|
What
is it?
The
are three forms of vitamin K
-
Vitamin
K1 comes from plant sources
-
Vitamin
K2 is produced by intestinal bacteria
-
Vitamin
K3 is produced synthetically
Functions
- what does it do?
Blood
Clotting.
Vitamin K plays an essential role in normal blood clotting.
It contributes to the synthesis of several blood-clotting factors.
Inactive
blood-clotting factors
Action of vitamin K
Active blood-clotting factors
Without
sufficient vitamin K, haemorrhaging (bleeding) occurs.
Bone
Health.
Vitamin K particpates in the synthesis of several bone proteins
that are essential for bone formation. Research is in progress
to determine the specific roles of these proteins in bone metabolism
and the risk of osteporosis.
Requirements
- How much do we need?
|
|
| |
Adequate
Intake*
(µg/day) |
| Life-Stage
(years) |
Males |
Females |
| 0
- 0.5 (0 - 6 months) |
2.0 |
2.0 |
| 0.5
- 1 (7 - 12 months) |
2.5 |
2.5 |
| 1
- 3 |
30 |
30 |
| 4
- 8 |
55 |
55 |
| 9
- 13 |
60 |
60 |
| 14
- 18 |
75 |
75 |
| Ages
19+ |
90 |
90 |
| Life-Stage
(years) |
Pregnancy |
Lactation |
| 18
and younger |
75 |
75 |
| 19
- 30 |
90 |
90 |
| Ages
31 - 50 |
90 |
90 |
| *Adequate
Intakes (AI) are used as no RDA is established. The
AI is a recommended daily intake level based on observed
or experimentally determined approximations of nutrient
intake by a group of healthy people who are assumed to be
maintaining an adequate nutritional state. |
|
Sources
- Where is it found?
|
|
Food
Sources |
| Nutrient
Density |
| High |
Medium |
Low |
|
| Excellent
sources |
Liver,
Green leafy vegetables (e.g. Kale, Turnip greens, Cabbage,
Spinach), Broccoli, Peas, Green beans |
| Other
sources |
Other
vegetables, Fruits, Cereals, Dairy products, Eggs, Meat |
| Vitamin
K is naturally produced by bacteria in the intestines. |
|
|
Deficiency
- When you have too little
Newborns
lack the intestinal bacteria to produce vitamin K and need a
supplement for the first week. A vitamin K injection is given
at birth to provide the nutrient until enough bacteria are present
in the infant’s intestine to make the amounts needed.
In
adults, deficiencies can occur in people using antibiotics for
prolonged periods, possibly due to the destruction of the intestinal
bacteria that produce vitamin K. People on anticoagulant drugs
(blood thinners) and those suffering from severe chronic fat
malabsorption
may also become deficient.
Toxicity
- When
you have too much
Oral
doses of vitamin K poses no risk of toxicity. Megadoses of vitamin
K reduce the effectiveness of oral anticoagulant drugs (blood
thinners) used by some people.
|
Upper
Limit+
(mg/daya)
|
| Life-Stage
(years) |
Males |
Females |
| All
ages |
ND |
ND |
| Life-Stage
(years) |
Pregnancy |
Lactation |
| All
ages |
ND |
ND |
| +Upper
Limits (UL) = The maximum level of daily nutrient intake
that is likely to pose no risk of adverse effects. Unless
otherwise specified, the UL represents total intake from
food, water, and supplements.
ND = Not
determinable due to lack of data of adverse effects in
this age group and concern with regard to lack of ability
to handle excess amounts. Source of intake should be from
food only to prevent high levels of intake. |
|
