B12).

Charles Darwin

There is no fundamental difference between man and animals in their ability to feel pleasure and pain, happiness, and misery. 


Genetics is the study of genes, genetic variation, and heredity in living organisms. A gene is the basic physical and functional unit of heredity. Genes, which are made up of DNA, act as instructions to make molecules called proteins. 

The Human Genome Project has estimated that humans have 20,000 - 25,000 genes. Every person has two copies of each gene, one inherited from each parent. Most genes are the same in all people, but less than 1% of genes are slightly different between people. Poplar tree genome suggests more than 45,000 genes. Apple