Iron is an essential element for the production of haemoglobin. Iron deficiency can lead to a lack of oxygen supply to the cells, leading to hair thinning and shedding. 

Vitamin D plays a key role in hair follicle cycling and hair growth. Its deficiency can cause hair loss conditions like alopecia areata and telogen effluvium. 

Vitamin B12 is important for red blood cell formation and DNA synthesis. Lack of B12 in the body can cause hair thinning and shedding. 

Zinc is essential for cell growth and formation. Its deficiency can lead to a disrupted hair growth cycle and hair shedding. 

Hair follicles are made of a protein named keratine. Lack of protein in the diet can lead to damaged and weak hair shafts and hair loss.