Much has been written about vitamin D in recent years. As reported cases of vitamin D deficiency have been increasing in incidence, public awareness on just how crucial vitamin D is for overall health has been growing too.
Vitamin D is not just important for healthy bones. Identification of the vitamin D receptor (VDR) in nearly all tissue types throughout the body tells us that vitamin D has diverse and widespread effects on most aspects of health. Vitamin D is believed to play a crucial role in disease prevention and the maintenance of optimal health. Several large-scale meta-analyses have now demonstrated an association between low vitamin D levels and increased (all-cause) mortality rates. In simple terms, this means that optimal vitamin D levels have been found to be associated with a longer lifespan.1-8
Unlike other essential nutrients, our primary source of vitamin D isn’t food, it’s sunshine! Our skin is able to make vitamin D when it comes into contact with the sun’s rays.
With a distinct lack of sunshine however, especially in the colder months, supplementation is generally accepted to be the most effective way to increase levels of vitamin D in the UK. In fact, Public Health England now recommends that everyone should supplement their diet with vitamin D during autumn and winter, and those identified to be at higher risk should supplement all year round. However, as with most aspects of health, the story isn’t quite as simple as that. If you choose to supplement with vitamin D, you also need to consume in your food, or take in supplement form, vitamin K2.
Vitamin D & K2 May Slow Arterial Calcification
Vitamin D and Vitamin K2 work together to produce and activate Matrix GLA Protein (MGP). This is an important substance, found around the elastic fibres of your arterial lining. MGP helps to protect against the formation of calcium crystals, which can lead to arterial calcification. Current medical opinion suggests that supplementing with vitamin D and K2 together may help to slow the progression of arterial calcification, whereas vitamin D on its own may not.9-10
Professor Cees Vermeer, one of the world’s leading K2 researchers commented on this mechanism,
“The only mechanism for arteries to protect themselves from calcification is via the vitamin-K dependent protein MGP. MGP is the most powerful inhibitor of soft tissue calcification presently known, but non-supplemented healthy adults are insufficient in vitamin K to a level that 30% of their MGP is synthesized in an inactive form.”11
MK-7 – The most effective form of vitamin K2
There are several different forms of vitamin K2, one of which is MK-7, and this is generally accepted to be one of the most effective, since it has a much longer half life (3 days) than others. A longer half-life means it has a much better chance of building up a consistent blood level.
Vitamin K in the most effective form of MK-7 is found naturally in high amounts in a Japanese fermented soy product called natto, which may contain up to 1100 mcg of K2 per 100g. Since natto is not a common feature of a typical Western diet, supplementation may be necessary to ensure optimal intake, especially if you are also supplementing with vitamin D.
Some groups are more at risk of deficiency of vitamin K2 than others, these include:
• Pregnant women
• Elderly people
• Patients with impaired intestinal absorption such as with Crohn’s Disease, Cystic Fibrosis and Galactosemia – all of which have been linked to poor vitamin K status.
Vitamin K2 Research highlights:
• Bone health – Research has shown that the combination of vitamin K2 & vitamin D3 is more effective in preventing bone loss than either nutrient alone.13
• Bone mineral density (BMD) – Numerous studies have shown that low vitamin K causes reductions in bone mineral density (BMD) and increases fracture risk. Vitamin K2 supplementation has been shown to promote bone formation and lessen fracture risk.4-18
• Cardiovascular health – A large-scale European clinical trial following 4,807 subjects aged over 55 over a 7 - 10 year period found dietary intake of vitamin K2 to be protective against arterial calcification and cardiovascular death. None of these beneficial outcomes were observed with vitamin K1 intake.19
Complex Science – Simple Message
Whilst the science may be complex, the message is simple. If you’re thinking of supplementing with vitamin D, you also need to think about vitamin K2 too, and that’s particularly important if you’re more at risk of deficiency.
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3. Chowdhury R, Kunutsor S, Vitezova A et al. Vitamin D and risk of cause specific death: systematic review and meta-analysis of observational cohort and randomised intervention studies. BMJ. 2014 Epub ahead of print April 1, 2014:1–13
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