Phylloquinone blood levels and diet in British adults
What it found
Blood levels of phylloquinone were higher in men than women and rose with the amount eaten.
This was measured in 1154 British adults aged 19 to 64 years.
What they found
Studies in people
Men had higher levels
The average blood level of phylloquinone was 1.13 nmol/l in 530 men and 0.81 nmol/l in 624 women. This difference held true regardless of other factors like age or smoking.
Age and season in women
Younger women aged 19 to 34 years had lower blood levels than older women. Women also had lower levels during summer compared with winter and spring. Men showed no clear differences by age or season.
Diet linked to levels
People who reported eating more phylloquinone tended to have higher amounts in their blood. Eating more vegetables, especially cooked leafy greens, was also linked to higher blood levels.
Other nutrients tracked together
After accounting for age and body size, blood phylloquinone rose alongside total cholesterol, LDL cholesterol, vitamin E forms and several carotenoids in both men and women.
Intake explained little variation
How much phylloquinone people ate explained only 8% of the differences seen in blood levels across the group. Other fat-soluble nutrients in the blood explained another 10%.
What the authors conclude
- They report that most British adults in this age range appear to have enough phylloquinone in their blood, though a notable share may fall short of ideal levels.
- They note that blood levels are influenced by many factors beyond just how much phylloquinone someone eats, including other fats and vitamins carried in the blood.
How it was done
Phylloquinone is a form of vitamin K that comes from food and may play a role in bone and heart health. The authors wanted to measure how much of it circulates in the blood of British adults and what influences those levels.
They looked at data from 1154 British adults aged 19 to 64 years who took part in a national diet survey in 2000 and 2001. Participants kept a weighed record of everything they ate and drank for 7 days. Blood samples were taken at various times of day without requiring people to fast first.
What it can’t tell you
- This survey measured things at one point in time, so it can show links but not prove that eating more phylloquinone causes higher blood levels.
- Because participants did not fast before giving blood, recent meals may have affected some of the measurements.
Who paid
- Funding
- Funded by Medical Research Council (from the PubMed record).
- Authors work at
- Elsie Widdowson Laboratory, UK
The paper
- Title
- Plasma phylloquinone (vitamin K1) concentration and its relationship to intake in British adults aged 19-64 years
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Thane CW, Wang LY, Coward WA (2006). Plasma phylloquinone (vitamin K1) concentration and its relationship to intake in British adults aged 19-64 years. The British journal of nutrition. doi:10.1017/bjn20061972Free full textPubMed 17181887DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error