The Ultimate Guide to Nutrition, Lifestyle, and Immunity

Diet & Nutrition Inspiring People

AUTHOR: Cliff Harvey, PhD (Clinical Nutritionist & Researcher)

The immune system is the body’s defense system. It protects us against pathogens (like viruses, bacteria, protozoa, and fungi) that can cause disease. It keeps us safe and helps us to preserve the balance between beneficial and disease-causing microbes (the “friendly” bacteria, yeasts, and fungi occurring throughout the body).

Because disease-causing microbes can rapidly mutate and evolve (especially viruses), our defense system needs to be responsive and have multiple defenses. The first line of defense is the innate response. This response is non-specific, meaning that it does not target specific bacteria, viruses, or parasites, but instead launches a general response against potential invaders.

Inflammation is one of the key innate responses. While people think of inflammation as “bad” or undesirable, it is part of the interplay of cells’ chemical signals in the body working to prevent pathogens from causing damage and clearing out waste products of the healing process. So, inflammation is essential to immunity, but it must be kept in balance as prolonged excessive inflammation is itself a risk factor for disease.

The adaptive response responds to specific threats, allowing us to better defend ourselves against future infections. It includes a range of different cells and systems that identify specific identifying markers on the surface of pathogens and build a large, targeted response specifically against them. That’s why for many illnesses, exposure to illness when young, or vaccination, will provide lifelong, or long-term immunity to the illness.

Disorders of the immune system can result in autoimmune diseases, inflammatory diseases, and cancer. Immunodeficiency occurs when the immune system is less active than normal, resulting in recurring and life-threatening infections. In humans, immunodeficiency can either be the result of a genetic disease such as severe combined immunodeficiency, or acquired conditions such as HIV/AIDS, or the use of immunosuppressive medication.

Autoimmunity results from a dysfunction of the immune system in which self-cells (or non-pathogenic microbes residing on tissue) are targeted by the immune system and result in damage to our tissue.

Signs your immune system is not as healthy as it should be:

  • Frequent or persistent colds or flu-like viruses
  • Severe hay-fever or other allergies
  • Autoimmune conditions

Note: Many serious conditions can result in these signs and symptoms. If you are experiencing any of these, please do not attempt to self-diagnose. Consult with your doctor for proper diagnosis and treatment.

Nutrients for a healthy immune system

We read a lot about “boosting” the immune system, but that’s not entirely accurate. To put the immune system into “overdrive” would be equally dangerous as not having a sufficient immune response! So, we don’t want to just “boost” the immune system, we want to make sure we have properly functioning, well-regulated immune function.

The foundation for a healthy immune system is a good diet that provides sufficient energy, essential fats, protein, and all the essential micronutrients, as well as some health-promoting secondary nutrients from plants.

Diets that are high in processed and refined foods, and especially those high in trans-fats and sugar, on the other hand, are likely to worsen responses to infections.

Also, many nutrients have been shown to help support immunity, such as:

