What Are Common Nutrient Deficiencies That Cause Anxiety?


Iron is essential for oxygen delivery from the lungs to organs and tissues as well as energy production and thyroid hormone production. All three of these functions massively impact brain function and in addition, iron is needed for the production of dopamine (motivation and reward neurotransmitter) and GABA (calming neurotransmitter). Iron deficiency can cause anemia, but can be deficient without anemia while causing other symptoms such as fatigue, exercise intolerance, hair loss, restless leg syndrome, and heavy menstrual bleeding. Iron deficiency also impacts the delivery of oxygen and energy to the brain which can cause cognitive function and mood problems including anxiety, ADHD, and depression.

B Vitamins

B Vitamins are a group of water soluble vitamins that have unique, but similar functions. 


Because of its role in DNA synthesis, red blood cell production, and methylation B12 has a large impact on systemic health, especially the immune and nervous system. B12 is essential for building the protective myelin layer of nerves, neurotransmitter signaling, and energy production which all impact stress, mood, and cognitive function. B12 deficiency can cause macrocytic anemia, anxiety, depression, concentration and inattention disorders, chronic stress, and chronic fatigue.


Folate (B9) is also an essential nutrient for DNA synthesis, red blood cell production, and methylation and is involved in B12 metabolism. Folate deficiency can cause megaloblastic anemia, poor immune function, and chronic fatigue as well as brain and mood problems including anxiety, depression, apathy, confusion, and dementia.

Vitamin B6

B6 is essential for many metabolic processes and is a cofactor in more than 50 different enzymes, including multiple mechanisms of mood and brain function. B6 directly promotes healthy brain function through its role in oxygen delivery, production of serotonin and norepinephrine, and conversion of glutamate (alert, excitatory neurotransmitter) to GABA (calming, inhibitory neurotransmitter). It also helps to balance blood sugar, which when imbalanced is a commonly overlooked cause of anxiety. B6 deficiency can cause anxiety, depression, insomnia, irritability, and confusion.


Magnesium is a mineral that is a cofactor for more than 300 different enzymes and is involved in nearly every metabolic process from DNA synthesis to muscle and nerve function to mood and brain health. It’s essential for energy production, plays a central role in the electrical conduction of the nervous system and heart, and can activate GABA receptors (calming, inhibitory neurotransmitter). Magnesium deficiency can cause many neurological problems including anxiety, depression, fatigue, panic attacks, chest tightness, headaches, muscle cramps and twitches, and chronic pain disorders.


Zinc is a mineral cofactor and antioxidant essential to healthy cellular, immune, thyroid, and cognitive function. Zinc deficiency can cause impaired sense of taste, pica, and infertility in men.  Zinc deficiency is linked to anxiety, depression, and concentration because it is needed for the function of GABA and NMDA receptors which balance the brain’s relaxing, inhibitory GABA pathway with the alert, excitatory glutamate pathway.

How Do I Know If Nutrient Deficiencies Are Causing My Anxiety?

Iron Deficiency

In my clinic I screen for iron deficiency with a complete blood count (CBC) and ferritin. A CBC screens for signs of anemia and ferritin checks how much iron is being stored in the body. Ferritin is often a better indicator of iron deficiency than other iron tests, because it’s more consistent and doesn’t fluctuate as much as iron and total iron binding capacity. If you suspect iron deficiency, talk to your health care provider about ordering the right lab testing for you.

B12, Folate, and B6 Deficiencies

In my clinical practice, I’ve found that blood tests for B12 and folate are not the most useful for identifying these nutrient deficiencies and the inflammation they can cause. Instead, I test blood homocysteine which is an amino acid that builds up when B12, folate, or B6 are deficient. High levels of homocysteine indicate high inflammation, especially in the cardiovascular system.

Magnesium Deficiency

There are blood tests for magnesium such as total serum magnesium or RBC magnesium, but it’s often normal unless there is severe magnesium deficiency. More reliable indicators of magnesium deficiency are symptoms such as anxiety, panic attacks, irritability, depression, insomnia, fatigue, muscle cramps, and muscle twitching. Magnesium is water soluble and excess magnesium supplementation will be excreted if it’s not needed.

Zinc Deficiency

Blood tests that directly test zinc are also unreliable unless the deficiency is severe. In my clinical practice I’ve found that the blood test RBC zinc is often normal even when the patient’s signs and symptoms indicate zinc deficiency. When evaluating zinc deficiency, I focus on the patient’s signs and symptoms including thyroid hormone production (which zinc is essential for!) as well as the blood marker alkaline phosphatase which has been demonstrated to be lower when zinc is deficient.

Why Do I Have Nutrient Deficiencies That Cause Anxiety?

