1: Overdosing on sugar: Eating or drinking 100 grams (8 tbsp.) of sugar, (the equivalent of about two cans of soda), can reduce the ability of white blood cells to kill germs by forty percent. The immune-suppressing effect of sugar starts less than thirty minutes after ingestion and may last for five hours.
2: Excess alcohol: Excessive alcohol produces an overall nutritional deficiency, depriving the body of valuable immune- boosting nutrients. Second, alcohol, like sugar, consumed in excess can reduce the ability of white cells to kill germs. Amounts of alcohol that are enough to cause intoxication are also enough to suppress immunity.
3: Food allergens: After many encounters with food allergens, the intestinal lining is damaged, enabling invaders and other potentially toxic substances in the food to get into the bloodstream and make the body feel miserable. This condition is known as the leaky gut syndrome.
4: Too much fat: Obesity can lead to a depressed immune system. It can affect the ability of white blood cells to multiply, produce antibodies, and rush to the site of an infection.