Many people do not realise how important it is to maintain adequate levels of vitamin K.
This fat soluble vitamin plays a vital role (as a cofactor) in many important metabolic pathways in the body. Some of the primary functions of vitamin K include; bone mineralisation, cell proliferation and clotting of blood.  There are two naturally occurring forms of vitamin K.
Phylloquinone (also known as vitamin K1)
This is the “predominant circulating form” in our body. It is synthesised from plants and can therefore be obtained from the food we eat. Such foods include green leafy vegetables, some oils (olive, hemp, canola, soybean & cottonseed oil), liver, and fish meal.
Vitamin K1 is responsible for maintaining a healthy blood clotting system and is the form of vitamin K often given to newborn babies (to help prevent a serious bleeding disorder). Vitamin K1 helps your bones retain calcium and develop the right crystalline structure, and has also demonstrated an ability to prevent our blood vessels from calcifying.
Menaquinones (also known as vitamin K2)
This form is produced by intestinal bacterial and is therefore found in high quantities in your gut. Vitamin K2 can also be found in chicken egg yolk, butter, cow liver and fermented foods, particularly cheese and the Japanese food natto, which is by far the richest source.
Recent studies conducted on vitamin K have found that vitamin K2 is far more effective in calcium and bone health, than vitamin K1. Results also found that a high dietary intake of vitamin K2 is associated with reduced coronary calcification (hardening of the arteries), which means a reduced risk of heart disease.
Evidence has suggested that vitamin K2 actually directs calcium into your skeleton, at the same time preventing it from being deposited in your arteries, organs and joint spaces. This could mean that without the help of vitamin K2, the calcium that your vitamin D is helping you absorb may be building up in your arteries rather than your bones.  
The third form of vitamin K – menadione (also known as vitamin K3) is a synthetic, manmade form. We do not recommend the use of vitamin K3.
The vitamin K and vitamin D relationship
Vitamin K and vitamin D also work together by supporting production of the heart protecting protein MGP (Matrix GLA Protein) – this protein is responsible for protecting blood vessels from calcification.
When soft tissues are damaged in the body they respond by initiating an inflammatory response, this can result in the deposition of calcium into the damaged tissue. In healthy arteries MGP will collect around elastic fibres of the arterial lining to help prevent calcium crystal formation (i.e. the build-up of plaque).
Vitamin K and Autism
Catherine Tamaro (B.S.M.E.) has written a paper on “Vitamin K deficiency as a cause of autistic symptoms” (2006). In this paper she discussed some of the interesting functions of vitamin K that relate autism…
- “Vitamin K regulates calcium in the body through osteocalcin and the matrix G1A protein. Both bone proteins are active only after undergoing carboxylation, a process in which Vitamin K is a required cofactor. Carboxylated bone proteins have a strong affinity for calcium and control its movement, directing it to the bones and teeth and preventing its deposition in soft tissues. Calcium management appears to be dysregulated in people with the E4 form of Apolipoprotein. Osteocalcin is found in the brain; in its absence, it appears that brain cells become more vulnerable to the effects of calcium. Vitamin K deficiency appears to play a role in the development of osteoporosis and in the deposition of calcium into blood vessels. Calcification of the arteries, known as “arteriosclerosis,” contributes to heart attacks and strokes.
- Vitamin K, an anti-oxidant that is more powerful than Vitamin E or CoQ10, is able to potently inhibit glutathione depletion-mediated oxidative cell death.
- Vitamin K inhibits production of Interleukin-6, an inflammatory cytokine.
- Vitamin K is found in high concentration in the pancreas and appears to be involved in controlling blood sugar.
- Vitamin K is involved in the development of the nervous system.
- Vitamin K has a role in glutamate conversion and its absence affects the rate of activity of the enzyme glutamate dehydrogenase.” 
Catherine Tamaro also discusses in great detail the link between vitamin K, “unregulated calcium movement” and “metabolic chaos” (seen in Autism). She explains how calcium dysregulation in the body may play a vital role in the development of calcium oxalate (CaOx) deposits.
CaOx salts are known to cause or increase inflammation and/or pain. Many Autistic patients are recommended to follow the Low Oxalate Diet (LOD); developed to lower dietary oxalates and therefore reduce and inflammation/pain in the body.
The LOD eliminates the consumption of green leafy vegetables (the richest sources of vitamin K1), since they are high in oxalates. Catherine Tamaro writes how she is concerned about … “the calcium freed from the calcium oxalate salts….” and “in the case of autistic children, it is probable that they have low levels of Vitamin K and therefore low levels of carboxylated bone proteins. Thus the children presumably have little ability to manage this freed calcium, which will circulate unimpeded into the nervous system and other organs and tissues.
This influx of unmanaged calcium into circulation and then into the nervous system is (Catherine believes) the reason that so many autistic children are exhibiting adverse responses to the LOD, including seizures, behavioural regression, hyperactivity, and depression.
These symptoms do not indicate that oxalates have moved from storage into circulation for transport to the disposal sites (termed “oxalate dumping” on the TLO listserve), but rather reflect the deleterious effects of an influx of unmanaged calcium into the nervous system.”
This is a fascinating article and I recommend if you have the time, to read over it. Catherine Tamaro also discusses her theories on the link between vitamin K and calcium with glutamate and the intestinal membrane.
As you can see, there is a lot more to vitamin K than people think! This essential vitamin can sometimes be forgotten. Please feel free to give us a call if you has any questions regarding vitamin K or anything else we have discussed
- Higdon J. An evidence based approach to vitamins and minerals. 2003. Thieme Medical Publishers, New York.
- Tamaro C. Vitamin K deficiency as a cause of autistic symptoms. Mercer Island, Washington. 2006.
- www.articles.mercola.com/sites/articles/archive/2010/08/26/this-could-be-even-bigger-than-the-vitamin-d-discovery.aspx. Accessed 14/11/12.