Vitamin K1 Linked to Lower COPD Risk and Better Lung Function in 179,000 Adults
A large UK Biobank study finds higher vitamin K1 intake — from leafy greens — is associated with a 16% lower COPD rate and measurably better lung function.
Summary
A prospective study of over 179,000 UK adults found that higher dietary vitamin K1 intake was associated with a 16% lower rate of COPD and meaningfully better lung function, including higher FVC and FEV1 measurements. The protective effect plateaued at around 250 micrograms per day — roughly one serving of kale or one to two cups of leafy greens. Vitamin K2 showed no significant association with COPD or asthma. Notably, the lung function benefits of vitamin K1 were strongest in smokers and people in high-risk occupations. No associations were found between either form of vitamin K and adult-onset asthma. These findings suggest that vitamin K1, abundant in green leafy vegetables, may play an important role in preserving respiratory health through its involvement in vitamin K-dependent proteins that maintain lung structure.
Detailed Summary
Lung disease is a leading cause of disability and death worldwide, yet dietary factors influencing respiratory health remain underexplored. Vitamin K-dependent proteins are known to play structural roles in lung tissue, making dietary vitamin K a plausible but understudied factor in respiratory outcomes.
This prospective cohort study analyzed data from 179,062 UK Biobank participants free of COPD or asthma at baseline. Dietary vitamin K1 and K2 intakes were estimated using the Oxford WebQ 24-hour dietary recall tool. Incident COPD and asthma were identified through hospital, death, and primary care records over a median follow-up of 10.5 years. Lung function was assessed cross-sectionally using FEV1, FVC, and the FEV1/FVC ratio.
Higher vitamin K1 intake was associated with a 16% lower rate of COPD in the highest versus lowest quintile (HR: 0.84; 95% CI: 0.75–0.94), with the protective association plateauing above approximately 250 micrograms per day. Vitamin K1 was also associated with better lung function — FVC was 44 mL higher and FEV1 was 32 mL higher in the top versus bottom quintile. These associations were particularly pronounced in smokers and workers in high-risk occupational settings. Vitamin K2 showed no significant association with COPD and only weak, non-linear associations with lung function. Neither form of vitamin K was associated with incident asthma.
The findings are clinically meaningful: 250 micrograms of vitamin K1 is achievable through a single serving of kale or one to two cups of leafy greens daily, making this a practical dietary target. The differential effect of K1 versus K2 may reflect distinct biological roles or differences in food sources.
Important caveats include the observational design, which precludes causal inference, and reliance on dietary recall data, which carries measurement error. The summary is based on the abstract only, limiting full methodological appraisal.
Key Findings
- Highest vitamin K1 intake linked to 16% lower COPD incidence versus lowest intake quintile.
- Protective effect plateaus at ~250 mcg/day — achievable with one serving of kale.
- Vitamin K1 associated with 44 mL higher FVC and 32 mL higher FEV1.
- Benefits strongest in smokers and high-risk occupational groups.
- Vitamin K2 and neither form of K showed association with asthma incidence.
Methodology
Prospective cohort study of 179,062 UK Biobank participants followed for 10.5 years, using Cox proportional hazards models for incident COPD and asthma and multiple regression with splines for cross-sectional lung function analyses. Dietary intake was estimated via the Oxford WebQ 24-hour dietary recall tool, with stratified analyses by sex, smoking status, and occupation.
Study Limitations
This is an observational study and cannot establish causation between vitamin K1 intake and respiratory outcomes. Dietary intake was estimated via self-reported 24-hour recall, which is subject to measurement error and may not reflect long-term dietary patterns. This summary is based on the abstract only, as the full text was not available, limiting assessment of confounding adjustment and other methodological details.
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