9 Vitamin and Nutritional Deficiencies That May Cause Depression

Vitamin D can be derived from sunlight as well as some food sources. It’s involved in calcium absorption in the gut, among a variety of other functions, including serotonin regulation.

Scientific evidence suggests that there may be a link between vitamin D deficiency and depression. For instance, a 2018 literature review of 14 studies with a total of 31,424 participants found that deficiencies in this nutrient are associated with depression.

Consistent with older theories suggesting that lower serotonin could be the cause of depression, it has been proposed that a deficiency in vitamin D may lead to depression, in part due to causing lower levels of serotonin.

In addition, decreased blood concentrations of vitamin D have been linked to inflammation, which has also been associated with depression.

These findings led to a line of studies looking at whether vitamin D supplementation or indirect increases in vitamin D, such as via light therapy, could help improve depression symptoms. But the current collection of research has not yet shown that taking vitamin D supplements eases depression symptoms, and more research is needed.

Evidence, for example from 2005 and 2016 review studies, suggests that there may be a link between low blood levels of vitamin B12 and depression.

Plus, research from 2020 found that people who didn’t get enough vitamin B12 through their diet and, therefore, had lower blood levels of this vitamin, had a greater risk of depression compared with people with sufficient dietary intake and higher blood levels of B12.

A possible explanation for the link between low blood levels of vitamin B12 and depression is the “homocysteine hypothesis,” which suggests that high levels of the amino acid homocysteine may cause psychiatric symptoms.

Since some B vitamins, including vitamin B12, B9, and B6, are involved in homocysteine metabolism, it’s been theorized that low blood levels of these vitamins may lead to excess homocysteine, which in turn may affect brain functioning, leading to changes in mood and depressive symptoms.

Still, it’s unclear whether supplementing with vitamin B12 has a positive effect on depressive symptoms or depression. But some research suggests that taking a B12 supplement early on when lower blood levels of the nutrient are detected may delay the onset of depression. Plus, B12 supplementation may improve the effectiveness of antidepressants.

The National Institute of Health (NIH) recommends that adults get 2.4 micrograms (mcg) of vitamin B12 per day, though the recommendation rises to 2.6 mcg for people who are pregnant and to 2.8 mcg for those who are breastfeeding or chestfeeding.

Vitamin B12 is mainly found in animal-derived foods. Liver, kidneys, beef, and clams are some of the richest sources of this nutrient.

For this reason, it may be more difficult for people who don’t eat animal foods to get enough B12 through their diet. Still, some plant foods like seaweed or mushrooms may contain B12, and some products like nondairy milk replacements, nutritional yeast, or cereals may be fortified with the vitamin.

Keep in mind that insufficient dietary intake may not be the only possible cause of vitamin B12 deficiency. Other causes may include:

• a lack of intrinsic factor due to pernicious anemia
• taking certain medications like metformin or proton pump inhibitors for a long time
• surgery on your gastrointestinal tract

Folate (vitamin B9) is a B vitamin that’s found naturally in many foods. It’s involved in cell division, DNA, and other important biological processes.

Deficiency in this nutrient is associated with depression, and supplementing with this vitamin has been found to be beneficial for people with depression, especially for those with treatment-resistant depression.

Folate and its synthetic form folic acid are found in many foods including:

• leafy greens
• beans
• citrus fruits
• fortified grains

The NIH recommends adults consume 400 mcg of folate daily.

Getting too much of the synthetic form of vitamin B9 — folic acid — in supplemental form may have harmful effects, so it’s best to get vitamin B9 from food sources.

Magnesium

Magnesium is an essential micronutrient for many biological processes. Hypotheses that magnesium deficiency may be linked to depression are mainly based on animal studies. Human studies are needed before more definite conclusions can be drawn.

Still, though one study showed that participants who had a magnesium deficiency as well as depression experienced improved depression symptoms after supplementing with magnesium, clinical research has been inconclusive about whether taking a magnesium supplement may help reduce symptoms of depression in people who are not deficient in this nutrient.

Food sources of magnesium include:

• nuts
• seeds
• green leafy vegetables
• whole grains

Daily recommendations for this nutrient vary depending on your age and sex, but the NIH recommends between 400 to 420 milligrams (mg) for men and 310 to 320 mg for women.

Iron

Iron is a mineral vital for the body’s growth and development. Iron deficiency is one of the most common deficiencies worldwide. It affects women more than men. In fact, one study found that 57.5% of female participants had lower levels of iron, compared with 7.6% of male participants.

