b'7 Threats to a Healthy Immune SystemANTIBIOTIC OVERUSE.Researchers have discovered that antibiotic overuse can increase the prevalence of drug-resistant bacteria. A prominent example is the spread of methicillin-resistant Staphylococcus aureus (MRSA)an increasingly common and dangerous antibiotic-resistant illness that readily causes a variety of infections. Take antibiotics only for bacterial infections, and take them properly. If you truly need them, make sure to take the entire course. Its also smart to avoid antibacterial soaps and cleansers. CHRONIC STRESS. Frequent or unremitting stress is a definite immunity buster because it can lower NK cell count and diminish macrophage activity. This may be why people are more likely to become sick after a stressful event like a divorce or the death of a spouse. FAST FOOD.A poor diet filled with unhealthy fats and refined carbohydrates can trigger chronic inflammation and promote elevated cortisol levels. This can suppress your overall immunity and increase your susceptibility to colds and other infections. Long-term reliance on fast food and other highly processed fare can also lead to nutrient deficiencies and may contribute to cardiovascular and gastrointestinal diseases. SLEEP DEPRIVATION.Too little sleep, especially on a regular basis, reduces the number of NK cells that fight germs. Trying to pack too much into your days at the expense of relaxation and sleep also leaves you more vulnerable to the immune-damaging effects of stress. SUGAR OVERLOAD.According to a study by the American Heart Association, the average American adult consumes 22 teaspoons of sugar every daya habit that can undermine immunity, say researchers at Loma Linda University. Their study, which appeared in the American Journal of Clinical Nutrition, found that this amount, which is about the same amount of sugar in one liter of soda, reduced the efficacy of immune cells, leaving people more vulnerable to opportunistic infections. SMOKING.Its no secret that exposure to tobacco smoke increases the risk of cancer, respiratory disorders, and cardiovascular disease. Thats not surprising since Virginia Commonwealth University reports that smokers have compromised B- and T-cells, which might limit the production of immunoglobulins that act as protective antibodies against pathogens, especially in the mouth. A NEGATIVE VIEW OF LIFE.Clinical trials show that a negative view of life can weaken immune function. In one study, researchers measured pessimism, cynicism, and defeatism in a group of elderly people and took blood samples to check the activity level of their immune systems. The immune system was less vigorous and less effective in those with the highest measure of these negative emotions.OPTIMAL IMMUNIT Y5'