As we approach the middle of winter with less access to fresh food, low light and shorter days, and bitterly cold days that keep us stuck inside with little physical activity, I’m sure you or someone you know has battled a period of sickness. Just like other symptoms such as digestive issues, brain fog, or unstable blood sugar, the frequency of your illnesses and the time it takes your body to recover can all serve as important indicators of a deeper underlying immune dysfunction that deserves attention sooner rather than later.
In our previous blog post we covered how the immune system works and the key nutrients needed from your diet to support a strong immune system. In this post, we're diving deeper into the main factors that contribute to a weakened immune system and, the signs and symptoms of immune impairment.
Contributing Factors to a Weakened Immune System
As with most systems in the body, immune weakness does not develop overnight—it typically unfolds gradually over time and is the result of multiple contributing factors working together. Understanding these factors is the first step toward restoring immune resilience. Below are the key contributors to immune system weakness:
- Nutritional deficiencies – Lack of adequate protein and key immune-building nutrients due to poor dietary choices or impaired nutrient absorption
- Lack of beneficial gut bacteria as a result of modern diets that don’t include pre and probiotic foods
- Poor quality sleep - Inadequate or disrupted sleep patterns, as deep, restorative sleep is essential for immune system repair and regeneration
- Poor digestion as a result of inflammation from food sensitivities, processed foods, sugar, alcohol and an imbalance of bad gut bacteria
- Skin disorders or mucous membrane weakness like eczema that weaken the body’s first line of defence against infection
- Chronic Stress (mental, physical, or psychological) results in high levels of cortisol (the stress hormone) which is immunosuppressive
- Food and environmental toxins - Regular contact with food additives and environmental toxins such as xenoestrogens, dry cleaning chemicals, pesticides, plastics, harsh chemical cleaners, and conventional cosmetics, all of which burden the body's detoxification pathways and weaken immune capacity
- Immunosuppressive medications – Steroid drugs and certain other medications that inherently suppress immune system function
- Intestinal Permeability AKA Leaky gut - A compromised intestinal lining that leads to chronically elevated immune responses, gradually exhausting the immune system over time. Leaky gut can result from chronic stress, regular consumption of processed foods, excessive alcohol and caffeine intake, pathogenic bacteria overgrowth, exposure to toxic chemicals, overuse of antacids or antibiotics, gluten sensitivity, frequent NSAID use, and artificial sweeteners like aspartame
- Persistent infections – Ongoing or previous exposure to bacterial infections (such as H. pylori, SIBO, or candida overgrowth) that compete for immune system resources, or lingering viral infections (like long COVID or Epstein-Barr virus) that can lead to long-term immune system impairment
- Lack of exercise and movement which directly impacts lymphatic system function and decreases the circulation and effectiveness of immune cells throughout the body
- Liver dysfunction – A stressed or overburdened liver that cannot effectively filter toxins and produce immune-supporting proteins. Liver stress can result from diets high in refined sugar and unhealthy saturated fats, obesity, excessive alcohol consumption, chronic infections, and repeated exposure to environmental toxins
Signs of Immune System Impairment
Fortunately, your body often provides clear signals when your immune system is struggling and needs additional support through lifestyle modifications or targeted interventions. Being aware of these warning signs can help you take proactive steps to strengthen your body's natural defenses before minor issues develop into more serious health concerns.
Common symptoms that may indicate your immune system requires attention include:
- Recurrent or frequent infections -such as catching every cold that goes around or experiencing multiple infections throughout the year
- Wounds that seem to take much longer than normal to close and repair properly
- Pre-existing inflammatory disorders -essentially any medical condition whose name ends in "itis," such as arthritis, dermatitis, or sinusitis
- Persistent seasonal allergies that seem to worsen over time
- Diagnosed autoimmune diseases where the immune system mistakenly attacks healthy tissues
- Chronic fatigue that doesn't improve with rest
- Poor gut health that feels like digestive issues or irregular bowel movements
- Recurring herpes outbreaks that appear more frequently than usual
If you're reading through this list, you're likely recognizing that you experience at least one—if not several—of these symptoms. You are not alone in this observation. The reality of our modern world is that the vast majority of people are walking around with immune systems that are chronically stressed and operating below optimal capacity due to the numerous factors we encounter in contemporary life.
When you consider the cumulative body burden of these modern stressors that our ancestors never faced, it becomes clear why immune system impairment has become so commonplace in today's society.