Oral treatment with alpha-lipoic acid improves symptomatic diabetic polyneuropathy: the SYDNEY 2 trial.
Diabetes Care 2006 Nov;29(11):2365-70.
FRCPE, Deutsche Diabetes-Klinik, Deutsches Diabetes-Zentrum, Leibniz-Institut an der Heinrich-Heine-Universitat, Auf'm Hennekamp 65, 40225 Dusseldorf, Germany. dan.ziegler@ddz.uni-duesseldorf.de
OBJECTIVE: The aim of this trial was to evaluate the effects of alpha-lipoic acid (ALA) on positive sensory symptoms and neuropathic deficits in diabetic patients with distal symmetric polyneuropathy (DSP).
RESEARCH DESIGN AND METHODS: In this multicenter, randomized, double-blind, placebo-controlled trial, 181 diabetic patients in Russia and Israel received once-daily oral doses of 600 mg (n = 45) (ALA600), 1,200 mg (n = 47) (ALA1200), and 1,800 mg (ALA1800) of ALA (n = 46) or placebo (n = 43) for 5 weeks after a 1-week placebo run-in period. The primary outcome measure was the change from baseline of the Total Symptom Score (TSS), including stabbing pain, burning pain, paresthesia, and asleep numbness of the feet. Secondary end points included individual symptoms of TSS, Neuropathy Symptoms and Change (NSC) score, Neuropathy Impairment Score (NIS), and patients' global assessment of efficacy.
RESULTS: Mean TSS did not differ significantly at baseline among the treatment groups and on average decreased by 4.9 points (51%) in ALA600, 4.5 (48%) in ALA1200, and 4.7 (52%) in ALA1800 compared with 2.9 points (32%) in the placebo group (all P <>/=50% reduction in TSS) were 62, 50, 56, and 26%, respectively. Significant improvements favoring all three ALA groups were also noted for stabbing and burning pain, the NSC score, and the patients' global assessment of efficacy. The NIS was numerically reduced. Safety analysis showed a dose-dependent increase in nausea, vomiting, and vertigo.
CONCLUSIONS: Oral treatment with ALA for 5 weeks improved neuropathic symptoms and deficits in patients with DSP. An oral dose of 600 mg once daily appears to provide the optimum risk-to-benefit ratio.
PMID: 17065669 [PubMed - indexed for MEDLINE]
Sunday, December 17, 2006
Saturday, December 16, 2006
Almonds protect against damage to cells caused by increase in blood sugar
Almonds lower the risk of oxidative damage to proteins by limiting blood glucose changes after a meal and by providing antioxidants; these actions may also underlie the link between consumption of nuts and decreased risk of coronary heart disease, according to researchers at the Division of Endocrinology and Metabolism, St. Michael's Hospital here.
Fifteen healthy subjects ate two control meals consisting of bread, and three test meals: almonds and bread; parboiled rice; and instant mashed potatoes—all balanced in carbohydrate, fat and protein (using butter and cheese). Researchers obtained blood samples at baseline and again four hours after eating (postprandial). Data from the three meals were pooled (P = 0.021); glycemic indices for rice (38) and almond meals (55) were less than for the potato meal (94; P < 0.003), as were the post meal areas under the insulin concentration time curve (P < 0.001).
No post-meal treatment differences were seen in total antioxidant capacity, however, the serum protein sulfhydryl group (thiol) concentration increased following the almond meal (15 mmol/L), indicating less oxidative protein damage; and decreased after the control bread, rice, and potato meals (–10 mmol/L). The change in protein thiols was also negatively related to the post-meal incremental peak glucose (P = 0.026) and peak insulin responses (P = 0.046). Researchers concluded almonds likely lower the risk of oxidative damage to proteins by decreasing the glycemic excursion and by providing antioxidants. They also noted these actions may relate to a decreased risk of CHD. The study was published in the Journal of Nutrition (136: 2987-2992, 2006).
