Probiotics & Vitamin D: the ultimate immune booster
For healthy gut flora and a strong immune system
Did you know that probiotics together with vitamin D are the ultimate immune booster? The combination of gut-friendly bacterial strains and the sunshine vitamin has been proven to strengthen your gut flora and thus supports your immune system in a safe and effective way.
The gut: the seat of our immune system
Around 100 trillion microorganisms live in our gut, forming a natural ecosystem: our gut flora (medical term: microbiome). Healthy gut flora plays an essential role in the metabolic processes in our body – and it is a prerequisite for a strong immune system. Because around 70 percent of all active immune cells are located in our gut!
The gut: our second brain
Our gut is also referred to as our second brain. Our entire gastrointestinal tract is permeated by a complex network of millions of nerve cells, the so-called enteric nervous system (ENS). This system communicates continuously with our brain. This means that our gut influences not only our physical health, but also our emotional well-being.
Probiotics help keep gut flora in balance
Probiotics are preparations that contain viable microorganisms such as lactic acid bacteria (Lactobacillus) or bifidobacteria. The word probiotics translates as “for life”. Probiotic bacterial strains promote the biodiversity of the physiological gut flora, support the normalization of the natural microbiome and thus ensure a balanced intestinal environment. Taking probiotics or probiotic foods therefore also improves the body’s own immune function.
You can find more information about the health effects of probiotic drinks and vegetables in our article “Fermenting for healthy gut flora”.
Vitamin D gets your immune system going
The sunshine vitamin D is one of the most important nutrients when it comes to strengthening our immune system. Only when it is present in sufficient quantities are our most important immune cells activated from a sleep-like state, enabling them to specifically fight pathogens. If no vitamin D is present, this mobilization of the body’s own defense cells does not take place. (1)
Vitamin D promotes healthy gut flora
But that’s not all: vitamin D also plays an important role in our gut health. Vitamin D receptors are found on the surface of our intestinal mucosa, especially in our large intestine. This means that vitamin D is not only crucial for stimulating our gut to absorb calcium and phosphorus, but also for building a healthy microbiome. A persistent vitamin D deficiency can lead to chronic dysbiosis, i.e. an imbalance of the gut flora, and pathogens, toxins or other invaders can pass from the gut into the bloodstream.
Why vitamin D levels are so important
A long-term vitamin D deficiency is closely linked to disrupted gut flora, a weak immune system, and also to numerous other diseases such as chronic inflammation, autoimmune diseases, metabolic disorders, cardiovascular diseases, diabetes or even cancer. Against this background, it is very important to ensure that vitamin D stores remain well filled over the long term in order to support our gut health and the smooth functioning of our immune system, thereby helping to prevent disease.
Since the body’s own production of vitamin D through sunlight is generally not sufficient in our latitudes to meet our actual needs, we recommend regular supplementation with vitamin D. A standard dose of 5,000 IU per day for a body weight of 70 kg – unless otherwise discussed with your doctor or therapist – is optimal here.
Vitamin D deficiency and excess weight
Numerous studies have now been able to demonstrate a connection between low vitamin D levels and an increased risk of being overweight. This effect is due, among other things, to the improvement of the bacterial composition of the gut flora through vitamin D. It is therefore advisable to have your vitamin D level tested before any planned weight reduction. (2)
You can find more information about vitamin D in our article “Vitamin D – the sunshine vitamin for the whole year”.

“Vitamin D is the universal medicine from the heavenly pharmacy”
Freely adapted from August von Kotzebue
(German jurist and playwright, 1816 – 1819)
Synergy with a powerful effect: probiotics and vitamin D
There are numerous studies indicating the positive health effect of taking probiotics and vitamin D together. Probiotics increase vitamin D levels and improve the expression of vitamin D receptors. The latter, in turn, support the effect of probiotics in protecting against inflammation and infections. (3 + 4). That’s not all: the combination of vitamin D and probiotics also has a lasting positive effect on our mental health.
Balance is everything:
ActiveBRAVO joghurt and VitaDK plus by dr.reinwald vital
With our VitaBRAVO package, you benefit from the synergistic mode of action of our vital products ActiveBRAVO joghurt and VitaDK plus. The more than 100 probiotic strains in ActiveBRAVO stimulate your immune system via the gut flora, and the vitamin D3 and K2 in VItaDK plus mobilize your immune cells.

ActiveBRAVO, our fermentation powder with colostrum and active probiotic cultures in a prebiotic matrix, supports:
- the normalization of the natural human microbiome
- the biodiversity of the physiological gut flora: the fermentation process produces more than 100 probiotic strains – some of which produce the enzymes ß-galactosidase and sialidase, which are so important for the body’s own macrophage activation (MAF)
- the supply of natural immune-stimulating antibodies from colostrum
VitaDK plus, the vegan sunshine power complex with vitamins D3 + K2, magnesium, zinc and boron, supports:
- the smooth functioning of almost all cells and organs
- the normal maintenance of bones, teeth and muscles
- the absorption of calcium and phosphorus, which has a positive effect on skeletal muscles
- the strengthening of the immune system
Our tip:
We recommend adding an additional 5 ml of olive oil to your ActiveBRAVO fermentation powder during preparation. The oil serves as a true functional booster for your BRAVO yogurt and at the same time supports the optimal absorption of fat-soluble vitamin D.
Do you have questions? Our friendly team – consisting of therapists and naturopaths – will be happy to advise you. Call now or use our chat.
Sources:
(1) Carsten Geisler (University of Copenhagen) et al.: Nature Immunology, advance online publication, doi: 10.1038/ni.1851 ddp/wissenschaft.de ? Ilka Lehnen-Beyel (https://www.wissenschaft.de/erde-umwelt/vitamin-d-macht-das-immunsystem-scharf/, 20.01.2023)
(2) Gesund mit Darm: https://schlank-mit-darm.de/vitamin-d-mangel-beheben-staerkt-darmflora-und-erleichtert-gewichtsreduktion/ (20.01.2023)
(3) Jones ML, Martoni CJ, Prakash S. Oral supplementation with probiotic L. reuteri NCIMB 30242 increases mean circulating 25-hydroxyvitamin D: a post hoc analysis of a randomized controlled trial. J Clin Endocrinol Metab. 2013 Jul; 98(7):2944-51.
(4) Shang M, Sun J. Review Vitamin D/VDR, Probiotics, and Gastrointestinal Diseases. Curr Med Chem. 2017; 24(9):876-887.