When a nutrient deficiency is identified, it’s important to ask why. Nutrient deficiencies are often the result of other health problems. Healing the cause of nutrient deficiencies provides better long term results than supplementation alone.

Poor Nutrient Intake

The most straight forward reason for nutrient deficiencies is a low intake of nutrients due to poor diet and malnourishment. If there is no reason that the nutrient is being used or lost at an accelerated rate nutrient deficiencies can be corrected through diet and supplementation.

Digestive Malabsorption

You might be eating all the right things, but are not able to absorb nutrients correctly. Adequate stomach acid, digestive enzymes, gallbladder function, gut function, and a healthy microbiome are all needed to help you extract nutrients from your food. If you experience digestive distress or irregular bowel movements, discuss malabsorption with your doctor.

Celiac Disease

Malabsorption, weight loss, and vitamin and mineral deficiencies are common in people who have undiagnosed celiac disease or gluten sensitivity. Celiac Disease and gluten sensitivity can be screened for with blood testing followed by elimination and reintroduction of gluten while working with your health care provider.

Digestive Infections

Digestive infections in the stomach, small intestine, or large intestine can cause nutrient deficiencies. Pathogens (bacteria, viruses, parasites, fungi, and worms) can steal nutrients and block absorption. In the case of iron deficiency, lowering iron due to chronic infection may be a preventive measure to protect you from inflammatory overload.⁠ In my clinic, we screen for digestive function and infections with a simple and effective stool test.

High Stress

High stress can increase the use of nutrients involved in the nervous system and energy production, especially B vitamins and magnesium.

Genetic Mutations

Folic acid is a synthetic version of folate and is an added ingredient in many processed fortified foods and supplements. This can be a problem for up to 60% of Americans who have a genetic mutation of an enzyme called MTHFR (methylenetetrahydrofolate reductase) which prevents them from converting folic acid into its natural, methylated (active) form.

Chronic Bleeding Disorders

If you have heavy menstrual bleeding, hormone imbalance may be the root cause of your heavy bleeding and iron deficiency. This can become a vicious cycle, because the heavier you bleed the more iron you lose and the more iron you lose the heavier you will bleed.⁠

Just like in the case of heavy menstrual bleeding, undiagnosed digestive bleeding can cause iron loss. In these cases it may be difficult to replenish iron until the cause of bleeding is identified and addressed. If you have a heavy menses or suspect digestive bleeding, do not delay meeting with your health care provider⁠.

How To Heal Nutrient Deficiencies That Cause Anxiety With Functional Medicine

Healing Iron Deficiency

Iron is highest in foods like beef, lamb, chicken and other meats. There is iron in leafy greens as well, but not the type of heme iron that helps you with iron deficiency. You can also add iron to your food by cooking in cast iron cookware.⁠ It is also essential to identify the cause of iron deficiency and rule out heavy menstrual bleeding or chronic digestive bleeding as discussed above.

Healing B12, Folate, and B6 Deficiencies

Folate and B vitamins can be consumed in dark leafy greens, grass-fed meats, and wild-caught fish.

In my clinic, we use methylated B12 and folate in combination with B vitamins such as B6 to avoid problems with conversion (such as MTHFR) that can cause build up of homocysteine and inflammation. One of my favorite ways to supplement these nutrients is a high quality multivitamin.

Healing Magnesium Deficiency

Magnesium can be found in dark leafy greens, dark chocolate, pumpkin seeds, almonds, and avocado. However, due to lower magnesium in foods due to soil depletion and high stress magnesium supplementation is often helpful.

When supplementing it is important to take the right type of magnesium. For example, magnesium citrate increases bowel movements and would be more appropriate for someone who has slow bowels than someone who has too much bowel movement. One of my favorites for brain health, anxiety, sleep problems, and headaches is Magnesium-L-Threonate. Talk to your doctor about choosing the right magnesium supplement for you.

Healing Zinc Deficiency

Zinc can be found in foods including lamb, grass-fed beef, pumpkin and hemp seeds, avocado, as well as cashews and almonds. It is especially important for people with hypothyroidism to optimize their zinc intake because zinc plays an important role in the activation of thyroid hormone. In my clinical practice, I often recommend a multivitamin that includes B vitamins and zinc.


Cho Y-E, Lomeda R-A, Ryu S-H, et al. Zinc deficiency negatively affects alkaline phosphatase and the concentration of Ca, Mg and P in rats. Nutr Res Pract. 2007;1(2):113–119. doi:10.4162/nrp.2007.1.2.113.

Gaby MD, Alan R. Nutritional Medicine. Concord, NH: Fritz Perlberg Publishing; 2011.

Młyniec, Gaweł, Doboszewska, Starowicz, Nowak. Chapter Ten The Role of Elements in Anxiety. sciencedirect; 2017:295–326. doi:10.1016/bs.vh.2016.09.002.

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