Skip to content

Spotting a vitamin deficiency

In partnership with Dr Hamish Black

Before you pop a vitamin pill, here's what to look for.

Young woman with red hair checking her blood results on her phone for signs of a vitamin deficiency
Young woman with red hair checking her blood results on her phone for signs of a vitamin deficiency

With vitamin supplements so readily available at the chemist and supermarket, it can be tempting to self-diagnose a vitamin deficiency, or try to prevent or cure an ailment by popping a vitamin pill.  

At nib, we consider ourselves your health partner, working with the experts to give you the tips and tricks to live your healthiest life yet. So, we spoke with nib’s Medical Advisor Dr Hamish Black to shed some light on how to spot and treat a true vitamin deficiency. 

Why do vitamin deficiencies occur? 

The average healthy person who eats a varied diet that includes the five food groups is likely to be getting all the vitamins and minerals they need through food.  

“There are, however, some groups of people that should seek a medical or dietetic review to discuss whether supplementation is necessary because they’re at higher risk of vitamin deficiencies,” says Hamish.  

He recommends talking to your GP or dietitian if you have: 

  • Excessive blood loss or inadequate intake of iron through your diet 

  • Experienced prolonged fasting (more than five days), such as with a major illness 

  • A vegan or excessively strict diet 

  • An eating disorder 

  • A significant chronic disease such as chronic liver or kidney disease 

  • Significant malabsorption due to gut or pancreatic disease 

  • Very dark skin, or you’re institutionalised or heavily covered for social or cultural reasons (these are risk factors for vitamin D deficiency). 

A 30 year old man at the doctor's getting a range of tests to determine any vitamin deficiencies

What are the signs and symptoms of a vitamin deficiency? 

The signs and symptoms of vitamin deficiencies vary depending on the vitamin. If you’re lacking in B vitamins, you may feel tired, weak, shaky and a numb or tingly sensation in your hands and feet. A vitamin C deficiency might cause a general feeling of unwellness, nausea, loss of appetite, diarrhoea and a weakened immune system. 

While a vitamin D deficiency may not have any obvious symptoms, it can lead to osteoporosis and bone and joint pain, so it’s important to have it diagnosed. 

What can you do if you think you have a vitamin deficiency? 

“By the time you have signs and symptoms of a vitamin deficiency, you’re likely to be severely depleted of that vitamin,” says Hamish. “It’s far healthier to be proactive by seeking a medical or dietetic review, especially if you're in a high-risk group.” 

If you do have symptoms that are concerning you, book an appointment with your GP. They may order blood tests to determine whether you have a vitamin deficiency that needs to be treated. 

Finding the right way to treat a vitamin deficiency 

“Most of the sources of vitamins and minerals come from food, so changing what we eat may be all we need to do to treat a vitamin deficiency,” advises Hamish. 

In some cases, supplementation may be necessary, he adds. Your GP or a dietitian will be able to advise on the best types and doses of supplements to get your vitamin intake and health back on track. 

Taking high doses of some vitamins such A, B6, D, E and K can be toxic, so make sure to seek advice before starting a vitamin supplement and always stick to the recommended dosage. 

Please note: The tips throughout this article serve as broad information and should not replace any advice you have been given by your medical practitioner.  

Dr Hamish Black

Dr Hamish Black

In partnership with

Dr Hamish Black

Dr Hamish Black has been a medical practitioner for more than 25 years. In addition to his role as nib group medical advisor, he still spends two days a week practising as a GP. He has spent many years working in emergency departments and in rural Australia, including a stint with the Royal Flying Doctor Service. Hamish also loves karaoke and dancing (though not that well at either, he says!), with Play that Funky Music by Wild Cherry being his karaoke favourite.