Just like your car needs all its fluids to run properly, we need vitamins.

When we lack all the vitamins our bodies need, signs of wear and tear show up. Bleeding gums, brittle, thinning hair, mood swings, and loss of muscle control are all signs of vitamin deficiency. Diet changes and sun exposure can help prevent and address vitamin deficiencies. Supplements can also help. 

This guide explains common symptoms associated with several vitamin deficiencies. It won’t cover every possible deficiency. But we will give you the facts you need to detect a possible deficiency and consult with your doctor.

Common Vitamin Deficiency Symptoms at a Glance

What is a vitamin deficiency?

A vitamin deficiency occurs when our existing diets and habits lack the vitamins and minerals our bodies need. Over time, our bodies can absorb vitamins and minerals less effectively than they once did.1 This means we could be losing vitamins and nutrients without realizing it.

Understanding vitamin deficiency at a glance:

• There are 13 essential vitamins that regulate everything from DNA to nerve signals.
• Certain medications can interfere with how we absorb these essential vitamins.
• Dietary changes or supplements may help restore vitamin levels. But this varies depending on the deficiency and its cause.
• Talk with your health care professional before starting a vitamin supplement.

What are essential vitamins?

Essential vitamins are so named because we can’t live without them.² There are 13 main “essential” vitamins, each with specific functions.³

“An essential nutrient is one the body requires but cannot manufacture or cannot manufacture in sufficient quantities to meet its needs. It therefore has to come from food and, when food intake or absorption is inadequate, from appropriate supplementation," said  James B. LaValle, clinical pharmacist, board-certified clinical nutritionist, precision health strategist, and Founder of Metabolic Code®.

What are common symptoms of vitamin deficiencies?

Vitamins support many key functions in your body, from producing energy to maintaining healthy nerves, vision, and skin. When you don’t get enough of certain vitamins, you may notice changes in how you feel or how your body functions.

Many people can improve their vitamin intake by eating a wide variety of healthy foods. This means including leafy greens, citrus fruits, whole grains, meat, fish, nuts, and seeds in your daily diet.³ But some concerns can make it difficult to get enough nutrients from food alone. Allergies, medications, health conditions, and food sensitivities may limit your options. In those cases, a health care professional may recommend a supplement.

“Symptoms tell us where to look," LaValle said. "They do not make the diagnosis.” For LaValle, the starting point of a vitamin deficiency diagnosis is a comprehensive evaluation and symptom questionnaire that digs into medical history, dietary history, and bloodwork. 

To diagnose a vitamin deficiency, LaValle said “I would want to know about appetite, food restrictions, gastrointestinal symptoms, antibiotic history, previous gastrointestinal surgery, alcohol intake, physical activity, sleep, stress, medical conditions, and all prescription and over-the-counter products.”

Symptoms of vitamin deficiencies vary depending on the nutrient involved. Talk with your doctor if you experience any of the following:

Fatigue and low energy

Persistent fatigue or weakness can sometimes indicate anemia. Anemia is a condition where the body lacks healthy red blood cells to carry oxygen to its tissues. Deficiencies in vitamins B6, B9, or B12 may contribute to anemia.⁴

Because the body cannot store B vitamins for long, you need to replenish them regularly. Fish, chicken, beef, beans, nuts, and seeds are useful sources.^3,5

A vitamin C deficiency is often called scurvy. Like a vitamin B deficiency, it can also cause fatigue and weakness.⁶ Citrus fruits and many other fruits and vegetables provide vitamin C.

Brittle nails and hair

Changes in your hair, skin, or nails may be associated with low vitamin A or B levels.⁷ Vitamin A helps maintain healthy cells and skin. It is also commonly included in hair-growth vitamins.

Fish provides vitamin A. Many yellow, orange, and dark-green fruits and vegetables contain beta-carotene. The body converts beta-carotene into vitamin A.⁸ Sources include sweet potatoes, carrots, butternut squash, and leafy greens.

Mouth ulcers and bleeding gums

Skipping floss isn’t the only cause of bleeding gums. They may also occur with a vitamin C or vitamin B12 deficiency.⁹ Low B12 levels can cause recurrent mouth ulcers. Swollen or bleeding gums can be a sign of severe vitamin C deficiency.⁶

Older adults may not absorb B12 well because the body produces less stomach acid with age.¹⁰ Adding more clams, trout, meat, poultry, eggs, and dairy products to your diet can help. Plant-based foods do not naturally contain B12. But fortified cereals, nutritional yeast, and some plant-based milks can be useful sources.³

Vision changes and difficulty seeing at night

Vitamin A deficiency is a known cause of night blindness.⁷ It can also cause corneal xerosis, a condition in which the cornea becomes dry and dull. Without treatment, severe cases may lead to vision loss.¹¹