  • Omega 3 fats help us to regulate immunity and inflammation in conjunction with the “pro-inflammatory” omega 6 fats. Omega 3 fats are found in fatty fish and vegan sources like flaxseeds and in algae.
  • Vitamin A is intricately involved in immunity,1 and sufficient Vitamin A associated with immunity to illness and infections.2, 3
  • Vitamin C, contrary to popular belief, probably won’t cure the common cold but research suggests that it might help to reduce symptoms of colds and shorten their duration,4 and might even help to prevent the occurrence of colds in athletes and others prone to higher levels of stress when taken regularly.5, 6
  • Vitamin E also has anti-inflammatory and immunomodulatory effects.7
  • Vitamin D is a key immune regulator and has also shown promise for aiding several auto-immune conditions like systemic lupus and rheumatoid arthritis.8
  • Zinc is also a key co-factor for immune responses. Evidence suggests that zinc supplementation might help reduce the duration and severity of the common cold.9, 10
  • Research shows that bioflavonoids from plants reduce upper-respiratory-tract infections.11 Other antioxidant-rich foods like grapeseed, rosehips, and cacao improve antioxidant status and immunity and reduce inflammation.12-17
  • Adaptogens are herbs that are stress “tonics” that help us to respond to stressors more effectively. Among the adaptogens, ginger, ginseng, gotu kola, ashwagandha, and astragalus have demonstrated a range of antioxidant, anti-inflammatory and immune-boosting properties.18-26
  • Common herbs like rosemary are anti-inflammatory and anti-microbial and may benefit immune status.27
  • Spices such as turmeric are likely to improve immune function.28
  • Many mushrooms help to provide immunity against infections. For example, shiitake mushroom is thought to aid immunity by increasing white blood cell activation.29, 30
  • Probiotic supplementation reduces the incidence and severity of respiratory infections,31-36 and probiotics are suggested for use to reduce inflammation and infection following several types of surgeries.37-40
  • Spirulina might reduce the effects of seasonal allergies, along with reducing oxidation and inflammation.41-43
  • Chlorella has demonstrated the capacity to provide a short-term “boost” to immunity by increasing levels of natural killer cells.44

Note! None of the above is a “cure” for any infection, including any cold or flu-like viruses. The key take-home message is that we want to make sure we are getting what we require for optimal health, including that of the immune system. That starts with food and can benefit from the intelligent use of a quality multi-nutrient or other supplements under the care of a qualified, registered health practitioner.

Lifestyle and immunity


Exercise improves health overall, and specifically the functions of the immune system. However, excessive amounts of exercise, leading to over-stress and overtraining can result in impaired immune function and greater risk of infections, especially colds and flu-like viruses.45


Stress, in particular work-related stress, is known to impact the immune system and reduce resistance to infections.46 Most importantly, if we perceive that we get too little reward from our work, this has a greater effect on immunity than simply overworking.47

Other factors that can affect immunity:

  • Poor sleep
  • Smoking
  • Excessive alcohol use

How to Support Immunity

Eat 6 servings of vegetables per day

Vegetables help to provide many essential and non-essential, yet health-promoting nutrients… and most of us don’t eat enough of them!

Make sure you are eating enough, and enough protein

Being consistently “under-fuelled” is a sure-fire way to put yourself at risk of colds and flu-like infections. Make sure that you are eating enough and always base your meals on a serve of a quality protein food.

Consider supplementing with a good-quality multi-nutrient

The key consideration for immunity is not to get massive doses of particular nutrients to “boost” immune function, but instead to make sure you have all the nutrients your immune system needs to function correctly. A quality multi-nutrient can help you to fill in the gaps in your nutrition and supply some of the nutrients you may not always take in each day.

Exercise, but not too much

If you’re new to exercise, start at a level you can do relatively easily and build from there. Work up to taking at least 7,500 steps per day and doing 2 sessions of weight-training or resistance work (like bodyweight workouts or progressive yoga if you don’t want to hit the gym). Add on extra cardio if you can.

Get 8 hours of sleep per night

Sleep is critical to health. Try to get to bed a little bit earlier if you’re not getting at least 7 hours of quality sleep per night. Also, try shutting off your phone and other devices around 2 hours before bedtime.

Reduce your life and work stress

Stress can impact immune function. If you have stressful relationships or environments (like work) try to change them to more fulfilling ones if able. Meditation is also a great way to reduce the impacts of life’s stresses on how we think and feel. As with exercise, start with just a little (even as little as 1 minute of meditation on day one!) and build over time until you are doing around 20 minutes or more per day.

A healthy, well-functioning immune system is a function of having a healthy, well-balanced life! There are no pills or potions that will magically “boost” your immune system but you can help to support the best functioning immune system you can have by following some simple guidelines of good food, movement, intelligent supplementation, and mindfulness.

The information provided on Nuzest is for educational and informational purposes only. The information provided on this site is not, nor is it intended to be, a substitute for professional advice or care. Please speak to your qualified healthcare professional in the event that something you have read here raises questions or concerns regarding your health.


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