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B12 for Sleep: Is There a Connection?

Want to know the latest research on Vitamin B12 for sleep?

Does B12 help with sleep patterns?

We understand the importance of sleep for gut-brain health.

B12 deficiency causes, deficiency symptoms, testing, rich food sources, and a B12 boost for sleep will be discussed in this article.

This information is for educational purposes only. As with any medical advice, always check with your doctor or healthcare professional for personal and age-appropriate recommendations.

Let’s get started.

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What is Vitamin B12?

Vitamin B12 is a water-soluble vitamin that is essential for (1):

  • Red blood cell production
  • DNA synthesis
  • Methylation
  • Mitochondria production

Intrinsic factor (from parietal cells) is necessary for B12 absorption in the small intestine.

Causes of B12 Deficiency?

There are several causes of B12 deficiency (2, 3, 4).

  • Autoimmune conditions
  • Absorption due to poor gut health
  • Inadequate dietary intake especially with vegans or vegetarians
  • Use of certain medications such as metformin, proton pump inhibitors or H2 blockers.
  • Age of greater than 75 years due to poor absorption

Symptoms of Low B12?

B12 Symptoms Fatigue

Potential symptoms of B12 deficiency include (5): 

  • Dizziness
  • Convulsion
  • Decreased muscle tone
  • Learning challenges
  • Tremor
  • Lack of balance
  • Tingling sensations
  • Blurring of vision
  • Fatigue 
  • Difficulty concentrating

Suboptimal B12 status (when the serum B12 < 407pg/mL or 300 pmol/L) occurs in 30-60% of the population worldwide especially in underdeveloped countries (6).

What is the Connection with B12 for Sleep?

Vitamin B12 plays a role in the body’s production of melatonin which is important for regulating sleep-wake cycles (7). B12 normalizes sleep patterns.

Studies have shown magnesium, melatonin, and B complex have a beneficial effect on insomnia however, what about B12 for sleep (8)?

Vitamin B12 and Narcolepsy

Disruption in your sleep/wake cycle can lead to insomnia or narcolepsy (9).

A study in 2022 showed a deficiency in B12 was correlated with narcolepsy (10). More studies are needed to see if supplementing with B12 helps reduce narcolepsy.

B12, Depression, and Sleep

B12 is needed for serotonin production, therefore may improve depressive symptoms.

Overall, optimizing B12 levels have been associated with a lower risk of depression and supplementation with B12 can delay the onset of depression (11). Additionally, sleep issues are commonly associated with depression (12, 13).  

In a recent review, B vitamins together with vitamin D treatment improved depression scores (14).

Studies show low B12 levels were found in about 20% of psychiatric patients so improving B12 levels may benefit mental health (15, 16).

Sleep Quality and B12

In a study on B12 and sleep with young female adults, they found that the participants with higher vitamin B12 levels had improved sleep quality scale and a lower use of sleep medication (17).

Prevention, early detection, and supplementation with B12 is important to prevent B12 deficiency and improve sleep and overall health

How Do You Test for B12?

To test for adequate B12 levels, you should test (18):

  • Complete blood count (CBC)
  • Serum B12
  • Serum methylmalonic acid (also called MMA)
  • Homocysteine
  • Folate (19)

Low B12, elevated homocysteine, and high methylmalonic acid levels was associated with poor cognitive performance in a large group of men and women aged 60-85 years old (20).

Maintaining an optimal level of B12 may protect against Alzheimer’s (21, 22).  

When checking serum B12, it is important to be off supplements for several days to get an accurate reading. Sometimes, serum B12 levels may be above normal even if a deficiency is present (intracellular levels low).

B12 levels may be increased (above 1000 pg/mL) due to excess supplementation, poor absorption, hematological or autoimmune conditions (23, 24).

Elevated B12 can also be associated with cancer of the liver and kidney so it is important to get it evaluated by your doctor (25, 26).

Functional nutrition practitioners often suggest optimal ranges around 500-1300 pg/ml for serum B12 levels and homocysteine less than 7 μmol/L (27).  

What Are Rich Food Sources of B12?

Best food sources of B12 include animal products such as red meat, dairy, fish, and eggs (28). If you are vegan or vegetarian, you may be at higher risk for a B12 deficiency. 

B12 Rich Foods

B12 Boost With a Supplement?

Studies suggest that taking vitamin B12 supplements may balance circadian rhythms which are the body’s internal clocks that regulate various physiological processes in the body. This may help improve sleep quality and quantity. 

B12 supplements are available in a variety forms including:

  • Methylcobalamin
  • Adenosylcobalamin
  • Hydroxocobalamin
  • Cyanocobalamin (synthetic form)

Intramuscular injections are also available especially for those with pernicious anemia (lack of intrinsic factor).

Supplementing with the natural forms of B12 (methyl, adenosyl, and hydroxocobalamin) has been recommended by researchers due to bioavailability and safety (29). Genetic variations may affect absorption, transport, and uptake of B12.

The RDA for B12 is about 2.4 mcg for adults however, much larger doses may be needed (30, 31).

High doses of B12 in any form of supplement (sublingual, liquid, capsule) can be absorbed by passive diffusion however, the larger the dose, the smaller percent of absorption (32, 33). Common supplement doses are 500-1000 mcg of B12.

A recent study in 2022 recommended those on plant-based diets should supplement with vitamin B12, consume B12 fortified products, have vitamin B12 levels monitored every 3-6 months, and seek the help of a health professional for guidance (34).

People with Crohn’s and other GI disorders may be at risk for B12 deficiency (35). 

Have your B12 checked to see if you need supplementation!

Final Thoughts

Vitamin B12 is a water soluble vitamin that is essential for many functions in the body.

B12 deficiency can be caused by inadequate intake from eating a plant-based diet, and poor absorption due to GI disorders, age, or medications.

Deficiency of B12 symptoms may include dizziness, fatigue, lack of concentration and many other symptoms.

Prevention, early detection, and supplementation with B12 is important to prevent B12 deficiency and improve sleep and overall health. 

Testing for B12 should include a CBC, serum B12, MMA, homocysteine, and folate.

Rich food sources of B12 are mainly from animal products.

Supplementing with the natural forms of B12 (methyl, adenosyl, and hydroxocobalamin) has been recommended by researchers due to bioavailability and safety.

Read the blog for more information on functional nutrition.

Test don’t guess. 

Contact me to schedule an appointment to review your personalized nutritional health.

© Amy Archer RDN, CLT, CHWC

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