Vitamin B12 is an essential nutrient that plays many critical roles in the body. One of its main functions is to help make DNA and produce red blood cells. B12 is also involved in proper nerve function. When vitamin B12 levels get too low, it can lead to a condition called vitamin B12 deficiency. This deficiency causes a wide range of symptoms, including potential issues with sleep. In this article, we’ll explore the link between B12 levels and sleep disturbances. We’ll also provide an overview of B12 deficiency and look at the scientific research that has investigated this relationship.
What is vitamin B12?
Vitamin B12 is a water-soluble nutrient that is necessary for good health. It’s required for DNA synthesis and red blood cell production. B12 also keeps nerve cells healthy and helps make neurotransmitters, which are chemical messengers in the brain. There are several different forms of B12 in supplements, including cyanocobalamin, methylcobalamin, hydroxocobalamin and adenosylcobalamin. In the human body, B12 is found mainly as methylcobalamin and adenosylcobalamin. Food sources of B12 include meat, fish, poultry, eggs and dairy products. The daily recommended intake is 2.4 mcg for ages 14 and up.
Causes and risk factors for B12 deficiency
There are two main causes of vitamin B12 deficiency:
Inadequate intake
Some people may not get enough B12 from their diet if they follow a strict vegan or vegetarian diet. Vegans avoid all animal foods, whereas vegetarians don’t eat meat but may consume eggs and dairy. Since the main dietary sources of B12 come from animal foods, these groups are at a higher risk of deficiency.
Decreased absorption
Certain medical conditions can reduce B12 absorption from foods. Pernicious anemia is an autoimmune disease that makes it difficult to absorb vitamin B12 from the digestive tract. Surgery that removes part of the stomach or small intestine can also impair B12 absorption. Other risk factors for B12 deficiency include:
– Older age: The ability to absorb B12 decreases with age.
– Long-term use of acid-reducing medications: Drugs like proton pump inhibitors suppress stomach acid production needed for B12 absorption.
– Heavy alcohol use: Chronic alcoholism is linked with low B12 status.
– Digestive disorders: Conditions like celiac disease and Crohn’s disease can damage parts of the digestive tract involved in B12 absorption.
Signs and symptoms of B12 deficiency
B12 deficiency causes a wide range of signs and symptoms that can affect many parts of the body:
– Fatigue and weakness
– Lightheadedness
– Palpitations and rapid heartbeat
– Shortness of breath and chest pain
– Headaches and dizziness
– Loss of appetite and weight loss
– Nausea and abdominal cramping
– Constipation or diarrhea
– Pale skin
– Sore mouth or tongue
– Neurologic issues like numbness and tingling in the hands and feet
– Problems with balance and walking
– Confusion, memory loss and depression
– Vision disturbances
Deficiency symptoms tend to come on gradually and worsen over time as B12 levels continue to decline. Neurologic problems in particular may become irreversible if the deficiency is not treated.
Diagnosing B12 deficiency
Doctors can check for vitamin B12 deficiency by ordering a simple blood test. Two lab tests are used to evaluate B12 levels:
Serum B12 level
This measures the amount of circulating vitamin B12 in the bloodstream. Levels below 200 pg/mL indicate a B12 deficiency. Borderline deficiency is defined as levels between 200-350 pg/mL.
Methylmalonic acid (MMA) test
MMA is a chemical that builds up in the blood when vitamin B12 levels are insufficient. Elevated MMA indicates impaired B12 function even if serum B12 levels are normal.
In addition to blood testing, doctors will take a full medical history and perform a physical exam. They’ll look for signs and symptoms associated with B12 deficiency. A diagnosis can usually be made based on decreased B12 blood levels combined with deficiency symptoms.
B12 deficiency and sleep disturbances
There are several ways in which low B12 levels may potentially disrupt normal sleep patterns:
Fatigue
One of the most common symptoms of B12 deficiency is severe and persistent fatigue. This lack of energy can make it very difficult to get through the day. It can also lead to excessive daytime sleepiness. Fatigue may cause trouble staying awake and alert during the day. It may also impact the ability to fall asleep at night due to impairment of the normal sleep-wake cycle.
Neurologic symptoms
When vitamin B12 levels get very low, nerve damage can occur. This leads to paresthesia, which causes abnormal sensations like pins and needles, burning, itching or tingling. Paresthesia commonly affects the hands and feet. The constant odd sensations can make it difficult to fall asleep or stay asleep through the night.
