The Ultimate Guide to Supporting Your Immune System

The human body is an incredible specimen. Given proper nourishment, healthy amounts of physical strain, and adequate conditions to recover and adapt, it becomes resilient enough to withstand incredible mental or physical stress.

Until you get sick.

If you get sick, you better hope your immune system is up for the challenge. This guide is designed to give you a deeper understanding of the actionable health choices and patterns that research has shown to support a healthy, resilient immune system.

It’s a helpful resource, but it’s not a replacement for actual medical diagnosis, treatment, or advice. For that, you should visit your medical provider(s).

Before we explore the “how to maintain good immune health” content, it’s important to briefly outline what your immune system is and what it’s supposed to do.

Your immune system is a collection of several biological processes that work to restore or maintain normal physiological conditions, no matter what types of pathogens we ingest or come in contact with.

It’s supposed to protect you from potentially harmful or infectious bacteria, parasites, yeasts, molds, or viruses.

Think of the immune system as two major categories:

1. Innate (or humoral) immunity consists of mechanical, chemical, and biological barriers and acts as a first line of defense against pathogens. These include mucous membranes, enzymes, pH (acidity/alkalinity), as well as temperature and oxygen levels.
2. Adaptive (or cell-mediated) immunity is antigen-specific and relies largely on the health of your white blood cells. It’s the part of the immune system that “learns from experience” so to speak.

Several lifestyle factors influence the health and resilience of both innate and adaptive immune function. This guide addresses them in three parts:

1. Nutrition and Supplementation
2. Exercise and Movement
3. Lifestyle

Each of these categories is important for immune health, but it’s difficult to argue any single category is more or less critical than the others. They’re all intertwined in such a complex way that even modern science struggles to tease out what’s actually happening with acute and long-term immune function when certain interventions are implemented.

For example, when you sleep poorly or travel across time zones, something changes with your immune resilience. But you can make a few adjustments to your workouts, nutrition or supplementation to protect you from negative outcomes. That’s just one example.

The process of achieving better immune health is simple. It may not be easy, but it is simple. Even Hippocrates knew this long ago.

If we could give every individual the right amount of nourishment and exercise, not too little and not too much, we would have found the safest way to health.

Hippocrates c. 460-377B.C.

Nutrition and Supplementation

Don’t “Diet”

To best support a strong, resilient immune system, eat a nutrient-dense diet. What does that mean?

• Eat enough calories to maintain normal metabolic function.
• Get most of your essential nutrients – vitamins, minerals, essential fatty acids, and amino acids – from wholesome, minimally processed foods whenever possible.
• Supplement your food intake with high-quality dietary supplements so your body has a consistent supply of critical nutrients your diet may not be providing enough of.
• Stay well hydrated by drinking more water than any other beverage.

Aiming for optimal nutrition means not approaching each day or each meal with a restrictive “dieting” mindset. You don’t need to fear of calories, fat, or certain food categories. Choose sources of nutrition based on their ability to provide more optimal amounts of nutrients to help you feel and function at your best and satisfy your energy and appetite needs.

Researchers have observed that prolonged calorie restriction, defined as two years of following a low-calorie diet, lowers white blood cell counts, which lowers immune system resilience.

Either over-training or under-nutrition may lead to an increased risk of infections.

Venkatraman, 2002

Without sufficient energy or quality nutrition, innate and adaptive immune resilience against any potential infection suffers. Your first lines of defense against pathogens cannot function as designed.

Training hard and dieting to get leaner may make you more susceptible to common cold viruses.

Put another way, nutrition and supplementation promote well-being, which includes enhancing your immune system function.

Eat a Nutrient-Dense Diet

Vegetables and fruits are critical sources of key vitamins, minerals, fiber, and phytonutrients, essential for innate and adaptive immunity.

Every major health organization has been urging us to consume an abundance of produce for decades. Yet, recent evidence from the CDC suggests only ten percent of adults eat the recommended amount of fruit and vegetables each day.

It’s important to note that the Recommended Dietary Allowances for each nutrient (RDA’s) are not based on specific requirements of the immune system and its ability to fight infection or control inflammation.

In the case of several nutrients, for example, optimal nutrient intake levels are actually higher for other body systems and cell types. For example, vitamin E, vitamin B-6, and zinc needs increase when the immune system is more active than normal.

