Ways to Improve Immunity and Defend Against COVID-19

What Do You Mean by Immunity-Boosting Foods?

Specific nutrients that are found in the foods you eat support your immune system, each in their own special way.

While each nutrient has its specific role in immunity, nutrients themselves do not prevent disease. They do support your immune system through a wide array of complex functions in the body.

Which Vitamins and Minerals Are Needed in the Diet to Boost Immunity?

Vitamins and minerals necessary to boost immunity include A, C, E, D, and zinc.

Vitamin A is essential to keep the skin and the tissues in the gastrointestinal and respiratory systems healthy. (1) The skin is the first barrier against pathogens, so healthy skin inside and out is important to protect against infections.

Vitamin C is known to stimulate the formation of antibodies. It is also a helper vitamin as it aids in the absorption of iron. (2) The addition of vitamin C to an iron-rich meal helps to increase the absorption rate.

Vitamin D is thought to play a role in immune health. (3) This vitamin is made in your skin when it is exposed to sunlight. Those who live in the dark, rainy climates are typically deficient in vitamin D. It is usually unlikely to obtain all the vitamin D your body needs from food sources alone.

Vitamin E is an antioxidant and helps to fight free radicals in the body and also is known to support immune function. (4)

Zinc helps aid wound healing and also has a role in immunity. Again, the skin is the frontline protection from foreign pathogens entering the body. Having an open wound or impaired skin integrity can increase the risk of infection, resulting in fluid loss, and increase your calorie, protein, and fluid needs above your daily needs. (5) 

Protein plays an important role in many processes in the body, including DNA replication and metabolic reactions, aids in the transport and movement of molecules, and gives structure to cells. Protein is vital to the repair and recovery of the body. (6)

Probiotics are a class of bacteria that are considered good for your GI tract, reproductive system, and overall health. They help with digestion, immunity, and many other vital functions.

Probiotics are bacteria that are naturally present in the body and can be derived from food sources as well. Other nutrients that have been studied for their ability to support the immune function are vitamin B₆, B₁₂, copper, folate, selenium, and iron. (7)

While these vitamins and minerals are the VIPs of the immune system, be sure to get all the nutrients your body needs to support your overall immunity.

What Foods Help in Boosting Immunity?

Foods are the preferred way to get the nutrients you need. However, many people often lack or are deficient in one or more nutrients that are missing from the diet. The best way to fulfill all your nutrient needs is to include all of the food groups and a wide variety of colorful produce in your regular diet.

Think of the rainbow when planning meals and strive to hit all of the colors. Each color of a fruit or vegetable indicates a specific vitamin, mineral, antioxidant, and phytonutrient.

A phytonutrient or phytochemical is a natural, active substance found in plants that provides protection from sun damage, pests, fungi, and germs. These plant-based compounds are believed to be protective against a variety of diseases.

Beta-carotene is the red-orange color found in carrots, red peppers, sweet potatoes, tomatoes, and green veggies such as broccoli and spinach. Beta-carotene is the nutrient that is converted to vitamin A in the body after you consume it. Vitamin A is also found in some enriched cereals.

Foods rich in vitamin C include all citrus fruits, strawberries, melons, bell peppers, tomatoes, and broccoli. The best “source” of vitamin D is sunlight as the sun’s UVB rays trigger vitamin D production in your skin, but you can also find it in certain foods such as eggs, fatty fishes such as salmon and mackerel, milk, and fortified juices.

Good sources of zinc are lean beef and poultry, eggs, and seafood. Zinc has a higher absorption rate from meat sources, but it can still be obtained from plant sources such as tofu, beans, whole grains, wheat germ, seeds, and nuts.

Probiotics are found in fermented foods such as kimchi and well-known cultured dairy products such as yogurt and kefir. Protein can be included in the diet from both animal and plant sources. Meats, poultry, fish, seafood, eggs, and dairy products all contain protein. Note that the sources at the start of the list will be higher in protein than dairy products.

Cottage cheese and Greek yogurt are two examples of dairy foods that are higher in protein. Plant sources of protein include beans, tofu, legumes, nuts, seeds, lentils, and some whole grains such as quinoa.

What Are the Easiest Ways to Boost Immunity?

The easiest ways to boost immunity are:

• Getting adequate rest
• Eating a balanced diet
• Drinking plenty of fluids

These three behaviors will provide your body with adequate nutrition and fuel to ward off illness and ensure repair and recovery are happening at night when you rest. Avoid alcohol, smoking, and other health-compromising behaviors that will hurt your immune system.

How Important Is Immunity During the COVID-19 Pandemic?

Staying healthy and doing everything in your power to remain that way during the COVID-19 pandemic is of utmost importance. If you feel that you cannot meet your nutrient needs through the foods you are eating, consider adding a multivitamin. Consult with your doctor or a registered dietitian if you feel you would like to add a vitamin or supplement.

Remember that all of these healthy behaviors will not make a difference if you do not reduce the risk of contracting the virus by staying inside and avoiding close contact with others.

