How the Immune System Affects Your Bones

Osteoporosis is a common bone disease that is characterized by low bone density and the deterioration of bone tissue that results from increased bone resorption. Bone resorption is the breakdown of bone, which the body then releases its minerals into the blood stream. This leads to impaired formation of the bone and increases the risk of fractures.

The immune and skeletal systems are closely correlated systems and the dysregulation of the immune system plays a large role in the development of osteoporosis. In fact, there is an entire study of this interplay called 'Osteoimmunology'. Aging and estrogen deficiency are major contributors to osteoporosis, with immune activation being a secondary cause (i.e. chronic inflammation, autoimmune condition).

What happens during an inflammatory response?

Cytokines are small proteins that are capable of altering the demeanor of other cells locally which can regulate inflammatory and immune responses. Pro-inflammatory cytokines function as chemical messengers in your immune system. They are activated by macrophages and are involved in the up-regulation of the inflammatory response. Proinflammatory cytokines such as interleukin-1 (IL-1) and interleukin-6 (IL-6) are important regulators of bone resorption. Cytokines produced during chronic inflammation induces an uncoupling of bone formation and resorption, resulting in significant bone loss; especially in those who have inflammatory autoimmune conditions such as Hashimotos or Inflammatory Bowel Disease.

You can see in the figure below where the up-regulation of inflammatory cytokines increase resorption of bone contributing to osteoporosis. As a side note, new research has found that interleukin levels might be one of the strongest predictors of future health outcomes. This make sense as many health conditions that individuals suffer from start with low-grade inflammation.

Keep in mind chronic stress and certain medications can also solicit inflammatory cytokines. For example, at present, research has found that job stress, low socioeconomic status, caregiver stress, and loneliness is related to greater circulating levels of IL-6. Inflammation is systemic and can affect your skeletal system even if the trigger is simply stress.

How to reduce inflammation:

There are several ways to lower inflammation to decrease bone resorption. It does revolve around the basics: Exercise, sleep, nutrition, and stress. We will briefly discuss what you need to know below!

Movement: Regular physical activity supplies a multitude of health benefits, including the reduction in risk of various conditions such as cardiovascular disease, diabetes, cancer, dementia, Alzheimer’s, adverse blood lipid profiles, non-alcoholic fatty liver disease (NAFLD) and disabling non-motor symptoms in Parkinson’s disease. In addition, exercise such as weight lifting and running stimulates antioxidant activities incrementally and diminishes oxidative stress, which ultimately leads to a reduction in mortality. Regular exercise can enhance immune function and dramatically prevent the spread of the cytokine response. The key is consistent and moderate training. Exercisingexcessivelyandatsuchhighlevelsofintensitycanactuallyincrease Exercising excessively and at such high levels of intensity can actually increase inflammatory cytokines. Exercising 3-4 days a week with a mix of resistance training, flexibility/mobility training, and aerobic conditioning is sufficient.
Sleep: Good quality sleep helps maintain normal interleukin levels. Poor sleep is typically related to lower melatonin production. Do you know what helps reduce cytokines such as IL-6? You guessed it; melatonin. Melatonin has an anti-inflammatory effect as it reduces tissue destruction during inflammatory reactions and has the ability to scavenge free radicals, which decreases molecular damage in all organs, not just bones. Now this doesn't mean we are suggesting taking supplements. Try your best to regulate your sleep and circadian rhythm as best as possible to naturally boost melatonin levels.

Some ways to increase melatonin naturally include:

1. Get sunlight in the morning as this triggers melatonin sooner to help you sleep earlier at night.

2. Decrease light exposure at night as this can reduce melatonin levels. Even nightlights may have a negative impact.

3. Reduce screen time from phones and televisions. Blue light from these devices impact melatonin levels.

4. Keep an eye on caffeine. Too much caffeine can block adenosine, which is necessary for melatonin production.

5. Exercise in the morning! This helps increase and keep melatonin levels steady throughout the day.

6. Take a closer look at your nutrition. Foods such as eggs, fish, milk, and bananas contain natural melatonin. Nutrition: Processed foods that are loaded with sugar is associated with high levels of IL-6 due to its ability to solicit insulin. Both insulin and glucose can be inflammatory if held at high levels for long periods of time. Diets rich in fiber, antioxidants, and healthy fats can help reduce chronic levels of inflammation. For example, berries contain antioxidants, which scavenge free radicals that cause damage and increase inflammation. Seafood such as fish is loaded with Omega-3 fats, which have also been shown to decrease inflammation.

Maintain a Healthy Body Weight:

Obesity is associated with chronic low-grade inflammation. Fat tissue increases the production of IL-6, as well as other pro-inflammatory cytokines. This occurs more so in visceral fat than subcutaneous fat. But it's not simply about fat loss. Maintaining healthy muscle mass is important to metabolic homeostasis. Simply put, it's not solely about having excess amounts of fat tissue. It's that many of us don't have enough healthy muscle tissue. Muscle tissue is protective. For example, it's the largest glucose sink in the body; this means that the muscle will help decrease inflammation by improving insulin sensitivity. Additionally, focusing on developing and maintaining healthy muscle tissue will improve metabolic function by limiting fatty acid synthesis.

Stress:

People that experience chronic stress such as fear, anxiety and even anger tend to have greater amounts of inflammatory cytokines. Stress is often very difficult to control but if you can manage it, it can have profound effects on your health. For example, studies have found that practicing mindfulness and even journaling can reduce internal inflammation.

So there you have it! Managing the inflammatory response is important to maintaining a healthy body and skeletal system. Chronic inflammation can accelerate bone loss leading to osteoporosis and increasing the risk of fractures and other injuries.