Interestingly, the “Five A Day” vegetable and fruit recommendation doesn’t even get you to your optimal micronutrient levels.

You’d be better off eating upward of nine or more cups of produce per day, but even that amount might not be enough.

Don’t worry about measuring exact amounts of produce. Just fill at least half your plate at each meal with colorful vegetables and fruits. Or, eat a pile of produce the size of your head each day.

The following are some of the most important nutrients you need to maintain a strong immune system.

Eat High-Quality Protein With Every Meal

In addition to eating a produce-rich, nutrient-dense diet packed with vitamins, minerals, and essential fatty acids, it’s imperative to eat high-protein to promote optimal immune system health.

Protein-energy malnutrition and/or deficiencies of single nutrients can impair production of key proteins involved in immune function.

Beisel, 1996

If you’re following a calorie deficit (whether through diet, exercise, or a combination of the two), protein intake is even more important. Energy and protein deficits break down healthy muscle tissue to supply amino acids needed to maintain immune function.

Severe cases of protein or energy malnutrition have been known to cause serious immune suppression, mostly in developing nations, but milder forms of such conditions are certainly possible in people who exercise intensely on a consistent basis while under-nourished.

The amino acids that makeup protein are critical as building blocks for everything our immune system relies on.

They are the building blocks of cellular organelles, cell membrane receptors, enzymes, antibodies, signaling molecules and structural tissues that make up protective barriers such as skin and mucus membranes.

Optimal protein needs are 1.4 to 2.0 grams per kilogram body weight per day, about double the current RDA at 1.4 to 2.0 g/kg/day.

At least one study investigating higher protein intakes and immune response showed better immune resilience and wound healing compared to lower protein intakes.

To simplify these protein recommendations, estimate your individual protein needs for more optimal immune function and exercise adaptation using 1 gram of protein per pound of body weight, or at least 1g/lb of ideal body weight per day.

Concerned about over-doing protein? Unless you have a medical condition warranting protein restriction there are several other benefits to consuming a higher protein diet.

Read more: High-Protein Diets: Health Benefits and Controversies.

Avoid Inflammatory Foods and Beverages

Alcohol

Alcohol can disrupt the structural integrity and permeability of the gut lining itself, allowing other inflammatory compounds to cross into the bloodstream. It can also alter the gut microbiome and all the downstream inflammatory and immune cascades influenced by our gut microbes.

Alcohol metabolism also depletes several vitamins and minerals, which may have indirect immune health impacts due to competing for nutrient uses with the immune system.

On top of that, alcohol consumption alters sleep quality or quantity in most people, which may have both short and long-term negative effects on immune resilience.

In the context of all the factors involved with healthy or optimal immune function, the evidence isn’t clear enough to recommend any alcohol use to promote immune health. In other words, it’s not necessary for proper immune function and may have too many potential ways of disrupting optimal immune function to justify regular drinking to help immune function.

Sugar and Sweeteners

Processed or added sugars are ubiquitous in modern diets and are widely recognized as less nutritious than whole-food sources of simple and complex carbohydrates.

Excess consumption of added sugars has been shown to encourage systemic inflammation and possibly suppress white blood cell counts or activity.

In mouse studies, short-term exposure to high sugar altered gut microbiota and monocyte function.

Artificial sweeteners are almost as common as added sugars in modern diets, but they’re known to not just lend calorie-free sweet taste to foods and beverages.

Aspartame, sucralose, and saccharin alter the gut microbiome in rodents and humans, so much so they are implicated as a causative factor in the development of insulin resistance. If the effects on the microbiome are this disruptive to insulin function, might they also shift gut and immune resilience as well? More research is needed in this area for sure.

Like added sugars and alcohol, there’s little to no evidence showing artificial sweeteners support optimal immune function, so they also fall under the “minimize or eliminate” intake category.

Take High-Quality Supplements

Why are supplements so important?

Supplementation with micronutrients may facilitate the immune system and compensate for [dietary] deficits in essential nutrients.

Venkatraman, 2002

Modern dietary patterns lack nutrient-dense foods. Even if we choose wholesome, minimally-processed foods, modern food is often less-nutritious than it was a few decades ago due to soil nutrient depletion and growing practices.