Although immunity plays an imperative role in how you endure illness and recover from it, a good immune system does not guarantee protection from COVID-19. Please refer to the CDC (8) and WHO (9) for information on COVID-19.

Social distancing regulations may vary depending on which state and county you reside in, but do your part by following the recommended guidelines to flatten the curve.

Can Drinking Ample Amounts of Water Boost Immunity?

Drink ample amounts of fluid to prevent dehydration. The body is 70% water, and water is essential for metabolic functions to take place. You lose water when you breathe, sweat, and pass urine and stool. It is important to replace these losses by drinking fluids throughout the day.

Drinking more water will not boost your immunity, but rather keep your body hydrated and hemodynamically stable by providing it with the nutrients it needs, to be a well-oiled machine. (10) Fever is one of the symptoms of COVID-19, and when you have a fever, you will lose fluids at a rather fast pace.

When a fever reaches 102°F in adults, 30 ounces of fluid are lost from sweating within 24 hours, and another 3 ounces are lost due to coughing and breathing. Additional fluid losses occur due to poor appetite and intake, nausea, vomiting, and/or diarrhea.

Replacing fluids is especially important during a fever, and fluid needs will actually increase during this time. Minimum needs are 2-4 ounces of fluids every 15 minutes, you should be drinking water or clear fluid every hour.

A simple way to assess your hydration is to make sure you are urinating every 3-4 hours, and your urine is clear or a pale yellow.

If you have vomiting and diarrhea, an oral electrolyte solution is necessary. You can either consume a packaged sports drink or prepare your own electrolyte by adding ½-¾ tsp salt, 1 cup of juice (orange, grape, apple, cranberry), and 3½ cups of water to a pitcher.

Is Drinking Fruit Juices More Advantageous Than Eating Fruits in Boosting Immunity?

It is not recommended to replace the whole fruit with fruit juices in general. Juices typically have added sugars and are missing the fiber from the whole fruit. Twelve ounces of juice count as a serving of fruit. However, look for labels that read “100% fruit juice.” (11)

If you see a juice that has fruit drink, cocktail, or concentrate on the label, the product will likely be high in added sugar and low in nutrients.

What Is the Best Way to Boost the Immune System in the Elderly?

Proper nutrition and hydration are the best ways to promote health in the elderly. Immunity does tend to decline with age, and risk for malnutrition increases as older adults may have reduced appetite, thirst, and mobility. Smaller meals and snacks can be an effective way to increase food intake during poor appetite.

Adequate protein intake and exercise help to preserve lean muscle mass, aid in mobility, keep skin healthy, and therefore help to reduce the risk of malnutrition. If you have a loved one that is not eating well or drinking enough fluid for 3 days or more, encourage them to see a doctor.

Nutrition supplements can also be used in the older population to help boost nutrition intake by providing extra calories, protein, vitamins, and minerals. Check with a registered dietitian or physician for recommendations.

An elderly person that has a chronic disease or multiple comorbidities is at high risk for a suppressed immune system. Always check with their provider before adding supplements, vitamins, and minerals to the diet.

Adults aged 65 and older without chronic diseases can boost their immunity by eating a balanced diet, drinking 64 ounces of fluids per day, staying active, and taking a multivitamin if necessary or as recommended by their doctor.

Does Eating Garlic Increase Immunity?

There is no research to suggest that garlic increases immunity. However, it has been studied for its antimicrobial and anti-inflammatory effects. (12) Garlic may interact with some OTC and prescription medications, so be sure to check with your doctor if you intend to use it as a supplement.

Is Sunlight Necessary to Boost Immunity?

Sunlight is necessary to make vitamin D in the body, and adequate nutrient intake is necessary for proper immune function.

Sunlight is also known as a mood enhancer, which may relieve stress. Stress and the hormones released during a stressed state have been suggested to be harmful to immunity.

Can the Stressful Environment of COVID-19 Decrease the Immunity of a Person?

Stress can have a detrimental effect on immune function. Research over the last couple of decades has concluded that stress increases the production of catecholamines and glucocorticoids, two neuroendocrine hormones often referred to as “stress hormones.” (13)

These stress hormones hamper your body’s ability to fight illnesses and infections by:

• Suppressing the natural killer activity of the body’s immune cells
• Reducing the production and proliferation of lymphocytes
• Decreasing antibody production
• Reactivating latent viral infections (13)(14)

This stress response is particularly concerning in the case of COVID-19 as it may result in reactivation of latent viral infections. Public health and medical providers are working diligently to study and understand the virus in the hopes of developing a vaccine.

Another matter of interest in vaccine development is the effect of stress hormones on the response to vaccinations. Past research suggests that an immune system debilitated by stress hormones may have an impaired response to vaccinations. (13)

Other implications are the development and progression of cancer and delayed wound healing, among many more.

What Is the Best Way to Test the Immunity of a Person?

A doctor can refer a patient for laboratory testing to assess markers of immunity.

