Vitamin K: Natural Support for Achieving Stronger Bones & A Healthier Circulatory System

The term “Vitamin K” generally refers to three related substances: K1, known as phylloquinone; K2, which consists of a group of compounds called the menaquinones (also menatetrenone); and a synthetic version of the vitamin known as K3 or menadione. The naturally occurring K compounds are found in the fatty part of foods. For example, green vegetables such as broccoli, as well as soybean, canola, sunflower and other plant oils are good sources of vitamin K1. Butter, some cheeses, chicken, liver, egg yolks, and fermented soybean foods contains K2.  

Unfortunately, the human body can only store a small amount of vitamin K in the tissue with primary but limited storage found in the liver. Therefore, Vitamin K-rich foods must be regularly consumed in order to meet nutritional requirements. In addition, it should be noted that a primary source for all forms of vitamin K comes from health-promoting bacteria found in our colons and intestinal tract. 

While all the forms of K are vital to our health, the K2 family of compounds (called menaquinones) is of compelling interest because a number of laboratory and clinical studies indicate that at least 2 of these (menaquinone 4 & menaquinone-7) play a crucial role in keeping calcium from being deposited in artery walls while at the same time helping to shuttle calcium into bone (This includes calcium deposited in blood vessel walls!) We will look at this in greater detail shortly.

Background on the Vitamin K & Deficiency-Related Woes    

In 1929, Danish scientist Henrik Dam discovered that when chicks were fed a diet void of fat, their blood began leaking out from various blood vessels. In addition, he observed that their blood-clotting abilities were seriously impaired. Closer scrutiny disclosed that this restricted diet also caused the reduction of a unique compound typically found in fat. He figured out that this compound was integral to the blood’s ability to coagulate or clot normally. Dr. Dam dubbed this compound that promoted blood clotting as the “koagulation vitamin,” which later became known as vitamin K (for “koagulation”). Years of follow-up research verified its integral role in coagulation, among other vital functions in the body.

Vitamin K is technically classified as 1, 2, 3, 4, and 5. The following compounds distinguish among the five K vitamins:

Vitamin K1: Phytonadione—Used to treat and prevent hypoprothrombinemia (deficiency of prothrombin) and hemorrhagic disease. It is also used as a supplement with excessive broad-spectrum antibiotics and excessive dosages of oral anticoagulants, and topically to treat burns and stretch marks.

Vitamin K2: Menaquinone 1 through 13 (also known as menatertenone)—For prevention and treatment of bone loss and reduction of calcification of the arteries. It may be supportive in reducing total cholesterol.

Vitamin K4: Menadoil—Used to treat hypoprothrombinemia (deficiency of prothrombin) via injections.

While it is true that most Western diets provide adequate levels of Vitamin K, deficiencies do arise due to use of certain prescription drugs and anticoagulants, illegal drug use, and consistent or excessive use of over the counter drugs like aspirin.

            The following birth defects have been liked to anticonvulsant drugs and vitamin K deficiency: 

1. Craniofacial abnormalities
2. Learning disorders
3. Hypertelorism
4. Microcephaly
5. Distal digit Hyperplasia (abnormally short pinkie finger)
6. Growth disorders
7. Epicanthic Folds
8. Flat nasal bridge
9. Short noses
10. Neural tube defects
11. Mental retardation
12. Long, thin overlapping fingers
13. Upslanting palpebral fissures
14. Cardiac disfunction

1. Calcification of soft tissue
2. Heavy menstrual bleeding
3. Hypercalciuria
4. Gastrointestinal bleeding
5. Fractures
6. Osteoporosis
7. Osteopenia
8. Purpura
9. Easy to bruise
10. Gum bleeding
11. Nosebleeds
12. Hematuria (bloody urin)
13. Eye hemorrhages
14. Anemia

Drug & Dietary supplement interactions

Antibiotics will kill off beneficial intestinal bacteria, some of which produce vitamin K.   Mineral oil reduces gastrointestinal absorption of vitamin K and thus, prolonged use is not recommended.   Cholestipol (Colestid) may reduce vitamin K absorption and serum levels, while Cholestyramin (Questran) also might have a reducing effect on vitamin K absorption and thus serum levels.   Lastly, Orlistat (Xenical) can also reduce absorption.  