Nutrient needs to support optimal health and immune function are often significantly higher than established RDAs, especially in individuals who exercise regularly and are seeking optimal function.

A vitamin is a substance that makes you ill if you don’t eat it

Albert Szent-Gyorgyi, Nobel Prize in Physiology & Medicine, 1937

Supplements can be confusing, and unfortunately there isn’t just one supplement that can optimize immune function by itself under all conditions (although Vitamin D is a remarkable supplement on its own).

This section covers the most-well understood supplements for supporting immune health in order of relative priority.  There may be others that have shown promise or have anecdotal support, but if they’re not included in this guide they aren’t worth covering just yet. As always, we encourage people to start their supplement plan with our Foundational Five.

High-Quality Multivitamin

(High-Quality) Multivitamins are the most convenient way to consistently help cover essential micronutrient needs (vitamins and most minerals).

Remember from earlier that many of these nutrients come in different forms with different absorption and bioavailability characteristics, and that amounts needed to optimize immune health may be much higher than established RDAs.

Well-formulated multivitamins will not only use the best forms of essential nutrients, they’re also delivered via stable and easy-to-digest methods, namely as capsules instead of tablets gummies, or liquids.

Inadequate micronutrient intake, sometimes at borderline levels of deficiency, has been linked to stunted growth and neurocognitive deficits, as well as increased risks of various symptoms and [health] conditions. Most nutrients act in all tissues, and all tissues need all nutrients; therefore, inadequate intakes may adversely affect every body system.

Ward, 2014)

Read more: High-Quality Multivitamin: What to Look For. Why It Matters.

Fish Oil

EPA and DHA Omega-3s from fish oil. Most people fail to consume enough dietary sources of these essential fatty acids so supplements are critical for managing inflammation, supporting cell membrane function and supporting immune response.

The best outcomes appear when total EPA + DHA intake is at least 2000mg per day, so look for a highly-concentrated supplement with at least 600mg of EPA+DHA per softgel from triglyceride form omega-3s.

Read more: Fish Oil: Benefits of Supplementing For Your Body and Brain.

Vitamin D

Vitamin D is important to supplement for several reasons; there aren’t many foods rich in active vitamin D3, most people don’t get adequate sun to produce their own, and insufficient vitamin D has direct and widespread negative effects on innate and adaptive immunity.

Half the world’s population may be deficient, and even more have sub-optimal levels. Many multivitamins contain minuscule amounts of vitamin D so look for a supplement with vitamin D3 as cholecalciferol combined with vitamin K2 (menaquinone) as these nutrients interact to support several aspects bone and cardiovascular health along with immune function.

The Vitamin D Council recommends at least 5,000 IU per day for most adults.

Read more: Vitamin D: Deficiency Symptoms and Benefits of Supplementation.

Magnesium

Magnesium is recommended as an additional supplement because even high-quality multivitamin/mineral formulas often can’t physically fit enough of this mineral without increasing the number of capsules.

It’s critical for several aspects of innate and adaptive immune function as well as literally hundreds of other metabolic reactions.

Magnesium is also helpful for promoting sleep onset and sleep depth, which we’ll cover later. Look for chelate or malate forms of magnesium for best absorption and aim for at least 300 mg per day in addition to dietary intake for best effects.

Read more: Magnesium: Health Benefits and Best Ways to Supplement.

Digestive Enzymes

Digestive Enzymes aren’t nutrients per se, but they do play a vital role in helping us access the nutrition from the food and supplements we consume.

Enzymes, including digestive enzymes are also part of our innate immune system; they play a role in intercepting and destroying pathogens we may ingest.

Digestive enzyme supplements make this list because the nutrients we eat and take can only lend their benefits if we digest, absorb and assimilate them completely.

Take a broad-spectrum digestive enzyme that includes hydrochloric acid (Betaine HCl) along with carbohydrases, lipases, and proteases to help with breakdown of carbohydrates/fibers, fats, and proteins.

Read more: Digestive Enzymes: What Are They? How Do You Use Them?

L-Glutamine

L-Glutamine is the most abundant amino acid in our bodies, and while we can synthesize it from other amino acids it’s a “conditionally essential” amino acid, which means under certain conditions our needs are elevated to the point where optimal health can only be achieved if we take in extra sources.

