What is the relationship between Vitamin D3 (Cholecalciferol) and Vitamin K?

From the Guidelines

Vitamin D3 and vitamin K should be taken together, with a recommended daily dose of 600-800 IU of vitamin D3 and 100-200 mcg of vitamin K2, to support bone health and cardiovascular function, as evidenced by the Institute of Medicine's guidelines 1. The synergistic relationship between vitamin D3 and vitamin K is crucial for maintaining optimal health, particularly in regards to bone health and cardiovascular function. Vitamin D3 (cholecalciferol) plays a key role in calcium absorption, while vitamin K (particularly K2) ensures that calcium is directed to bones rather than accumulating in arteries and soft tissues.

• The Institute of Medicine recommends a daily dose of 600 IU of vitamin D3 for individuals from 1 to 70 years of age, and 800 IU for individuals 71 and older 1.
• The recommended "safe upper limit" of dietary vitamin D intake is 4000 IU daily, above which the risk of toxicity begins to increase 1.
• Vitamin K2, specifically the MK-7 form, is preferred due to its better bioavailability, with a recommended dose of 100-200 mcg per day.
• It is essential to note that vitamin D3 and vitamin K2 supplements are best taken with a meal containing some fat to enhance absorption.
• Blood testing for vitamin D levels (25-hydroxyvitamin D) is recommended before starting supplementation, with optimal levels generally considered to be between 30-50 ng/mL, although the Endocrine Society and Institute of Medicine have proposed different criteria for vitamin D deficiency 1.
• Individuals with certain medical conditions, such as blood clotting disorders, should consult healthcare providers before taking vitamin K supplements, as it may interfere with anticoagulant medications like warfarin.
• The combination of vitamin D3 and vitamin K2 supports bone health, cardiovascular function, and immune system regulation, making it valuable for overall health maintenance, and their use may not require daily, weekly, or even monthly replenishment, as 25(OH)D3 has a half-life of 2 weeks to 3 months and is stored primarily in adipose tissue and, to a lesser extent, in the liver 1.

From the Research

Vitamin D3 and Vitamin K Interaction

There is no direct evidence in the provided studies regarding the interaction between vitamin D3 and vitamin K.

Vitamin D3 Supplementation

• The use of vitamin D supplements has increased substantially over the last decade, with epidemiologic evidence linking vitamin D deficiency to various illnesses 2.
• Vitamin D supplementation in doses of 800-5000 IU/day can improve musculoskeletal health, reducing the rate of fractures and falls in older adults 2.
• A daily vitamin D supplementation with 2000 IU (50 µg) may be considered a simple, effective, and safe dosage to prevent and treat vitamin D deficiency in the adult general population 3.
• The Endocrine Society suggests empiric vitamin D supplementation for children and adolescents, those aged 75 years and older, pregnant individuals, and those with high-risk prediabetes 4.

Health Effects of Vitamin D Supplementation

• Vitamin D supplementation can prevent and cure nutritional rickets in infants and children, but the causal link between vitamin D and many extra-skeletal outcomes remains unclear 5.
• Randomized clinical trials have indicated that vitamin D supplementation of vitamin D-replete adults does not prevent cancer, cardiovascular events, falls, or progression to type 2 diabetes mellitus 5.
• Mendelian randomization studies have found null effects of lifelong genetically lowered serum 25OHD concentrations on various outcomes, except for an increased risk of multiple sclerosis 5.

Cardiovascular Risk

• Vitamin D supplements should not be prescribed for the primary purpose of cardiovascular disease (CVD) prevention, as recent meta-analyses and randomized clinical trials have failed to find a beneficial effect 6.
• There is some concern related to calcium use and increased CVD risk, and it may be best to achieve the recommended daily allowances of calcium intake through food and reserve calcium supplementation only for those at risk for calcium intake deficiency 6.