What Special Immunity-Boosting Items Should Be Consumed by Pregnant Women During the Time of COVID-19?

Pregnant women should focus on balanced eating, hydration, and taking a prenatal vitamin recommended by their ob-gyn.

Pregnant women should maintain appropriate calorie needs dependent on the weight gain they have experienced during pregnancy and what trimester they are in. Pregnancy increases certain nutrient needs, such as folate and calcium.

Pregnant women should avoid unpasteurized food items, undercooked foods, raw fish, deli meat, and excess fish due to mercury, and they should follow the nutrition interventions provided by their doctor or registered dietitian.

Other than some of the specialized nutrient needs and food restrictions that apply to pregnant women, they can follow the same tips for immunity for adults mentioned earlier. As always, it is recommended to do what is necessary to avoid contracting the virus.

Do Immunity-Boosting Supplements Help Increase Immunity?

Immunity-boosting supplements are useless if they are not coupled with a healthy, balanced diet or not taken in the dosage directed by your doctor or registered dietitian.

Extra supplementation of different vitamins and minerals will not increase immunity. Once the body has absorbed what is needed, it will excrete the rest of the nutrient in the urine.

Over supplementation is not necessary and can be harmful and even lead to death, depending on the nutrient and if the toxicity level is reached.

What Kind of Exercises Can Boost Immunity?

All exercise is beneficial for immunity. Maintain physical activity and do not get stuck in the routine of watching TV all day. Melting into the couch won’t necessarily relieve symptoms of stress.

Exercise preserves lean muscle mass, improves the respiratory system, and improves flexibility, balance, posture, and mood by producing endorphins (feel-good hormone, runner’s high), and the list goes on and on! (15)

Many bodyweight exercises, such as pushups, squats, lunges, and tricep dips, do not require equipment. Try yoga along with the deep breathing and meditation to combine mindfulness with flexibility and strength exercise. The sun is starting to shine a bit more often, so get outside and enjoy a walk or a jog!

If you are at work, try getting up and moving around every 30 minutes. Walk or do office exercises on your lunch break. Get the whole family involved at home by encouraging your kids to stay active safely. Try friendly competitions such as seeing who can do the most jumping jacks or pushups.

How Can People With Preexisting Medical Conditions, Such As Hypertension and Diabetes, Boost their Immunity?

Some conditions, such as diabetes and hypertension require a therapeutic diet, lifestyle changes such as exercise, and medication management. Those who have a chronic disease should maintain a healthy lifestyle through a balanced diet, exercise, taking prescribed medication, and following the recommendations from their doctor and registered dietitian.

What Foods Should Be Included in the Diet of an Average Person?

A normal, healthy individual must consume a wholesome, well-balanced diet that includes all the major food groups, namely fruits, vegetables, whole, grains, and lean proteins.

Research has shown that the typical American diet is lacking in the recommended servings of fruits and vegetables, (16) which for adults is 2 servings of fruit and 3 servings of vegetables per day.

Plant-based diets have shown to have better overall health outcomes than diets that include large amounts of meat, particularly meats high in saturated fats. Plant-based does not mean strictly vegetarian, but rather focusing more on plant foods and limited meat sources to small servings of lean meat.

Examples of lean meats include fish, seafood, poultry without the skin, lean cuts of beef such as filet mignon or skirt steak, and pork tenderloin or chops with the fat trimmed. Plant sources of protein include beans, tofu, lentils, nuts, seeds, and some whole grains such as quinoa.

Does Consuming Ample Amounts of Herbs Boost Immunity?

Consuming herbs or herbal supplements will not boost immunity, as one nutrient alone cannot cure disease or illness. Herbs are a wonderful way to create flavorful dishes without the addition of salt.

If you are looking to start using herbs as a dietary supplement, consult a doctor or registered dietitian before beginning. Some herbs may interact with certain medications, such as the effect of garlic on blood clotting for those who take blood-thinning agents like warfarin.

What Foods Are Considered Harmful to the Immune System?

Any one nutrient taken in excess can be harmful to the body. Foods that have shown to increase the risk of chronic disease are foods high in added sugars, sodium, and saturated fats.

To avoid these foods, shop the perimeter of the grocery stores. The perimeter includes the fresh produce section, the deli where fresh meats can be purchased, and the coolers where you can select your dairy and eggs.

The center aisles of the grocery store contain all the packaged and processed foods that typically contain added sugars, sodium, and saturated fats.

When selecting fruits and vegetables, all forms count, which means you can still reap the benefits by selecting frozen or canned. When selecting frozen, avoid veggies that are in a sauce as this indicates added sodium and fats. When selecting canned, choose low sodium or rinse the items in a colander to wash away excess sodium.

Canned fruits should be purchased in 100% juice rather than syrups to decrease added sugars.

¼ cup of dried fruit yields one serving as dried fruits are preserved by removing all of the fluid, leaving a higher amount of concentrated sugar. Add them into a trail mix with nuts and a whole-grain cereal for an easy on-the-go snack.