Most importantly for immune health, L-Glutamine serves as fuel for most immune cells and immune response can be impaired when glutamine reserved become depleted and dietary intake is inadequate.

It’s an inexpensive, odorless, tasteless powder that can be easily added to any food or beverage, 5 grams twice a day as a general recommendation.

Probiotics

Probiotic supplements are sources of microorganisms that can shift the microbial balance of our lower intestine.

A recent meta-analysis showed that probiotic supplementation reduced the incidence of upper respiratory infections (URIs) by approximately half, shortened URI duration by approximately 2 days, and reduced antibiotic prescription rates.

Researchers are just scratching the surface of understanding which strains of bacteria are most helpful to each individual, so the type and amounts of colony-forming units (CFUs) to look for in a supplement isn’t as clear.

Well-researched strains will be indicated on supplement labels with a specific letter-number code after the name of the strain, such as Bifidobacterium bifidum (BI-04), which is a clinically studied strain shown to support healthy immune function (just one of the strains in Life Time’s MultiPro 30B Probiotic).

Other Supplements to Consider

Spirulina evidence that suggests that supplementing with the blue-green algae spirulina promotes mucosal immunity.

Melatonin may be a helpful nutrient to supplement to promote immune health indirectly through improving sleep onset and sleep depth.

Curcumin, a component of turmeric root may be powerful botanical ingredient that could help modulate immune response and cell signaling.

Overwhelmed? Don’t be.

The main takeaways regarding nutrition and supplementation are to eat a nutrient-dense diet with plenty of vegetables and fruit, get ample protein (probably more than you consume now), and upgrade/optimize your supplement routine.

Simple. Maybe not easy, but simple.

Exercise and Movement

Are you wondering why activity choices matter for immune system resilience?

Exercise can and should be an extremely beneficial part of a healthy lifestyle.

We know that a little exercise is better than none, moderate amounts are quite good, but a lot of exercise could turn out to be bad.

Some direct benefits of exercise for immune system health recognized in the literature are:

• Heavier breathing during exercise may help flush bacteria or viruses from the lungs and airways.
• It stimulates changes in white blood cell function and circulation (adaptive immune response).
• The temporary rise in body temperature during and after exercise may help prevent bacteria from growing, helping the body better manage infection.
• Exercise can modulate stress hormones.

Exercise tolerance varies by individual and depends on your experience and training history along with other genetic and nutritional considerations. To maintain good immune health while training, it’s recommended to start with low to moderate volume and intensity and apply gradual, periodized increases in training loads to limit risk of negative adaptations or immune compromise.

In other words, if you’re just starting be careful not to add too much too soon. If you’re an avid exerciser, evaluate whether or not your current routine is helping or hindering your immune resilience.

Keep Building Muscle

Building and maintaining muscle throughout the lifespan is perhaps the best insurance policy against any potential negative health conditions, acute or chronic. If you have limited time for exercise, then use it for resistance training (lifting weights).

Lean muscle tissue not only looks healthy, but it also it gives us strength to maintain better balance and resist injury from falls, and it’s the largest reservoir of amino acids our bodies draw from in the event we need to mount an immune response – especially when dietary protein or amino acid intake is inadequate.

Critical conditions such as infection, traumatic injury, and advanced cancer rely on amino acids from muscle tissue more than starvation or fasting, so the more muscle tissue you have in the event one of these scenarios arises, the more likely you are to emerge from it with your health intact.

It’s recommended we exercise more days than not, so try to strive for four days a week of resistance training to achieve and maintain optimal health.

Move Often

Forceful muscle contractions, like those unique to resistance training, and consistent, regular movement are both critical to help the body circulate immune cells through our lymphatic system.

Like our circulatory system, the lymphatic system is a network of tissues and canals throughout our body that’s used to circulate immune cells, antibodies, and fatty acids. However, it doesn’t have a pump; we are the pump.

Other studies have also shown low-intensity walking may be helpful for stimulating circulation of Natural Killer cells and T-cells, which may help with resilience against potential infections.

Beyond these direct immune supportive effects, taking periodic breaks throughout the day may be a helpful strategy to better manage other life demands or stressors too, so make it a point to get up and move often even if it’s not for a dedicated workout.

