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10 Ways you can Strengthen Your Immune System To Keep you Healthy This Winter Season

Updated: Jun 28, 2023

As we are in the midst of a “Tridemic” (Flu / Covid-19 / R.S.V.), it is important to understand how to boost your immune system to defend itself and help fight off seasonal illnesses. Dietitian- Nutritionist, Maryann Gallucci, with nutrition tips for winter survival

By Maryann Gallucci

Making sure your body has enough macro and micronutrients helps to create an effective defense system against harmful viruses. The immune system’s main function is to protect your body. There are three parts to your immune system:

1. Physical barriers preventing bacteria and viruses from entering your body. This includes your skin, the lining of your intestinal tract, mucous, tears, etc.

2. Innate immunity – this is your first response to infections. Protein plays a key role in providing your body the ability to defend itself when being attacked.

3. Adaptive immunity – these defenses respond to foreign invaders that your body has seen before and delivers a quick attack targeted to each specific type of infection.

White blood cells are one of the key components of your immune system responsible for surveillance and defense. There are several varieties of white blood cells, each with specialized jobs. Other components of your immune system are equally important and have specific jobs. They are all warrior cells. Some fight parasites, produce fighter chemicals, or develop antibodies. These components of your immune system are continuously at work. When they are called upon to defend the body, they require more fuel.

Your immune system relies upon a continuous supply of water, vitamins, minerals and other bioactive compounds for efficient functioning. All of these nutrients can be found in whole foods and are the drivers of your immune system’s white (killer) cells’ activity. Conversely, processed foods derail cell function, sabotaging your body’s ability to consistently activate an effective line of defense. While vitamin and mineral supplements are also a way of getting some of these nutrients, they are not recommended to replace a healthy diet, so I wanted to focus on foods, since many of these foods also contain an abundance of phytonutrients that have a synergistic effect when obtained from food sources.

Whole foods are in their natural state. They provide fiber, enzymes, prebiotics, probiotics, essential fats, proteins, vitamins, minerals and many other important bioactives. Fresh ingredients that are in season are the best choices. This also include frozen fruits and vegetables. Whole organic foods contain only the ingredients found in nature. These nutrients direct all aspects of your metabolism. Consuming processed or convenience food deprives your body of essential nutrients. They typically also deliver lots of toxic nonfood ingredients. Over time, this will negatively affect your appearance, energy, mood and overall health. Many processed foods are compromised by the addition of artificial colors, flavors, chemical preservatives, artificial sweeteners, excess refined salt and sugar. Processing results in loss of vital nutrients. Therefore, the goal is to saturate your cells with a consistent supply of nutrients by choosing whole foods, including an abundance of Vegetables, fruits, nuts, seeds and legumes (beans).

Let’s look at some specific vitamins, minerals and bioactives along with the foods that provide these nutrients to support your immune system and keep it performing optimally. As well, sleep and physical activity are also key components to keeping your immune system fit.

Protein is key in your adaptive immunity. Specialized proteins called Antibodies work to inactivate harmful foreign invaders such as disease-causing bacteria and viruses. Once your body knows how to create antibodies against a specific invader, it stores that information, and you have immunity to that pathogen. So, the next time that invader enters your body, you can respond very quickly (producing up to 2,00 precise antibodies per second) to fight it. When this rapid immune response works efficiently, it prevents the virus or other invader from multiplying to levels high enough to make you sick. Therefore, it is important to eat an adequate amount of protein daily to help your body’s immune system. Arginine, glutamine and cysteine are three amino acids significant in supporting the immune system. These are “conditional” amino acids; meaning, the body can produce them naturally, except in time of illness and stress, they are essential and should be obtained in our foods. Foods high in these amino acids are red meat, fish, whole grains, eggs, dairy (yogurt), legumes (lentils), nuts and seeds (especially sunflower and pumpkin seeds). The amount of protein needed is determined by age, level of physical activity. Healthy adults should consume enough dietary protein to replace the amount they use each day. Recommendations based on numerous studies advise that 10 to 35 percent of your total daily calories should come from protein. At the high end, aim for 20 to 30grams of protein per meal.

Vitamin A is not just for vision. Your skin and the lining of your intestine, lungs and eyes provide a barrier to pathogens entering your body. Vitamin A and folate are needed to make the tissues that keep foreign material from entering your body. It also helps to make mucus that coats some of these tissues, without which become more prone to infection. There are several different immune cells that your body produces, depending on the threat identified. Vitamin A helps determine the population of cells your body produces so that you have the right cells to do the job when an infection hits. Beef liver, eggs and fortified milk provide vitamin A. However, plant-based foods that contain beta-carotene will convert to vitamin A. Increase your intake of dark colored fruits and vegetables such as spinach, kale, sweet potatoes, pumpkin, carrots, squash, peppers, persimmons.

"Although it is not the first thing that comes to mind when talking about supporting immunity, water plays a crucial role in it! Water carries nutrients vital for immune health, It helps maintain healthy skin which is our first line of defense against viruses and infection, and it eliminates the bacteria that can be harmful and weaken your immune system. Staying hydrated can lessen symptoms like headache and muscle stiffness", Dietitian- Nutritionist, Maryann Gallucci

Vitamin D helps immune cells make proteins that kill bacteria and viruses. Vitamin D also influences the type of immune cells that your body produces in order to provide an appropriate immune response to an infection. While we do produce our own vitamin D with sunshine, those living in northern regions do not produce enough vitamin D year-round. The foods most abundant in vitamin D are fatty fish such as salmon, mackerel, and sardines. Mushrooms also provide some vitamin D. Vitamin D is added to some orange juices, milk and nut milks.

