Cold and flu season is here. These five habits are what health experts point to for supporting your immune system.
Keep Vitamin D in Mind
From October through March, northern sunlight is too weak for skin to make much vitamin D. The NHS advises considering a daily 10-microgram supplement through autumn and winter, and Health Canada sets the adult target at 600 IU a day. A February 2026 study of more than 36,000 adults found the lowest vitamin D levels linked to a 33 percent higher hospitalization risk for respiratory infections — an association, not proof of cause.
Guard Your Sleep
Adults who sleep too little tend to get sick more often. The CDC recommends at least seven hours of sleep per night for adults, and sleep specialists say a consistent schedule matters most.
Eat the Rainbow
Different produce colors carry different vitamins and antioxidants, so nutrition experts advise variety. Aim for a colorful mix of fruits and vegetables every day.
Stay Hydrated
Water supports nearly every system in the body. Experts advise drinking water steadily through the day, especially once indoor heating dries the air.
Wash Your Hands
Here is a number: the CDC reports handwashing can prevent about 30 percent of diarrhea-related sicknesses and about 20 percent of respiratory infections like colds. Twenty seconds with soap does it.
Sources: NHS, Health Canada, CDC, Harvard Health
