The aim of the study is to obtain insight into a dose-dependent effect of vitamin K2 on oxidative stress and specific markers of the immune system.

Inclusion Criteria:

• Self-reported postmenopausal (at least one year after the final menstruation)
• BMI ≥25 and ≤32 kg/m2;
• Plasma dp-ucMGP concentration in highest 50-66% of the screened population
• Non-smoking, defined as not smoking currently and not having smoked (at all) in the year before study start;
• Healthy as assessed by the health questionnaire and according to the judgment of the study physician;
• Voluntary participation;
• Having given written informed consent;
• Willing to comply with study procedures;

Exclusion Criteria:

• Plasma dp-ucMGP concentration >1000 pmol/L at screening
• Treatment with oral antibiotics within 2 months of the start of the study
• Any vaccination in the month before study start or any scheduled vaccination during the study period
• Use of antioxidant or vitamin K and D supplements;
• Use of antioxidant or vitamin K and D supplements in the month before the start of the study;
• Use of aspirin or medication with established antioxidant or anti-inflammatory properties;
• Use of medication that interferes with vitamin K or blood coagulation;
• Use of statins to reduce level of low-density lipoprotein cholesterol in the blood;
• Hyperlipidaemia, diabetes, hypertension, intestinal disease, diseases with an inflammation component;
• Hormone replacement therapy in women;
• Follow a vegetarian or vegan diet;
• Participation in any clinical trial including blood sampling and/or administration of substances up to 30 days before day 1 of this study;
• Alcohol consumption for men > 28 units/week and >4/day; for women: >21 units/week and >3/day;
• Reported unexpected weight loss or weight gain of > 3 kg in the month prior to pre-study screening, or intention to lose weight during the study period;
• Reported slimming or medically prescribed diet;
• Recent blood donation (<1 month prior to Day 01 of the study);
• Not willing to give up blood donation during the study;