NSTK · 01.2026Independent supplement reference
NutriStack
Edition 1.0Updated August 1, 2026

Supplement × Supplement·Evidence index

Vitamin A and Vitamin K2: what the published research says

PubMed indexes 4 records that name Vitamin A and Vitamin K2 together, either in the title or in an interaction, co-administration, or pharmacokinetic context. Each one is listed below with its study design and, where the abstract states one, the authors’ own conclusion, quoted and linked. This page reports that literature. It does not tell you whether to combine them.

Read this first

An evidence index, not guidance.

Every statement below is attributed to a named, dated, linked source.

This page lists published research relevant to Vitamin A and Vitamin K2. It deliberately does not state whether the combination is safe, whether it interacts, in which direction, at what dose, or how far apart to take them.

The research

4 studies naming Vitamin A and Vitamin K2.

Strongest relevance first: papers naming both substances in the title, then human trials and systematic reviews.

Non-Fat Fermented Milk Enhanced the Bioavailability of Fat-Soluble Vitamins in Humans: A Crossover Study.

Journal of nutritional science and vitaminology · 2026 · PMID 41765411

Randomized Controlled Trial

“Our findings suggest a new nutritional means by which fat-soluble vitamin bioavailability can be enhanced via co-ingestion with non-fat fermented milk. This approach could improve nutritional deficiencies of global health concern.”

Morifuji et al. · From the abstract

Names Vitamin A and Vitamin K2 together in an interaction, co-administration, or pharmacokinetic context.

Fat-Soluble Vitamin Supplementation Using Liposomes, Cyclodextrins, or Medium-Chain Triglycerides in Cystic Fibrosis: A Randomized Controlled Trial.

Nutrients · 2021 · PMID 34960106

Multicenter StudyRandomized Controlled Trial

“-0.34 µg/mL (-1.71-2.15), p = 0.010). Liposomes may augment the bioavailability of vitamin A and cyclodextrins may strengthen the supplementation of vitamins D3 and E relative to MCT in pancreatic-insufficient CF but further studies are required to assess liposomal vitamin E (German Clinical Trial Register number DRKS00014295, funded from EU and Norsa Pharma).”

Nowak et al. · From the abstract

Names Vitamin A and Vitamin K2 together in an interaction, co-administration, or pharmacokinetic context.

Low vitamin K1 intake in haemodialysis patients.

Clinical nutrition (Edinburgh, Scotland) · 2017 · PMID 27234935

Multicenter StudyObservational StudyHuman subjects

“Haemodialysis patients had a significantly low intake in vitamin K1, which could contribute to increase the risk of bone fractures and vascular calcifications. Since the deficiency of vitamin K intake seems to be remarkable, dietary counselling to HD patients should also address the adequacy of vitamin K dietary intake and bioavailability.”

Fusaro et al. · Authors' conclusion

Names Vitamin A and Vitamin K2 together in an interaction, co-administration, or pharmacokinetic context.

Limitations

What this evidence cannot tell you.

Search-based evidence indexes have real limits, and it is worth being explicit about them:

NutriStack

Track what you actually take.

NutriStack is a free iPhone app for organising a supplement routine: what you take, when, and what the published record says about it. Its exploratory interaction checker covers Vitamin A, Vitamin K2, and several hundred other substances.

The checker is a research and organisation tool, not a clinical decision aid, and its per-pair assessments are excluded from search until they pass claim-level review.

NutriStack is an informational and organizational tool, not a medical service, and not a substitute for professional advice. Always consult a qualified healthcare professional before starting, stopping, or changing any supplement or medication.