How Genetics May Affect Vitamin B12 Levels

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How Genetics May Affect Vitamin B12 Levels

Date of Content: February 6, 2024
Written by: Harvey Talento
Reviewed by: Maarit Tiirikainen, PhD


An Overview of Vitamin B12

Vitamin B12, also known as cobalamin, is a water-soluble vitamin that is essential for several physiological processes, such as normal nervous system functioning, red blood cell development, DNA synthesis, and energy metabolism.

It is important to note that the human body cannot produce vitamin B12 on its own, and it must be obtained through diet or supplements. It occurs naturally in animal-based foods like fish, meat, poultry, eggs, and dairy products. For those preferring plant-based options, fortified breakfast cereals and nutritional yeasts are accessible alternatives.

In optimizing Vitamin B12 levels, multivitamin/mineral supplements are also available. Doses vary from 5 to 1,000 mcg (micrograms). The most common form in supplements is cyanocobalamin, with no significant differences in absorption rates among different forms.

Although there are many available sources of vitamin B12, deficiency is still common. General physical symptoms of vitamin B12 deficiency can include feeling very tired or weak, experiencing nausea, vomiting, or diarrhea, not feeling as hungry as usual, weight loss, having a sore mouth or tongue, and yellowish skin.

Vitamin B12

Importance of Vitamin B12

Let’s dive deeper into the key roles of vitamin B12, and learn how it helps our well-being.

Red Blood Cell Formation

Vitamin B12 is essential for the production and maturation of red blood cells in the bone marrow. These cells are vital for carrying oxygen to tissues and organs throughout the body. A deficiency in B12 can lead to a type of anemia known as megaloblastic anemia, where red blood cells are larger and less functional.

Neurological Function

Vitamin B12 is crucial for maintaining the health of the nervous system. It plays a role in the formation and maintenance of the myelin sheath, a protective covering around nerve fibers that facilitates proper nerve transmission. Deficiencies in B12 can lead to neurological issues, including numbness, tingling, and problems with coordination.

DNA Synthesis

Vitamin B12 is involved in the synthesis of DNA, the genetic material in cells. It plays a crucial role in cell division and the maintenance of genetic information during replication. This is particularly important for rapidly dividing cells, such as those in the bone marrow and the lining of the gastrointestinal tract.

Homocysteine Regulation

Vitamin B12, along with other B vitamins, helps regulate the levels of homocysteine in the blood. Elevated homocysteine is associated with an increased risk of cardiovascular diseases, and adequate B12 levels contribute to maintaining a healthy homocysteine balance.

Energy Metabolism

Vitamin B12 is involved in the conversion of food into energy. It plays a role in the metabolism of carbohydrates and fats, contributing to the overall energy production in the body.

Cell Division and Growth

Vitamin B12 is essential for proper cell division and growth, especially in rapidly dividing tissues such as those found in the bone marrow.

Genetics of Vitamin B12 Levels

Genetics plays a crucial role in determining various aspects of our well-being, including the regulation of vitamin B12 levels. Understanding the specific genes associated with vitamin B12 is essential for gaining insights into potential risks and developing targeted interventions.

FUT6 Gene

In the exploration of factors affecting Vitamin B12 levels, the FUT6 gene variant rs708686 emerges as a significant contributor. Identified through a 2017 study, this variant is associated with circulating B12 concentrations.

While it also appears in Europeans, subtle differences suggest potential variations in its role across populations. The variant seems to control fucosylation, influencing the interaction between the body and intestinal microbes, and consequently, impacting Vitamin B12 levels. These findings highlight the need to consider population-specific variants in understanding the regulation of Vitamin B12.

MS4A3 and CLYBL Genes

In a study of Vitamin B12 levels in the Chinese population, two crucial genes have been identified—MS4A3 and CLYBL. The variant rs2298585 in the MS4A3 gene on chromosome 11q12.1 and rs41281112 in the CLYBL gene on chromosome 13q32 are associated with elevated serum Vitamin B12 levels.

While these findings deepen our understanding of B12 metabolism, further research is needed to pinpoint the specific roles these genes play in the complex pathways governing Vitamin B12 levels. These insights have potential implications for personalized interventions in addressing Vitamin B12-related health conditions.

FUT2 Gene

A genome-wide association study (GWAS) in the Nurses’ Health Study (NHS) NCI-Cancer Genetic Markers of Susceptibility (CGEMS) project uncovered a significant association between plasma vitamin B12 levels and common variants in the FUT2 gene on chromosome 19q13. 

Variants rs602662 and rs492602 (both SNPs linked to rs516246) exhibited a strong correlation with plasma vitamin B12 levels.


The CUBN gene takes a prominent role in determining baseline Vitamin B12 levels. Three independent SNPs in the CUBN gene are associated with vitamin B12 levels (rs60015357, rs12261966, and rs1801222).  

As B vitamins play an important role in homocysteine metabolism, B12 vitamin deficiencies can result in increased levels of homocysteine and consequently increased risk for stroke. This particular study found out that certain, and SNPs within CUBN were showing associations with stroke. 

These genetic variants in CUBN offer avenues for further investigation, providing direct insights into the genetic factors governing Vitamin B12 metabolism, particularly in the context of the risk for stroke.

TCN1 Gene

The TCN1 gene has also emerged as a significant player in influencing baseline Vitamin B12 levels As TCN1 is crucial in Vitamin B12 transport, strong genetic association of a missense SNP like rs34324219  directly highlights its substantial role in modulating Vitamin B12 concentrations. Further exploration into the specific actions of TCN1 can potentially reveal targeted strategies for individuals at risk, particularly in the context of stroke prevention.