Don’t “Over-do” Cardio

There are many potential benefits of aerobic or cardiovascular training, but as with anything that may be good, too much may also be detrimental at a certain point.

High-intensity and/or long-duration cardiovascular training is stressful on the body, that’s part of why it works for developing higher levels of fitness (if you can tolerate and adapt positively to the training stress). The metabolic stress of “doing cardio” produces massive amounts of oxidative stress, and the mechanical stress of the sustained, repetitive motions creates a great deal of tissue breakdown. To be clear, these insults are what stimulates the body to adapt, so they’re not always a negative thing.

However, if you’re not optimizing your nutritional status or are replacing resistance training with strenuous cardio training, you may not be helping your immune system or overall health all that much.

Acute, intensive exercise appears to depress several aspects of adaptive immune function for up to 24 hours, but that suppression may become chronic if recovery between sessions is inadequate for any number of reasons (nutrition, sleep, or other life stressors).

Longer-duration, higher-volume/intensity cardio leads to more significant inflammatory and immune responses over time. Comparing those training for marathons against those who performed lower-intensity walking for their aerobic training, the marathon trainers incurred significantly higher amounts of stress hormones and inflammatory cytokines and experiences less favorable changes to both innate and adaptive immune resilience.

More or harder exercise isn’t always better. Better exercise is better.

Now, of course there are outliers to this principle. How else could you explain that some professional and elite marathon runners appear to thrive on their extremely strenuous training regimens?

Include Active Recovery

If you think you might be over-doing cardio but want to stay active between resistance training sessions, remember there are a number of exercise modalities that will complement your overall health and wellbeing.

There’s emerging evidence showing mind-body activities such as yoga and Pilates are also supportive of healthy stress management, inflammation control, and immune resilience, possibly through their own unique mechanisms not fully understood yet.

Interesting clinical research in these areas is being done and we’re probably not far off from having solid “proof” that we should be doing yoga and/or Pilates more often. If you don’t yet include restorative activity in your routine, maybe it’s time you start.

Lifestyle

Immune health isn’t just influenced by nutrition, supplements, and exercise patterns. Evidence suggests how and where we spend our time away from exercise and eating has significant impacts on immune and overall health. Good hygiene, restorative sleep, time outside, and healthy stress management are all critically important to a strong immune system.

Master Good Hygiene

Infectious diseases often spread through contact with other people or contaminated surfaces, so it’s easy to understand why one of the easiest ways to maintain healthy and immune resilience is to wash your hands regularly.

The CDC reports that good hand-washing practices significantly reduces the spread of infectious disease, and recommends washing with soap and water several times throughout the day, basically anytime you touch anything.

Here are the five steps to handwashing the right way:

1. Wet your hands with clean, running water (warm or cold), turn off the tap, and apply soap.
2. Lather your hands by rubbing them together with the soap. Lather the backs of your hands, between your fingers, and under your nails.
3. Scrub your hands for at least 20 seconds. Need a timer? Hum the “Happy Birthday” song from beginning to end twice.
4. Rinse your hands well under clean, running water.
5. Dry your hands using a clean towel or air dry them.

Oral hygiene is also important for healthy immune function. The American Dental Association recommends brushing your teeth thoroughly twice a day and cleaning between teeth with floss once a day. Mouth rinses may also be recommended to help maintain healthy mucus membranes.

Get Outside Every Day

When we’re exposed to sunlight, we have a better chance of producing adequate vitamin D, but research shows it also helps activate and transport T cells to locations where they’re needed, which appears to enable adaptive immune response.

It just feels good to get outside and experience fresh air and nature, doesn’t it? Scientists studying our biochemical responses to exposure to nature (walks in nature, viewing nature scenes, going to a park, etc.) observe that the health benefits of these experiences may be driven mainly by enhancements in our immune health through multiple, complex mechanisms.

Nature doesn’t just have one or two active ingredients. It’s more like a multivitamin that provides us with all sorts of nutrients we need. That’s how nature can protect us from all these different kinds of diseases–cardiovascular, respiratory, mental health, musculoskeletal, etc. — simultaneously.

