Vitamin D is an ancient hormonal molecule that serves, in its primary role, as a pro-survival agent.  It is photosynthesized in all forms of life, starting from the phytoplankton (~750 million years ago) to mammals and humans. Most likely, vitamin D was the first essential molecule used in the stress and immune response. It also helps the innate cells to kill bacteria and viruses.

Vitamin D works best in combination with other important nutrient – Vitamin K. Whereas one of Vitamin D’s main functions is to ensure adequate blood calcium levels, Vitamin K promotes calcium accumulation in bones and teeth while reducing its accumulation in soft tissues such as blood vessels. The main natural source of vitamin D is own synthesis in the lower epidermis initiated by UVB radiation. Vitamin D can also be ingested from diet and supplements.

About 1 billion people globally have a vitamin D deficiency. In Europe +40% of the population may not have adequate vitamin D levels. Major reasons are lack of sun exposure connected with sedentary indoor lifestyle and poor diet.

The latest comprehensive study by scientists the University of South Australia has linked low vitamin D levels with an increased risk of premature death – all-cause mortality increases by 25% when vitamin D levels are within the deficiency range.

In NutriStella Vegan Vitamin D3+K2 we do care about maximum results with possibly low side-effects and waste. Premium active ingredients – vegan Vitamin D2 from lichen and superior form of Vitamin K2 – MenaQ7® (the only clinically validated, patented Vitamin K2) are delivered via oral mucosa assuring heighest absorbency levels.

Vegan. Lactose-, gluten- and GMO-free. Tastes good. Tooth friendly formula (sugar-free). Long lasting.

The term Vitamin D refers to a group of fat-soluble molecules responsible for increasing intestinal absorption of calcium, magnesium, and phosphorus. In humans, the most important compounds in this group are vitamin D3 (sun- and animal-derived cholecalciferol) and vitamin D2 (plant-derived ergocalciferol).

Vitamin D3 is the preferred form of Vitamin D and most commonly found in nutritional supplements because it demonstrates better efficiency than Vitamin D2 at raising and maintaining Vitamin D levels in the body.

After Vitamin D is synthetized by the skin or acquired from food or supplements it circulates in the blood for about 24 hours. Then, native Vitamin D is stored in the fat tissue for approximately two months. Here it remains inactive until it’s needed. When the body needs more Vitamin D, Vitamin D-2 and Vitamin D-3 are converted by the liver and kidneys to their active form (called calcitriol) and then released into the blood. The released active Vitamin D can circulate in the body for approximately three weeks. After the body is replenished, the biologically active form is stored in fat tissue for months and is released from the storage depending on the body’s need.

This active Vitamin-D form promotes absorption of calcium and phosphorus from the intestine.Calcium and phosphorus are incorporated into bones to make them strong and dense (a process called mineralization). Thus, calcitriol is necessary for the formation, growth, and repair of bones. Without enough vitamin D, the body can only absorb 10% to 15% of dietary calcium, but 30% to 40% absorption is the level when vitamin reserves are normal.

The vitamin D status (internal exposure) is best measured by the serum concentration of 25-hydroxyvitamin D3 (25-OH-D3), as this reflects both the dietary intake and the endogenous synthesis. Levels of 50 nmol/L (20 ng/mL) or above are adequate for most people for bone and overall health. Levels below 30 nmol/L (12 ng/mL) are too low and might adversaly affect health. Levels above 125 nmol/L (50 ng/mL) are too high and might also cause health problems.

With regular outdoor exposure from late March/early April to the end of September the majority of people should be able to make 80% to 90% needed Vitamin D from sunlight on their skin, while oral intake should make only a minor contribution (10% to 20%). Little to no vitamin D can be produced by the skin in the winter months due to the sun’s position. In all the places north of 37 degrees latitude (most of Europe, above Sicily and Sevilla) Vitamin D needs to be delivered in food and supplements.

Vitamin K is a fat-soluble vitamin that naturally occurs in two forms: phylloquinone -Vitamin K1 (found in green leafy vegetables, contributing to blood clotting) and menaquinones – Vitamin K2 (found in some animal foods and fermented foods, essential in building and maintaining strong bones and inhibiting calcium deposits). Menaquinones can also be produced by gut bacteria in the human body. Healthy arterial tissues have shown to contain 100 times more Vitamin K2 than unhealthy arteries.

