The Harold Leever Regional Cancer Center

Giving Your Immune System a Boost: Is it Possible?

Posted on by Karen Sabbath, MS, RD, CSO

There are more than 1000 supplements currently available in stores and online that claim to boost one’s immunity. Their claims to fend off infection, help you bounce back from injuries, reduce the likelihood of cancer and other diseases, and prevent damage from environmental pollutants are just a few of the purported benefits. Who wouldn’t want to swallow them by the fistful? But do they work?

A healthy immune system should do all of those things – and when it is in peak form, the molecules, cells, tissues, and organs that comprise our immunity work quite effectively to combat the many assaults to our body on a daily basis. Occasionally, a germ invades our system and we get sick, but our immune system kicks into high gear and helps restore us to health, sometimes with the help of medications, like antibiotics.

In autoimmune diseases, like lupus, Crohn’s, rheumatoid arthritis, multiple sclerosis, or Type 1 diabetes, to name just a few, the immune system goes into overdrive and takes aim at its own cells, causing damage, inflammation, and impaired quality of life.

The concept of “boosting your immunity” is a tempting idea to embrace, but the immune system is just that: an intricate system, not a single entity. And because of its complexity, it is hard to single out one or two things that will alone increase its function. There is no one single food or supplement that has been found to affect the entire immune system. Research continues in this area, but to date, there is little to no concrete evidence.


Current research finds that certain vitamin or mineral deficiencies can increase the risk of infection, but providing those supplements does not appear to enhance immune function. These include vitamins A, C, D, E, as well as the mineral zinc. Unfortunately, the common myths that vitamin C prevents colds and the use of zinc can shorten the duration of a cold have not panned out in clinical trials. In fact, taking too much zinc, iron, vitamin A, or folate can actually impair the immune system. Research continues in this area.


As we age, our immune system weakens, which is why older people are more prone to infections, slower to heal from surgery, and get less benefit from protective vaccines, according to Janko Nikolich-Zugich, MD, PhD, an immunologist from the University of Arizona. He also notes that “the strength of the immune system is tied to healthy lifestyle, exercise, good nutrition, and sufficient rest.” As people age, it can be difficult to meet these goals, which can further reduce immunity.

But before you throw up your hands in frustration, keep in mind that there are many things you can do to maximize your immunity and lower the risk of infection.

  • Eat Well. Consume a diet that is high in fruits, vegetables, and whole grains. By eating a variety of healthy foods, you will ensure that you are getting all of the nutrients that are essential for good immune health.
  • Exercise regularly. A target of 30 minutes of physical activity a day is a great goal.
  • Maintain a healthy weight.
  • Keep your alcohol intake to a minimum. Too much alcohol can suppress immunity.
  • Try to get 7-8 hours of sleep a night. Adequate sleep appears to help our immune system fight off viruses.
  • Take steps to avoid infection, such as frequent and thorough hand washing and safe food handling practices.
  • Try to minimize stress. We all have stress in our lives, but scientists are trying to determine the effects of chronic stressors on health and immunity.
  • Don’t smoke!
  • Probiotics: These are the good bacteria that live in your gut and keep it healthy, as well as keeping your immune system strong. Some people take probiotic supplements if they are unable to get them from food or if they are taking certain antibiotics.
    Food sources: Yogurt, kefir, sauerkraut, and kombucha
  • Prebiotics: These are foods that provide fuel for probiotics, and are found in the non-digestible fibers in high-fiber foods.
    Food sources: Oranges, beans, oats, asparagus, and bananas
  • Fish oils and/or omega-3 fatty acids: These beneficial fats help the heart by preventing blood clots and reducing inflammation. They may also play a role in lowering risk of other medical conditions, including cancer.
    Food sources: Fatty fish, like salmon, or certain plant foods, like walnuts and flaxseeds, that contain fats that are converted to omega-3s
  • Phytochemicals: These are biologically active compounds and antioxidants found in plants that promote health and immunity.
    Food sources: Fruits, vegetables, whole grains, beans, and nuts
  • Foods containing vitamins A, C, D, and E, plus minerals zinc and copper: These all contribute to a healthy immune system. Many of the foods that are rich in these vitamins also contain phytonutrients and antioxidants.
    Food sources:
    Vitamin A: Sweet potatoes, carrots, winter squash and pumpkin, cantaloupe, whole milk, liver, and eggs
    Vitamin C: Citrus fruits, kiwi, mango, cauliflower, and green peppers
    Vitamin D: Absorbed through your skin from exposure to the sun, as well as in egg yolks, saltwater fish and fortified foods like milk
    Vitamin E: Found in vegetable oils, nuts, seeds, and leafy greens
    Zinc: Found in dark meats, nuts, whole grains, and beans
    Copper: Found in beans, nuts, leafy greens, and shrimp

Eating too much added sugar, processed foods, refined starches (like white bread and white rice), excessive amounts of saturated fats (from red meat, butter, lard, or coconut fat), or trans-fats, can increase inflammation, contribute to chronic disease and weight gain, and provide little nutrition. Eating them once in a while is okay, but try to include these foods sparingly.


Because of its complexity, it is difficult to determine exactly what makes the immune system function at its peak. But we know that our best bet for immune and overall health is to eat a variety of healthy foods, especially fruits, vegetables, whole grains, nuts and seeds, lean protein and healthy fats, and adopt a healthy lifestyle. Although many people would rather pop a pill to get the desired benefits, it’s the benefits derived from our diet that appear to have the greatest impact.

Questions about nutrition? Contact our nutritionist, Karen Sabbath, MS, RD, CSO, at 203-575-5510 or email her at