The most important thing you can do to prevent any illness is to maintain a strong immune system.

How do you accomplish that?

The first step is to eat a healthy diet, and the first step to a healthy diet is to maintain optimal hydration. The immune system will not function optimally in a dehydrated state. The body is made up of 70 percent water, while the brain is 80 percent water. I always encourage my patients to drink enough water.

Here’s how you do it: Take your body weight in pounds, divide by two and the resulting number is the amount of water you should drink daily, in ounces.

But it has to be pure water. Drinking beverages loaded with sugar and caffeine will actually worsen dehydration.

The next piece of dietary advice to optimize immune system function is to eliminate refined sugar from your diet.

In this country, we eat a tremendous amount of refined sugar. In 1915, the national average of sugar consumption was around 15 to 20 pounds per person per year. Today, it is estimated that Americans ingest more than 130 pounds of refined sugar per person per year.

Refined sugar is profitable for the food industry because the refined product has a longer shelf life.

But the refining process removes the nutrients that are usually found in sugar. This results in a devitalized food source — and eating a devitalized food source leads to a devitalized body.

Studies have shown that ingestion of refined sugar also results in a depressed immune system.

In fact, the amount of refined sugar in two cans of regular soda — about 75 to 100 grams — can suppress the immune system’s white blood cells.

Specifically, this kind of sugar has been shown to inhibit white blood cells’ ability to engulf and destroy bacteria.

At the University of Utah, researchers found that female mice that ate a diet of 25 percent added sugar — similar to a human drinking three cans of regular soda per day — died at twice the normal rate, and the males were less likely to hold territory and reproduce.

The authors of the study concluded, “Our results provide evidence that added sugar consumed at concentrations currently considered safe exerts dramatic adverse impacts on mammalian health.”

The next step to maintaining an optimal immune system is to avoid eating food contaminated with pesticides and synthetic hormones.

For this reason, it is best to eat organic fruits and vegetables as well as animal products that come from organically fed livestock raised in humane conditions.

Finally, it is helpful to supplement with vitamin C. Humans are one of the few animal species that do not manufacture their own vitamin C. But vitamin C is an essential nutrient, which means that we must get it from our diets or we develop scurvy and die.

It takes approximately 3,000 to 5,000 mg of vitamin C per day to saturate the receptors on the red and white blood cells. If your stomach tolerates it, I recommend taking 3,000 to 5,000 mg of vitamin C per day.