Other vitamin deficiencies may also affect the eyes. Low vitamin B2 levels have been associated with blurred vision. At the same time, deficiencies in B9 or B12 may contribute to optic neuropathy, or damage to the optic nerve. Research has also linked insufficient levels of vitamins B9, B12, C, and E to age-related macular degeneration. Vitamin K deficiency may cause bleeding in or beneath the retina.¹¹

A varied diet can help supply these nutrients. Leafy greens contain folate and vitamin K, while shellfish and fortified nutritional yeast provide B12. Avocados, pumpkin, nuts, seeds, and plant-based oils contain vitamin E. You can add folate to your diet through fruits, vegetables, and legumes. But the body absorbs the form used in folic acid supplements more readily.^3,12

Tingling or numbness in hands and feet

Tingling or numbness in the extremities is most closely associated with a vitamin B12 deficiency.¹³ B12 helps maintain healthy nerves, so insufficient levels can affect sensation. The body cannot produce B12 on its own. So it's important to get enough through food, fortified products, or supplements.³

Mood changes

B vitamins play a role in producing brain chemicals that influence mood. Low levels of folate and B12 have been associated with depression.¹⁴ 

Frequent irritability may also occur with a vitamin C deficiency.¹⁵ But deficiencies are not the only possible cause of mood changes.

Memory and concentration problems

A B-vitamin deficiency may contribute to memory problems, confusion, or difficulty concentrating.7 But these symptoms can have many causes. So you'll want to talk with your doctor rather than trying to diagnose or treat them on your own. A blood test can help identify whether your vitamin levels are low.

Muscle control problems

Deficiencies in vitamin E or certain B vitamins can affect coordination. They may contribute to ataxia, a condition involving problems with balance and muscle control.¹⁶

Vitamin E protects cells from free radicals. These are unstable molecules that can damage cells. It also supports immune function and helps prevent blood clots from forming. A severe deficiency can damage nerves and muscles, leading to weakness or loss of coordination.¹⁷

Sources of vitamin E include almonds, sunflower seeds, peanut butter, plant-based oils, avocados, and mangos.

LaValle cautions that vitamin deficiency symptoms may mask other causes. “These symptoms can result from nutrient deficiencies, but they can also be caused by thyroid problems, anemia, neurological conditions, cardiovascular issues, medication effects, kidney disease, or other medical problems.”

How to diagnose and treat vitamin deficiencies

Vitamin deficiencies can have several causes, including diet, absorption problems, and medication use. Prolonged use of antibiotics or anti-seizure medications has been linked to vitamin deficiencies. If you experience one or more of the symptoms listed above, talk with your health care professional. They may recommend vitamin testing to identify the cause.¹⁸ 

Get tested for vitamin deficiencies

Your doctor can order you a vitamin panel test, but you can also pay a local lab to run one for you. Vitamin panels test your blood for the 13 essential vitamins. If you take supplements, ask the laboratory or your health care professional whether you should stop taking them before testing.

Costs, coverage, and turnaround times vary by test and laboratory. Before ordering a test, check the price. You may be able to pay using a health savings account (HSA) or flexible spending account (FSA), if applicable.

Change your diet

All 13 essential vitamins occur in food. Adjusting your diet may help restore your body’s essential vitamins.³ But over time, we absorb less of the vitamins that we once did. And some medications require you to stop eating certain foods that may be rich in the essential vitamins. If you’re not able to get your vitamins from food, consider a supplement.

Consider a supplement 

You may have heard of supplements in the context of hair loss treatments. Supplements can also help replace vitamins and minerals you may be missing. But be careful when adding supplements to your diet. Taking too much supplemental vitamin A can be harmful. Talk with your health care provider before taking any supplements.¹⁹ 

Supplements can fill small gaps in your diet.  Your health care provider can guide you based on your personal health and whether you take medications or have a health condition.

Frequently asked questions

What is the most common vitamin deficiency?
Vitamin A deficiencies, while rare in the United States, are extremely common worldwide. A chronic lack of Vitamin A can cause blindness.7 

What are some of the diseases caused by vitamin deficiency?
Common conditions caused by a lack of vitamins include depression, ataxia (loss of coordination), and anemia (chronic fatigue). Deficiencies in vitamins C, D, or zinc can weaken the immune system, leading to a range of medical conditions.²⁰ 

How long does it take to fix a vitamin deficiency?
It can take weeks or even months to fix a vitamin deficiency. It often takes about the same length of time to develop a vitamin deficiency.²¹ 

What are the first signs of B12 deficiency?
Mouth ulcers can indicate a B12 deficiency, as can tingling or numbness in the hands and feet. Depression and changes in mood might also be a sign of a B12 deficiency.¹⁴ 

