Why do you need it?
Vitamin K plays an important role in healthy blood clotting, which is essential for wound healing when you injure yourself. Your blood needs to start clotting very quickly otherwise you might bleed to death. Vitamin K also keeps your bones healthy and strong and low levels have been associated with an increased risk of osteoporosis and arthritis.Find out about the different types of vitamin K below.
Find out about the different types of vitamin K below. Click here to read more.
There are two types of vitamin K – K1 and K2. Vitamin K1 is found in leafy greens and some other vegetables while vitamin K2 is usually found in small amounts in animal-based foods as well as being produced by bacteria (which convert plant sourced K1 into K2).
Deficiency
Deficiency can lead to reduced blood clotting which may lead to easy bruising and prolonged bleeding, increased bone fragility and infections. Vitamin K deficiency may occur in people with severe liver or digestive tract diseases and people who take antibiotics for extended periods because antibiotics tend to kill the good gut bacteria that produce vitamin K2.
Babies and vitamin K
Babies are born with low levels of vitamin K, but the amount they have is usually sufficient to prevent problems. However, some may be at risk of vitamin K deficiency bleeding (VKDB), formerly known as haemorrhagic disease of the newborn (HDN). This is a serious, but rare condition. However, one study based in Uganda found low levels of vitamin K in one-third of mothers and two-thirds of newborn babies. This doesn’t mean they will suffer bleeding due to vitamin K deficiency, but it is a concern. Because of this, the WHO/FAO expert panel recommends that all breast-fed babies should receive vitamin K supplementation at birth according to nationally approved guidelines to prevent VKDB.
How much do you need?
The World Health Organisation (WHO) recommends 55 micrograms (μg) of vitamin K a day for women and 65 micrograms a day for men. The recommended intakes for infants, children and adolescents, as well as pregnant and lactating women are given below.
Recommended nutrient intakes for vitamin K. Click to read more…
| Age group | Recommended nutrient intake μg/day |
|---|---|
| Infants and children | |
| 0-6 months | 5* |
| 7-12 months | 10 |
| 1-3 years | 15 |
| 4-6 years | 20 |
| 7-9 years | 25 |
| Adolescents | |
| 10-18 | 35-55 |
| Adults | |
| Females, 19+ years | 55 |
| Males, 19+ years | 65 |
| Pregnant woman | 55 |
| Lactating woman | 55 |
Source: WHO, FAO. 2004. Vitamin and mineral requirements in human nutrition. 2nd ed. Geneva: WHO.
Where to find vitamin K
The best plant-based sources of vitamin K are leafy greens, other green vegetables and vegetable oils. Try to include at least one portion of leafy greens in your daily diet. Vitamin K is a fat soluble vitamin, so combining leafy green vegetables with a little drizzle of soya or rapeseed oil might help you absorb it better.
- Green leafy vegetables: Moringa leaves, kale, spinach, chard and collard greens are all good sources of vitamin K and are commonly used in soups, stews and other traditional dishes in Uganda. A cup (42 grams) of cooked moringa/drumstick leaves contains 45 micrograms of vitamin K, meeting well over half your daily needs. One cup (30 grams) of raw spinach contains 145 micrograms, while a cup (180 grams) of cooked spinach contains a massive 889 micrograms.
- Cruciferous vegetables: Perhaps not as easily available as some green leafy vegetables in Uganda, broccoli, Brussels sprouts and cabbage are all excellent sources of vitamin K. Half a cup (78 grams) of cooked broccoli contains 110 micrograms of vitamin K.
- Vegetable oils: Soya bean and canola (rapeseed) oils and to a slightly lesser degree, olive oil, all provide a good source of vitamin K. One tablespoon (14 grams) of soya bean oil contains 26 micrograms of vitamin K and one tablespoon of canola oil contains 10 micrograms.
- Other vegetables: Green Beans, okra and peas can all provide a boost your vitamin K intake. Half a cup (80 grams) of cooked okra contains 32 micrograms of vitamin K.
Excessively high levels of vitamin K can interfere with blood thinning medication. If you take drugs that affect blood clotting, such as Warfarin, talk to your doctor before taking vitamin K supplements as they too can interfere with it.