Four weeks of supplementation with 300 milligrams per day of vitamin K2 followed by another four weeks at 150 mg per day led to a 12% increase in maximal cardiac output, while there were also indications of benefits for heart rate and lactate levels, according to data published in Alternative Therapies in Health and Medicine.
“The current study’s finding of a 12% increase in maximal cardiac output might translate into an effect on endurance exercise capacity,” explained researchers from the University of North Texas. “Without the vitamin K2 supplement, training-induced changes in maximal cardiac output could take 6 to 9 months of continuous training to achieve. Supplementation with vitamin K2 during training may reduce that training window by approximately 60%.”
Sports and anti-aging
The study used Nu Science Trading's MenaquinGold Vitamin K2-7 product, and Kiran Krishnan, VP of science and business development at Nu Science Trading, welcomed the study's findings: "Based on mitochondrial work we have done with vitamin K2, we suspected that it may improve the function of the heart as a muscle," he told us. "The heart has the highest concentration of mitochondria in the body and K2 seems to improve the energy output from the mitochondria, as was seen in unpublished research we completed in Texas. Using MenaquinGold Vitamin K2-7 in the study, we were excited to see a statistically significant improvement in cardiac output (power of the heart) with just 8 weeks of supplementation.
"We also believe that this has enormous anti-aging implications as one of the hallmarks of aging, is the continual drop in cardiac output as the heart muscle becomes weaker over time."
There are two main forms of vitamin K: phylloquinone (vitamin K1), which is found in green leafy vegetables such as lettuce, broccoli and spinach, and makes up about 90% of the vitamin K in a typical Western diet; and menaquinones (vitamins K2), which make up about 10% of Western vitamin K consumption and can be synthesized 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.
The new study, led by Brian McFarlin, PhD, FACSM, is reportedly the first to examine the potential of dietary supplements of vitamin K2 (MK-7) to boost the effectiveness of cardiovascular training.
“During strenuous training, you can have a decrease in some aspects of cardiovascular performance. This can a negative effect cardiac output, which in turn affects endurance type exercise performance (think mile run time). It appears that the K2 may slightly offset this normal downward trend. Thus, it could be beneficial to training,” explained Dr McFarlin in an email to NutraIngredients-USA.
The Denton, TX-based researchers recruited 26 males and female athletes and randomly assigned them to receive either placebo or the vitamin K2 supplements for eight weeks. All participants continued with the normal exercise habits throughout the study period.
The data indicated that vitamin K2 supplementation was associated with significant improvements in cardiac output, while there was a trend towards changes in heart rate and stroke volume, compared to the control group.
A “potentially interesting” trend was also observed for reduced levels of lactate in the blood in the vitamin K2 group, compared to placebo.
Despite the promising results, the researchers urged caution when interpreting the findings, pending additional studies to validate the observations.
“The inclusion of the placebo group and its lack of change does help; however, more mechanistic work is likely needed, perhaps within an animal or cell culture model to measure changes in cardiac myocyte ATP production before and after supplementation/exposure to vitamin K2,” they wrote.
Dr McFarlin confirmed that researchers plan to do a follow-up study with untrained individuals and use this as a component of training, but this would rely on securing funding for the study.
“We want to test it further in patients who are starting a training program for the first time,” he added.
Source: Alternative Therapies in Health and Medicine
Volume 23, Number 4, Pages 26-32, doi:
“Oral Consumption of Vitamin K2 for 8 Weeks Associated With Increased Maximal Cardiac Output During Exercise”
Authors: A.L. Henning et al.