Vitamin E is an antioxidant that protects cell membranes and other places containing fats from damage from reactive compounds. Inside of immune cells, vitamin E also helps cells respond to an infection, and keep the intensity of the response in proportion to the infection, without overdoing it. Vitamin E is found in plant oils, nuts and seeds. Be sure to add healthy oils such as olive oil, avocado oil along with snacking on nuts such as almonds, pistachios, pumpkin seeds. Just note, these are all high in calories, so be mindful of moderation.

Vitamin C helps maintain your physical defense system, in other words, our skin and other tissues that are exposed to materials found outside your body. Vitamin C is also an antioxidant, meaning it can also fight free radicals in the body, thereby decreasing inflammation and supporting the immune system. Citrus fruits (orange, grapefruit, lemons, tangerines), kiwi, pineapple, strawberries, peppers, broccoli, and cantaloupe are all rich in Vitamin C.

Zinc sends signals in your immune cells that direct how they respond to infections in your body. Zinc keeps your skin healthy, which prevents foreign

invaders from entering your body. Zinc is also an important mineral for your sense of smell and taste. Foods such as whole grains, red meat, some seafood (oysters, clams, tuna) are all good sources of zinc.

Probiotics are good bacteria that promote health. While we may not think of the immune system as living in the belly, 70 to 80% of our immune system is located in the gut. The gut and the immune system are completely intertwined. However, two strains have been widely researched for immune health: Lactobacillus acidophilus and Bifidobacterium lactis.

Lactobacillus acidophilus is a strain of Lactobacillus bacteria, which produce lactic acid and primarily live in the small intestine. One in-vitro study indicates that Lactobacillus may be effective at triggering the expression of viral defense genes, therefore stimulating the immune system. They're also protective against harmful bacteria, like E. coli. Bifidobacterium lactis - (Bifidus) is the most common in the colon or large intestine. They produce the short-chain fatty acid butyate, which keeps the colon cells functioning optimally. In one study, researchers found that subjects who consumed bifidobacteria showed enhanced levels of natural immunity. You'll find these strains of probiotics in cultured dairy products such as yogurt and in fermented foods, such as kefir and kimchi.

"Regular physical activity might contribute to a more effective immune response - it may help flush bacteria out of the lungs and airways. Also, the brief rise in body temperature during and right after exercise, may prevent bacteria from growing." Dietitian- Nutritionist, Maryann Gallucci

Hydration, although it is not the first thing that comes to mind when talking about supporting immunity, water plays a crucial role in supporting your immune system! Water carries nutrients vital for immune health to where they need to go within the body. It helps maintain healthy skin which is our first line of defense against viruses and infection. Water also plays a role in eliminating the bacteria that can be harmful and weaken your immune system. If you are sick, sometimes we don’t feel like drinking, but staying hydrated can lessen symptoms like headache and muscle stiffness. Hydration also includes fluids such as chicken soup. Your favorite recipe likely has properties that fight inflammation, promote hydration and get mucus flowing. Drink plenty of liquids, such as water, broth or sports drinks with electrolytes.


Since sleep is imperative for all of your body’s functions, it will probably come as no surprise that sleep can have a major impact on your immune system. Research shows that hours of sleep have an inverse relationship with the risk of catching a cold. To ensure your immunity is up to snuff, make sure you’re getting a good night’s rest with between 7-9 hours of quality sleep per night.


There is evidence that regular physical activity might contribute to a more effective immune response, providing enhanced protective immunity to infections

  • Physical activity may help flush bacteria out of the lungs and airways. This may reduce your chance of getting a cold, flu, or other illness.

  • Exercise causes change in antibodies and white blood cells (WBC). These antibodies and WBCs circulate more rapidly, so they could detect illnesses earlier than they might have before. However, we do not know whether these changes help prevent infections.

  • The brief rise in body temperature during and right after exercise may prevent bacteria from growing. This temperature rise may help the body fight infection better. (This is similar to what happens when you have a fever.)

  • Exercise slows down the release of stress hormones. Some stress increases the chance of illness. Lower stress hormones may protect against illness.

Regular exercise (most days of the week) can result in better sleep, improved moods, lower stress levels and increase circulation of immune cells in your body – all factors that contribute to a healthy immune system.

While we may not be able to always prevent catching a virus or cold. By staying hydrated and eating fruits and vegetables, nuts, seeds and legumes, whole grains, fish and lean meats rich in Vitamin A, C, E, D, Zinc and eating an optimal amount of protein and foods rich in good bacteria, and exercising most days of the week and getting and adequate amount of sleep will certainly provide your body with a fighting chance to stay healthy and defend itself.


About Dietitian Nutritionist, Maryann Gallucci

MS, RDN, CDN, ACSM-EP-C, ACE-Health Coach.

✔️ Works in Private Practice providing nutrition counseling and fitness training.

✔️ Awarded “2021 Long Island Dietitian of the Year” by the Long Island Academy of Nutrition and Dietetics.

✔️ Adjunct Lecturer in the Family, Nutrition, and Exercise Sciences Department at Queens College.

✔️ Serves as the Nutrition Services and Payment Specialist Co-chair for the Long Island

✔️ Academy of Nutrition and Dietetics.

✔️A member of multiple Dietetic Practice Groups.


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