This warning will almost certainly come as welcome news to those who want to keep their blood and nerves healthy, especially now that we're entering the chilliest part of winter.

The non-profit medical centre in Rochester, Minnesota warned that, “if you're concerned that you're not getting enough vitamin B12 or other specific nutrients, consult your doctor - especially if you're an older adult or a vegetarian”.

According to the Mayo Clinic's specialists, the recommended daily amount of Vitamin B12 for adults is at least 2.4 micrograms.

They cautioned that those who stick to a vegetarian or vegan diet may face Vitamin B12 deficiency because plant foods don't contain this substance.

Such a deficiency may finally result in severe damage to a human’s brain and nervous system, also increasing the risk of cardiovascular disease.

The UK’s National Health Service (NHS) has highlighted that vitamin B12 deficiency is more common in older people, and that it affects about one in 10 individuals aged 75 or over and one in 20 people aged between 65 and 74.