Good place to highlight vitamin b12 deficiency ----
This can be a very serious - and underdiagnosed/misdiagnosed - deficiency. And note that normal ranges in North America are lower than many other countries (Japan gives b12 injections at 500 pg/mL- some Canadian provinces start their normal ranges
at 138. One could have issues in the low normal range)
You might have it due to diet - vegetarian/vegan (although brown rice/seaweed/legumes contain b12 ). Easily remedied with b12 supplements.
But some, ie. anyone - including those with a diet full of b12, could have an inability to absorb vitamin b12 properly due to age, genes, stomach issues, type one diabetes etc.
This issue can occur at any age, including babies that show a failure to thrive.
The elderly often have a decreased ability to absorb b12.
Pernicious anemia, one cause for b12 deficiency/absorption issues, used to be deadly up until the 1920s. If found one will need b12 injections, in order to bypass the stomach. And note most b complex vitamins have insufficient amounts of b12 to alleviate any deficiency.
Signs of b12 deficiency include -
*dizziness
*balance issues - unexplained falls
*change in gait
*numbness - pins and needles in extremities (not the normal my foot's asleep)
*cognitive changes/issues including memory, concentration and word finding
*headaches/migraines
*double vision
*sensitivity to light
*fatigue
*loss of muscle strength/muscle recovery - easy find for active people
*mood changes
*tongue glossy/feeling enlarged - possible mouth ulcers
*nerve issues - can include facial pain and feeling a sudden electrical type surge/zap in body
Obviously some of these symptoms are common for other health issues - the exact reason why a vitamin b12 deficiency is often misdiagnosed.
This is a long video but very informative. Besides case studies, it also highlights how a lot of doctors are unfortunately ill-informed on the issue -
And an article about the possible causes of b12 deficiency -
https://pernicious-anaemia-society.org/b12deficiencyandperniciousanaemia/