What it does: Antioxidant properties help to protect against free radicals and carcinogens, reduces inflammation, stimulates immune system to fight infections, promotes a healthy heart, required for male reproductive system, needed for metabolism.

Deficiency Signs: Premature ageing, cataracts, high blood pressure, frequent infections.

Best food sources: Tuna, oysters, molasses, mushrooms, herrings, cottage cheese, cabbage, beef liver, courgettes, cod, chicken.