Fifteen healthy subjects ate two control meals consisting of bread, and three test meals: almonds and bread; parboiled rice; and instant mashed potatoes—all balanced in carbohydrate, fat and protein (using butter and cheese). Researchers obtained blood samples at baseline and again four hours after eating (postprandial). Data from the three meals were pooled (P = 0.021); glycemic indices for rice (38) and almond meals (55) were less than for the potato meal (94; P < 0.003), as were the post meal areas under the insulin concentration time curve (P < 0.001).
No post-meal treatment differences were seen in total antioxidant capacity, however, the serum protein sulfhydryl group (thiol) concentration increased following the almond meal (15 mmol/L), indicating less oxidative protein damage; and decreased after the control bread, rice, and potato meals (–10 mmol/L). The change in protein thiols was also negatively related to the post-meal incremental peak glucose (P = 0.026) and peak insulin responses (P = 0.046). Researchers concluded almonds likely lower the risk of oxidative damage to proteins by decreasing the glycemic excursion and by providing antioxidants. They also noted these actions may relate to a decreased risk of CHD. The study was published in the Journal of Nutrition (136: 2987-2992, 2006).
Fish and whole grains provide protection from asthma
An increased consumption of whole grains and fish could reduce the risk of developing asthma by about 50 per cent, suggests a new study from The Netherlands.The International Study on Allergy and Asthma in Childhood 2 (ISAAC-2) looked at dietary intakes for a range of foods, including fish, fruits, vegetables, dairy and whole grain products, for 598 Dutch children aged between 8 and 13.
“Our findings suggest that a high intake of whole grain products and fish may have a protective effect against asthma in children,” wrote lead author Cora Tabak in the current issue of the journal Thorax.
According to the European Federation of Allergy and Airway Diseases Patients Association (EFA), over 30m Europeans suffer from asthma, costing Europe €17.7bn every year. The cost due to lost productivity is estimated to be around €9.8bn.
The condition is on the rise in the Western world and the most common long-term condition in the UK today. According to the American Lung Association, almost 20m Americans suffer from asthma. The condition is reported to be responsible for over 14m lost school days in children, while the annual economic cost of asthma is said to be over $16.1bn. “The rise in the prevalence of asthma in western societies may be related to changed dietary habits,” said Tabak.
The researchers, from the Dutch National Institute of Public Health and the Environment, Utrecht University, University Medical Center Groningen, used semi-quantitative food frequency questionnaires completed by the children’s parents to assess dietary intakes for a range of food items. Data on asthma and wheezing were also assessed using questionnaires, and also from medical tests.
Tabak and co-workers report that intake of fruits, vegetables, and dairy products were not associated with asthma, a result that is at odds with other studies that supported a link between antioxidant intake, particularly vitamins C and E, to the incidence of asthma.
However, both whole grains and fish were related to asthma incidence, said the researchers. In children with a low intake of both foods, the prevalence of wheezing was almost 20 per cent, but this was significantly less in children with a high intake of both foods (4.2 per cent wheezing prevalence). Low intake of fish and whole grains was also linked to a higher prevalence of current asthma (16.7 per cent) compared to high intake of both foods (2.8 per cent).
After adjusting the results for possible confounding factors, such as the educational level of the mother, and total energy intake, Tabak reports that high intakes of whole grains and fish were associated with a 54 and 66 per cent reduction in the probability of being asthmatic, respectively. The probability of having asthma with bronchial hyperresponsiveness (BHR), defined as having an increased sensitivity to factors that cause narrowing of the airways, was reduced by 72 and 88 per cent when children had a high-intake of whole grains and fish, respectively.
Additional research is needed to further investigate the potential link between fish and whole grain intake, as well as the reason why no relationship between fruit and vegetable intake was observed, in contradiction to other studies.
