The 10 Most Common Vitamin Deficiencies and How to Address Them

Written by James H. Lyons, BHSc Nutritional Medicine

James Lyons is a registered clinical nutritionist with special interest in preventative medicine, endocrine conditions and LGBTQI health. He is passionate about health education and patient autonomy, and he supports resources that empower everyone to make informed decisions about their health. James lives in the eastern beaches area of Sydney, Australia and works globally.

Nutrient deficiencies are notoriously tricky to diagnose and treat – the symptoms of an iron deficiency can look like a vitamin D deficiency, and how much of any nutrient you are really absorbing through your diet? Some deficiencies respond to diet changes, while others require supplementation – but sometimes supplementation is dangerous. To make it simple, we've identified the top 10 most common nutrient deficiencies, how to spot them, and what to do next:

1. Iron

Iron deficiency is the most common nutrient deficiency – in fact, it is the most common health problem in the world.

Iron is an essential component of haemoglobin, a protein found in red blood cells that carries oxygen through the body. Low levels of iron cause red blood cells to contain poorly formed or completely missing haemoglobin, leading to impaired oxygen delivery and anaemia.

Iron is also required for a strong immune system, mood stability, cognition and mental health, DNA synthesis, growth, and it even acts as an antioxidant.

Symptoms of iron deficiency include:

Fatigue
Weakness
Lethargy
Shortness of breath
Frequent infections, or slow recovery
Dizziness
Coldness in hands and feet
Headaches
Pale skin, particularly inside the eyelids
Chest pain
Poor quality hair and nails
Heavy menstrual periods
Unusual cravings for foods
Desire to eat things that aren't foods
Insomnia

Iron deficiency is usually caused by inadequate dietary intake, but other causes can include subtle internal bleeding, inflammatory bowel disease, undetected infections, absorption issues or liver conditions. Speak to your doctor if you suspect you may have an iron deficiency to confirm the diagnosis.

A mild iron deficiency may be resolved by incorporating iron-rich foods into the daily diet, including beef, chicken, parsley, tempeh, tofu and quinoa.

TIP: Iron is difficult for the body to absorb. Eat iron-rich foods with vitamin C, which improves its digestion and absorption by up to 75%. Avoid calcium-rich foods such as milk, cheese or yoghurt as calcium inhibits iron's absorption.

Supplementation may be recommended for moderate to severe deficiencies and anaemia. However, the severity of the deficiency needs to be confirmed with a blood test before taking iron as high doses can accumulate, leading to toxicity and liver damage. For those who need supplementation, Nu U Nutrition’s Liquid Iron supplement offers a vegetarian and vegan friendly solution with Vitamins B2, B6, B12 and Vitamin C for an easy-on-the-stomach solution.

2. Vitamin D

Over 1 billion people worldwide suffer from insufficient levels of vitamin D. Most vitamin D in the body is created in a chemical reaction that occurs when UV radiation from the sun interacts with skin cells. It is also available in small amounts from certain foods, though some of this vitamin D is lost during digestion.

Deficiency can be caused by multiple factors, especially the amount of UV exposure that the skin receives. This can be affected by latitude, season, weather conditions, air pollution and skin tone – people with fair skin types produce six times more vitamin D than those with dark skin.

Symptoms of vitamin D deficiency include:

Fatigue
Depressed mood
Anxiety
Muscle aches and weakness
Osteoporosis
Headaches
Dizziness
Loss of appetite
Frequent infections

The first step to solving a vitamin D deficiency is to confirm the diagnosis with a blood test. Supplements are then prescribed with particular dosage for the individual. Taking a vitamin D supplement without a clear vitamin D deficiency can lead to toxicity. Improving intake of vitamin D rich foods is a safer way to boost vitamin D before getting a blood test. Try UV-exposed mushrooms, salmon, tuna, sardines and tofu.

3. Vitamin B12

Vitamin B12 (cobalamin) is a vitamin with a cobalt centre. It is essential for enzymatic reactions and required for the production of red blood cells, nerve function, DNA synthesis and brain health. It is a water soluble vitamin, meaning that it is easily excreted from the body in times of stress.

People at risk of vitamin B12 deficiency are vegetarians, vegans as there are only a few plant-based sources of vitamin B12. Absorption of vitamin B12 decreases with age, so the elderly are also at risk.

