Bioavailability of Different Vitamin K Vitamers Studied Using 13C-labelled Vitamin K Vitamers

Launched by UNIVERSITY OF COPENHAGEN · Jun 19, 2025

Keywords

ClinConnect Summary

This clinical trial is studying how well different forms of vitamin K are absorbed and used by the body. Researchers want to compare four types of vitamin K—called PK, MK-4, MK-7, and MK-9—to see which one the body takes up the best. To do this, they will use special versions of these vitamins that can be tracked in the body. The study will help us understand which form of vitamin K might be most effective for health.

Adults between 18 and 65 years old who speak Danish and are generally healthy may be eligible to join. Participants should have a body weight within a certain range (BMI of 30 or less), agree to take a small daily dose of vitamin D, and avoid other vitamin or mineral supplements during the study. People who smoke regularly, have certain health conditions, or take specific medications will not be eligible. If selected, participants will visit the study center several times over about six weeks. During these visits, they will take the vitamin K supplements and provide blood, urine, and stool samples so researchers can measure how much vitamin K the body absorbs and uses. This study is not yet recruiting participants but aims to provide important information about vitamin K forms and their benefits.

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • Men and women
• • Between 18 and 65 years old (including both 18 and 65 year olds)
• • Danish-speaking
• • Willingness to consume/comply with consumption of study-related intervention products/diet
• • Willing to take 10 µg vitamin D3/day and omit intake of all other (vitamins and mineral) supplements before and during the trial
• • BMI ≤ 30.0 kg/m2
• Exclusion Criteria:
• • Daily smokers/users of all kinds of nicotine-containing products. Occasional smokers/user can be included if they are willing to refrain from all kinds of nicotine-containing products during the trial (from screening to end of trial)
• • Blood donation \<3 months prior to study-related blood sampling
• • Intensive physical training (\> 10 hours of strenuous physical activity per week)
• • Participation in other clinical studies at the time of the study
• • Pregnant, lactating or planning to become pregnant within the study period
• • Habitual alcohol intake above current recommendation (\> 10 alcoholic units/week)
• • History of cancer within the past five (5) years except basal cell skin cancer and cervix
• • Diagnosed with chronic inflammation disorders
• • Diagnosed with gastrointestinal diseases
• • Diagnosed with bone related diseases
• • Diagnosed with psychiatric disorder including depression that requires medical treatment
• • Medical treatment of diabetes
• • Medical treatment of cardiovascular related disease
• • Surgical change of the gastrointestinal tract (removal of appendix is allowed)
• • Use of prescription medication that can affect their safety or impact on data
• • Inability, physically or mental, to comply with the procedure required by the study protocol and evaluated by the principal investigator (PI), study manager or clinical responsible
• • Medical treatment with anticoagulation medication (warfarin-like types)
• • Allergy or intolerance related to intervention products