In severe cases, iron deficiency develops into iron deficiency anemia (IDA), which is when iron blood levels are so low that they negatively affect red blood cell production.

Some evidence suggests a possible association between iron deficiency and depression. For instance, in one study, participants who reported having IDA were more likely to also report having depression.

Another study noted that women with low iron levels who were pregnant had higher levels of depression at the start of the study and were more likely to develop depression during pregnancy.

Some research found that people with IDA who took an iron supplement experienced a significant decrease in psychiatric disorders, including depression, compared with people with IDA who did not take an iron supplement.

These findings indicate that for people who have iron deficiency anemia or show signs of iron deficiency anemia in addition to depression, treating and managing this condition may prevent depression.

Still, more research is needed on the link between iron deficiency and depression and whether taking an iron supplement may be beneficial.

Foods rich in iron include red meat, fish, and poultry. The NIH recommends that most adults consume between 8 to 18 mg of iron daily, depending on age, gender, and diet.

Zinc

Zinc is an essential trace element crucial for brain growth and development. It’s also involved in cellular metabolism, a set of chemical processes that fuel our cells and keep us alive.

Having balanced zinc levels is vital for zinc homeostasis in various parts of the brain, including those associated with depression, such as the hippocampus, amygdala, and cerebral cortex. This means that zinc levels are in a constant, stable state, making for optimal function within those brain areas.

Current research studies have shown that there may be a link between zinc deficiency and depression, and that zinc supplements can be used alongside antidepressant medication to alleviate symptoms of depression.

Besides taking supplements, you can get zinc through foods like red meat, oysters, and crab. The NIH recommends men and women consume 11 mg and 8 mg of zinc daily, respectively.

Omega-3 fatty acids

Omega-3s are fatty acids involved in enhancing brain function and reducing inflammation.

Studies have shown that there may be a link between depression and omega-3 deficiencies, though it’s important to note that research is overall still inconclusive. While taking an omega-3 supplement may help reduce depression symptoms for some, it may not be a solution for all.

Your body cannot produce omega-3s. You need to get them from foods or supplements. Foods rich in omega-3s include fatty fish, nuts, and plant oils.

Limited research suggests that deficiencies in manganese and selenium may be associated with depression. However, it’s important to keep in mind that deficiencies in these nutrients are extremely rare.

Manganese

Manganese is a mineral nutrient that humans need in small amounts. It’s plentiful through some food sources, which is why manganese deficiency is quite rare.

Although a deficiency in manganese has been linked to depressive and anxiety symptoms based on a single study, research has not yet shown that supplementation with manganese can alleviate symptoms in people with depression.

Foods rich in manganese include:

• whole grains
• clams
• oysters
• mussels
• nuts
• soybeans
• rice
• leafy vegetables
• coffee
• tea
• black pepper

The NIH recommends 2.3 mg daily for men and 1.8 mg daily for women. However, it’s important to note that daily recommendations are based on a variety of factors including age and sex.

Selenium

Selenium is a vital trace element and crucial for brain function. It’s also involved in proper thyroid function.

Selenium has been suspected to play a role in the development of depression. However, studies have not been consistent about its exact role. Some studies observed that supplementing with selenium may help ease depression symptoms, while others did not.

Selenium can be derived from seafood, poultry, dairy, and eggs. Most adults are recommended to consume around 55 mcg of selenium daily by the NIH.

If you suspect a vitamin deficiency may be contributing to symptoms of depression, it can help to speak with your doctor about it. They may recommend a blood test to confirm any possible deficiencies.

Once you know for sure whether you have a nutrient deficiency, you and your treatment team can discuss whether taking a supplement may be worth a try. Ideally, your primary care physician or internist and your therapist or psychiatrist should collaborate to determine the best treatment plan.

It’s important not to add any new supplements to your diet before talking to a healthcare professional first, as they can help find the ideal dose and determine if there are any potential medication interactions or side effects.

It’s good to keep in mind that evidence is often lacking as to whether taking a supplement to treat a deficiency may also reduce depression symptoms. Don’t be discouraged if a supplement doesn’t help. Depression is highly treatable, and you and your doctor can figure out the right treatment plan for you.

Treatment plans often involve a multifaceted approach, including therapy, medication, dietary changes, supplementation, and various self-help strategies.

Easing symptoms can take time, so do your best to stay patient. Try to be honest with yourself, your loved ones, and your care team about your experience with depression to find the best treatment options for you.