A very popular nutritional supplement called Coenzyme Q-10 (Co-Q-10) is chemically similar to Vitamin K-2 and may also have similar effects in the body as Vitamin K-2. Taking Co-Q-10 with Vitamin K-2 may increase the risk of clotting in people taking anticoagulants.

            Similarly, taking herbs that naturally contain vitamin K or herbs that have been through an extract process such that they contain even high amounts of vitamin K than occur in nature should also increase the risk of clotting in people taking anticoagulants. Some of these products include alfalfa, cabbage, parsley, nettle, plantain, and others. Vitamin E at higher dosages can antagonize the effects of Vitamin K.   Vitamin E also appears to reduce Vitamin K absorption and inhibit K dependent enzymes. 

Vitamin K2 (Menaquinones 4 & 7) & Bone & Arterial Integrity 

In bones K2 – menaquinone-4 and menaquinone-7 -- plays a role in the production of the protein osteocalcin, as well as is involved in the formation of matrix Gla-protein (MGP). Both contribute to the genesis of bone and its maintenance.

Vitamin K’s specific role with respect to osteocalcin lies in the fact that this protein must undergo a process called carboxylation before it can be effective in bone formation [Carboxylation refers to melding a carboxyl group (-COOH) or carbon dioxide into a compound] Vitamin K acts as a cofactor that helps the enzyme that brings about the carboxylation of osteocalcin do its job. It also is important to the manufacture of MGP in smooth muscle cells that line healthy blood vessel walls.

As it turns out, MGP is not only a contributor to bone matrix formation, but is also a potent inhibitor of calcification of arteries and cartilage. There is, in fact, evidence that vitamin K levels must not fall below certain levels, otherwise MGP will not be generated in sufficient quantities to prevent arterial calcification.

In laboratory studies, mice who fail to produce enough MGP develop extensive calcification of their blood vessels.

Humans too appear to suffer in a similar way when vitamin K levels are below par. Support for this comes from research done in the Netherlands.

In order to assess the role of vitamin K levels and atherosclerosis, a Dutch team of scientists gleamed data from a previously published study known as the Rotterdam Study. This particular study was started in 1990 in Ommoord, a suburb of Rotterdam, and involved tracking 10,994 men and women aged 55 and over.  The purpose of the study was to investigate the prevalence, incidence of and risk factors for various chronic diseases in the elderly including cardiovascular, neurologic, movement and various eye diseases. The vitamin K-atherosclerosis study focused on analyzing dietary data on 4,807 participants with no history of heart attack, tracking them until the year 2000.

What the researchers found was this: Both vitamin K1 (phylloquinone) and vitamin K2 were associated with the artery-beneficial high-density lipoprotein (HDL), while only vitamin K2 was seen to affect a decrease in total cholesterol. Compared to those whose vitamin K2 intake was in the lowest third of the 4.807 participants, those folks whose intake was in the top third boasted a 41% reduction in both fatal and nonfatal heart attacks, sudden cardiac deaths, and other forms of heart disease related to compromised arterial blood flow. In addition, death from both coronary heart disease and all other causes was significantly reduced for those with the highest vitamin K levels. Most intriguing of all was the fact that participants who had a high vitamin K2 intake bolstered the lowest levels of calcification in their aortas, while low vitamin K intake was linked to an increased risk of dying from coronary heart disease.

How much K2 is needed?

The official recommended daily intake of Vitamin K is about 1 mcg per kilogram (2.2 lbs) of weight. In light of the fact that undercarboxylation of MGP appears to be a risk factor for calcification of blood vessels and high levels seem to protect against this, the RDA make error on the low side. This has often proven to be the case in the past with other nutrients and vitamins.

At present the published studies have yet to fully reveal an optimum dose for Vitamin K, although many experts feel 1000-5000 mcg (1 to 5 mg) would be in the ballpark. This intake lines up well with what has been found to be the case with respect to Japanese women who consume the K2-rich fermented soybean foodstuff called Natto along with dark green vegetables.

A daily intake of this much vitamin K can be achieved by eating a diet rich in green leafy vegetables and fermented soy foods such as Natto, and by using oral supplements rich in the main heart-healthy member of the K2 family, menaquinone-7 (MK-7). 

Readers are invited to check out 2 very high quality European K2-containing products: CARDIUM and BONEGENESIS

Larry M. Howard is President of Weller Health and co-author of “Health Benefits of Vitamin K2” (Basic Health Publications).