Vitamin K: Phylloquinone & Menaquinones.
Vitamin K is a fat-soluble vitamin that is mostly made up of two sub-groups, K1 and K2. Vit K1, also known as phylloquinone, is found in plant matter. The next largest group of compounds are the vit K2 group, called menaquinones, found mostly in animal products. Vitamin K must be consumed in conjunction with fat for your body to absorb it well. Vitamin D levels must also be adequate within the body for optimal function of this nutrient.
While found naturally in many foods, in some rare cases it may need to be taken as a dietary supplement or as an injection.
Function
Vitamin K is essential for bone formation and blood coagulation (clotting) within the body. It is also vital for the healthy function of the liver and kidneys.
Food Source
Phylloquinone is found in green leafy vegetables such as spinach, broccoli and asparagus. Menaquinone is found in animal products such as liver, egg yolks, and cheese.
RDI (Recommended Daily Intake)
The recommended daily intake; as with all vitamins varies for men and women. 70mcg is considered to be a sufficient daily intake for men who are in good health.
For women, 60mcg is the recommended daily intake.
Food Portion Guide
Just 1 cup of broccoli can contain up to 70mcg of phylloquinone. Another way of achieving your daily recommended intake through diet is to include egg or cheese. Just one egg yolk contains 16mcg of menaquinone while hard cheese, depending on the type, can contain up to 76mcg per 100g.
Possible Symptoms of Deficiency
Deficiency in healthy adults is very rare and the safe natural forms of phylloquinone and menaquinone are extremely unlikely to cause toxicity. As it is synthesized by intestinal bacteria within the body, people who are on antibiotics or have liver disease may require a higher intake of foods containing Vit K. Newborn infants are most at risk of deficiency as their intestinal bacteria may not started working immediately after birth. As such some paediatricians may recommend a vitamin K injection be administered to a newborn shortly after birth. Possible side effects of deficiency are easy bruising, internal bleeding or haemorrhaging. Reduced levels have also been linked to an increased risk of coronary heart disease and osteoporosis.
Possible Side Effects Of Overdose
An overdose is near impossible when consumed via natural food sources.
Of the three synthetic forms (vitamins K3, K4 and K5) only Vit K3 (also known as menadione) is known to be toxic in large doses and is not available over the counter as a supplement.
Pregnant women or breast feeding women should not take Vit K supplements unless advised by their physician.
In summary, a healthy dose of vitamin K is readily available in a range of leafy green vegetables and animal products.
If you have any concerns regarding your vitamin levels, always consult with your local health practitioner before commencing a vitamin K supplement.