Vitamin D is called the sunshine vitamin for a reason. And new research gives us another reason to pay attention to it.
A 2026 paper published in Diseases explores the relationship between vitamin D, intestinal barrier integrity, the gut microbiome, inflammation, and cardiovascular disease.
The connection is important because your gut and your heart are not separate.
When the intestinal barrier becomes dysfunctional—what most people call leaky gut—microbial products can cross the intestinal barrier and contribute to immune activation and systemic inflammation. That inflammatory environment can affect the endothelium and the health of your blood vessels.
Leaky gut can contribute to what I call a leaky heart. And vitamin D may be an important part of that relationship. I have written before about how your gut may be the hidden driver of heart disease.
Vitamin D Is About Much More Than Bones
Most people were taught that vitamin D is important for calcium and strong bones. That is true, but incomplete.
Vitamin D signaling is involved in immune regulation, intestinal barrier function, inflammation, and cardiovascular physiology. The 2026 review discusses evidence connecting vitamin D deficiency with changes in gut microbial composition, impaired intestinal barrier integrity, increased inflammatory signaling, and cardiovascular disease.
In other words, low vitamin D status may be one piece of an unhealthy gut-heart environment.
That matters. Because instead of asking only, “How do we lower cholesterol?” I want to ask: why is the vascular environment becoming unhealthy in the first place?
The gut may be part of the answer. Vitamin D may be part of the answer. And sunshine is where humans have traditionally gotten much of the signal that drives vitamin D production.
Get Outside
Modern humans spend an extraordinary amount of time indoors. We work indoors. Exercise indoors. Eat indoors. Then stay awake after sunset surrounded by artificial light.
Our ancestors lived under the sun. Sun exposure enables the skin to synthesize vitamin D, while natural light exposure also influences circadian biology and other physiological systems.
That is why sunshine is a major part of my 100 Year Heart Method. Get outside. Get appropriate sun exposure while avoiding burns. Stop treating sunlight like something humans were designed to avoid.
Sunshine + Animal Foods
The other major piece is nutrient-dense animal food. Vitamin D is naturally found in relatively few foods, with fatty seafood and certain animal foods among the important dietary sources.
That is one reason animal foods are another major part of my 100 Year Heart Method. I recommend nose-to-tail nutrition, including nutrient-dense organ meats. Kickstart My Heart makes that easy by providing New Zealand elk liver, heart, and kidney.
And for marine nutrition, my favorite is Wild Salmon Roe. Salmon roe provides vitamin D along with EPA, DHA, phospholipids, choline, astaxanthin, and other naturally occurring nutrients in a whole-food matrix. I have also written about why wild salmon roe is my favorite supplement for eye health.
The message does not need to be complicated. Get sunshine. Eat nutrient-dense animal foods.
- Your gut needs nutrients.
- Your immune system needs nutrients.
- Your blood vessels need nutrients.
- Your heart needs nutrients.
And vitamin D appears to sit at an important intersection between several of these systems.
Build Your 100 Year Heart
Sunshine and animal foods have always been part of the human story. They are also major parts of my 100 Year Heart Method.
- Get outside.
- Eat organs.
- Eat seafood.
- Build a healthier gut.
- Build healthier blood vessels.
You can read the 2026 paper in Diseases for yourself. And if you want to know where your own vitamin D status, gut health, and cardiovascular markers actually stand, test—do not guess. Schedule a free heart health discovery call and we will look at the whole picture with you. You can also see what I consider the best supplement for your heart.
Frequently Asked Questions
Vitamin D signaling is involved in immune regulation, intestinal barrier function, inflammation, and cardiovascular physiology. A 2026 review in Diseases discusses evidence connecting vitamin D deficiency with changes in gut microbial composition, impaired intestinal barrier integrity, increased inflammatory signaling, and cardiovascular disease.
It is my term for what can follow a leaky gut. When the intestinal barrier becomes dysfunctional, microbial products can cross it and contribute to immune activation and systemic inflammation. That inflammatory environment can affect the endothelium and the health of your blood vessels.
Vitamin D is naturally found in relatively few foods. Fatty seafood and certain animal foods are among the important dietary sources, which is why I recommend nose-to-tail nutrition and wild salmon roe alongside appropriate sun exposure.
Get outside and get appropriate sun exposure while avoiding burns. Needs vary by skin type, latitude, and season, so this is something to work through with a clinician who knows your history.
Nutrient-dense organ meats such as those in Kickstart My Heart, and Wild Salmon Roe, which provides vitamin D along with EPA, DHA, phospholipids, choline, and astaxanthin in a whole-food matrix.
