Vitamin D3 (cholecalciferol) is a fat-soluble compound that the body primarily produces itself through sun exposure to the skin. Only small amounts are absorbed through food – mainly through fatty fish, eggs, and fortified foods. Especially in the autumn and winter months, the body's own production can be severely limited in northern latitudes.
What is Vitamin K2?
Vitamin K2 (menaquinone) is also a fat-soluble vitamin and belongs to the group of vitamin K compounds. It occurs naturally in fermented foods such as natto, certain cheeses, and animal products. K2 plays an important role in the body's calcium metabolism.
What does science say? – Approved Health Claims
The European Food Safety Authority (EFSA) has approved the following health claims for vitamins D and K:
Vitamin D contributes to:
the normal function of the immune system
the maintenance of normal bones
the maintenance of normal muscle function
normal blood calcium levels
the normal absorption and utilization of calcium and phosphorus
Vitamin K contributes to:
normal blood clotting
the maintenance of normal bones
Why combine D3 & K2?
Vitamin D3 and K2 are often taken together because both vitamins play a role in calcium metabolism. While vitamin D3 supports calcium absorption in the intestines, vitamin K2 is involved in activating proteins that transport calcium in the body. Both vitamins are fat-soluble and should therefore ideally be taken with a fatty meal.
What to look for in quality?
Form: D3 (cholecalciferol) is the more bioavailable form compared to D2
K2 form: MK-7 is considered to be more effective for longer than MK-4
Dosage: Transparent indication in IU (International Units) or µg
Carrier oil: Fat-soluble vitamins require an oil as a base for optimal absorption
Origin: Laboratory-tested quality, ideally Made in Germany
Vitamin D contributes to the normal function of the immune system and the maintenance of normal bones. Vitamin K contributes to the maintenance of normal bones.
