People with undiagnosed symptoms should consider that they may have a vitamin B12 deficiency.

While it's unlikely that your symptoms are caused by the condition, there are still many people that have a lack of B12.

A quick blood test could reveal whether you should be adding more B12 to your diet.

You should consider having your B12 levels checked if you develop any of these five warning signs.

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"Unfortunately, B12 deficiency is common, especially in the elderly," said dietitian Helen West.

She wrote for medical website Healthline: "Youre at risk of deficiency if you dont get enough from your diet or arent able to absorb enough from the food you eat.

"Unfortunately, symptoms of a vitamin B12 deficiency can take years to show up, and diagnosing it can be complex.

"If youre at risk and have any of the symptoms above, speak to your doctor."

For many people, a B12 deficiency can be easily rectified by making some simple diet swaps, she added.

The best sources of vitamin B12 include beef, liver, dairy foods, eggs, and salmon.

Around one in 10 people aged 75 or over have a B12 deficiency.

But, taking B12 supplements could also help to treat a deficiency.

It's crucial that you speak to a doctor as soon as possible, if you think that you're at risk of the condition.

That's because it can lead to some severe complications if it's left untreated.

The deficiency may lead to heart conditions, or problems with the nerve system, if it isn't treated as early as possible.

Some treatments can lower your risk of developing these complications, but some - like nerve damage - may be irreversible.

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Vitamin B12 deficiency: Five common symptoms to watch out for - and when to see a doctor - Express