Still Think Plant Based is the Healthy Option?
What you need to know about the four stages of vitamin B12 deficiency and the permanent damage it can do
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Vitamin B12 is the largest and most complex of all vitamins, found only in animal-based foods. Plants do not make, use, or contain this vitamin. Even so, many people make the conscious decision to avoid all foods containing natural B12. It is vital that they supplement their diets, and monitor their B12 status, because deficiency can have devastating consequences.
A water-soluble vitamin, B12 is crucial to the brain and nervous system, red blood cell formation and DNA.
Bioavailability - absorption - of B12 can vary, depending on the source. About 50% of B12 from meat and fish is absorbed into the bloodstream. That’s quite good - most of the nutrients you consume pass right through you.
Shortage of this vitamin can take several years to become apparent. That is because the adult body stores around 2–5mg of B12, half of which is in the liver. That is enough B12 to last 3–5 years, although deficiency can arise within just a year if stores are low to start with.
Deficiency occurs in four stages. You will only become aware of any symptoms at stage 4.
The four stages of vitamin B12 deficiency
Stage 1
This is when “serum depletion” becomes evident. Blood tests reveal low levels of the B12 carrier protein TCII. TCII levels drop within just a few days of eating a diet devoid of the vitamin.
Stage 2
As stage one progresses to stage 2, low vitamin B12 can be detected at a cellular level. Like stage 1, there are no discernible symptoms.
Stage 3
At this stage, there is another detectable change in the blood. Levels of an amino acid called homocysteine begin to rise above normal, creating a condition sometimes called ‘hyperhomocysteinemia’. It’s a see-saw act: as B12 levels rise, homocysteine levels fall, and vice versa.
Raised homocysteine (Hcy) in the blood is a clear indication of B12 deficiency.
Stage 4
This is the clinical deficiency stage — signs and symptoms start to appear. Some of these are more serious than others, and some are more obvious than others. If left untreated, stage four will progress to irreversible damage to the central nervous system.
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