Phylloquinone

Studies in people

• Open question

  Blood clotting and diet³

  In people taking coumarin blood thinners, it is unclear whether steady phylloquinone intake changes their effects.

• Benefit

  Type 2 diabetes risk⁹

  People who ate more phylloquinone had a lower chance of getting type 2 diabetes.

• Open question

  Bone strength in women¹¹

  Women who ate the least vitamin K1 had slightly lower bone density than those who ate more.

• Open question

  Bone strength after menopause¹³

  In postmenopausal women, taking phylloquinone for 6 weeks changed blood markers but did not change bone turnover.

• Benefit

  Bone breakdown in older women¹⁵

  In postmenopausal women, eating more phylloquinone modestly reduced a marker of bone breakdown, but bone strength effects are unknown.

• Open question

  Blood clotting with warfarin¹⁷

  In people low in vitamin K, multivitamins with phylloquinone weakened warfarin's blood-thinning effect.

• Open question

  Vitamin K in breast milk¹⁸

  Mothers who took phylloquinone supplements had more vitamin K in their breast milk.

Animal and lab studies only

• Benefit

  Bone loss after menopause²²

  In animal studies, phylloquinone helped prevent bone loss after ovary removal, and worked better combined with calcium.

How it’s made and used

• Blood clotting²

  Phylloquinone is vitamin K1, found in leafy greens, and the body keeps it in the liver to help blood clot.

• Vitamin K intake in dialysis patients⁴

  Dialysis patients ate far less vitamin K1 than healthy people, which may raise their risk of bone fractures.

• Vitamin K absorption⁵

  Scientists found gene differences may explain why people absorb phylloquinone from supplements differently.

• Diet and age differences⁶

  Phylloquinone intake was lower in Irish adults aged 18 to 35 than in older age groups.

• Blood pressure in older adults⁷

  Older adults who ate too little phylloquinone were more likely to have high pulse pressure.

• Heart artery calcium⁸

  In people, low phylloquinone levels were linked to more artery calcium buildup, mostly in those taking blood pressure medicine.

• Vitamin absorption from meals¹⁰

  In people, phylloquinone was absorbed better when taken with some meals than others.

• Vitamin K status¹²

  In 9 adults, urinary levels of a phylloquinone byproduct rose and fell with how much phylloquinone they ate.

• Vitamin K levels in the blood¹⁴

  Blood levels of phylloquinone were higher in men than women, and rose with age in women.

• Children's vitamin K intake over time¹⁶

  In 4-year-old British children, phylloquinone intake was higher in 1950 than in the 1990s.

• Vitamin K absorption from food¹⁹

  Phylloquinone from broccoli and from fortified oil raised blood levels about the same in younger and older adults.

• Bone protein rhythm²⁰

  In people, extra phylloquinone in the diet changed one form of a bone protein through the day, but not the overall rhythm.

• Vitamin K in the body²¹

  In animal studies, phylloquinone eaten in food turned into another form of vitamin K in the body.

The signal at the top counts the findings in people and in animal and lab studies. A concern in studies of people outranks animal and lab studies, and “No concerns” needs at least one finding in people. When most findings in people point one way, the page leans that way (“Mostly”), and every finding is still shown. Findings whose study type is not stated are shown but not counted. This page is a reference, not medical advice. It describes what regulators and published research say. Talk to a doctor or dietitian about your own diet.