1. Weakness, tiredness, or light-headedness
2. Heart palpitations and shortness of breath
3. Pale skin 
4. Smooth tongue
5. Constipation, diarrhoea, loss of appetite, or gas 
6. Nerve problems like numbness or tingling, muscle weakness, and problems walking
7. Vision loss 
8. Mental problems like depression, memory loss, or behavioural changes