Het belang van voldoende vitamine K tegen het ouder worden*
Volgens een Amerikaanse studie is het regelmatig eten van groene bladgroenten en andere groenten rijk aan
vitamine K erg belangrijk ter voorkoming van allerlei ouderdomsziektes zoals
botontkalking, aderverkalking, hart- en vaatziekte en zelfs kanker. Vitamine K is betrokken bij wel 16 proteďnes. Bijna de helft daarvan is betrokken bij de bloedstolling doch de andere zijn betrokken bij het voorkomen van de ouderdomsziektes. Steeds meer wetenschappers constateren dat mensen te weinig vitamine K binnen krijgen zeker als ook nog eens antistollingsmiddelen (bloedverdunners) worden gebruikt.
Scientists find lack of vitamin K could cause age-related diseases
Here's a compelling reason to eat a variety of green, leafy vegetables regularly, including cabbage, cauliflower, Swiss chard and spinach: they could slow down the aging process and prevent a host of serious, life threatening diseases. The veggies' secret? These foods are rich sources of vitamin K. And a new analysis of dietary intakes of this nutrient strongly suggests that adequate amounts of vitamin K may prevent a wide range of age-related conditions such as weak bones, arterial and kidney calcification, cardiovascular disease and even
cancer.
The study, conducted by Children's Hospital Oakland Research Institute scientists Joyce McCann, PhD, and Senior Scientist, Bruce Ames, PhD, involved reviewing data from hundreds of published articles dating back to the 1970's. Dr. Ames has been on the trail of how vitamins and other micronutrients positively affect health for years. In fact, back in 2006 he proposed his "triage" theory which states diseases associated with aging like cancer, heart disease and dementia -- as well as the rate of the aging process itself -- may be unintended consequences of mechanisms developed during evolution in order to protect humans when there were shortages of vitamin and mineral rich
foods.
The new analysis, slated for publication in the American Journal of Clinical Nutrition, strongly supports this theory and could have huge implications for preventive medicine because Dr. Ames believes even modest vitamin and mineral deficiencies, which are common, could result in age-related illnesses. His theory calls for a new scientifically based and consistent strategy for establishing what vitamin and mineral intakes are truly optimal and for looking for early biomarkers of chronic disease.
"Encouraging support for the triage theory from our vitamin K analysis suggests that experts aiming to set micronutrient intake recommendations for optimal function and scientists seeking mechanistic triggers leading to diseases of aging may find it productive to focus on micronutrient-dependent functions that have escaped evolutionary protection from deficiency," Dr. McCann said in a statement to the media.
Dr. Ames and Dr. McCann have announced plans to conduct a series of scientific literature-based reviews to test the basic ideas behind the triage theory. Their goal is to document how micronutrients may help halt disease. In a press release, a reviewer of the current vitamin K analysis stated it "...provides a unique perspective of consequences of vitamin K insufficiency and may serve as an important future reference, as new vitamin K dependent proteins are identified and new (non-clotting) functions of vitamin K are elucidated. More broadly, an assessment of micronutrient sufficiency from the perspective of triage theory may provide a valuable point of view, as current recommendations for nutrient intakes are reconsidered."
Vitamin K is a fat-soluble vitamin derived from the German word "koagulation", which refers to the fact the vitamin is essential for blood clot coagulation. However, while about half of the 16 known proteins that depend on vitamin K are necessary for blood coagulation, other vitamin K-dependent proteins are involved in a variety of different functions involving the skeletal, arterial, and immune
systems.
The new analysis by Dr. McCann and Dr. Ames supports what many nutrition experts have claimed for years: higher intakes of vitamin K are needed for health than are currently recommended by mainstream medicine.
Vitamin K, an example of triage theory: is micronutrient inadequacy linked to diseases of aging?1,2,3
Joyce C McCann and Bruce N Ames
1 From the Children's Hospital Oakland Research Institute, Oakland, CA.
2 Supported by the Bruce and Giovanna Ames Foundation and by a generous donation from Elizabeth B and J Burgess Jamieson.
3 Address correspondence to JC McCann or BN Ames, Children's Hospital Oakland Research Institute, 5700 Martin Luther King Jr Way, Oakland, CA 94609. E-mail: jmccann@chori.org or bames@chori.org.
adstract:
The triage theory posits that some functions of micronutrients (the 40 essential vitamins, minerals, fatty acids, and amino acids) are restricted during shortage and that functions required for short-term survival take precedence over those that are less essential. Insidious changes accumulate as a consequence of restriction, which increases the risk of diseases of aging. For 16 known vitamin K–dependent (VKD) proteins, we evaluated the relative lethality of 11 known mouse knockout mutants to categorize essentiality. Results indicate that 5 VKD proteins that are required for coagulation had critical functions (knockouts were embryonic lethal), whereas the knockouts of 5 less critical VKD proteins [osteocalcin, matrix Gla protein (Mgp), growth arrest specific protein 6, transforming growth factor β–inducible protein (Tgfbi or βig-h3), and periostin] survived at least through weaning. The VKD -carboxylation of the 5 essential VKD proteins in the liver and the 5 nonessential proteins in nonhepatic tissues sets up a dichotomy that takes advantage of the preferential distribution of dietary vitamin K1 to the liver to preserve coagulation function when vitamin K1 is limiting. Genetic loss of less critical VKD proteins, dietary vitamin K inadequacy, human polymorphisms or mutations, and vitamin K deficiency induced by chronic anticoagulant (warfarin/coumadin) therapy are all linked to age-associated conditions: bone fragility after estrogen loss (osteocalcin) and arterial calcification linked to cardiovascular disease (Mgp). There is increased spontaneous cancer in Tgfbi mouse knockouts, and knockdown of Tgfbi causes mitotic spindle abnormalities. A triage perspective reinforces recommendations of some experts that much of the population and warfarin/coumadin patients may not receive sufficient vitamin K for optimal function of VKD proteins that are important to maintain long-term health.
American Journal of Clinical Nutrition, doi:10.3945/ajcn.2009.27930 (November
2009)
