There are so many nutrients that play a role in mental health. We can’t accurately test for every nutrient deficiency in a convenient and well validated way. Luckily, B12 is one of the nutrients that we can actually test with a fair amount of confidence about the accuracy of the results in many cases. 

There have been a number of studies about B12 and depression. Studies have found that lower levels of B12 in certain populations may be related to depression symptoms. Higher intake of B12 has been associated with a lower risk of depression. However, it’s unclear how much B12 supplements improve depression symptoms. Some studies have show promise, other have not. B12 may also help with other symptoms that are common among depressed patients such as low energy.

B12 might impact mental health because of its role in producing certain neurotransmitters in the brain which are important for mood regulation. It can also help lower other compounds in the body such as homocysteine which have been linked to depression.  

Vitamin B12 deficiency can happen when you are not consuming enough of the vitamin. Common sources of B12 are chicken, eggs, fish, dairy and meat. It’s also fortified in certain foods like some brands of nutritional yeast and is easily found in supplement form. Deficiency can also happen when you’re not absorbing enough B12 from the foods you eat. This can be due to a medical reason like gastritis or celiac disease. B12 deficiency has also been linked to certain medications. Sometimes we don’t know why the body is not able to absorb B12 well from the diet. 

The easiest way to determine if vitamin B12 deficiency is playing a role in your mental health is to test for deficiency and treat it. Not everyone needs a B12 test but it’s something I do for many of my patients along with other testing to determine if hormones or nutrient deficiencies are playing a role in their mental health symptoms.