In a recent narrative review published in the Nutrients Journal, researchers explored how Vitamin K dietary supplementation could promote healthy aging.
Study: Vitamin K and Hallmarks of Ageing: Focus on Diet and Gut Microbiome. Image Credit: ratmaner/Shutterstock.com
Background
Dietary vitamin K is a diet-microbiome-health axis modulator; thus, researchers are pursuing evidence of how it impacts the gut microbial composition and metabolic activities implicated with host health outcomes, especially in the older adults of the general population.
People aged >60 years outnumbered children below five years in 2020, and this aged population will nearly double to 2.1 million, outnumbering young people by 2050.
Thus, there is an urgent need to implement lifestyle interventions that could effectively reduce, prevent, or reverse aging-related chronic diseases and physiological perturbations.
Role of a diet containing Vitamin K in healthy aging
Diet or food pattern is a strong determinant of optimum human health. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019 showed that poor diet, i.e., low in vegetables/fruits, whole grains and high in processed foods, sugar, and sodium, is the second and third risk factor for death in 13.5% and 14.6% females and males globally.
Similarly, the EAT-Lancet Commission advocated that shifting from an industrialized to a plant-based diet could avert about 11 million deaths.
The impact of healthy eating as a preventive and therapeutic strategy to combat aging could be immense. The gut microbiome is another key factor mediating the relationship between diet and age-related health.
Thus, unraveling the interplay between diet, the gut microbiome, and host health could help devise a wholesome strategy to promote healthy aging and decrease the gap between health and life spans.
Green vegetables are the primary source of dietary vitamin K or vitamin K1 (phylloquinone). Convenience food, e.g., burgers, pizza, french fries, etc., comprises other sources of phylloquinone, mainly due to phylloquinone-rich vegetable oils used during their preparation, suggesting an underestimation of dietary vitamin K1 intake in current food consumption data pools.
While vitamin K1 is a dietary source of vitamin K, menaquinones or Vitamin K2 is a byproduct of gut microbiome biosynthesis. Cheese, a rich source of saturated fats, is another good source of K2.
Since ready meal-derived phylloquinone might have greater bioavailability than phylloquinone derived from fresh fruits\vegetables, fundamental questions regarding the dietary source and bioavailability of phylloquinone and menaquinones remain unanswered.
Observational studies and randomized controlled trials (RCTs) investigating the role of vitamin K in age-related diseases have yielded inconsistent results. Elucidating the link between diet and health, for instance, portion size estimation, could help resolve these equivocal findings from epidemiological studies evaluating vitamin K nutrient intake through dietary recall.
Though studies have implicated many other bioactive compounds in research on aging, observational studies have discovered that Vitamin K and Vitamin K-dependent proteins (VKDPs) are associated with a large spectrum of age-related diseases. Yet, evidence for the direct impact of vitamin K on cellular senescence remains unknown.
Though the salutogenic impact of vitamin K on human health remains unclear, studies have established its effect on hallmarks of aging, such as genomic instability, cellular senescence, mitochondrial dysfunction, and epigenetic dysregulation.
Vitamin K drives cellular and macromolecular aging processes via direct uptake of reactive oxygen species (ROS) and mitigating its damage. Its anti-inflammatory activity also arrests chronic low-level inflammatory burdens accompanying aging. Furthermore, vitamin K inhibits nuclear factor kappa B (NF-кB) activity.
The human body stores small amounts of vitamin K, and its reserves deplete quickly in the lack of dietary supplementation. However, intriguingly, the human body has a vitamin K recycling system that enables the utilization of small amounts of vitamin K in the γ-carboxylation of VKDPs and minimizes the adverse effects of insufficient dietary intake of Vitamin K.
VKDPs are involved in various pathophysiologic pathways, e.g., prothrombin is a VKDP of the coagulation system, and extrahepatic Gla proteins, such as matrix Gla protein (MGP) play an essential role in bone and vascular health.
Furthermore, diet-derived K1 or K2 could help combat Alzheimer's disease (AD) in older adults. Thus, adherence to good quality food could improve well-being and promote healthy aging.
Conclusions
The researchers highlighted the need to acknowledge several critical caveats regarding the interplay between diet, vitamin K, gut microbiome, and host health that is pivotal for elucidating the role of vitamin K in aging.
Investigations into vitamin K and its role in human aging and age-related dysfunctions are progressing exponentially. Future studies on the clinical impact of vitamin K on human health might help elucidate some of the conflicting results from clinical trials regarding vitamin K supplements and health outcomes, neglecting the gut microbiome profile.
So, while healthy food pattern is crucial in determining vitamin K intake and its impact on human health, a thorough consideration of the interplay between diet-microbiome needs to be implemented to evaluate vitamin K's impact on human health.
Interestingly, the total vitamin K intake may remain unaltered with a reduced healthy food intake and be compensated by an unhealthy food source.
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