Vitamin K is rapidly metabolized and excreted in urine or stool. The body retains only about 30% to 40% of an oral physiological dose, while about 20% is excreted in the urine and 40% to 50% in the feces via bile. This rapid metabolism accounts for vitamin K’s relatively low blood levels and tissue stores (including the liver, brain, heart, pancreas, and bone) and is the reason why Vitamin K rarely reaches toxic levels in the body even with high intakes, as may sometimes happen with other fat-soluble vitamins.

The German Federal Institute for Risk Assessment (BfR) recommends a maximum level of 20.0 µg (800 IU) of vitamin D and a maximum level 25.0 µg of vitamin K2 per daily recommended dose of a food supplement.

Vitamin D deficiency

If a person has between 30-49 nmol/L (nanomoles per liter) of vitamin D in their blood, they are considered at risk of inadequacy. Under 30 nmol/L or less, the person is at risk for vitamin D deficiency.

Risk factors:

  • Strict vegan diet. Most natural sources of Vitamin D are animal-based thus plant based diet requires usually supplementation.
  • Limited exposure to sunlight due to: season, living in northern latitudes or having occupation, lifestyle or condition that prevents sun exposure, wearing long robes or head coverings for religious reasons, air pollution.
  • Dark skin. The pigment melanin reduces the skin’s ability to make vitamin D in response to sunlight exposure. Some studies show that older adults and people with darker skin are at high risk of vitamin D deficiency.
  • Impaired kidneys ability to convert Vitamin D to its active form. Apart of medical conditions this may happen as people age.
  • Weak Vitamin D absorption due to digestive tract malfunctions i.e. Crohn’s disease, cystic fibrosis, and celiac disease that affect intestine’s ability to absorb vitamin D from the ingested food.
  • Vitamin D is trapped by fat cells, altering its release into the circulation. People with a body mass index of 30 or greater often have low blood levels of vitamin D.

Vitamin D deficiency symptomes

In addition to blood test readings, symptoms of vitamin D deficiency include:

  • frequent illness or infections
  • bone fragility, osteoporosis, rickets in children,
  • bone pain
  • tiredness and fatigue
  • depression, anxiety
  • impaired wound healing
  • muscle weakness, pain, or twitching
  • stiff joints
  • hair loss
  • weight gain

Vitamin D overdosing

An excess of vitamin D causes abnormally high blood concentrations of calcium (hypercalcemia), which can cause overcalcification of the bones, soft tissues, heart and kidneys as well as hypertension. Symptoms of vitamin D toxicity appear several months after excessive doses of vitamin D are administered.

Vitamin D overdosing symptoms

  • weight loss, nausea, weakness, vomiting, constipation, frequent urination and poor appetite,
  • insomnia, irritability, fatigue, mental confusion
  • anomalies of heart rhythms
  • bone and muscle pain and kidney problems, such as the formation of calcium stones.

Vitamin K deficiency and overdosing

Acute Vitamin K deficiency in adults is rare, but may occur in people taking medications that block vitamin K metabolism such as antibiotics, or in those with conditions that cause malabsorption of food and nutrients. A deficiency is also possible in newborn infants because vitamin K does not cross the placenta, and breast milk contains a low amount. The limited amount of blood clotting proteins at birth increases the risk of bleeding in infants if they are not given vitamin K supplements.

Unfortunately, the Western diet does not contain sufficient Vitamin K2, so supplementing with MenaQ7® Vitamin K2 as MK-7 is a viable alternative recommended by experts. The deposition of calcium in soft tissues, including arterial walls, is quite common, especially in those who have atherosclerosis, suggesting that Vitamin K deficiency is more common than previously thought.

Vitamin K deficiency can contribute to significant bleeding, poor bone development, osteoporosis, and increased cardiovascular disease.

Vitamin K is fast metabolized and excreted from the body rarely resulting in overdose.