A study published earlier this year in the journal Chest (Vol. 129, No. 1, pp. 39-49)also reported alink between fish intake and protection against exercise-induced bronchoconstriction (EIB) in asthma sufferers. EIB is a temporary narrowing of the airways that can be triggered by vigorous exercise measured changes in a variety of markers that together appeared to contribute.
The team of researchers, from Indiana and Wales, reported a decrease in the levels of the inflammatory marker leukotriene LTB4, proinflammatory cytokines, and a partial replacement of arachidonic acid (AA) in inflammatory cell membranes.
Source: Thorax>br> Volume 61, Pages 1048-1053, doi:10.1136/thx.2005.043034“Diet and asthma in Dutch school children (ISAAC-2)”Authors: C. Tabak, A.H. Wijga, G. de Meer, N.A.H Janssen, B. Brunekreef and H.A. Smit
“Our findings suggest that a high intake of whole grain products and fish may have a protective effect against asthma in children,” wrote lead author Cora Tabak in the current issue of the journal Thorax.
According to the European Federation of Allergy and Airway Diseases Patients Association (EFA), over 30m Europeans suffer from asthma, costing Europe €17.7bn every year. The cost due to lost productivity is estimated to be around €9.8bn.
The condition is on the rise in the Western world and the most common long-term condition in the UK today. According to the American Lung Association, almost 20m Americans suffer from asthma. The condition is reported to be responsible for over 14m lost school days in children, while the annual economic cost of asthma is said to be over $16.1bn. “The rise in the prevalence of asthma in western societies may be related to changed dietary habits,” said Tabak.
The researchers, from the Dutch National Institute of Public Health and the Environment, Utrecht University, University Medical Center Groningen, used semi-quantitative food frequency questionnaires completed by the children’s parents to assess dietary intakes for a range of food items. Data on asthma and wheezing were also assessed using questionnaires, and also from medical tests.
Tabak and co-workers report that intake of fruits, vegetables, and dairy products were not associated with asthma, a result that is at odds with other studies that supported a link between antioxidant intake, particularly vitamins C and E, to the incidence of asthma.
However, both whole grains and fish were related to asthma incidence, said the researchers. In children with a low intake of both foods, the prevalence of wheezing was almost 20 per cent, but this was significantly less in children with a high intake of both foods (4.2 per cent wheezing prevalence). Low intake of fish and whole grains was also linked to a higher prevalence of current asthma (16.7 per cent) compared to high intake of both foods (2.8 per cent).
After adjusting the results for possible confounding factors, such as the educational level of the mother, and total energy intake, Tabak reports that high intakes of whole grains and fish were associated with a 54 and 66 per cent reduction in the probability of being asthmatic, respectively. The probability of having asthma with bronchial hyperresponsiveness (BHR), defined as having an increased sensitivity to factors that cause narrowing of the airways, was reduced by 72 and 88 per cent when children had a high-intake of whole grains and fish, respectively.
Additional research is needed to further investigate the potential link between fish and whole grain intake, as well as the reason why no relationship between fruit and vegetable intake was observed, in contradiction to other studies.
A study published earlier this year in the journal Chest (Vol. 129, No. 1, pp. 39-49)also reported alink between fish intake and protection against exercise-induced bronchoconstriction (EIB) in asthma sufferers. EIB is a temporary narrowing of the airways that can be triggered by vigorous exercise measured changes in a variety of markers that together appeared to contribute.
The team of researchers, from Indiana and Wales, reported a decrease in the levels of the inflammatory marker leukotriene LTB4, proinflammatory cytokines, and a partial replacement of arachidonic acid (AA) in inflammatory cell membranes.
Source: Thorax>br> Volume 61, Pages 1048-1053, doi:10.1136/thx.2005.043034“Diet and asthma in Dutch school children (ISAAC-2)”Authors: C. Tabak, A.H. Wijga, G. de Meer, N.A.H Janssen, B. Brunekreef and H.A. Smit
Thursday, December 14, 2006
Beta Glucan Blunts Insulin Response After Eating
Consuming foods containing beta-glucan could reduce the insulin and glucose response after a meal, thereby easing a risk factor for diabetes and cardiovascular disease, says a new study.Lead researcher Dr. Kevin Maki told NutraIngredients.com that such a reduced response may translate into the blood pressure reduction observed in the obese/ high-BMI people participating in the study.
