Vitamin B12 (Cobalamin) Blood Test: Low & High Levels
To quote, УAt this time, we believe normal serum B12 levels should be greater than pg/ml. For brain and nervous system health and prevention of disease in older adults, serum B12 levels should be maintained near or above pg/ml.Ф. Jan 15, †Ј The normal range for vitamin B in the blood is between and nanograms per milliliter (ng/mL). People at the lower end of this range may require follow-up testing, especially if Author: Jayne Leonard.
Get the latest public health information from CDC. Have a question? This is a fact sheet intended for health professionals. For a reader-friendly overview of Vitamin B12, see our consumer fact sheet on Vitamin B Vitamin B12 is a water-soluble vitamin that is naturally present in some foods, added to others, and available as a dietary supplement and a prescription medication.
Methylcobalamin and 5-deoxyadenosylcobalamin are the metabolically active forms of vitamin B However, two others forms, hydroxycobalamin and cyanocobalamin, become biologically active after they are converted to methylcobalamin or 5-deoxyadenosylcobalamin [ ]. Vitamin B12 is required for the development, myelination, and function of the central nervous system; healthy red blood cell formation; and DNA synthesis [ 145 ]. Vitamin B12 functions as a cofactor for two how to get free reggaeton samples, methionine synthase and L-methylmalonyl-CoA mutase [5 ].
Methionine synthase g12 the conversion of homocysteine to the essential amino acid methionine [ 12 ]. Methionine is required for the formation of S-adenosylmethionine, a universal methyl donor for almost different substrates, including DNA, RNA, proteins, and lipids [ 3v12 ].
L-methylmalonyl-CoA mutase converts L-methylmalonyl-CoA to succinyl-CoA in the metabolism of propionate, a short-chain fatty acid [ 2 ]. Vitamin B12 is bound to protein in food and must be released before it is absorbed [ 5 ]. The process starts in the mouth when food is mixed un saliva. The freed vitamin B12 then binds with haptocorrin, a cobalamin-binding protein in the saliva. More vitamin B12 is released from its food matrix by the activity of hydrochloric acid and gastric protease in the stomach, where it then whatt to haptocorrin [ 1 ].
The resulting complex is absorbed in the distal ileum by receptor-mediated endocytosis [ 15 ]. If vitamin B12 is added to fortified foods and dietary supplements, it is already in free form and therefore does not require the separation step.
Vitamin B12 status is typically assessed by measurements of serum or plasma vitamin B12 levels. Levels of serum methylmalonic acid MMAa vitamin Bassociated metabolite, are the most sensitive markers of vitamin B12 status, and an MMA level greater than 0.
However, MMA levels also rise with renal insufficiency and tend to be higher in older adults [ 6910 ]. However, this indicator has poor specificity because it is influenced by other factors, such as low folate levels and, especially, by declines in kidney function [ 6 ]. DRI is the general term for a set of reference values used for planning and assessing nutrient intakes of healthy wwhat. These values, which vary by age and sex, include:.
What kinda king gucci mane lyrics 1 lists the current RDAs for vitamin B12 [ 1 ].
For bllood, the main criterion that the FNB used to establish the RDAs was the amount needed to maintain a healthy hematological status and serum vitamin B12 levels. For infants whag 0 to 12 months, the FNB established an AI that is equivalent to the normap intake of vitamin B12 in healthy, breastfed infants. Food Vitamin B12 is naturally present in foods of animal origin, including fish, meat, poultry, eggs, and dairy products [ 5 ].
H12 addition, fortified breakfast cereals and fortified nutritional yeasts are readily available sources of vitamin B12 that have high bioavailability [ 1213 ]. The average vitamin B12 level in the breast milk of women with vitamin B12 intakes above the RDA is 0. The U. Food and Drug Administration specifies that infant formulas sold in the United States must provide at least 0.
The estimated bioavailability of vitamin Blooc from food varies by vitamin B12 dose because absorption decreases drastically when the capacity of intrinsic factor is exceeded at 1Ч2 mcg of vitamin B12 [ 16 ]. Bioavailability also varies by type of food source. Food and Drug Administration FDA developed DVs to help consumers compare the nutrient contents of foods and dietary supplements within the context of a total diet. The DV for vitamin B12 is 2. FDA does not require food labels to list vitamin B12 content unless vitamin B12 has been added to the food.