Ming Kuo, Ph.D

Don’t Sacrifice Sleep or Downtime

We spend roughly a third of our lifespan in the mysterious state we call sleep. It’s a fascinating phenomenon humans have sought to understand for centuries. Entire books, courses, fields of research, and careers have been dedicated to understanding the importance of sleep.

Sleep is the ultimate reset for our entire body. It’s essential to restore homeostasis, regulate the immune system, repair damaged tissue, clear out damaged cells, imprint memories, restore neurotransmitter balance, and prepare our brain and body for the next day of physical and cognitive challenges.

According to experts, adults need at least seven hours of restful sleep every night.

Regarding the immune system specifically, short-term and chronic sleep restriction can both negatively impact systemic and local immune response.

“Normal” sleep is known to help restore healthier adaptive immune response to viral infections by allowing better distribution of immune cells throughout the body and enhancing the expression of antiviral cytokines. (Irwin, 2019)

To optimize sleep hygiene, the following strategies are recommended:

• Be consistent with your bedtime and wakeup time, to the best of your ability
• Be active or exercise, and get outside during daylight hours
• Avoid caffeine after early-afternoon (stop caffeine consumption by 2pm)
• Eat your last meal of the day at least a few hours before bedtime
• Minimize or avoid alcohol as it disrupts sleep quality
• Be sure your sleep environment is cool, dark, quiet, and comfortable
• Avoid or minimize exposure to electronic screens after sundown, or at least wear blue-light blocking glasses to minimize blue light stimulation
• Consider natural sleep-supportive supplements to help with sleep onset and sleep depth, such as evening time magnesium or melatonin (or potentially other botanical ingredients shown to help with sleep)

If you can’t or don’t get adequate sleep, it’s not the end of the world.

Just control what you can and emphasize nutrient-dense dietary choices, get ample protein, take quality supplements, and consider adjusting your exercise intensities or duration to better support your resilience.

According to one study, some of the negative effects of sleep restriction were mitigated by supplementing the participants with higher protein (1.5 g/kg/day vs. 0.8 g/kg/day), plus additional amino acids (arginine and glutamine), zinc, vitamin C, vitamin D3 and omega-3 fatty acids.

As with anything, some people thrive on more or less sleep, and there are other methods of relaxation that have immune-supporting evidence too, like using a dry sauna and or getting a massage.

One of the main mechanisms sauna and massage may support immune function is through the positive effects they have on managing stress hormones and related inflammatory response, which brings up another critical controllable health pattern you should pay attention to if you want to optimize immune function.

Actively Manage Stress

Without some stress, we would die. And not all stress is bad stress. Our bodies are designed to encounter and adapt to incredible amounts of physical and psychological stress.

However, stress can become destructive or disruptive if we don’t manage it well. If we don’t manage stress in healthy ways, there isn’t a single metabolic or organ system that isn’t affected by chronic stress.

For example, research has shown psychological stress is associated in a dose-response manner with an increased susceptibility to the common cold and weakens the immune system over time if not properly managed.

In addition to exercise, sauna, and massage, healthy stress management techniques to implement for healthier immune function include:

• Relaxation and breathing exercises like meditation or positive thinking
• Behavior modification coaching
• Social and community support
• Laughter

However you choose to manage the stress you encounter in a healthy way, your immune system will benefit, there’s no doubt.

Healthy People Have Healthy Immune Systems

You can’t change what you don’t measure, so take responsibility for your health by learning more in-depth information about how your lab markers compare to measures of optimal health. If you already feel amazing and just read this guide for fun, be sure to continue to visit your doctor regularly for checkups and measure how your efforts are impacting your short and long-term health risks.

As mentioned earlier, don’t let the amount of information contained here stall you from taking action. The process of improving and optimizing your health should feel manageable and simple, even if it’s not easy every step of the way. Recruit help from family or friends. Hire an expert to teach you how to implement these practices into your life.

Imagine how amazing you’ll feel and how resilient you will be when you put all the information in this guide to use.

Sure, maybe you’ll be less likely to catch whatever illness is going around and you’ll probably be quicker to bounce back to normal if you to end up getting ill.

Maybe you’ll be more productive at work, be more optimistic, achieve new levels of fitness, or just have more energy to be social with friends and family?

Just make a promise to yourself to never stop pursuing excellent health. It’s your lifetime. Get the most out of it.