It’s surprisingly easy to do…

Nobody wants to spend time sick in bed feeling miserable with a cold, the flu or any other illness.

But here’s the catch: Even if you stay well-rested, exercise and eat healthfully, you still could be sabotaging your immune system. Most people are unknowingly making it harder for their bodies to fight off illnesses. How to stop hurting your immune system…

• Skip the germ-killing soaps. Studies now show that triclosan, the key ingredient in many antibacterial hand soaps (as well as some shaving gels, shampoos, cosmetics, deodorants and other personal-care items), fuels the growth of ­antibiotic-resistant bugs in the public at large. With frequent use, triclosan also can hurt you personally by setting up your body to develop a secondary “superinfection” that can occur as a complication of colds, the flu or viral pneumonia.

Among the best ways to prevent colds and the flu: Vigorous, frequent hand-washing with plain soap is all you need, but here’s the key—you need to scrub long enough (count to 20).

If you like the reassurance offered by a hand sanitizer, products with at least 60% alcohol, such as Purell or Germ-X, are widely recommended. However, the alcohol in such hand sanitizers can lead to dry, cracked skin, which provides an entry point for bacterial or fungal skin infections. Alcohol-based products are supported by strong research, but if dry skin is a problem, rely on hand-washing and/or a hand sanitizer that contains natural antibacterial plant oils such as citrus, oregano, rosemary and/or thyme.

Good choice: CleanWell, $10.99 for three one-ounce spray bottles,

• Take a pass on sugar. Sugar, refined carbohydrates and high-fructose corn syrup can impair the effectiveness of our immune cells. As soon as you notice cold or flu symptoms, cut these foods out of your diet. Beware: The caramelized sugar found on cinnamon rolls, donuts or sticky buns is particularly harmful to our immunity. Certain molecular structures in this type of sugar resemble bacteria, and our immune system receptors mistakenly bind to them, interfering with their ability to respond effectively to true infections. If you need a sweetener: Try raw honey, which has immune-building properties.*

• Watch out for pesticides. Most nonorganic pro­duce gets showered with pesticides, which damage your im­mune system.

What to try instead: Load up on fresh, organic fruits and vegetables to arm your immune system with disease-fighting vitamins and nutrients. Organic berries, citrus fruits, grapes and spinach are especially rich in antioxidants that support immune function. When fresh berries aren’t available, try frozen organic berries. You can save money by opting for nonorganic citrus fruits and other peelable items (such as bananas) that are less likely to harbor dangerous pesticides than produce without peels.

Power Up Your immunity

Many people rely on well-known immunity boosters such as vitamin C and/or echinacea, but you’re likely to get better results from using the following on a daily basis as a preventive during cold and flu season (or year-round if you work directly with the public)…**

• Probiotics. By far, probiotics are the best way to enhance your immunity. These “good” bacteria, including Lactobacillus and Bifidobacterium, reside in your digestive tract, where they keep intestinal microbes in check and elevate your number of infection-fighting T cells.

Fermented foods, such as kefir, yogurt, kimchi, sauerkraut and kombucha, are all naturally rich in probiotics. Aim for two (four- to six-ounce) servings a day.

In general, however, probiotic supplements are more potent and may be more reliable than ­probiotic-rich foods. If you opt for a supplement, use a combination of Bifidobacterium and/or Lactobacillus species.

A probiotic found in studies to boost immunity: Culturelle, $39.99 for 80 capsules,

• N-acetylcysteine (NAC). The body easily converts this amino acid into a usable form of glutathione, an immunity-protecting antioxidant that itself is poorly absorbed from the gastrointestinal tract.

Scientific evidence: Italian researchers found that taking 1,200 mg daily of NAC throughout flu season reduced the frequency, severity and intensity of flulike symptoms.

Typical dose: 600 mg to 1,200 mg daily as a preventive…at the first sign of infection, increase the dose to 3,000 mg daily (taken in doses of 600 mg each throughout the day).

• Elderberry syrup. When used within the first 48 hours of feeling flu-ish, this syrup (made from naturally antiviral elderberries) has been shown to relieve symptoms four days faster than a placebo.

If you are not taking elderberry syrup as a daily preventive, start using it within the first two days of developing cold or flu symptoms. Follow label instructions.

Good choice: Sambucol Black Elderberry Immune System Support, $19.99 for 7.8 ounces,

Don’t Go It Alone!

What do close relationships have to do with immunity? A lot, according to research.

When researchers exposed 276 adults to a rhinovirus (a cause of the common cold), subjects with only one to three relationships (such as fulfilling marriages or friendships with colleagues, neighbors and religious community members) were four times more likely to get sick than those who had more than six relationships.

Possible explanation: Social interactions help ease the negative effects of stress—a known threat to immunity.

*Infants under age one and people who are allergic to pollen or immunocompromised should not consume raw honey.

**Consult your doctor before trying dietary supplements—especially if you take prescription medication and/or have a chronic medical condition.