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How to Prevent Getting Sick: 3 Simple Steps

BY Adam D’Agostino

Winter is coming, and with it the cold and flu. Naturally bolster your defenses against seasonal invaders with simple strategies.

As we gear up for the winter season, it’s time to start considering the importance of a strong immune system. With endless advice circulating out there about how you can protect yourself from the outside in, I think it is even more pressing to focus on how you can do it from the inside out. Locking up your immune fortress is the key to long-term health and wellness. 

If you wait until you are feeling under the weather to start thinking about your immune system, it’s too late. So what can you do to bolster our defense against seasonal invaders? Here, we explore several specific options which fall into two broad categories: Nutrition and Lifestyle. 

1. Focus on Your Nutrition Habits

Nutrient deficiency can alter the body’s immune response, putting you at greater risk for infection. Poor diet and/or malnutrition can impair the production and activity of immune cells and antibodies. So, how do you prevent this? For starters, eat a balanced diet that includes plenty of fruits and vegetables, whole grains, lean protein, and plenty of water. This may seem rather basic, but many people struggle with simplicity and neglect the basics. Eliminating processed foods and excessive sugar as much as possible is also crucial. 

Vitamins and Minerals

Micronutrient deficiencies are common worldwide, and as a result, resistance to infection is compromised. Some important nutrients for immune system function include iron, folic acid, and B-vitamins. Here are several more of the key players you want on your immune team, including which foods you should eat to get them: 

  • Zinc: Shellfish (oysters, crab, shrimp, mussels), legumes (chickpeas, lentils, beans), seeds (pumpkin, flax, sesame), nuts (cashews, almonds, peanuts, walnuts), red meat (limit consumption and opt for unprocessed/grass-fed), and dark chocolate (saved the best for last!). Be aware that legumes contain phytates, which reduce the absorption of zinc. Heating, sprouting, soaking, or fermenting will help to improve bioavailability.
  • Selenium: Brazil nuts, fish, ham, poultry, eggs. 
  • Vitamin A: Carrots, broccoli, cantaloupe, squash, sweet potatoes, liver, fish, green leafy vegetables. 
  • Vitamin C: Citrus fruits, kiwi, strawberries, tomatoes, potatoes, red & green peppers, broccoli, brussel sprouts, spinach. 
  • Vitamin D: Salmon (opt for wild-caught), tuna, herring, sardines, egg yolks, mushrooms, cod liver oil. 
  • Vitamin E: Nuts, seeds, green leafy vegetables, salmon, avocado. 

If you don’t normally consume most of these foods, it might seem like a daunting task to start. However, the key is varying your sources of each nutrient and being consistent with healthy eating over the long term. As athletes, an added benefit is that many of these foods will help with performance and recovery as well.

Herbal Supplements 

What else can you do to implement an extra layer of nutritional protection? Herbs such as echinacea, garlic, turmeric/curcumin, oregano, and green tea catechins have been used for many years as natural health remedies. They contain potent antioxidants and phenols that support your body’s natural defenses and restore balance to your gut microbiome. Using these in home cooking and meal preparation is a great way to add them to your diet. Additionally, colostrum has been shown to fortify the body with vitamins, minerals, and enzymes that support your immune system and promote a healthy gut lining. 

Pre- and Probiotics

The gut microbiome plays a key role in immune function and the production of antimicrobial proteins. Therefore, a diet containing prebiotic and probiotic foods is beneficial. Probiotic foods contain live helpful bacteria, while prebiotic foods contain fiber and oligosaccharides that feed and maintain healthy colonies of those bacteria. Examples of probiotic foods include yogurt (with live active cultures), fermented vegetables, kefir, kombucha tea, sauerkraut, tempeh, kimchi, and miso. Some good prebiotic foods choices are asparagus, bananas, onion, garlic, leeks, artichokes, and seaweed. 


Medicinal mushrooms, which have become increasingly popular recently, are another stellar option for a nutritional immune boost. Used in Eastern medicine for thousands of years, their list of health benefits is extensive. More specifically, Chaga mushrooms are an antioxidant powerhouse that ward off free radicals and inflammation. Other friendly fungi include Reishi, Turkey Tail, and Cordyceps. Popular methods of consumption include mushroom coffees, teas, and protein/superfood shake mixes. 

