B12, also known as cobalamin, is an essential vitamin that plays many important roles in the body. One of the questions surrounding B12 is whether it can improve mood. There are several hypothesized mechanisms by which B12 could potentially impact mood:
B12 and neurotransmitters
Some research has suggested that B12 may be involved in synthesizing neurotransmitters like serotonin, dopamine, and norepinephrine. These neurotransmitters regulate mood, so altered levels could affect emotions and mood. However, the impact of B12 levels on neurotransmitter production remains unclear.
B12 and homocysteine
Homocysteine is an amino acid linked to stress and mood disorders when elevated. B12 helps convert homocysteine into methionine. When B12 is low, homocysteine levels rise, potentially contributing to mood disturbances.
B12 deficiency and depression
Severe B12 deficiency can cause neurological symptoms like depression, even in the absence of anemia. This suggests B12 itself may directly impact mood regulation. Treating deficient patients with B12 has been reported to improve depressive symptoms.
Overall, there are some plausible ways B12 could influence mood, though direct evidence remains limited. Let’s examine what the current research says.
B12 deficiency and depression
Several studies have found associations between B12 deficiency and depression, especially in the elderly. For example:
– A 2013 meta-analysis of 10 studies found that B12 deficiency was associated with a 1.69 times higher risk of depression.
– A cross-sectional study of over 900 Korean adults over 65 found those deficient in B12 had a 1.58 times higher risk of depressive symptoms.
– A study of over 700 adults in Finland found very low B12 levels (
Study Participants Intervention Outcome Hvas et al. 2004 145 adults with B12 deficiency and depression 2 months B12 injections Depression scores improved more in the B12 group than placebo Okereke et al. 2010 100 older adults with B12 deficiency 12 weeks oral B12 or placebo Depressive symptoms improved more with B12 vs placeboThese studies provide some evidence that B12 supplementation can improve mood in those with deficiencies. However, the studies are small and short-term.
B12 and mood in healthy individuals
While B12 may help depressive symptoms in those with deficiencies, research on whether it benefits mood in healthy people with adequate B12 levels is more limited.
Several studies have examined associations between blood B12 levels and mental health in general populations:
– A study in over 2900 older adults found those in the top 25% of B12 levels had lower depression scores and odds of depression than those in the bottom 25%.
– A study in over 1500 middle-aged women found higher plasma B12 was associated with decreased anxiety.
– However, a study in over 2900 young adults found no links between B12 levels and mental health, anxiety, or depression.
These observational findings are mixed and cannot establish cause and effect. Higher B12 could improve mood, but it’s also possible those with better moods have healthier diets with more B12.
There are a few randomized controlled trials testing B12 supplements in healthy, non-deficient populations:
| Study | Participants | Intervention | Outcome |
|---|---|---|---|
| Stott et al. 2019 | 195 healthy women age 70-80 | 1 year oral B12 or placebo | No difference in mood, depression, or anxiety |
| Bryan et al. 2002 | 211 healthy young women | 1 month oral B12 or placebo | No improvements in mood |
These studies found no mood benefits from B12 supplementation in healthy populations without deficiencies. More clinical trial data is still needed.
Does B12 deficiency affect mood?
Based on the current evidence:
– B12 deficiency is associated with an increased risk of depression, especially in the elderly. Treating deficiency may improve depressive symptoms.
– However, benefits for mood have not been consistently demonstrated in healthy populations with adequate B12 status.
– While B12 is involved in important functions like neurotransmitter synthesis, direct evidence that it improves mood via these mechanisms remains limited.
– More rigorous clinical trials are still needed to determine if B12 supplements can enhance mood and mental health in those without deficiencies.
Who may benefit from B12 supplements?
The current research suggests certain groups are more likely to experience mood benefits from B12 supplementation or treatment of deficiencies:
– Older adults: Cognitive and mood disorders are more common with advancing age. Older adults also have higher rates of B12 deficiency, so may be more likely to respond.
– Vegetarians/vegans: Plant-based diets increase the risk of B12 insufficiency. Supplements may help stabilize mood in deficient vegetarian populations.
– Those with depression and B12 deficiency: Treatment of deficiency appears to improve depressive symptoms.
– Those with gastrointestinal disorders: Conditions like celiac disease and Crohn’s disease can impair B12 absorption from food. Supplements may help.
– Those taking acid-reducing medications: Medications like proton-pump inhibitors hinder B12 absorption, increasing deficiency risk.
If you fall into one of these higher risk categories, consult your doctor about testing your B12 status and whether supplements could benefit your mood and mental health.
Dosage considerations
There are no established recommendations for B12 intake specifically for mood. General daily intake recommendations to maintain healthy B12 levels are:
– 2.4 mcg for adults
– 2.6 mcg for pregnant women
– 2.8 mcg for breastfeeding women
The tolerable upper limit is set at 1000 mcg per day. Toxicity from excessive B12 is very rare.
Typical dosages used in studies showing mental health benefits range from 500-1000 mcg per day. It’s likely best to stick to the lower end of this range unless otherwise advised by your doctor.
B12 is available in oral supplements, sublingual tablets, nasal sprays, injections, and topical gels and patches. In those with absorption issues, injections tend to be more effective for raising B12 levels. Talk to your doctor about the best supplementation method for your needs.
Safety and side effects
B12 is considered very safe, even at high doses. No serious side effects have been reported from excessive B12 intake from food or supplements. Minor side effects like itching, rashes, and diarrhea have occasionally been reported with supplementation.
B12 has few interactions with medications. However, it should be used cautiously in those with gout or kidney stones, as it may exacerbate these conditions.
Conclusion
In conclusion, while B12 is linked to mood-regulating neurotransmitters and deficiencies are tied to increased depression risk, there is still limited direct evidence that B12 definitively improves mood in healthy populations. Treating deficiencies may boost mood in the deficient elderly and those with absorption issues. But there is currently little proof of cognitive and mental health benefits from B12 supplements in healthy people with adequate B12 intake. More research is needed to clarify if B12 has mood-enhancing potential for the general public. Those concerned about mood or mental health should first have their B12 status evaluated by a doctor before beginning supplementation.