NutriStella Vegan D3+K2

DIRECTIONS: Adults 4 sprays per day under the tongue or on the inner cheek, children over 3 years of age two sprays per day.  Before first use, press the pump 2-3 times until the contents appear. Shake before use. Rinse nozzle with water when congested.

DOSAGE: Contains 800 IU (20 μg) of vitamin D3 (400 % NRV*) and 25μg of vitamin K2 (33,3% NRV*) per daily dose for adults (4 sprays), and 400 IU (20μg) of vitamin D3 (200 % NRV*) and 12,5μg of vitamin K2 (16,7% NRV*) per daily dose for children (2 sprays).

*Nutrient Reference Value.

Please note that NutriStella Vegan D3+K2 is much better absorbed via oral cavity than conventional vitamin forms ingested through gastrointestinal tract. The research data shows 1,9-2,6x better bioavailability and absorption of Vitamin D3 spray than softgel capsules.

Should you still consider tablets or capsules please note the following factors impacting the effectiveness of Vitamin D absorbed in intestine:

Vitamin D Absorption Enhancers

Because Vitamin D is a fat-soluble vitamin, it’s best absorbed in the bloodstream in the presence of dietary fat. It also helps to eat Vitamin D-rich food from animals and take supplements that contain Vitamin D3. Combining vitamin D with magnesium may also help to increase absorption.

Vitamin D Absorption Inhibitors

Vitamin E, vitamin A and high doses of Vitamin K impose competitions for vitamin D absorption in intestine. Recently a research demonstrated that high concentration of vitamin A reduces bioavailability of vitamin D by 30%. Functional ingredients that reduce cholesterol levels i.e. phytosterols, plant sterols may also impair Vitamin D absorption.

INGREDIENTS: Coconut oil – MCT, peppermint essential oil (Mentha arvensis L.), sweet orange essential oil (Citrus sinensis (L) Osbeck), vitamin D3 (vegan lichen cholecalciferol), Vitamin K2 (menachinon-7),

NutriStella Vegan D3+K2 is a vegan premium product. The Vitamin D3 is obtained from lichens. Lichens are a complex life form, a symbiotic community of two different organisms – a fungus and an algae. These small organisms can survive in extreme climates (from polar regions to deserts) and are capable of growing and accumulating significant amounts of beneficial nutrients. To protect themselves from harmful sunlight, lichens produce Vitamin D. Vitamin D3 derived from lichens is not only free from toxins and other contaminants, but it is also a natural form of D3 that corresponds to the one produced by the human body under sunlight exposure. Its bioavailability is comparable to that of animal sources, such as lanolin from sheep.

Vitamin K2 in the form of Menachinon-7 (MK-7) is the most bioavailable, long-lasting, and bioactive form of Vitamin K. In NutriStella Vegan D3+K2, we use MenaQ7® Pharma Pure – the only clinically supported, patented all-trans Vitamin K2 on the market, which was awarded the Nutri Award for the best functional ingredient in 2015. The purity of MenaQ7® Pharma Pure is twofold and is measured by: isomeric purity, i.e., the percentage of the trans-isomers (the active form of Vitamin K2 as MK-7), and general purity, i.e., the percentage of other substances originating from the manufacturing process (contaminants from fermentation, bacterial residues). MenaQ7® PharmPure is the only available synthetic All-Trans Vitamin that is bioequivalent to soy and natural chickpea preparations. It offers the same technical and clinical benefits but is free from all known allergens.

The MCT oil used in NutriStella Vegan D3+K2 is a fractionated ingredient derived from coconut oil. MCT molecules (medium-chain triglycerides) are smaller than the LCT molecules (long-chain triglycerides) commonly found in foods. As a result, they are more easily digestible and can be quickly absorbed into the bloodstream. MCT oil can support weight loss, fat breakdown, ketone production, and improvement of the gut environment. It also possesses antimicrobial and antifungal properties.

NutriStella Vegan D3+K2 contains only natural flavors.

