Your Immune System

3 min

The primary job of your immune system is to distinguish self from non-self, which enables it to recognize and take appropriate action against anything that shouldn’t be in your body, including abnormal and damaged components. A healthy immune system can seek out and destroy germs and cells infected by germs as well as recognize and destroy tumor cells. Along with the common-sense steps you can take to protect yourself from being exposed to or infected with COVID-19 and other illnesses, keeping your immune system in optimum working order is your best defense.

Be aware that as we age our immune system’s ability to fight off illness begins to wane. It also can be weakened by overuse of antibiotics as well as smoking and stress. Beyond that, HIV and AIDS can compromise immunity by disabling immune cells, as can autoimmune related diseases including:

Given the importance of the immune system, what can you do to keep it healthy? Here are my suggestions for modulating the immune system:

Exercise: Be sure to get regular, moderate physical activity. A study from the UK published in 2020 looked at the effect of exercise on immune function. The authors wrote that it is widely agreed that regular, moderate intensity exercise is beneficial for immunity but noted that some experts believe more vigorous exercise without an adequate period of recovery may suppress immune function.
Reduce stress: Laughter as well as expressing positive emotions, such as optimism, are associated with better immune function and a number of other health benefits, including lowered production of the stress hormone cortisol and reduced risk of chronic diseases. If you are stressed out or anxious and tend to become negative as a result, follow my recommendations below:
Get adequate rest and sleep.
Maintain a healthy diet: Specifically, avoid polyunsaturated vegetable oils and products made from them. Their tendency to form free radicals makes them dangerous to immune system cells.
Consume less protein: Residues of protein metabolism can irritate the immune system, especially in people prone to allergy and auto-immunity. A plant-based diet with an abundance of fruits, vegetables and fiber is good for immunity as well as general health.
Do not eat many foods of animal origin: Meat, poultry, and dairy products often carry residues of antibiotics and steroid hormones that can interfere with immunity. If you do eat these foods, opt for organic versions.
Minimize consumption of meat and milk products: This is especially important if you are prone to allergy or autoimmunity. Cow’s milk protein is a common immune system irritant.
Take antioxidant supplements: Here’s where you can find a list of antioxidants.
Astragalus tea: The root of a plant found in northern China, Mongolia and Korea, astragalus (Astragalus membranaceous) has been used for thousands of years as a healing tonic. The root also contains abundant antioxidants, which help protect cells against damage. Astragalus is a key component in fu zheng therapy, a contemporary Chinese herbal treatment designed to restore immune function in patients undergoing chemotherapy and radiation. If you would like to try astragalus tea, here’s my favorite recipe:
- Brew astragalus tea bags as you would any tea
- Or simmer one tablespoon of dried, shredded astragalus root with 2 cups of water covered, for 10 minutes.
- Strain and serve hot or iced.

You can find slices of dried astragalus root at Chinese groceries and at some health-food stores – seek out organic versions. Astragalus also is available in pill form and as liquid extracts and tinctures. Always follow the directions on the labels of these products for proper use and dosages.

Astragalus is non-toxic and can be used year-round to help support normal immune function when faced with colds, the flu, and other infectious illnesses. Check with your doctor before taking astragalus if you take lithium or drugs that suppress the immune system.

Andrew Weil, M.D