Craving sweets. Constantly snacking on candy, chocolate, and other sugary treats not only increases cavity risk but also compromises immunity. A study published in the American Journal of Clinical Nutrition found that consuming 100 grams of sugar (equivalent to about three cans of soda) significantly impairs white blood cells' ability to kill bacteria for up to five hours. Therefore, if you start craving sweets, pay attention to your immunity.
Forgetting to drink water. Doctors often advise patients with colds to drink plenty of water to help flush toxins from the body. In other words, insufficient water intake can impair immune function. A good indicator of adequate hydration is light yellow urine—dark yellow indicates dehydration, while very clear urine suggests overhydration. It's important to note that after drinking coffee or tea, you should follow it with a glass of plain water, as these beverages have diuretic effects that accelerate fluid loss.
Rapid weight gain. Excess weight and obesity not only harm the heart, brain, and other organs but also weaken the immune system. Studies show many swine flu patients have a BMI over 40. Extra weight triggers hormonal imbalances and inflammation, both of which impair immune function.
Dry nasal passages. While a runny nose may seem unappealing, it's the body's defense against colds and flu. Nasal mucus helps expel viruses from the body. Persistently dry nasal passages, however, make it easier for viruses to invade.
Constant tension.High stress from work or studies can overwhelm the immune system. A report by the American Psychological Association notes that office workers are prone to colds after completing major tasks, as prolonged stress dulls the immune response. Philip Henno, Director of Clinical Microbiology and Immunology at NYU, explains that combining a cold with stress is like adding fuel to the fire, worsening symptoms.