Restless legs syndrome
Restless legs syndrome (RLS) is a condition characterized by uncomfortable sensations in the legs combined with an irresistible urge to move them. Symptoms are most bothersome at night. Studies indicate that B12 deficiency may predispose some people to restless legs syndrome. RLS is closely linked to disrupted sleep.
Circadian rhythm imbalance
Low B12 levels are associated with reduced melatonin secretion. Melatonin is the sleep hormone produced at night to induce drowsiness. Impaired melatonin production can throw off the body’s natural circadian rhythms. This deregulation makes it harder to fall and stay asleep.
Depression and anxiety
Neuropsychiatric disturbances like depression and anxiety frequently occur in B12 deficiency. Psychological distress can in turn cause major sleep troubles, such as insomnia.
Scientific research on B12 deficiency and sleep
While the exact mechanisms are still being investigated, a number of studies have uncovered links between low vitamin B12 levels and various sleep disorders:
Insomnia
A cross-sectional study in Taiwan looked at B12 status in patients with and without insomnia. Researchers found that serum B12 concentrations were significantly lower in those with insomnia compared to the control group. The prevalence of deficiency was also higher in the insomnia group.
Excessive daytime sleepiness (EDS)
In a study of 140 older adults in Brazil, researchers investigated connections between vitamin B12 levels and EDS. Participants with EDS had substantially lower serum B12 levels compared to those without EDS.
Delayed sleep phase syndrome (DSPS)
A trial in Japan examined 8 patients with DSPS, a disorder in which the circadian rhythm is shifted later. After 3 months of B12 supplementation, 7 out of 8 patients had renormalized sleep wake cycles. This suggests B12 may help correct misaligned circadian rhythms.
REM sleep behavior disorder (RBD)
RBD involves acting out vivid dreams during REM sleep due to paralysis impairment. A cohort study followed 17 patients with B12 deficiency and RBD. With B12 treatment, almost all patients experienced complete remission of RBD symptoms.
While more research is still needed, these study findings indicate that restoring normal vitamin B12 levels may help relieve various sleep disorders.
Treating B12 deficiency
The main treatment for B12 deficiency involves B12 replacement therapy. Patients are given supplemental B12 in one of two forms: cyanocobalamin or hydroxocobalamin. For those with decreased intrinsic factor from pernicious anemia, B12 shots or high oral doses are necessary. Improvement of symptoms is typically seen within a few weeks of starting therapy.
Along with B12 supplementation, the underlying cause of deficiency should be addressed. For instance, pernicious anemia requires lifelong B12 injections or high oral doses. Those with decreased stomach acid may benefit from medication. Digestive disorders need appropriate disease management.
When caught early, the neurologic symptoms of B12 deficiency can be reversed with prompt treatment and normalization of B12 levels. However, nerve damage may become permanent if the deficiency goes uncorrected for an extended period.
Dietary changes for increasing B12 intake
Anyone at risk for deficiency should aim to consume more vitamin B12 foods:
– Beef and calf liver: 1 serving contains over 1,000 mcg B12, well over the RDA.
– Fish and shellfish: 3 ounces of cooked clams provides over 100 mcg B12.
– Meat: 3 ounces of beef chuck contains about 3 mcg.
– Eggs: One large egg has about 0.6 mcg.
– Dairy products: One cup of plain yogurt provides 1.4 mcg.
– Fortified foods: Many breakfast cereals and non-dairy milks are enriched with B12.
Vegans can meet needs by consuming B12 fortified foods or by taking a daily supplement providing at least 2.4 mcg. Those over age 50 should get extra B12 from fortified foods or supplements because of decreased absorption.
The bottom line
In summary, vitamin B12 deficiency appears to be associated with some types of disordered sleeping patterns such as insomnia, hypersomnia, delayed sleep phase syndrome and REM behavior disorder. Exact mechanisms connecting B12 and sleep are still under investigation. Fatigue, neurologic symptoms, circadian misalignment and mood disorders related to low B12 may mediate this relationship.
Correcting a B12 deficiency with supplementation, dietary changes or by treating the underlying absorption problem can potentially help normalize sleep. More clinical research is needed to establish B12 levels as a modifiable risk factor for sleep disturbances. Assessing B12 status may be warranted in those with unexplained insomnia or other sleep disorders.
References
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