Vitamins D and K are both fat-soluble vitamins and play a central role in calcium metabolism. Vitamin D promotes the production of vitamin K-dependent proteins, which require vitamin K for carboxylation in order to function properly.
Vitamin D is a cofactor in many metabolic functions, such as; protects fat cells from becoming insulin resistant, it lifts our moods, it can protect against prostate cancer, it modulates our immune system, and it increases the absorption of calcium. It’s found in fatty fish, dairy products, and eggs, but is mainly synthesized by the human skin when exposed to sunlight.
In the liver, it is converted to 25(OH)D, the main circulating vitamin D metabolite, and this is what’s measured in your lab tests. From the liver, it goes to the kidneys and is converted to its full biological most active form 1,25-dihydroxyvitamin D (1,25(OH)D), also known as calcitriol.
Osteocalcin, also known as bone gamma-carboxyglutamic acid-containing protein, is a small non-collagenous protein hormone found in bone and dentin, first identified as a calcium-binding protein in chick bone. The synthesis of osteocalcin is vitamin K dependent.
Vitamin K2, menaquinone, is mainly found in fermented dairy and produced by lactic acid bacteria in the intestine. It has been described as a key element in the preservation of bone health, given that it plays an integral role in the gamma-carboxylation of osteocalcin, and promotes the integration of calcium into the bone. It also maintains the coagulation function, so when antibiotics are overused, it destroys Vitamin K (easy bruising).
Vitamins D and K in Diabetes
It may improve insulin metabolism through an effect on upregulation of the insulin receptor genes, the regulation of insulin secretion from the pancreatic beta-cell, the enhancement of β-cell proliferation, and suppression of parathyroid hormone (parathyroid function is releasing calcium from the bones=kidney stones).
Chronic hyperglycemia as a consequence of decreased insulin sensitivity, which contributes to bone demineralization and could also be related to changes in serum levels of osteocalcin and insulin, particularly when coupled with a deficiency in the daily consumption of vitamins D3 and K2.
Supplementation of vitamin K2 has been shown to reduce the risk of diabetes development, that just 10 µg/day of K2 decreases diabetes risk by 7%.
Taken together, animal and human studies suggest that optimal concentrations of both vitamin D and vitamin K are beneficial for bone, diabetes, and cardiovascular health as supported by genetic, molecular, cellular, and some human studies.
Take away Vitamin D and K work together, where vitamin K2 integrates calcium into the bones, vitamin D increases the absorption of calcium. Remember they are both “fat-soluble” vitamins so “less is more”. The best plan is to have both your Vitamin D and K checked before you dive in.
Effect of supplementation with vitamins D3 and K2. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7436967/
The Synergistic Interplay between Vitamins D and K