OPTIMAL DOSAGE – 800 IU D3, i.e. 20 µg cholecalciferol from lichen per serving and 25 µg high-quality vitamin K2 in the form of MenaQ7 PharmPure all-trans. Family pack – dosage suitable for adults and children from 3 years, dosage according to the recommendations of the German Federal Institute for Risk Assessment. The bottle with air-free technology protects the product from microbes and decomposition and prolongs shelf life. 53 daily servings

HIGH BIOACTIVITY AND SYNERGY- According to studies, vitamin D served in the form of an oral spray is absorbed 1.9-2.6 times better than conventional capsules. Vitamin D is responsible for regulating calcium and phosphorus metabolism in the body, while vitamin K2 is its ideal complement – ensuring that these minerals are redirected and stored in the right place

IMMUNE DEFENSE SUPPORT – Vitamins D and K primarily influence the health of bones, muscles, teeth and joints and support the smooth functioning of the cardiovascular system. Vitamin D supports the immune system and contributes to cell division and development.

CONVENIENT, VEGAN SUPPLEMENT WITH NO UNNECESSARY ADDITIVES – easy to use, no swallowing required, handy, no aerosol, airplane safe. The product contains no harmful preservatives, fillers, artificial flavours or colours. Food supplement without gluten, GMO ingredients, lactose, sugar, gelatine or soy. Thanks to natural sweet orange and mint oils, it has a refreshing, pleasant taste. Contains high-quality MCT oil (coconut)

FOR WHOM? – For all those who want to strengthen their immunity and the condition of their body and at the same time want to use food supplements that do not burden the stomach and digestive system



Vitamin D can modulate the innate and adaptive immune responses. The immune system defends the body from foreign, invading organisms, promoting protective immunity while maintaining tolerance to self. Deficiency in vitamin D is associated with increased autoimmunity (where the body’s immune system attacks its own organs and tissues) as well as an increased susceptibility to infectious diseases such as tuberculosis and seasonal flu.

The beneficial effects of vitamin D on protective immunity are attributed to its role in the transcription of peptides with potent bacterialcidal activity such as cathelocidin and beta defensin. These peptides disrupt bacterial cell membranes and have potent anti-microbacterial activity.

Vitamin D acts in its primary role as potent antioxidant targeting the reactive oxygen species (ROS) originating from metabolism and stressors. Vitamin D not only helps the immune system to be dampened during an excessive or chronic reaction (anti-inflammatory potential) but also to rapidly reach its completion or exhaustion, influencing cell life cycle and helping innate cells to kill bacteria or viruses. In this sense, vitamin D maintains its fundamental role as a pro-survival molecule.

Current evidence suggests a direct impact of vitamin D deficiency on cardiovascular diseases. Both in vitro and in vivo animal models showed that vitamin D deficiency can cause or worsen endothelial dysfunction, favoring the onset and progression of atherosclerotic plaque. Impaired endothelial cells and smooth muscle cells regulated by Vitamin D impact blood pressure. Human observational studies reported an association between vitamin D deficiency and risk of hypertension, atherosclerosis, and heart failure. These cardio-vascular risk factors appear to be linked to a higher mortality and cardio-vascular incidence.

In the last several decades, a growing number of clinical studies of the muscular effects of vitamin D supplementation and research on the vitamin D receptor in muscle cells have helped to improve our understanding of the role and functions of vitamin D in muscle tissue and on physical performance.

Vitamin D may help increase muscle strength by preserving muscle fibers, which in turn helps to prevent falls, a common problem that leads to substantial disability and death in older people. A combined analysis of multiple studies found that taking 700 to 1,000 IU of vitamin D per day lowered the risk of falls by 19%, but taking 200 to 600 IU per day did not offer any such protection.

Animal and human studies suggest that optimal concentrations of both vitamin D and vitamin K are beneficial for bone health. The combination of vitamin K and D can significantly increase the total bone density.  Whereas vitamin D is contributing to the absorption of calcium, vitamin K is responsible for depositing calcium at the right places in the body – i.e. in the bones and teeth. It also prevents calcification, the accumulation of calcium in places where it is not required – i.e. in the soft tissues and organs such as the arteries, kidneys, lungs, and brain. Calcium deposits can cause problems with how these blood vessels and organs work.

