All about fruitarianism with a long-term fruitarian, Lena

Vitamin B12 bioavailability significantly decreases with increasing intake of this vitamin per meal. Vitamin B12 is partially degraded and loses its biological activity during cooking and storage of foods.

The intrinsic factor-mediated gastrointestinal absorption system in humans has evolved to selectively absorb active vitamin B12 from naturally occurring vitamin B12 compounds, including its degradation products and inactive corrinoids.  This absorption system is estimated to be saturated at about 1.5 - 2.0 mcg of cobalamin (B12) per meal, 50% of dietary vitamin B12 is absorbed by healthy adults with normal gastro-intestinal function.

Some plant foods, dried green and purple lavers (nori) contain substantial amounts of vitamin B12, although other edible algae contained none or only traces of it. Most of the edible blue-green algae (cyanobacteria) used for human supplements predominantly contain pseudovitamin B12, which is inactive in humans.

The bioavailability of vitamin B12 in healthy humans from fish meat, sheep meat, and chicken meat averaged 42%, 56%-89%, and 61%-66%, respectively, in eggs it seems to be poorly absorbed (< 9%).

Linus Pauling

I have something that I call my Golden Rule. It goes something like this: 'Do unto others twenty-five percent better than you expect them to do unto you.' … The twenty-five percent is for error.

Vitamin B3 Niacin

Vitamin B3, Niacin, nicotinic acid, helps to convert food into energy and is essential for healthy skin, blood cells, brain, and nervous system. It is one of 8 B vitamins. It is water-soluble, which means it is not stored in the body. It has 2 other forms, niacinamide (nicotinamide) and inositol hexanicotinate, which have different effects. 

Niacin occurs naturally in food and can also be made by your body from the amino acid tryptophan, with the help of B6

It is rare for anyone in the developed world to have a Vitamin B3 deficiency; alcoholism is the main cause of it in the US.

Recommended daily amount: 14 - 16 mg.

Example sources: whole grains, mushrooms, peanuts and other legumes. 

Fruits (100 g) : 

  1. Peaches or Apricots, dried - Niacin: 4 mg 
  2. Avocados, raw or Dates, medjool  - Niacin: 2 mg 

Seeds (100 g):

  1. Rice bran, crude - Niacin: 34 mg 
  2. Sesame flour - Niacin: 13 mg 
  3. Sunflower seed kernels, dried - Niacin: 8 mg 

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