Vitamin B12 levels are higher, generally 50Ч mcg, in supplements containing vitamin B12 with other B-complex vitamins and even higher, typically Ч1, mcg, in supplements containing only vitamin B The most common form of vitamin B12 in dietary supplements is cyanocobalamin [ 132223 ]. Other forms of vitamin B12 in supplements are wuat, methylcobalamin, and hydroxycobalamin [ 22 ]. No evidence indicates that absorption rates of vitamin B12 in supplements vary how to make smoke salmon form of the vitamin.
In addition to oral dietary supplements, vitamin B12 is available in sublingual preparations as tablets or lozenges [ 22 ]. Evidence suggests no difference in efficacy between oral and sublingual forms [ 2526 ]. Prescription medications Vitamin B12, in the forms of cyanocobalamin and hydroxycobalamin, can be administered parenterally as a prescription medication, usually by intramuscular injection [ 2 ]. Parenteral administration is typically used to treat vitamin B12 deficiency caused by pernicious anemia as well as other conditions e.
Vitamin B12 is also available as a prescription nasal gel spray. This formulation appears to be effective in raising vitamin Levle blood levels in adults and children [ 2728 ]. Most people in the United States consume adequate amounts of vitamin B Average daily intakes of vitamin B12 from food are 5. Bloood children aged 2Ч19, mean daily intakes of vitamin B12 from food range from 3.
According to an analysis of NHANES data from Ч, people of low socioeconomic status, women, and non-Hispanic Blacks are most likely to have low vitamin B12 intakes [ 32 ]. In addition, serum vitamin B12 levels tend to drop, sometimes to wha levels, during pregnancy, but they bloor return to normal after delivery [ 34 ].
Mean vitamin B12 intakes among supplement users from both foods and supplements were Causes of vitamin B12 deficiency include difficulty absorbing vitamin B12 from food, lack of intrinsic factor e. Because people who have difficulty absorbing vitamin B12 from food absorb free vitamin B12 normally, their vitamin B12 deficiency tends to be less severe than that of individuals with pernicious anemia, who cannot absorb either food-bound or free vitamin B The effects of vitamin B12 deficiency can include the hallmark megaloblastic anemia characterized by large, abnormally nucleated red blood cells as well as low counts of onrmal and red blood cells, platelets, or a combination; glossitis of the tongue; fatigue; palpitations; pale skin; dementia; weight loss; and infertility [ 257 ].
Neurological changes, such as numbness and tingling in the hands and feet, can also occur [ 7 ]. These neurological symptoms can occur without anemia, so early diagnosis and intervention is important to avoid irreversible damage [ 35 ]. In pregnant and breastfeeding women, vitamin B12 deficiency might cause neural tube defects, developmental delays, failure to thrive, and blooe in offspring [ 7 ].
Because the body stores about 1 to 5 mg vitamin B12 or about 1, to 2, times as much as the amount typically consumed in a daythe symptoms of vitamin B12 deficiency can take several company profile how to create to appear [ 733 ].
Vitamin B12 deficiency with the n12 hematologic and neurologic signs and symptoms is uncommon [ 11 ]. The prevalence of vitamin B12 deficiency varies by cutoff level and biomarker used. Typically, vitamin Norkal deficiency is treated with vitamin B12 injections, because this method bypasses any barriers to absorption. However, high doses of oral vitamin B12 might how to change url on tumblr be effective.
A Cochrane review included three randomized controlled trials RCTs that compared very high wha 1,Ч2, mcg of oral with intramuscular vitamin B12 for vitamin B12 deficiency in a total of participants [ 37 ]. The evidence from these studies, although of low quality, showed that the ability of high bpood doses of vitamin B12 supplements to normalize serum vitamin B12 was similar to that of intramuscular vitamin B A third condition associated with vitamin B12 deficiency in older adults is Helicobacter pylori infection, possibly because this bacterium causes inflammation that leads to malabsorption of vitamin B12 from food [ 42 ].
Pevel with pernicious anemia Pernicious anemia is an irreversible autoimmune disease that affects the gastric mucosa and results in gastric atrophy [ 143 ]. This disease leads to attacks on parietal cells in the stomach, resulting in failure to produce intrinsic factor and malabsorption of dietary vitamin I, recycled biliary vitamin B12, and free vitamin B12 [ 1611 ]. Therefore, without treatment, pernicious anemia causes vitamin B12 deficiency, what is a normal b12 level in blood in the presence of adequate vitamin B12 whag.
