The truth about vitamin B12 and insomnia

Vitamin capsules scattered across table

We all know that diet can have a profound effect on the quality of our sleep. Vitamins and minerals are vital to our health, and vitamin B12 plays a critical role in functioning normally every day. Low levels of vitamin B12 have been linked with fatigue and depression, but is there a link between vitamin B12 and insomnia?

What is vitamin B12?

Vitamin B12, also known as cobalamin, is essential to our wellbeing. It helps the body produce red blood cells and DNA, as well as maintaining a healthy nervous system. It is the largest and most structurally complex vitamin, and the only one to contain a metal ion, cobalt.

Low blood levels of vitamin B12 have been linked with a number of major health conditions, including dementia, depression, osteoporosis and age-related macular degeneration. Low levels of vitamin B12 can also lead to anaemia.

Despite its vital importance to our health, vitamin B12 deficiency is quite common. There are two possible causes of a vitamin B12 deficiency: inadequate intake, or inability to absorb it into the body. Vegetarians and vegans are particularly vulnerable, because B12 is derived from animal foods. Older people are also at risk because they are more likely to have problems absorbing B12.

Other at-risk groups include people with coeliac or Crohn’s disease, those who have had weight loss surgery, and those with atrophic gastritis or pernicious anaemia. These conditions can affect the body’s ability to absorb B12.

What are the symptoms of B12 deficiency?

One of the reasons that vitamin B12 deficiencies are so common is that the symptoms are so broad and varied that it can be easily overlooked or mistaken for something else.

Some of the symptoms include:

  • tingling or numbness in the hands, feet or legs

  • cognitive difficulties or memory loss

  • a swollen, inflamed tongue

  • difficulty walking/balance issues

  • anaemia

  • depression

  • weakness

  • fatigue

The only way to know for sure is through a blood test.

How does vitamin B12 affect sleep?

Vitamin B12 and insomnia have long been linked, however the research available remains inconclusive.

Several case studies have been published over the years in which vitamin B12 has helped patients with delayed sleep phase disorders. High doses of B12 were successful in bringing the subjects’ sleep-wake cycles back into a normal range. This suggests that B12 has an influence over our circadian rhythm, however researchers are yet to determine the exact connection.

Research has also shown that people with higher levels of vitamin B12 are less likely to suffer from depression. People with depression often also suffer from insomnia and other sleep disturbances. B12 also plays a role in the production of melatonin, a hormone that helps regulate our circadian rhythms. It is possible that a deficiency of B12 could lead to disrupted sleep patterns.

Vitamin B12 also helps in the production of energy. Low levels of B12 cause a reduction in the formation of red blood cells. The blood cells don’t develop properly, and are unable to move into the bloodstream at the correct rate.

This can lead to anaemia, a condition in which not enough oxygen is transported to the vital organs. This can lead to fatigue and weakness.

While there is no evidence that B12 can provide an energy boost in those with healthy levels of the vitamin, increased levels of B12 in those with a deficiency may improve symptoms of fatigue.

What are the best sources of B12?

Vitamin B12 is found almost exclusively in animal-based products.

Unused B12 is stored in the liver, so it’s no surprise that the number one source of the vitamin is organ meat. Just 75g of liver provides a whopping 881% of the recommended daily intake of B12, while the same amount of beef kidney provides 311% of the RDI.

If you find those options somewhat unappetising, other good sources of B12 include red meat, poultry, fish, eggs and milk.

Articles about vitamin B12 often refer to fortified products such as cereals that can provide a dietary source of B12. However, fortified foods are much less common in Australia than in the US. While some yeast spreads, soy milks and soy-based meat-replacement products are fortified with B12, it is recommended that vegetarians and vegans take a supplement in order to maintain adequate levels.

If supplements are required, most over-the-counter multivitamins contain more than enough B12 to cover your daily requirement. In some cases, injections may be required to achieve normal levels.

What other vitamins and minerals can affect sleep?

Vitamin B12 is not the only vitamin involved with healthy sleep. Vitamin D, vitamin E, vitamin C and vitamin B6 all have different roles to play in making sure you get a good night’s sleep. Minerals, such as magnesium, are also important.

As with all aspects of our health, the most important thing is to maintain a balanced diet and to talk to your doctor if you have any concerns.

IF YOU’RE EXPERIENCING PERSISTENT DISRUPTIONS TO YOUR SLEEP, CONSULT WITH A PHARMACIST OR TRUSTED MEDICAL PROFESSIONAL TO DISCUSS POSSIBLE SOLUTIONS.

Any advice provided in this content is of a general nature and does not take into account your objectives, health or needs. The information in this post is not intended to substitute medical advice, diagnosis or treatment and should not be exclusively relied on to diagnose or manage a medical condition. You need to consider the appropriateness of any information or general advice we give you, having regard to your personal situation, before acting on our advice or purchasing any over-the-counter sleep product.



Peter Shakespeare