What the Science Really Shows About Inflammation, Autoimmune Health and Vitamin D

Winter brings shorter days, less sunlight, and a predictable drop in natural vitamin D production. Vitamin D is created in the skin when UVB light activates a cholesterol based precursor. During winter in northern regions, UVB is too weak to consistently trigger that process. Many people step into winter already low in vitamin D and then slide even lower as the season progresses.

Large national surveys show that roughly 1/3 of American adults have insufficient vitamin D and that rates are higher in people with autoimmune conditions, gut issues, higher body weight, or darker skin pigmentation. Vitamin D is tightly connected to immune regulation, inflammation, muscle function and mitochondrial energy production. When levels fall, the whole system becomes more vulnerable.

This raises a natural question. Can cold therapy help support vitamin D levels during winter

The honest science based answer is that cold therapy does not directly synthesize new vitamin D the way sunlight does. However, cold therapy does something just as important. It lowers inflammation. When inflammation drops, the body is able to use and mobilize the vitamin D you already have more effectively. This matters for everyone but it matters even more for individuals with autoimmune conditions whose inflammatory load is already elevated.

The clearest human example comes from one of the most recent studies on cold exposure and vitamin D.

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The Multiple Sclerosis Cryotherapy Study

A real human example of how reducing inflammation changes vitamin D behavior

This study is the strongest evidence we have so far and it tells a powerful story about inflammation.

Published in 2025 in the Journal of Clinical Medicine, the study followed 50 women in Poland. All blood work was fasting and measured professionally in a clinical setting.

Design overview

Participants
15 women with multiple sclerosis who completed cryotherapy
20 women with multiple sclerosis who did not do cryotherapy
15 healthy women who completed cryotherapy

Intervention
20 whole body cryotherapy sessions
1.5 to 3 minutes each
Minus 120 degree Celsius chamber
Five days per week over four weeks

Measurements
Blood vitamin D levels [25 hydroxy vitamin D] measured day 1 and day 20.

What happened
Women with multiple sclerosis who completed cryotherapy saw their vitamin D rise by an average of 11.85 ng per milliliter.
Healthy women who completed cryotherapy saw a smaller rise of about 2.19 ng per milliliter that did not reach statistical significance.
Women with MS who did not do cryotherapy saw no meaningful change.

Why is this important

It is not because cold created vitamin D out of thin air. It is because cold exposure sharply decreased inflammation. Autoimmune conditions like multiple sclerosis involve chronic inflammatory activity. High inflammation traps vitamin D inside tissues and makes it less available in circulation. When inflammation goes down, vitamin D stored in fat and muscle tissue becomes more accessible and more easily mobilized. In other words, vitamin D begins functioning the way it is supposed to.

This explains why the MS group experienced the biggest improvement. They began with more inflammation and more immune dysregulation. When cryotherapy reduced inflammatory signaling, the body was finally able to release and circulate vitamin D that had previously been stuck or inactivated.

This is the missing piece in most social media posts. The power is not in cold creating vitamin D. The power is in cold reducing inflammation so the body can use the vitamin D it already has.

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Inflammation and Vitamin D: The Connection People Miss

Vitamin D is stored in body fat, muscle tissue and liver. Chronic inflammation changes how vitamin D is:

—>stored
——>released
——->transported
———>activated

When inflammatory cytokines are high, vitamin D tends to stay stored in tissue rather than circulating in the blood. Even if you have adequate vitamin D intake or supplement regularly, inflammation can blunt your levels.

Once inflammation drops, the system opens up. Vitamin D moves into the bloodstream more efficiently. Enzymes inside your cells convert it into its active hormonal form more effectively. Your immune system, mitochondria and muscle tissue respond better.

This is true for people with autoimmune disease. It is true for people without autoimmune disease who still live with hidden inflammation from stress, poor sleep, blood sugar imbalance or poor food quality.

Reducing inflammation is where everything begins. When you lower inflammation, every hormone and every micronutrient works better. Vitamin D is just the easiest one to measure on lab work, which is why the MS study stands out so clearly.

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Winter Strategies to Support Vitamin D and Lower Inflammation

While cold therapy is a powerful tool, it works best as part of a complete winter wellness plan.

Use morning light to support cortisol rhythm

Cortisol rises naturally in the morning. This helps regulate your circadian rhythm. Morning light strengthens that rise and stabilizes energy, mood and appetite cycles.

Step outside for ten to twenty minutes within one hour of waking or use a bright ten thousand lux light box if mornings are dark. This supports hormonal balance even though it does not directly create vitamin D.

Use vitamin D rich foods consistently

Foods that provide meaningful vitamin D include:

Fatty fish
Rainbow trout
Salmon
Sardines
Herring

Fortified foods
Cow milk
Almond milk
Soy milk
Oat milk
Orange juice
Yogurt

Egg yolks
Mushrooms exposed to UV light

These do not fully replace summer sunlight, but they add consistent small doses of vitamin D throughout the week.

Use supplements when needed

Most adults require 600 to 800 IU daily as a baseline. Many clinicians use higher doses temporarily for people who test low. The only way to know your personal needs is to measure your level with a simple blood test.

Add cold therapy for inflammation control

Cold exposure does not replace sunlight but it is one of the fastest ways to lower inflammation and activate brown fat and mitochondrial function. When inflammation falls, vitamin D becomes more available and your immune system works more efficiently.

The MS study shows this clearly. The cold did not create vitamin D. The cold removed the inflammatory block that was preventing the body from using it.

This is the message people need in winter. Reduce inflammation first. Everything else becomes easier. Hormones stabilize. Energy stabilizes. Mood stabilizes. Vitamin D becomes usable. Your immune system becomes more responsive. Fat metabolism improves. Recovery improves. Inflammation is always the starting line.

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The bottom line for your clients

Cold therapy does not act like sunlight. It does not generate vitamin D inside your skin. What it does do is support the physiology that allows vitamin D to work the way it should. Inflammation blocks vitamin D. Cold therapy lowers inflammation. When inflammation goes down, vitamin D can finally move, activate and support the systems it was designed to support.

This is why cold therapy is powerful in autoimmune conditions. It is powerful in high stress lifestyles. It is powerful during winter when inflammation tends to rise as vitamin D falls.

Call us today to learn more, Email us vitalityhealthandwellness22@gmail.com or Book Here