Dr. Maki, formely with Radiant Research, Chicago, and now with Provident Clinical Research, wrote in the European Journal of Clinical Nutrition: “The results of the present trial suggest beneficial effects of foods containing beta-glucan from oats on carbohydrate metabolism, and on blood pressure in obese subjects.”
Beta-glucan, a non-starch polysaccharide found in oats, has been the subject of increasing attention with some reports showing the soluble fibre can decrease LDL-C levels.
The new study, funded by the Quaker Oats Company, focussed on 97 men and women with systolic and/or diastolic blood pressure of 130–179 mmHg and 85–109 mmHg, respectively. The average age of the subjects was 60 and the average BMI was 32.4 kg per sq. m.
The subjects were randomly assigned to foods containing oat beta-glucan or control foods (maltodextrin) for 12 weeks in a double-blind, controlled design.
Peak insulin levels were found to have decrease after 12 weeks of consuming beta-glucan-containing foods, while the control group’s levels were not significantly changed, said the researchers.
Blood pressure was not changed significantly for the study population, they added. “However, in subjects with body mass index above the median (31.5 kg/m2), both systolic (8.3 mmHg) and diastolic (3.9 mmHg) blood pressures were lowered in the beta-glucan group compared to controls,” they said.
This is not the first time that blood pressure reductions have been reported following beta-glucan-containing foods. Indeed, a pilot study from 2002 by Joseph Keenan at the University of Minnesota reported that daily consumption of an oat cereal containing 5.5 grams per day of beta-glucan led to systolic and diastolic blood pressure reduction of 7.5 and 5.5 mmHg, respectively in moderately hypertensive men and women with high insulin levels (Journal of Family Practice, Vol. 51, p. 369).
No dietary differences between the beta-glucan group and the control group were documented at the start of the study, and as expected the total insoluble and soluble fibre intake of the beta-glucan group increased, compared to controls. Magnesium intake in the beta-glucan group also increased as a result of the higher magnesium in the beta-glucan-containing products. Dietary analysis also showed that sodium and calcium levels decreased, while potassium intakes increased.
Moreover the researchers state that, based on previous studies, it was unlikely that the blood pressure reduction observed in the obese people in this trial were exclusively to the changes in mineral levels.
Compliance amongst the beta-glucan groups was lower than the control group, said Maki, but this was more likely to be due to palatability of the products rather than tolerance.
“Additional research is needed to test [that alterations in carbohydrate homeostasis may have played a role] and define the mechansisms by which repeated consumption of viscous soluble fibre enhances the blunting of postprandial insulin response,” concluded the researchers.
Dr. Maki confirmed that research was continuing in this area with future focus likely to be on loger-term studies with people with documented insulin resistance.
Source: European Journal of Clinical NutritionPublished on-line ahead of print, doi: 10.1038/sj.ejcn.1602562“Effects of consuming foods containing oat beta-glucan on blood pressure, carbohydrate metabolism and biomarkers of oxidative stress in men and women with elevated blood pressure”Authors: K.C. Maki, R. Galant, P. Samuel, J. Tesser, M.S. Witchger, J.D. Ribaya-Mercado, J.B. Blumberg and J. Geohas
Dr. Maki, formely with Radiant Research, Chicago, and now with Provident Clinical Research, wrote in the European Journal of Clinical Nutrition: “The results of the present trial suggest beneficial effects of foods containing beta-glucan from oats on carbohydrate metabolism, and on blood pressure in obese subjects.”
Beta-glucan, a non-starch polysaccharide found in oats, has been the subject of increasing attention with some reports showing the soluble fibre can decrease LDL-C levels.