Symptoms and consequences of a B12 deficiency are serious:

Lethargy
Muscle weakness
Nerve damage
Numbness or tingling
Depressed mood
Irritability
Poor memory
Dizziness
Dry eyes
Eyesight problems
Weight loss
Abdominal pain

Once a vitamin B12 deficiency is established, supplementation is required to restore healthy levels. Sublingual or liposomal supplements are effective, but the absorption of vitamin B12 is more complex than other vitamins, and requires a particular protein called intrinsic factor found in the gut. People who are unable to create this protein may require vitamin B12 injections.

Moderate insufficiencies may be rectified by increasing intake of B12-rich foods such as meat, fish, eggs, tempeh, miso, and raw vegetables.

4. Zinc

Zinc is an essential mineral for over 300 enzymatic reactions throughout the body and is required for growth and development, hormone production, immune function, energy production, and antioxidant protection. It is mostly found in the bones, teeth, skin, liver, muscles, immune cells and testes.

Zinc deficiencies are very difficult to confirm and often go undetected. With zinc being involved in so many different functions in the body, a deficiency can cause vague or non-specific symptoms:

Slow recovery from infections or wounds
Weak nails
Brittle hair
Acne or eczema
Stretch marks
Alopecia
Loss of taste
Salt cravings
Diarrhoea
Low testosterone
Poor mood
Apathy

Zinc deficiency is usually caused by an insufficient dietary intake of the mineral and is best detected by a qualified nutritionist. Other causes can include underlying infections, or impaired absorption due to a gastrointestinal condition.

Boost your intake of zinc-rich foods such as oysters, pumpkin seeds, whole grains and nuts to restore a mild insufficiency. Supplements can effectively restore zinc levels in the body but taking zinc can be dangerous without supervision from a qualified health practitioner.

5. Magnesium

Magnesium is the “feel-good” mineral. It relaxes muscles and soothes the nervous system. It is also required for bone and teeth strength, muscle recovery and relaxation, nerve communication and brain function. Unfortunately, it is quickly depleted when the body is under any type of stress, including illness, emotional worries, or over-exercising, and arecent survey found that over 70% of the UK population could be deficient.

Symptoms of magnesium deficiency include:

Fatigue
Muscle soreness
Facial tics (e.g. twitching eye or eyebrow)
Restless leg syndrome
Fatigue
Migraines
Insulin resistance
High blood pressure

Magnesium is fairly easy for the body to absorb, either taken orally or topically. Epsom salt baths or magnesium oil sprays are effective treatments for muscle fatigue or soreness, as the magnesium can absorb through the skin directly to the muscles. Learn more about Nu U Nutrition’s magnesium oil spray, suitable for vegetarians and vegans, and with 200ml per bottle. Oral magnesium supplements are generally considered safe and are best absorbed in powdered form rather than tablets or capsules.

To boost your dietary intake of magnesium, go for whole grains, green leafy vegetables and nuts.

6. Calcium

Calcium isn't just for strong bones and teeth – it is needed by every cell in the body, especially during times of peak growth like pregnancy, foetal development, puberty, and body-building.

Calcium is essential for cell signalling, particularly between cells in the heart. To supply the heart with what it needs to continue beating, the body will do everything it needs to do to ensure that calcium levels in the blood remain constant. When there isn't enough calcium in the blood (i.e. a state of deficiency), calcium is taken out of the bones to supply the blood. This results in weak, brittle bones and leads to osteoporosis.

Symptoms of a calcium deficiency include rickets in children, and osteoporosis later in life. Other symptoms can include:

Back and leg cramps
Confusion
Depression
Headache
Vision disturbances
Vomiting
Dry scaly skin
Brittle nails
Coarse hair
Memory loss
Abnormal heart rhythms

The most common cause of calcium deficiency is low vitamin D, followed by other health conditions such as kidney disease, and some medications. It is important to supply the body with enough calcium through the diet from rich sources such as tahini, broccoli, and dairy.