Sources

1. Russell R. Factors in Aging that Effect the Bioavailability of Nutrients. The Journal of Nutrition. April 2001. Found on the internet at https://www.sciencedirect.com/science/article/pii/S0022316622148558

2. National Institute on Aging. Vitamins and Minerals for Older Adults. Jan. 2, 2021. Found on the internet at https://www.nia.nih.gov/health/vitamins-and-supplements/vitamins-and-minerals-older-adults

3. National Library of Medicine. MedlinePlus. Vitamins. Found on the internet at https://medlineplus.gov/ency/article/002399.htm

4. American Society of Hematology. Anemia. Found on the internet at https://www.hematology.org/education/patients/anemia

5. Hannah M., et al. B Vitamins: Functions and Uses in Medicine. The Permanente Journal. June 17, 2022. Found on the internet at https://pmc.ncbi.nlm.nih.gov/articles/PMC9662251/

6. Maxfield L., et al. Vitamin C Deficiency. StatPearls. National Center for Biotechnology Information. Nov. 12, 2023. Found on the internet at https://www.ncbi.nlm.nih.gov/books/NBK493187/

7. Almohanna H.M., et al. The Role of Vitamins and Minerals in Hair Loss: A Review. Dermatology and Therapy. Dec. 18, 2018. Found on the internet at: https://link.springer.com/article/10.1007/s13555-018-0278-6 

8. Grune T., et al. β-carotene is an Important Vitamin A Source for Humans. The Journal of Nutrition. Oct. 27, 2010. Found on the internet at https://pmc.ncbi.nlm.nih.gov/articles/PMC3139236/

9. Boukssim S., et al. Oral Manifestations of Vitamin B12 Deficiency Associated with Pernicious Anemia: A Case Report. International Journal of Surgery Case Reports. June 2024. Found on the internet at: https://pmc.ncbi.nlm.nih.gov/articles/PMC11254220/ 

10. Park S., Johnson M.A. What is an adequate dose of oral vitamin B12 in older people with poor vitamin B12 status? Nutrition Reviews. August 2006. Found on the internet at https://pubmed.ncbi.nlm.nih.gov/16958314/

11. Pereira A., et al. Associations Between Vitamin Deficiencies and Ophthalmological Conditions. Clinical Ophthalmology. July 19, 2023. Found on the internet at: https://pmc.ncbi.nlm.nih.gov/articles/PMC10363387/ 

12. Centers for Disease Control. Folic Acid: Sources and Recommended Intake. July 15, 2026. Found on the internet at https://www.cdc.gov/folic-acid/about/intake-and-sources.html

13. Badar Ahmed. Neuropsychiatric Disorders Associated With Vitamin B12 Deficiency: An Autobiographical Case Report. Cureus. Jan. 21, 2022. Found on the internet at https://pmc.ncbi.nlm.nih.gov/articles/PMC8858590/

14. Sangle P., et al. Vitamin B12 supplementation: Preventing onset and improving prognosis of depression. Cureus. Oct. 26, 2020; Found on the internet at https://pubmed.ncbi.nlm.nih.gov/33251075/

15. Bari B., et al. Mild vitamin C deficiency is common in the inpatient psychiatric setting. The Journal of Clinical Psychiatry. June 14, 2023. Found on the internet at https://pmc.ncbi.nlm.nih.gov/articles/PMC10428288/

16. National Ataxia Foundation. Ataxia with Vitamin B12 Deficiency. Found on the internet at https://www.ataxia.org/ataxia-with-vitamin-b12-deficiency/

17. National Institutes of Health. Office of Dietary Supplements. Vitamin E: Fact Sheet for Health Professionals. March 26, 2021. Found on the internet at: https://ods.od.nih.gov/factsheets/VitaminE-HealthProfessional/

18. Zempleni J., et al. Biotin and Biotinidase Deficiency. Expert Review of Endocrinology and Metabolism.Sept. 1, 2009. Found on the internet at: https://pmc.ncbi.nlm.nih.gov/articles/PMC2726758/ 

19. Daley S., et al. Vitamin A Toxicity. StatPearls. June 19, 2026. Found on the internet at: https://www.ncbi.nlm.nih.gov/books/NBK532916/ 

20. National Institutes of Health. Dietary Supplements for Immune Function and Infectious Diseases. March 10, 2025. Found on the internet at: https://ods.od.nih.gov/factsheets/ImmuneFunction-Consumer/ 

21. National Institutes of Health. Office of Dietary Supplements. Dietary Supplement Fact Sheets. Found on the internet at https://ods.od.nih.gov/factsheets/list-all/