These genetic insights provide a foundation for understanding the complex regulation of vitamin B12 levels in the body. As we unravel the genetic basis of various health parameters, the potential for personalized interventions to address vitamin B12 deficiencies and related risks becomes tangible. These insights show the importance of genetic understanding in optimizing our nutritional well-being.

The LifeDNA Vitamin B12 report includes a focus on TCN1 rs34324219 and TCN1 rs526934. This offers a direct glimpse into an individual’s genetic makeup, aiding in the optimization of nutritional well-being and addressing Vitamin B12 deficiencies and associated risks.

Non-Genetic Factors Influencing Vitamin B12 Levels

Various factors play a significant role in determining vitamin B12 levels within the body. Understanding these factors is crucial for maintaining optimal health. Here, we explore key elements influencing vitamin B12 levels, encompassing dietary choices, age-related considerations, and the impact of certain medical conditions.


As mentioned, vitamin B12 is predominantly present in animal products like meat, eggs, dairy, fish, and poultry. Individuals adhering to a vegetarian or vegan diet may face challenges in obtaining sufficient B12 from their food, necessitating the use of supplements or fortified foods. Conversely, those with a high intake of animal products may exhibit elevated vitamin B12 levels.


As individuals age, their ability to absorb vitamin B12 from food may diminish due to factors such as reduced stomach acid production, changes in the intestinal lining, or the use of specific medications that interfere with absorption. Older adults, consequently, are more susceptible to vitamin B12 deficiency and may require supplements or injections.

Medical Conditions

Several diseases and disorders can impact the production, absorption, or metabolism of vitamin B12. Conditions like pernicious anemia, which hinders intrinsic factor production, can lead to vitamin B12 deficiency.

Conversely, ailments such as Crohn’s disease, celiac disease or gluten sensitivity, gastric bypass surgery, chronic alcoholism, and certain infections can also contribute to low vitamin B12 levels. On the other end of the spectrum, conditions such as liver disease, kidney disease, leukemia, and polycythemia vera may cause elevated vitamin B12 levels.

Awareness of both the genetic and non-genetic factors influencing vitamin B12 levels is vital for individuals to make informed choices about their diet, lifestyle, and potential supplementation needs. Maintaining an adequate balance of vitamin B12 is essential for overall health and can mitigate the risk of associated deficiencies or imbalances. Regular monitoring and consultation with healthcare professionals can ensure that individuals are effectively managing their vitamin B12 status.

Maintaining Adequate Vitamin B12 Levels

Ensuring optimal vitamin B12 levels is crucial for overall health, and several strategies can be employed to enhance or maintain these levels:

Dietary Choices

Include foods rich in vitamin B12 in your diet. Animal products such as meat, poultry, fish, eggs, and dairy are excellent sources. For those following a vegetarian or vegan diet, consider fortified foods or supplements to meet B12 requirements.

Vitamin B12 Supplements

Supplements are a convenient way to boost vitamin B12 levels, especially for individuals with dietary restrictions or those who may have difficulty absorbing B12 from food. Consult with a healthcare professional to determine the appropriate dosage.

Fortified Foods

Incorporate fortified foods into your diet, such as fortified breakfast cereals, plant-based milk, or nutritional yeast that is naturally rich in B vitamins. These options can provide a reliable source of vitamin B12, particularly for individuals with limited access to animal products.

Regular Health Check-ups

Regularly monitor your vitamin B12 levels through blood tests, especially if you fall into high-risk categories such as older adults, individuals with certain medical conditions, or those following specific dietary patterns. This proactive approach allows for early detection and intervention if deficiencies are identified.

Address Underlying Medical Conditions

If you have medical conditions that affect vitamin B12 absorption or metabolism, work closely with your healthcare provider to manage these conditions effectively. Treating underlying issues can contribute to maintaining adequate vitamin B12 levels.

Maintain a Healthy Lifestyle

A healthy lifestyle, including regular exercise and a balanced diet, can positively impact overall health, including vitamin B12 status. Adopting habits that support digestive health may enhance B12 absorption.

Limit Alcohol Intake

Excessive alcohol consumption can negatively affect vitamin B12 absorption. Moderating alcohol intake may contribute to maintaining optimal B12 levels.

Before making significant changes to your diet or taking supplements, it is advisable to consult with a healthcare professional. They can provide personalized guidance based on your specific needs, ensuring a well-rounded approach to maintaining adequate vitamin B12 levels for optimal health and wellness.

About the LifeDNA Vitamins and Supplements Report

For a more precise approach to your wellness, consider obtaining the LifeDNA Vitamins and Supplements Report today. This report provides specific insights into the Vitamin B12 Levels trait, helping you understand how your body processes and utilizes this essential nutrient. By learning about the genetic factors affecting your vitamin B12 metabolism, you can make more informed decisions about your supplementation needs.

Take this opportunity to gain detailed information about your genetic predispositions now!


  • Vitamin B12, essential for the nervous system and energy metabolism, is primarily found in animal-based foods, requiring supplementation or fortified options for those with dietary restrictions.
  • Key roles, including red blood cell formation, neurological function, and DNA synthesis, highlight the vital impact of vitamin B12 on overall well-being.
  • Genetic variation in genes like CUBN, TCN1, and FUT2 reveal insights into the complex regulation of vitamin B12, paving the way for personalized interventions.
  • Understanding dietary, age-related, and medical condition-related factors influencing vitamin B12 levels emphasizes the need for regular monitoring and professional consultation.
  • Optimizing vitamin B12 levels involves dietary choices, supplements, fortified foods, regular health check-ups, addressing medical conditions, maintaining a healthy lifestyle, and limiting alcohol intake for personalized well-being.


Customer Reviews

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I got some pretty useful insight that helped me with my diet.

*Understanding your genetics can offer valuable insights into your well-being, but it is not deterministic. Your traits can be influenced by the complex interplay involving nature, lifestyle, family history, and others.

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