7. Vitamin A

Ever heard that eating carrots helps you see in the dark? Vitamin A precursors are found in carrots, and a deficiency in this vitamin is the world's leading cause of blindness. Vitamin A is the first fat-soluble nutrient on this list – it requires dietary fat for its absorption, and it acts in fatty parts of the body such as eyes, skin, and cell membranes. It also has roles in bone and teeth development and strength.

More than 75% of people who eat a western diet are vitamin A deficient, and an estimated 30% of Indian women suffer from vitamin A deficiency. Even a mild vitamin A deficiency can result in temporary eye damage.

Other symptoms include:

Impaired night vision
Growth and developmental delay
Frequent infections
Dry eyes
Dry, scaly skin
Respiratory infections

Boost your dietary intake of vitamin A to resolve a deficiency. Organ meats and fish are the richest animal sources of vitamin A. Plant-based sources include sweet potatoes, carrots, and dark leafy green vegetables, but keep in mind that the pro-vitamin A in these sources requires additional conversion in the body to form vitamin A. This conversion requires another commonly deficient nutrient – iron.

8. Iodine

Iodine deficiency is one of the most common nutrient deficiencies, affecting nearly one third of the world's population. This trace mineral has a very particular role in the body – it is required for the formation of thyroid hormones, and to ensure the health of the thyroid gland. This gland is kind of a “control centre” for metabolism, growth and development, with influence on reproductive hormones, brain health, and bone maintenance.

Deficiency in iodine can cause hypothyroid states, where the thyroid is unable to produce adequate amounts of thyroid hormones. The thyroid may swell into a goitre in an effort to “trap” more iodine.

Common symptoms include:

Unintentional weight gain
Increased heart rate
Shortness of breath
Sensitivity to the cold
Hair loss
Dry skin
Dry mouth, or lack of saliva
Digestive issues
Muscle and joint pain
Serious consequences in children include developmental and cognitive abnormalities.

The best way to remedy an iodine deficiency is to increase dietary intake of iodine. Supplementation is only safe under direction of a qualified practitioner as high levels can be toxic and may cause harm to the thyroid gland.

Dietary sources of iodine include sea vegetables such as kombu, nori, wakame, arame and hiziki; seafood, and dairy – but the amount of iodine in these sources varies wildly depending on where it's grown and the levels of iodine in the ocean or soil there. Speak to a qualified nutritionist for personalised advice on how to safely boost your iodine intake.

9. Folate (Folic Acid)

Folate, or vitamin B9, is an essential vitamin for reproductive health and growth, including the formation of red blood cells. If you're low on folate, red blood cells will be abnormally large and will break down quickly, leading to anaemia. Having a folate deficiency during pregnancy can lead to neural tube defects in the unborn child.

Symptoms of folate deficiency include:

Fatigue
Weakness
Pale skin
Lethargy
Shortness of breath
Irritability
Poor immune function

If you think this sounds like to the symptoms of an iron, B12 or vitamin D deficiency, you're right! All of these nutrients are essential for healthy blood formation, so their symptoms can look the same – which is why it's important to see a qualified nutritionist or integrative doctor to confirm and treat any suspected nutrient deficiency. If you can't make it see a professional right away, boost your levels of folate by eating leafy vegetables (think “folate = foliage”), broccoli, asparagus and chickpeas.

10. Omega-3 Fatty Acids

Rather than a vitamin or a mineral, omega-3 is a “healthy fat” that the body needs for growth, brain function, nerve signals, managing cholesterol levels, protecting the heart, and to reduce inflammation. Low concentrations of omega-3 fatty acids are associated with increased risk of cardiovascular disease and inflammation throughout the body.

Early deficiency symptoms include:

Dry or flaky skin
Rough patches of skin
Slow wound healing
Dry eyes
Soft or brittle nails
Joint discomfort
Fatigue
Poor sleep
Low mood
Problems with attention and concentration

Supplements such as fish oil, algae omegas, and krill oil all contain high amounts of omega-3 which may seem like a quick-fix to remedy a deficiency. However, research shows that the best treatment is to boost your intake of omega-3 in the diet from sources include fatty fish (e.g. salmon), walnuts, tofu, soy milk, sardines, mackerel and flax seeds.

Self-diagnosis and self-prescribing can result in ineffective or even dangerous treatments. Speak to a qualified nutritionist or integrative doctor for personalised advice on how to improve your health with nutrition.

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