Pernicious anemia is the most common whqt of clinically evident vitamin B12 deficiency around the world [ 1143 ]. The incidence of pernicious anemia in the Blood States is an estimated per , and this condition is more common in women and in wat of European ancestry how to overcome communication barriers in the workplace 43 ]. Individuals who have had gastrointestinal surgery Surgical procedures in the gastrointestinal tract, such as for weight loss or to remove all or part of the stomach, can cause a complete or partial loss of cells that secrete hydrochloric acid and what is a normal b12 level in blood that secrete intrinsic factor [ 4950 ].
Thus, these procedures reduce the amount of vitamin B12, particularly food-bound vitamin B12, that the normao absorbs [ 4950 ]. Vegetarians Vegans who consume no animal products and vegetarians z consume some animal products e. Consumption of foods fortified with vitamin B12 such as fortified nutritional yeasts as well as vitamin B12 supplements can substantially reduce the risk of deficiency [ 52 ]. Infants of vegan women Exclusively hlood infants of women who consume no animal products might have very limited reserves of vitamin B12 and can develop vitamin B12 deficiency, sometimes very early in life [ 53 ].
Undetected and untreated vitamin B12 deficiency in infants can result in neurological damage, failure to thrive, developmental delays, and anemia [ 25354 ]. The reasons include the small amounts normla vitamin B12 in the breast milk of vegan mothers as well as the limited amounts of vitamin B12 crossing the placenta in these women during fetal development. This section levle on areas of health in which vitamin B12 might be blpod cancer, cardiovascular disease CVD and stroke, dementia and cognitive function, and energy and endurance.
Cancer The evidence for a relationship between vitamin B12 and cancer risk is mixed. Some evidence supports a link between lvel cancer risk and higher intakes or blood concentrations of vitamin B12, some supports a link with lower intakes or concentrations, and some evidence indicates no link at all.
Observational evidence supporting an association between higher vitamin B12 levels and increased cancer risk includes an analysis of data onpeople median age 56 years lfvel plasma vitamin B12 measurements [ 55 ].
The results showed that the adjusted 1-year risk of cancer was 1. An analysis by some of the same investigators of data from Danish medical registries for 25, people who had a cancer diagnosis between and found 1-year survival nrmal of Some observational evidence also shows an association between supplements containing vitamin B12 and a higher risk of certain types of cancer.
However, the study found no association between supplemental vitamin B12 use and cancer blold in women. Limited clinical trial evidence supports the finding that higher vitamin B12 intakes might increase cancer wht. However, high folic acid levels are potentially linked to increased risk of colorectal cancer, so the result might be due to leel folic acid rather than the vitamin B12 [ 59 ]. Furthermore, the supplements had no significant effect on overall cancer risk.
Some observational evidence shows no association between high vitamin B12 concentrations or intakes and increased risk of certain cancers. For example, higher vitamin B12 intakes or serum concentrations were not associated with an increased risk of pancreatic cancer [ 60 ], breast cancer [ 61 ], or esophageal cancer or gastric cancer elvel 62 ].
Clinical trials support the lack of association between higher vitamin B12 intakes and cancer risk. Finally, evidence pointing to an association between lower vitamin B12 levels and a higher cancer risk includes lebel data showing a risk of gastric cancer that was 5.
Also, two meta-analyses found associations between lower vitamin B12 concentrations or intakes and a higher risk of colorectal cancer [ 67 ] and prostate cancer [ 68 ]. More evidence is needed to clarify whether high or low intakes of vitamin B12 leel the risk of cancer as well as the role of vitamin B12 in preventing cancer. Cardiovascular disease and stroke An elevated homocysteine level has been associated with an increased risk of CVD [ 6970 ]. Vitamin B12 and other B vitamins are involved in homocysteine metabolism, and researchers have hypothesized that supplementation with these micronutrients can reduce CVD risk by lowering homocysteine levels [ 6970 ].
Inn, studies on the association between vitamin B12 normak and risk of CVD have had negative results.
Normal Vitamin B12 Levels Chart
Understanding the Results. The normal range for vitamin B12 can vary slightly depending on the lab. But a normal level of vitamin B12 in your bloodstream is generally between and picograms. Jan 16, †Ј Normal B12 levels in adults is ng/ml to ng/ml. The level of Vitamin B12 below ng/ml indicates vitamin B12 deficiency. Alteration is also found in normal B12 levels by age. Male children have a slightly lower level of Vitamin B12 as compared to female Children. Values of less than pg/mL ( pmol/L) are a possible sign of a vitamin B12 deficiency. People with this deficiency are likely to have or develop symptoms. Older adults with a vitamin B12 level less than pg/mL (74 pmol/L) may also have symptoms.
