Vitamin B12 is needed throughout life for normal growth and development, healthy functioning of the nervous system and cell division.
A deficiency of B12 can cause tiredness, anaemia, tingling and numbness of the extremities, memory loss and even dementia.
Low levels of B12 at conception increases the risk for neural tube defects, and a deficiency across the life course can contribute to cardiovascular disease, high blood pressure and type 2 diabetes.
The recommended dietary intake for most adults is 2.4mcg of B12 each day.
Vegetarians and vegans are most at risk of deficiency as B12 is found naturally only in animal foods.
People regularly eating animal foods including red meat are likely to have an intake of 3mcg or more each day.