The new study, funded by the Quaker Oats Company, focussed on 97 men and women with systolic and/or diastolic blood pressure of 130–179 mmHg and 85–109 mmHg, respectively. The average age of the subjects was 60 and the average BMI was 32.4 kg per sq. m.
The subjects were randomly assigned to foods containing oat beta-glucan or control foods (maltodextrin) for 12 weeks in a double-blind, controlled design.
Peak insulin levels were found to have decrease after 12 weeks of consuming beta-glucan-containing foods, while the control group’s levels were not significantly changed, said the researchers.
Blood pressure was not changed significantly for the study population, they added. “However, in subjects with body mass index above the median (31.5 kg/m2), both systolic (8.3 mmHg) and diastolic (3.9 mmHg) blood pressures were lowered in the beta-glucan group compared to controls,” they said.
This is not the first time that blood pressure reductions have been reported following beta-glucan-containing foods. Indeed, a pilot study from 2002 by Joseph Keenan at the University of Minnesota reported that daily consumption of an oat cereal containing 5.5 grams per day of beta-glucan led to systolic and diastolic blood pressure reduction of 7.5 and 5.5 mmHg, respectively in moderately hypertensive men and women with high insulin levels (Journal of Family Practice, Vol. 51, p. 369).
No dietary differences between the beta-glucan group and the control group were documented at the start of the study, and as expected the total insoluble and soluble fibre intake of the beta-glucan group increased, compared to controls. Magnesium intake in the beta-glucan group also increased as a result of the higher magnesium in the beta-glucan-containing products. Dietary analysis also showed that sodium and calcium levels decreased, while potassium intakes increased.
Moreover the researchers state that, based on previous studies, it was unlikely that the blood pressure reduction observed in the obese people in this trial were exclusively to the changes in mineral levels.
Compliance amongst the beta-glucan groups was lower than the control group, said Maki, but this was more likely to be due to palatability of the products rather than tolerance.
“Additional research is needed to test [that alterations in carbohydrate homeostasis may have played a role] and define the mechansisms by which repeated consumption of viscous soluble fibre enhances the blunting of postprandial insulin response,” concluded the researchers.
Dr. Maki confirmed that research was continuing in this area with future focus likely to be on loger-term studies with people with documented insulin resistance.
Source: European Journal of Clinical NutritionPublished on-line ahead of print, doi: 10.1038/sj.ejcn.1602562“Effects of consuming foods containing oat beta-glucan on blood pressure, carbohydrate metabolism and biomarkers of oxidative stress in men and women with elevated blood pressure”Authors: K.C. Maki, R. Galant, P. Samuel, J. Tesser, M.S. Witchger, J.D. Ribaya-Mercado, J.B. Blumberg and J. Geohas
Monday, December 11, 2006
Vitamin K reverses artery calcification
12/11/2006- A high-dose vitamin K supplement reduced calcium precipitates associated with hardening of the arteries by 37 per cent in rats, scientists from The Netherlands have reported.If the results can be reproduced in humans, high-dose vitamin K could have potential clinical implications for reducing arterial calcification, which is an important independent risk factor for the development of cardiovascular disease (CVD).
“High vitamin K intake not only prevents calcification, but even regresses arterial calcifications,” lead researcher Leon Schurgers from Maastricht University told NutraIngredients.com.
There are two main forms of vitamin K: phylloquinone, also known as phytonadione, (vitamin K1) which is found in green leafy vegetables such as lettuce, broccoli and spinach, and makes up about 90 per cent of the vitamin K in a typical Western diet; and menaquinones (vitamins K2), which make up about 10 per cent of Western vitamin K consumption and can be synthesised in the gut by microflora.
Menaquinones (MK-n: with the n determined by the number of prenyl side chains) can also be found in the diet; MK-4 can be found in animal meat, MK-7, MK-8, and MK-9 are found in fermented food products like cheese, and natto is a rich source of MK-7.