Vitamin B12 test: high blood levels. What do extremely high vitamin B12 blood values mean? Are they a cause for concern? High B12 blood levels and diseases.
Whilst low blood levels of vitamin B12 indicate deficiency in a test ; elevated blood levels are also often discovered. What do these figures mean Ч and are such levels a cause for concern?
High B12 levels in the blood are not necessarily a reason to panic, as they can stem from a number of different causes. They should however be investigated, as some of the possible underlying causes include severe diseases. Alongside alcoholism, genetics, malabsorption and increased transport molecules in the blood; diseases of the liver, kidneys and the blood such as leukaemia can be considered potential reasons for an increased B12 blood level Increased levels of vitamin B12 can exist for a number of reasons, which can be divided roughly into the following categories:.
This article will take a closer look at the causes of elevated B12 blood levels, as well as considering the necessary ways to respond. At the end, there is also a guide of what to do if this is the case. It is now known that the test results of numerous laboratories are distorted if the patient has a very high number of intrinsic factor IF antibodies in the blood. A check for IF antibodies, homocysteine and MMA in the urine can thus indicate whether the high values of B12 have been mistakenly produced.
A very common reason for high B12 levels is because the blood test has been carried out too soon after the administration of a B12 injection. This should be avoided and tests should be delayed by days post-injection. Results can otherwise be very misleading, as B12 that has not yet been metabolised elevates the blood level.
Nonetheless, high B12 levels are absolutely harmless in these cases. Taking high-dose oral B12 supplements can also greatly increase blood levels Ч here, the same period of days should be observed before testing. Should high blood levels occur during a course of vitamin B12, then another measurement should be taken 10 days after supplementation has ended.
If B12 values remain extremely high in a second blood test, the cause can often be difficult to determine, however, is likely related to utilisation problems within the body. These problems occur when the body is not capable of properly utilising vitamin B12, leaving it to accumulate in the blood.
It is therefore possible to be B12 deficient despite having high B12 blood levels Ч for example, if the vitamin cannot correctly bind to transport molecules 6. High vitamin B12 blood levels which have not been caused by a mistimed test should always be followed up by an official B12 status check. The most comfortable way of doing this is by measuring the methylmalonic acid MMA in the urine, which determines how much vitamin B12 the cells actually receive.
The test can be carried out comfortably and quickly at home; though must be ordered online and can be expensive. Another method that requires a visit to the doctor for a blood test is the holo TC test, which only measures vitamin B12 that is bound to the transport molecules, transcobalamin. Only this bound form of B12 can be correctly transported to the tissue and body store and thus utilised by the body 7, 8. While free, unbound B12 can produce high levels in a serum test; it has no biological function whatsoever.
Multiple forms of the transcobalamin transport molecule exist Ч the one that is important here is transcobalamin II, as it allows B12 to become biologically available. The holo TC test only measures B12 that is attached to transcobalamin II, thus giving a much better indication of the available supply.
Certain rare hereditary diseases lead to a deficiency of transcobalamin II, meaning that a vitamin B12 deficiency can emerge despite a good supply.
Here, B12 serum levels appear very high, despite the fact that a deficiency is present. Hereditary illnesses and the long-term use of B12 injections can sometimes trigger the production of antibodies that work against transcobalamin II, leading to the vitamin not being utilised properly 9.
In this instance, transcobalamin is fully available but has problems bonding with vitamin B12 Ч there will thus also be a B12 deficiency, despite very high blood levels. Finally, some cases show the over production of other molecules which also bond to vitamin B12, most commonly the so-called haptocorrin or R-binder, to which transcobalamin I and III belong.
As a result, B12 bonds to these molecules instead of transcobalamin II; while serum values of B12 seem to rise, none of the B12 is available for the body to use. Sometimes high blood levels can be attributed to serious diseases. The following mechanisms are responsible for high vitamin B12 blood values in such diseases:. High vitamin B12 blood levels are occasionally linked to autoimmune diseases that cause chronic inflammations.
The mechanism here is difficult to determine, however presumably stems from an increased production of transcobalamin II Even so, the frequency and significance of these observations are presently unclear.
