Some current facts. In the United States (US) and United Kingdom (UK) approximately 6% of population above 60 years old increasing with age are deficient <148 pmol/L blood levels and 20% are marginal status blood levels 148-221pmol/L.1 In other areas of world like India for all age groups it is much worse where 70-80% are deficient. 2,3 I and others believe these accepted “normal” blood levels are too low and should be higher, thus more people in US and UK thus using higher levels more are affected.4 We measure Vitamin B12 via serum or plasma vitamin B12 levels.

Then others believe values below approximately 17-250pg/ml (120-180picomol/l) for adults show a vitamin B12 deficiency. But these levels and even that we measure them may not be important and the reason measuring its blood or serum levels may not be accurate as evidence suggests that serum vitamin B12 concentrations might not reflect intracellular concentrations. 5 Intracellular levels are key as that is where most of the important use of it occurs.

I am not saying not to trust your doctor, but most have probably forgotten this as many don’t think of vitamins as important. Their thinking being it’s only a vitamin after all. Yea one that its deficiency can make you ill.  This gives you a general idea that it is not that straight forward, but if you suffer from vitamin B12 deficiency it is 100%. That is, you need to fix this deficiency.

So back to vitamin B12 deficiency and what is most important.

Deficiencies can cause disease and sub optimal levels make you prone to:

  • Anemia
  • Behavioral Changes
  • Constipation
  • Depression
  • Diarrhea
  • Fatigue
  • Gas
  • Heart Palpations
  • Peripheral neuropathy
  • Tiredness
  • Weakness


Then when you reeve up the body with optimal dosing of vitamin D3 it makes sense you would need more vitamin B12 as your body’s metabolism is increased. Here again we are dealing with the small intestines and absorption of vitamins. After absorption vitamin B12 the body uses it in many processes throughout the body. One of the known diseases caused by deficiencies of vitamin B12 is pernicious anemia.

Also, only certain foods contain vitamin B-12:

  • Animal organ meets like liver
  • Clams
  • Sardines
  • Beef
  • Fortified foods like cereals
  • Tuna
  • Fortified Yeast
  • Trout salmon
  • Fortified nondairy milk

Thus, those who are vegetarians may have to take supplemental vitamin B-12. Also, those who consume very little meat or dairy products are at greater risk of deficiency which taking optimal doses of vitamin D3. As this will increase your metabolism which will happen with taking optimal doses of vitamin D3 will require more vitamin B-12.

  1. Allen LH. (2009) How common is vitamin B12 Deficiency, The American journal of Clinical Nutrition, 89:693s-696s.
  2. Taneja S, Bhandari N, Strand TA, et al. (2007) Cobalamin and folate status in infants and young children in a low-to-middle income community in India. Am J Clin Nutr. 86:1302–9.
  3. Refsum H, Yajnik CS, Gadkari M, et al. (2001) Hyperhomocysteinemia and elevated methylmalonic acid indicate a high prevalence of cobalamin deficiency in Asian Indians. Am J Clin Nutr.74:233–41.
  4. Pennypacker LC, Allen RH, Kelly JP, et al. (1992) High prevalence of cobalamin deficiency in elderly out-patients. J Am Geriatr Soc. 40:1197-1204.
  5. Clarke R. (2008) B-vitamins and prevention of dementia. Proc Nutr Soc. 67:75-81.

*The information posted above is for educational purposes only. Always check with your doctor before initiating any changes in your medical treatment. If you do not, then The Two-Minute Health Fact, Dr. Judson Somerville, nor The Optimal Dose is responsible!


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