Children who took vitamin D supplements during the cold and flu season escaped seasonal flu and asthma attacks, according to a study published in the American Journal of Clinical Nutrition and reported by Reuters.

For the three-month study, done during cold and flu season, researchers from the Jikei University School of Medicine in Tokyo randomly assigned 167 children, ages 6 to 15, to take 1,200 international units (IU) of vitamin D-3 or a placebo each day.

Vitamin D-3 is more readily absorbed and more potent than vitamin D-2 (usually found in multivitamins).

Scientists noted that only 18 children taking vitamin D caught influenza A compared with 31 kids taking the placebo. Overall, the vitamin D group was 58 percent less likely to catch influenza A.

In addition, vitamin D also seemed to suppress asthma attacks in children with a history of asthma. Two children taking the supplement had asthma attacks compared with 12 children taking the placebo.

Based on the study, researchers concluded that vitamin D-3 supplements may reduce influenza A. They also suggested parents check with their pediatricians about giving their children 1,200 IU of vitamin D per day starting in September to prevent asthma and flu during the flu season.

Learn more about vitamin D here.