Answers by Ms Ong Chengsi, Senior Dietitian, Nutritio​​n and Dietetics, KK Women's and Children's Hospital (KKH), a member of the SingHealth​ group.

Diet tips to relieve and prevent flu: ask the specialist

Do supplements, especially vitamin C, have proven effects against the flu?

Some studies have shown that vitamin C supplements may help in recovering from the flu faster, but have no significant effect in preventing the flu. As for zinc and echinacea, two popular supplements for flu relief and prevention, current studies show variable results. By following nutrition guidelines, most children should be able to meet the Recommended Dietary Allowances of vitamins and minerals through food, so there might not be any added benefit in giving supplements. Over-supplementation can also put a child at risk for vitamin or nutrient toxicity, so do not exceed the recommended dose of any supplement.

What are some useful dietary tips when a child is down with the flu?

A child's appetite may decrease when down with the flu, so encourage him or her to have small, frequent and well-balanced meals. Ensure that the child is getting sufficient fluid through water, soup and other non-caffeinated drinks. Avoid caffeinated drinks like cola drinks and tea as these have a diuretic effect and can make the child lose more fluids. Also make sure that the food is properly prepared or well- cooked. There may also be some truth in the age-old remedy of giving chicken soup, as chicken soup may have anti-inflammatory and anti-congestive effects, thus helping to relieve cold and flu symptoms.

So are there some foods or fruits that can help boost the immune system against flu?

There are no proven foods to take or avoid that can prevent one from catching the flu. A well-balanced diet for the individual's age (refer to the Health Promotion Board's recommendations) will provide antioxidants like vitamins A, C, E, beta- carotene and zinc, which can help boost immunity to fight infections. In addition, foods like garlic and mushrooms may also help the immune function.

Ref: U11