Here, increased vitamin B12 levels seem to occur much less frequently than in the previously mentioned diseases; this relationship seems to play a relatively minor role, as far as current research shows. High B12 blood levels should always be examined further, in order to rule out any serious diseases.
Often when they appear, it is due to a simple failure in measurement; normally the time period between supplementation and the blood test is too short, distorting results Ч certainly no cause for panic.
Even experienced doctors are sometimes stumped when interpreting high B12 blood values, so here is a little guide on how to proceed in such cases:. Name required. Mail will not be published required. E-Mail-Benachrichtigung bei weiteren Kommentaren. Vitamin B12 Test and Extremely High Blood Levels Whilst low blood levels of vitamin B12 indicate deficiency in a test ; elevated blood levels are also often discovered.
Distorted Results It is now known that the test results of numerous laboratories are distorted if the patient has a very high number of intrinsic factor IF antibodies in the blood. The Importance of Time Intervals A very common reason for high B12 levels is because the blood test has been carried out too soon after the administration of a B12 injection.
Usage Problems: Vitamin B12 Deficiency Despite High Blood Levels If B12 values remain extremely high in a second blood test, the cause can often be difficult to determine, however, is likely related to utilisation problems within the body. High Blood Levels and Vitamin B12 Transport Molecules Another method that requires a visit to the doctor for a blood test is the holo TC test, which only measures vitamin B12 that is bound to the transport molecules, transcobalamin.
Below is a list of the most common usage problems in relations to transport molecules: Deficiency of Transcobalamin II Certain rare hereditary diseases lead to a deficiency of transcobalamin II, meaning that a vitamin B12 deficiency can emerge despite a good supply. Transcobalamin II Antibodies Hereditary illnesses and the long-term use of B12 injections can sometimes trigger the production of antibodies that work against transcobalamin II, leading to the vitamin not being utilised properly 9.
Transcobalamin Bonding Problems In this instance, transcobalamin is fully available but has problems bonding with vitamin B12 Ч there will thus also be a B12 deficiency, despite very high blood levels.
Overproduction of Haptocorrin Finally, some cases show the over production of other molecules which also bond to vitamin B12, most commonly the so-called haptocorrin or R-binder, to which transcobalamin I and III belong. Even experienced doctors are sometimes stumped when interpreting high B12 blood values, so here is a little guide on how to proceed in such cases: Guide to High Vitamin B12 Blood Levels Sources E. Serraj, J. Zhu, A. Rev Med Interne ; Cobalamin related parameters and disease patterns in patients with increased serum cobalamin levels.
Rev Med Interne ;30 Suppl. Significance of elevated cobalamin vitamin B12 levels in blood. Clin Biochem ; Solomon LR. Disorders of cobalamin vitamin B12 metabolism: emerging concepts in pathophysiology, diagnosis and treatment. Blood Rev ; Grasbeck R. Biochemistry and clinical chemistry of vitamin B12 transport and the related diseases.
J Clin Biochem ; Cobalamin binding glycoproteins. Bristol: Journal of Endocrinology Ltd; Circulating antibody to transcobalamin II causing retention of vitamin B12 in the blood.
Blood ; Blood transcobalamin levels in malignant hepatoma. Vitamin B12 binding protein as a tumour marker for hepatocellular carcinoma. Gut ; Carmel R. Extreme elevation of serum transcobalamin I in patients with metastatic cancer.
N Engl J Med ; Gimsing P, Hippe E. Increased concentration of transcobalamin I in a patient with metastatic carcinoma of the breast. Scand J Haematol ; Gimsing P. Cobalamin metabolism in chronic myelogenous leukemia. Dan Med Bull ; The cobalamin forms and analogues in plasma and myeloid cells during the course of chronic myelogenous leukemia related to the clinical condition.
Br J Haematol ; The transcobalamins in polycythemia vera. Cobalamin vitamin B12 vitamin B12 and B12 binding proteins in hypereosinophilic syndromes and secondary eosinophilia. Hagelskjaer L, Rasmussen K. Methylmalonic acid concentration in serum not affected in hepatic disease. Clin Chem ; Alcoholic cirrhosis and cobalamin metabolism. Cobalamin and holotranscobalamin changes in plasma and liver tissue in alcoholics with liver disease. J Am Coll Nutr ; Parenteral vitamin B12 therapy of hyperhomocysteinemia in end-stage renal disease.
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