Whether you opted for a flu shot or not, you probably should consider ways to build a strong immune system, a pillar of holistic health. And just where is your immune system located?

A study at Johns Hopkins Medicine found a lot of interaction between the bacteria in the gut and the body’s immune system.

“A huge proportion of your immune system is actually in your GI tract,” said Dan Peterson, an assistant professor of pathology at Johns Hopkins. “The immune system is inside your body, and the bacteria are outside your body,” and yet they interact.

Your immune system is your gatekeeper of good health, and keeping it strong means experiencing fewer illnesses and benefiting from a quick recovery if you become ill.

Just as you eat healthful foods and wash your hands to keep germs away, the following tips are a few proven immune-building practices you can easily implement into your daily life to improve gut health and increase stamina.

My top five:

  • Tea. Dandelion, holy basil and green teas are among the types that can help you relax and restore your immunity.

Dandelions, those pesky yellow flower weeds that grow abundantly in your spring garden, can help fight off a cold. Researchers found that chemical compounds in dandelions can flush toxins from your system. In Chinese and Ayurvedic medicine, dandelion supports the liver and kidneys. If you are on medication, check with your doctor because dandelion can act as a diuretic.

Holy basil, also known as tulsi, is different from the basil you grow for cooking. It is loaded with antioxidants that work against viruses, bacteria and fungi.

Green tea is rich in polyphenols called catechins. Research found that green tea is 25 times more potent than vitamins C and E. Three cups per day can fight infection, according to a study at Brigham and Women’s Hospital for the National Academy of Sciences.

Any of those teas can be purchased at natural food stores.

  • Aromatherapy. Did you know that essential oils are the immune-protecting ingredients of plants and flowers? They are synergistic with the human body and work in the same way to provide protection and destroy viruses and bacteria. They have the highest vibrational frequency of any substance on the planet, meaning that they are immune powerhouses.

Not all oils are created equal (like different grades of gasoline for your car), so it’s best to choose therapeutic-grade or organic essential oils. Essential oils can easily be applied to your body with a carrier oil, such as sesame, coconut or jojoba.

For adult gut health, try fennel, ginger or peppermint. Apply two drops to the feet or abdomen mixed with jojoba, sesame or coconut oil. This amount is not suitable for children under age 12. Check with your holistic professional, and avoid these oils if you’re pregnant.

  • Garlic. Garlic contains several compounds, including allicin, with antiviral, antifungal and antibacterial properties. Together, they rev up your immune system throughout the cold and flu season.

Try roasting garlic cloves in olive oil and eating the garlic during the day, or cook it in olive oil and add it to vegetables. Garlic is a key ingredient in the Mediterranean diet, and research suggests it supports heart health and can reduce cholesterol.

Try this great ginger-garlic immune booster: Combine one crushed clove of garlic, one 1-inch piece of fresh ginger, half an organic lemon and 1 to 2 teaspoons of honey (raw and unpasteurized if possible), and steep the ingredients in hot water for five minutes. Then drink the liquid.

  • Laughter. Yes, belly laughing is a proven remedy for your immune system. No wonder that my Aunt Rose lived until 95 — she always smiled and laughed. “Tell me something funny,” she often said.

Studies show that laughter can trigger the release of endorphins, which reduce stress and thus improve your resistance to disease. Endorphins promote an overall sense of well-being and can temporarily relieve pain. Perhaps this is why laughter yoga has gained popularity.

  • Immune-boosting foods. Apples (my grandmothers’ favorite cooked fruit) support the immune system because they contain antioxidants and both insoluble and soluble fiber, which cleanses the bowel. All sweet, juicy fruits — pears, peaches, plums, sweet pineapple, mangos — enhance immunity because they transform quickly into what Ayurvedic medicine calls “ojas,” which is vitality. I like to cook apples in a slow cooker with a stick of cinnamon for fresh applesauce.

Cooked leafy greens such as Swiss chard, kale, mustard greens and spinach are great immunity boosters because they provide iron, calcium and other nutrients while cleansing the bowel.

Broccoli, cabbage and cauliflower contain antioxidants, flavonoids and other immune-enhancing nutrients.

Flu shot or not, give yourself the self-care you are worthy of and know that, just as your body can build muscles, it can also get stronger with simple daily practices designed by nature.