Vitamine K complément alimentaire

Often unknown to the general public, vitamin K is an essential nutrient for many bodily functions. While it is primarily associated with blood clotting, its role extends far beyond that: it also contributes to the maintenance of normal bones.

This is why it is playing an increasingly important role in the field of nutrition and dietary supplements.

What is vitamin K?

Vitamin K is a fat-soluble vitamin, meaning it dissolves in fats and can be stored in certain parts of the body, particularly the liver, adipose tissues, and muscle cells. It plays a fundamental role in several biological processes:

• Vitamin K contributes to normal blood clotting,
• Vitamin K contributes to the maintenance of normal bones.

Additionally, this vitamin primarily exists in two active forms in humans: vitamin K1, or phylloquinone, and vitamin K2, or menaquinone.

Vitamin K1 and vitamin K2: origins and roles in the body

Vitamin K comes in two main forms, which differ in their origin and mode of action in the body.

Vitamin K1, or phylloquinone, is primarily of plant origin. It is found in large quantities in leafy green vegetables, such as spinach, kale, broccoli, and lettuce. After ingestion, this form is absorbed in the intestines and then transported in the blood to various tissues, particularly the liver.

Vitamin K2, called menaquinone, is partly produced by the intestinal bacterial flora, meaning our microbiota naturally contributes to its intake. In addition, it is present in certain fermented foods, such as natto (a traditional Japanese fermented soybean product), some aged cheeses, and animal products like liver. Unlike vitamin K1, K2 has a better ability to be stored in tissues, particularly in bones, where it helps maintain normal bone structure.

Dietary sources of vitamin K: how to ensure sufficient intake?

To meet your vitamin K needs, it is important to include a variety of sources rich in both forms in your diet.

• Vitamin K1 (phylloquinone): It is mainly provided by leafy green vegetables.
• Vitamin K2 (menaquinone): Less present in the typical Western diet, vitamin K2 is found in fermented foods.

It should be noted that cooking can sometimes reduce the bioavailability of vitamin K1, especially during prolonged cooking. However, a balanced diet, rich in fresh and fermented vegetables, generally ensures an adequate intake. Some people, especially athletes, may need a dietary supplement to reach the recommended intake.

Dietary supplements: Vitamin D3 K2

In the field of dietary supplements, vitamin K is frequently associated with vitamin D3 (under the name vitamin D3K2), as these two complementary nutrients have common benefits.

Vitamin D3 contributes to the normal absorption and utilization of calcium, which allows the body to effectively capture this essential mineral. In addition, vitamin D3 contributes to the maintenance of normal bones, just like vitamin K2.

In parallel, calcium also plays a role in blood clotting and bone structure.

Buying guide: how to choose a good vitamin K supplement?

Choosing an effective and safe vitamin K supplement requires considering several criteria.

• Form of vitamin K: Prioritize vitamin K2 for better absorption. The mention of patented ingredients like K2VITAL® is often a guarantee of purity, stability, and traceability.
• Quality and traceability: Choose supplements from laboratories or brands that are transparent about ingredient sourcing, quality testing, and certifications. Products should be free of controversial additives, contaminants, or unnecessary fillers.
• Form of the supplement: Vitamin K2 is generally available in the form of capsules or liquid solutions. The choice will depend on your preferences and daily convenience.
• Precautions: Consult a healthcare professional before starting supplementation, especially if you are on medication or have particular pathologies.

Vitamin K dietary supplement: in summary

Vitamin K is a key nutrient with multiple benefits, ranging from blood clotting to bone maintenance.

Certain situations may justify taking dietary supplements, particularly in the form of vitamin K2, often in combination with vitamin D3. The choice of supplement should be made carefully, prioritizing quality, transparency, and appropriate dosage, and always under medical advice.

By following these principles, it is possible to fully benefit from the advantages of vitamin K.

Sources:

1. ANSES, Les références nutritionnelles en vitamines et minéraux, 2025, https://www.anses.fr/fr/content/les-references-nutritionnelles-en-vitamines-et-mineraux
2. Přemysl Mladěnka et al., Vitamin K - sources, physiological role, kinetics, deficiency, detection, therapeutic use, and toxicity, OEMONOM researchers and collaborators, 2022, DOI: https://academic.oup.com/nutritionreviews/article/80/4/677/6362591