Zinc is essential for a healthy immune system and it can help shorten the duration of a cold and make symptoms less severe. Zinc helps your body fight infections by boosting the production of antibodies. The WHO has reported that zinc deficiency may be responsible for 13% of diseases such as pneumonia and flu in children under the age of five. And zinc deficiency is common among the elderly – and a major reason why they are susceptible to infection. The easiest solution is regular supplements.