Taking vitamin D stimulates the body to produce more of the vitamin K2-dependent proteins that transport calcium. These proteins have many health benefits, but cannot be activated if insufficient vitamin K2 is available. As the intestines only produce small quantities of vitamin K, it needs to be provided from foods or supplements that are rich in vitamin K.

People over the age of 50 are particularly vulnerable to osteoporosis and cardiovascular disease, at the same time they might be able to deliver less vitamin K from ingested food and have limited exposure to sunlight due to weaker outdoor activitities, thus leading to deficiencies in both vitamin K and vitamin D. Please note that vitamin D and calcium supplementation along with vitamin K deficiency might induce long-term soft tissue calcification and cardio-vascular deasease, particularly in vitamin K antagonist users and other high-risk populations. Supplementing high-dose vitamin D alone, unless indicated differently, might be connected with health risks.


Factors influencing the absorption of vitamin D in GIT: an overview

Factors influencing the absorption of vitamin D in GIT: an overview

Vitamin D refers to a group of secosteroid compounds and recognized as the antirachitic vitamin, as it counters rickets, mineral desorption from fully-grown bones (Osteodistrophy), bone, joint disorders, and fragility of bones...

A randomized two way cross over study for comparison of absorption of vitamin D3 buccal spray and soft gelatin capsule formulation in healthy subjects and in patients with intestinal malabsorption

A randomized two way cross over study for comparison of absorption of vitamin D3 buccal spray and soft gelatin capsule formulation in healthy subjects and in patients with intestinal malabsorption

Vitamin D deficiency has been proposed to contribute to the development of malabsorption diseases...

Vitamin D deficiency in Europe: pandemic?

Vitamin D deficiency in Europe: pandemic?

Vitamin D deficiency has been described as being pandemic, but serum 25-hydroxyvitamin D distribution data for the European Union are of very variable quality...


Yes. It is caused by supplementing with high doses of vitamin D rather than sunlight. Do not take more than 100 micrograms (4,000 IU) of vitamin D a day as it could be harmful. This applies to adults, including pregnant and breastfeeding women and the elderly, and children aged 11 to 17 years. You cannot overdose on vitamin D through exposure to sunlight. But always remember to cover up or protect your skin if you’re out in the sun for long periods to reduce the risk of skin damage and skin cancer. The body only needs a small amount of UV to make vitamin D. Any extra UV exposure will just add to skin damage, not vitamin D. You can’t naturally overdose on vitamin D.

It is very rare since vitamin K is quickly metabolised and excreted from the body. The Rotterdam Study (2004)26 shows that high dietary intake of Vitamin K2 – but not vitamin K1 – has a strong protective effect on cardiovascular health. Findings from this 10-year population-based study, which followed 4,807 initially healthy men and women >55 years of age from start, indicate that eating foods rich in natural Vitamin K2 (at least 32 mcg/day) results in 50% reduction of arterial calcification, 50% reduction of cardiovascular risk, and 25% reduction of all-cause mortality.

It might. In an analysis of more than 427,000 White European participants using Mendelian randomization, a 54% higher risk of dementia was seen among participants with low vitamin D blood levels of <25 nmol/L compared with those having adequate levels of 50 nmol/L.
In summer and spring it is possible, with 22% of uncovered skin, 1000 IU vitamin D doses are synthesized in 10-15 min of sun exposure for adults. In winter and autumn, the recommended vitamin D production is unachievable, since up to 6.5 h of sun exposure might be necessary considering 8-10% of uncovered skin surface. Catching the sunlight in a sunny office or driving in a car unfortunately does not count as window glass completely blocks UVB ultraviolet light preventing vitamin D production. The vitamin D food intake only represented 10% of the recommended vitamin D production and remained unchanged throughout the year therefore many people suffer vitamin D inadequacies in autumn/winter season.

It seems that D3 is a better choice. Most studies show that vitamin D3 is more effective than vitamin D2 at raising blood levels of vitamin D. Studies suggest also that vitamin D2 is more sensitive to humidity and fluctuations in temperature. For this reason, vitamin D2 supplements may be more likely to degrade over time.