Zinc, an essential mineral found in many foods, regulates the function of over 200 enzymes in the human body. It is needed for example in the production vitamin A, insulin and hormones. Zinc also promotes the function of essential fatty acids (GLA, EPA, DHA) in the tissues and it plays essential role in prevention of colds and allergies as well as in maintaining good immunity.
Recent study shows that zinc helps fight the common cold when taken at onset of symptoms. The results of study showed that when zinc syrup or lozenges were taken within 24 hours of the onset of symptoms the colds suffered were shorter of duration and less severe. It has also been shown that zinc improves immunity against influenza and other respiratory diseases like pneumonia, especially in elderly.
Best source for zinc is well-balanced diet. Almost all foods contain at least little amounts of zinc, good sources are protein rich foods like meats (especially liver) and fish, but also nuts, beans, milk (preferably raw) and cheese (preferably raw). RDA for zinc is (depending of country you live in) about 15 milligrams per day for adults, 5-8 milligrams per day for children and about 3 milligrams per day for infants . However as only 15-40% of zinc from food is absorbed, it is highly unlikely that you will get too much zinc just by eating.
Most multi-vitamin or zinc supplements contain about 15mg of zinc which makes them safe to take daily. When used as a cold remedy for short period of time the recommended amounts are 30-60mg per day for adults and 15-30mg per day for children. Zinc supplements come in many forms such as tablets, liquid, capsules and lozenges. Zinc chelate and zinc picolinate are the most effective and absorbable zinc supplements. According to some studies zinc absorption is greatly improved if it is taken as lozenge and dissolved in the mouth.
In general the toxicity of zinc is low and excess zinc is fast excreted from body. Excess zinc doesn’t cause mutations, cancer or fetal damages. Long term usage of zinc supplement can however interfere with the absorption of other nutrients like iron and copper and therefore supplement is best to be taken before bed away from food. In the long run excess supplement misuse can cause nausea, vomiting, and diarrhea and lead to poor immune system function.
When taken correctly benefits of taking zinc supplements far out weight the possible (if any) side effects that are experienced and can be a great benefit in fight against common cold.