Some sources have said that MK-4, also known as menatetrenone, is synthetic vitamin K2, which is not correct. However, MK-4 is distinct from other MKs because it not a major constituent of the spectrum of MKs produced by gut microflora, but can be derived from K1 in vivo.
A synthetic form of vitamin K, known as K3, does exist but is not recommended for human consumption. The new study, published on-line ahead of print in the journal Blood, is said to be the first in rats to show that arterial calcification (calcium build-up that produces hardening) and the subsequent decreased elasticity of the blood vessels may be reversible by high vitamin K intake.
"The medical community used to believe that calcification passively occurred in the end stages of cardiovascular disease," said Schurgers. "However, in the last 10 years we have learned that Vitamin K-dependent proteins are directly involved in the inhibition of vascular calcification, and that Vitamin K2 is necessary to activate these proteins. This study demonstrates a significant potential role for Vitamin K2 in cardiovascular health."
In the new study, the researchers induced arterial hardening in rats by interfering with vitamin K-metabolism, by adding the vitamin K-antagonist warfarin to the diets. Vitamin K is reported to act on a protein called matrix Gla-Protein (MGP), said to be the strongest inhibitor of arterial calcification.
Initially, the rats were divided into two groups, a control group with vitamin K added to the diet, and a warfarin treated group to induce calcification. After six weeks of treatment with warfarin, the researchers report that the rats showed signs of significant arterial hardening.
The warfarin treated rats were then further divided into four groups and assigned to one of four intervention groups for a further six weeks: a standard diet plus warfarin, a standard diet plus vitamin K1 at normal dose (5 micrograms per gram of food, purchased from Sigma), a standard diet plus high-dose vitamin K1 (100 micrograms per gram of food), or the standard diet plus high-dose vitamin K2 (MK-4, 100 micrograms per gram of food, gifted from Eisai, Japan).
Schurgers and his co-workers report that during the second six week period, the calcifications in the warfarin-treated control group continued linearly, as did the calcification in the normal dose vitamin K1 group, indicating that dietary vitamin K1 intake had no effect.
However, in both high-dose groups (K1 and K2) no continued calcification occurred, but the existing hardening was found to be reversed by about 40 per cent after six weeks of supplementation.
Interestingly, vitamin K2 concentration in the tissues of both groups were similar, which showed the vitamin K1 was converted into vitamin K2.
"The effect of K1 and the conversion rate of K1 to K2 was due to the extremely high dose of K vitamins used in this model,” said Schurgers. “This would be probably less in a normal diet, even with supplemental K1. In contrast, the Rotterdam study showed a significant protective benefit with Natural Vitamin K2 at just 45mcg per day, whereas K1 had no correlation at all."
The researchers also report that the reduced calcification was also accompanied by improved arterial elasticity in the high vitamin K groups to a similar level as in the control rats.
“In this study we provide evidence that warfarin-induced medial vascular calcification in rats is preventable or even reversible by high vitamin K intake, with a putative role for the vitamin K-dependent protein MGP,” wrote the researchers.
“Whether increased vitamin K intake could have such an effect in humans has to be investigated,” they concluded. “Obviously this is only possible in patients not receiving oral anticoagulant treatment.”
Source: Blood First Edition PaperPublished on-line ahead of print. doi: 10.1182/blood-2006-07-035345“Regression of warfarin-induced medial elastocalcinosis by high intake of vitamin K in rats”Authors: L.J. Schurgers, H.M.H. Spronk, B.A.M. Soute, P.M. Schiffers, J.G.R. DeMey, and C. Vermeer
“High vitamin K intake not only prevents calcification, but even regresses arterial calcifications,” lead researcher Leon Schurgers from Maastricht University told NutraIngredients.com.
There are two main forms of vitamin K: phylloquinone, also known as phytonadione, (vitamin K1) which is found in green leafy vegetables such as lettuce, broccoli and spinach, and makes up about 90 per cent of the vitamin K in a typical Western diet; and menaquinones (vitamins K2), which make up about 10 per cent of Western vitamin K consumption and can be synthesised in the gut by microflora.
