Cold & Flu Season or Vitamin D Deficiency Season?

by Matt Vidler, PTBO Chiro

For many Canadians, wintertime means less sun rays, more time indoors, and extra layers of clothing. Add in a crackling fireplace, and you have yourself a cozy winter night. However, these seasonal factors (minus the fireplace) also contribute to something much less pleasant: vitamin D deficiency. Because vitamin D plays such an essential role in immune health, low levels can weaken our defenses and increase susceptibility to illnesses, like colds and flu.1 Instead of cozy winter nights, you could have days of feverish, coughing and sneezing.

Vitamin D deficiency is most prevalent during the peak of cold and flu season

Although vitamin D deficiency is most prevalent during the during winter months (the peak of cold and flu season), supplementation can help reduce the occurrence and symptoms of colds and flu.16 For example, one research study analyzed nearly 11,000 participants (that’s a lot of people!) between the ages of 0 and 95 years (that’s a big range!) and found that daily doses of vitamin D supported respiratory tract health and reduced the incidence of common seasonal infections.4

Vitamin D helps regulate the immune system

Vitamin D supplementation helps boost your immune system by stimulating naturally occurring antimicrobial peptides, which protect the body by destroying invading microbes.8 These antimicrobial peptides live in immune cells throughout the body, including cells lining the upper and lower respiratory tract. There, they are able to directly fight off viruses and bacteria that cause common immune and respiratory infections like colds and flu1,9

Take vitamin D this cold and flu season

Supplementing with vitamin D is important for immune health throughout the entire year, but especially during the peak of the cold and flu season when vitamin D levels are at their lowest. So, before cozying up by the fireplace with your hot chocolate this winter, take your daily dose of vitamin D. Your immune system will thank you.

We recommend liquid Vitamin D3 for absorption and efficacy.

Just the facts

The immune system defends the body from foreign, invading organisms, promoting protective immunity while maintaining tolerance to self. The implications of vitamin D deficiency on the immune system have become clearer in recent years and in the context of vitamin D deficiency, there appears to be an increased susceptibility to infection and a diathesis, in a genetically susceptible host to autoimmunity.

It is now clear that vitamin D has important roles in addition to its classic effects on calcium and bone homeostasis. As the vitamin D receptor is expressed on immune cells (B cells, T cells and antigen presenting cells) and these immunologic cells are all are capable of synthesizing the active vitamin D metabolite, vitamin D has the capability of acting in an autocrine manner in a local immunologic milieu. Vitamin D can modulate the innate and adaptive immune responses. Deficiency in vitamin D is associated with increased autoimmunity as well as an increased susceptibility to infection. As immune cells in autoimmune diseases are responsive to the ameliorative effects of vitamin D, the beneficial effects of supplementing vitamin D deficient individuals with autoimmune disease may extend beyond the effects on bone and calcium homeostasis.

Vitamin D3 enhances calcium absorption and retention, a key nutritional function in supporting healthy bones and teeth. Decreased exposure to sunlight, a vegetarian diet and a low intake of vitamin D-fortified foods often contribute to inadequate vitamin D levels. Clinical studies involving vitamin D supplementation suggest the importance of both vitamin D and calcium for bone health. Calcium intake, when combined with sufficient vitamin D, a healthy diet and regular exercise, may reduce the risk of developing osteoporosis. Vitamin D supplementation alone also supports bone health. It promotes intestinal calcium and phosphorous absorption, and reduces urinary calcium loss, essential mechanisms for maintaining proper calcium levels in the body and healthy bone composition. You can read the science here.


No discussion about supporting your immune system would be complete without acknowledging the role of stress. There is significant study and science regarding the effects of stress on the immune system and on disease. You can read some of the meta-analysis of 30 years of research here, and other science here.

The linkages between stress and immunity may be mediated by specific health behaviors, psychosocial factors, or both. For instance, stress has been linked to being in troubled relationships, having negative or competitive social interactions, and feeling lonely, which have each in turn been linked to increases in pro-inflammatory responses to stress. Other potential mediators, like getting good sleep, are increasingly being recognized as important pieces of the stress-immunity puzzle. Even one night of total sleep deprivation was recently found to significantly increase neutrophil counts and decrease neutrophil function in healthy men.

Chiropractic for Pain, Stress, and Nervous System Health

Let’s be honest, Life is Stressful. It is easy to find things to stress about with all that is going on today.

Job pressure, finances, health issues, relationship troubles, the media, and other environmental factors can weigh us down. All these stresses of life can lead to an unhealthy amount of chronic stress which can lead to a plethora of health issues and symptoms associated with them. Chiropractic care, however, can greatly reduce the negative effects that chronic stress can have on our health.

Chiropractors are experts on spinal and nervous system health. By making sure the spine is aligned and free of subluxations, a chiropractor greatly reduces nervous system interference, which makes it easier for our bodies to adapt to stress.

So, what is a subluxation? Well, a subluxation is a misaligned vertebra in the spine. This misalignment causes undue stress and irritation to the nervous system tissue (spinal cord and nerve roots), and this irritation leads to an unhealthy nervous system. The nervous system is the master system of the body, so for our bodies to adapt to stress and stay healthy we must have a healthy nervous system.

The nervous system oversees all coordination and functions of the body. Some we can consciously control, and others we have no control over. The autonomic nervous system (ANS) is the component that regulates all involuntary processes including heart rate, blood pressure, respiration, digestion, gland function etc. The ANS is mostly split into 2 divisions: sympathetic and parasympathetic.

  1. Activation of the sympathetic nervous system (SNS) leads to a state of elevated activity and attention called the “fight or flight” response. This process increases blood pressure and heart rate making our body available to respond to stressful stimuli.
  2. The parasympathetic nervous system promotes the “rest and digest processes: heart rate and blood pressure lower. The parasympathetic has a calming effect on our body.

There must be a healthy balance between both divisions of the ANS for our bodies to express optimal health and well-being. However, we live in an ever-increasing stressful society. Most people are sympathetic dominant; meaning they do not have enough parasympathetic activity.

Sympathetic dominance leads to the negative effects associated with chronic stress like cardiovascular disease and poor immune system function. Without proper parasympathetic activity acting as the sedative “brake” to our stress response, cortisol and epinephrine, the main stress chemicals in the body, are gradually leaked into the blood stream thus leaving the body revved up and on high alert. Persistent epinephrine can damage blood vessels, increase blood pressure and increase risk to heart attack and stroke. Elevated cortisol levels lead to a buildup of fat tissue and weight gain increasing the likelihood of obesity. So, where does chiropractic care come in?

Well, chiropractic care is aimed at creating a healthier nervous system with a proper balance between sympathetic and parasympathetic activity. The health of our nervous system is directly related to the health of your spine. By removing misalignments, called subluxations, in the spine, we can directly influence our nervous system in a positive manner and create a healthier balance between the sympathetic and the parasympathetic nervous systems. Chiropractic care has been shown to decrease the levels of cortisol, thus reducing the damaging effects that chronic stress has on our overall health.

If you are experiencing any of the body signals associated with chronic stress – fatigue, headaches, indigestion, poor immune function, pain – or know anyone who is, a chiropractor may be able to help. Do not let chronic stress damage your health and lead to a poor quality of life. We are here to help you heal from within. Reach out today, we are here for you.

The organization of the stress response, and its relevance to chiropractors:

Understanding the stress response:


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