Vitamin K2 is one of those nutrients that is rarely discussed, but it is crucial for ensuring calcium ends up where it belongs: in the bones and teeth, and not in the arteries. While for years attention has focused on vitamin D3, more and more studies indicate that without sufficient vitamin K2, the body does not fully utilize the benefits of vitamin D. In this article, we explain what it is, what it's for, where to find it, and how to choose a good supplement.

What is vitamin K2 and how does it differ from K1?

Vitamin K is not a single substance, but a family of fat-soluble compounds. Vitamin K1 (phylloquinone) is found primarily in leafy green vegetables such as spinach or broccoli, and its main function is related to blood clotting. Vitamin K2 (menaquinone), on the other hand, is produced to a lesser extent by intestinal flora and is also obtained from fermented foods and animal products. Its role is different: it activates proteins like osteocalcin and MGP protein, responsible for directing calcium to the bones and keeping it away from arterial walls.

Benefits of vitamin K2 for bones and heart

The main benefits of vitamin K2 can be summarized in two broad areas:

Bone health: By activating osteocalcin, vitamin K2 helps calcium bind to the bone matrix, contributing to stronger bones and reducing the risk of fractures, especially relevant for women after menopause. If you are interested in this topic, in our women's health collection, you will find formulas designed for this stage.

Cardiovascular health: By preventing calcium from depositing in the arteries, vitamin K2 helps keep them flexible, which translates into better long-term support for heart health.

Vitamin K2 and vitamin D3: why they go hand in hand

Vitamin D3 improves calcium absorption in the intestine, but it is vitamin K2 that is responsible for directing that calcium to the correct place. Taking vitamin D3 without enough vitamin K2 can mean that some of that additional calcium is not optimally utilized. For this reason, many nutrition experts recommend combining both nutrients, especially in autumn and winter, when vitamin D levels typically drop due to less sun exposure. You can consult our vitamin D3 collection to see options that include this combination.

Where is vitamin K2 found? Food sources

Unlike vitamin K1, K2 is not abundant in fruits and vegetables. Its main food sources are:

Natto (fermented soybeans typical of Japan), one of the foods with the highest concentration of K2 (in its MK-7 form); aged cheeses and other fermented dairy products; egg yolk; liver and other organ meats; and, to a lesser extent, butter and some cured meats. Since many of these foods are not a regular part of the Mediterranean diet in the necessary quantities, supplementation has become a practical alternative to meet recommended levels.

Recommended dosage and how to choose a good supplement

There is no official recommended daily intake for vitamin K2 in Europe, but available studies typically work with doses between 45 and 180 micrograms per day, generally in its MK-7 form, which has a longer half-life in the body than MK-4. When choosing a supplement, it is important to look at three aspects: that it specifies the form (MK-7 is the most studied), that it indicates the exact dose in micrograms, and that it ideally comes combined with vitamin D3 if you are looking for joint support for bones and the immune system.

Who should be cautious with vitamin K2

Vitamin K2 is directly involved in the clotting process, so people taking anticoagulants such as warfarin should always consult their doctor before incorporating this supplement, as it can interfere with treatment. The same applies if you are pregnant, breastfeeding, or have any liver or kidney pathology: professional supervision is always the first step before starting any new supplementation.

Vitamin K2 is a silent but essential nutrient for calcium to work in your favor, both in your bones and your heart. If you already take vitamin D3 or are considering strengthening your bone health, adding vitamin K2 can make a difference. At andavida.es, you will find a selection of quality supplements to support you at every stage of your well-being.