Menaquinones (MK-n: with the n determined by the number of prenyl side chains) can also be found in the diet; MK-4 can be found in animal meat, MK-7, MK-8, and MK-9 are found in fermented food products like cheese, and natto is a rich source of MK-7.
Some sources have said that MK-4, also known as menatetrenone, is synthetic vitamin K2, which is not correct. However, MK-4 is distinct from other MKs because it not a major constituent of the spectrum of MKs produced by gut microflora, but can be derived from K1 in vivo.
A synthetic form of vitamin K, known as K3, does exist but is not recommended for human consumption. The new study, published on-line ahead of print in the journal Blood, is said to be the first in rats to show that arterial calcification (calcium build-up that produces hardening) and the subsequent decreased elasticity of the blood vessels may be reversible by high vitamin K intake.
"The medical community used to believe that calcification passively occurred in the end stages of cardiovascular disease," said Schurgers. "However, in the last 10 years we have learned that Vitamin K-dependent proteins are directly involved in the inhibition of vascular calcification, and that Vitamin K2 is necessary to activate these proteins. This study demonstrates a significant potential role for Vitamin K2 in cardiovascular health."
In the new study, the researchers induced arterial hardening in rats by interfering with vitamin K-metabolism, by adding the vitamin K-antagonist warfarin to the diets. Vitamin K is reported to act on a protein called matrix Gla-Protein (MGP), said to be the strongest inhibitor of arterial calcification.
Initially, the rats were divided into two groups, a control group with vitamin K added to the diet, and a warfarin treated group to induce calcification. After six weeks of treatment with warfarin, the researchers report that the rats showed signs of significant arterial hardening.
The warfarin treated rats were then further divided into four groups and assigned to one of four intervention groups for a further six weeks: a standard diet plus warfarin, a standard diet plus vitamin K1 at normal dose (5 micrograms per gram of food, purchased from Sigma), a standard diet plus high-dose vitamin K1 (100 micrograms per gram of food), or the standard diet plus high-dose vitamin K2 (MK-4, 100 micrograms per gram of food, gifted from Eisai, Japan).
Schurgers and his co-workers report that during the second six week period, the calcifications in the warfarin-treated control group continued linearly, as did the calcification in the normal dose vitamin K1 group, indicating that dietary vitamin K1 intake had no effect.
However, in both high-dose groups (K1 and K2) no continued calcification occurred, but the existing hardening was found to be reversed by about 40 per cent after six weeks of supplementation.
Interestingly, vitamin K2 concentration in the tissues of both groups were similar, which showed the vitamin K1 was converted into vitamin K2.
"The effect of K1 and the conversion rate of K1 to K2 was due to the extremely high dose of K vitamins used in this model,” said Schurgers. “This would be probably less in a normal diet, even with supplemental K1. In contrast, the Rotterdam study showed a significant protective benefit with Natural Vitamin K2 at just 45mcg per day, whereas K1 had no correlation at all."
The researchers also report that the reduced calcification was also accompanied by improved arterial elasticity in the high vitamin K groups to a similar level as in the control rats.
“In this study we provide evidence that warfarin-induced medial vascular calcification in rats is preventable or even reversible by high vitamin K intake, with a putative role for the vitamin K-dependent protein MGP,” wrote the researchers.
“Whether increased vitamin K intake could have such an effect in humans has to be investigated,” they concluded. “Obviously this is only possible in patients not receiving oral anticoagulant treatment.”
Source: Blood First Edition PaperPublished on-line ahead of print. doi: 10.1182/blood-2006-07-035345“Regression of warfarin-induced medial elastocalcinosis by high intake of vitamin K in rats”Authors: L.J. Schurgers, H.M.H. Spronk, B.A.M. Soute, P.M. Schiffers, J.G.R. DeMey, and C. Vermeer
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