For more information on supplementing and other types of adaptogens, check out this blog: Adaptogens for Athletes: Benefits, Types & How to Supplement

2. Consider Your Lifestyle Choices 

Now that you have your nutrition in check, your herbal cabinet stocked, and your Chaga mushroom coffee poured, it’s time to explore other areas that may be having a detrimental effect on your immune squadron.

Maintaining a healthy lifestyle is the single most important step you can take to keep your immune system functioning efficiently. If you think of your immune system as aerodynamic efficiency in cycling, the following will determine how much drag you have: 


Experts recommend a range of 7-9 hours for ideal body restoration. Even a single night without sleep (or poor sleep) can negatively impact your body’s ability to fight off pathogens, bacteria, viruses, etc. Having a consistent sleep schedule maintains a balanced circadian rhythm (your body’s natural clock) so that you get more restful sleep. Do not make the mistake of underestimating this factor! 


My favorite one, obviously. Given my audience, this should be the easiest one to check off the list. Research shows that obesity has been identified as a risk factor for viruses such as the flu, likely due to impaired function of T-cells (a type of white blood cell). Regular exercise helps to maintain a healthy body weight, improve cardiovascular health, lower blood pressure, and protect against many diseases. It may even contribute more directly by promoting good circulation, which allows immune cells to move through the body freely and work more efficiently. 

Eliminate Environmental Toxins

This includes air pollution, smoke, and excessive alcohol consumption. If you smoke, make it a priority to quit as soon as possible. If you drink alcohol, do so in moderation. These substances can suppress and impair the normal activity of immune cells. 

Manage Stress 

I know, this a tough one. But have you actually tried a healthy strategy for stress reduction and given it ample time? Many people will try one thing for a day or two, then decide to bail when it “doesn’t work” well enough. Anything that truly helps you manage stress effectively will take time to implement and practice. Some examples include exercise (there it is again), meditation, yoga, reading, writing, tai chi, breathing techniques, and being outside in sunlight or near water. There are many others, and often the best overall stress management strategy includes several of these used in combination on a regular basis. 

Furthermore, managing stress plays an important role for athletes because their total stress (physical + non-physical) is much higher. If someone has high mental stress, emotional stress, and environmental stress, adding training stress into the equation is a recipe for disaster. We can certainly bob and weave our way through these stress jabs for a few rounds, but it eventually all catches up.

Ultimately, there is a clear interaction between nutrition and immunity: the immune system is compromised when nutrition is poor, predisposing you to sickness and/or infections. Additionally, a poor nutritional state may be exacerbated by your body’s immune response to an infection. Although this article focuses primarily on athletes, everyone can benefit from the nutrition and lifestyle recommendations outlined above. 

By implementing the strategies discussed here, you’ll equip your immune system with the tools it needs to fend off illness this winter. If you are unsure where to begin on your journey or need help making adjustments to your current plan, seek qualified assistance. The guidance of a certified coach can be a valuable resource on your path to achieving the next level of performance! Be advised to consult your physician before making any major changes to your nutrition as well. 

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About Adam D’Agostino

Adam D’Agostino is a USA Triathlon (USAT) Level 2 Certified Coach, IRONMAN Certified
Coach, TrainingPeaks Level 2 Certified Multisport Coach, & US Masters Swimming (USMS)
Level 3 Coach. Adam is a National Academy of Sports Medicine (NASM) Certified Personal
Trainer (CPT) and has additional certifications from NASM as a Corrective Exercise
Specialist (CES), Mixed Martial Arts Conditioning Specialist (MMACS), & Nutrition/Weight
Loss Specialist (WLS). In addition, he holds TRX certifications in Suspension Training (STC)
& Functional Training (FTC). Adam competes in triathlons of all distances and qualified for
the USAT National Championships 10 times (2012-2019, 2022, 2023). He is a multiple-time
IRONMAN, as well as a two-time qualified athlete on Team USA for the ITU Multisport World
Championships in Long-Distance Triathlon (2017 & 2019). Adam is the owner and head
coach of Next Level Training & Performance in NJ, where he specializes in Triathlon
Coaching, Personal Training, Nutrition, & Athlete Performance.

Visit Adam D’Agostino's Coach Profile

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