Vitamin D3 and K2 Taken May Benefit Health and Performance
Vitamin D has been praised for its ability to improve bone health, immune function, and hormone balance. Learn how taking vitamin D3 and K2 may benefit health and performance.
What are D3 and K2 Vitamins
Vitamin D3 and K2 are essential nutrients needed for optimal health.
Vitamin D is a fat-soluble vitamin also known as calciferol. It comes in two main forms D2 ergocalciferol (D2) and cholecalciferol (D3) [R].
Ergocalciferol (D2) vs Cholecalciferol (D3)
Cholecalciferol (D3) is made in mammals and fish. Humans make D3 from absorbing the sun's UV rays. When the sun touches human skin it produces D3
D2 and D3 Need Convert to Active Vitamin D
Both D2 and D3 need to be activated for vitamin D levels to increase blood levels. First the liver metabolizes D2 and D3 into 25-hydroxyvitamin D (25OHD). The kidneys then convert 25OHD into the active form 1,25-dihydroxy vitamin D also known as calcitriol.
Often vitamin D status will be measured as 25OHD but can also be in the active calcitriol form of the vitamin [R]. Calcitriol is needed for hormone production, muscle function, blood sugar regulation, and immune function [R].
Vitamin K2 is a subset of the fat-soluble vitamin K.
MK-7 vs. MK-4
There are about 13 types of K2 but the most common forms are the menaquinone-7 (MK-7) and menaquinone-4 (MK-4).
MK-7 appears to be the more active form. MK-7 has been detected within 48 hours of consumption while MK-7 supplementation did not increase serum MK-4 levels [R].
Vitamin D3 and K2 Health Benefits
Vitamin D3 and K2 have been studied for their possible improvements on health.
Vitamin D3 Health Benefits
Vitamin D3 may improve sleep along with immune function, cardiovascular, blood sugar regulation, and bone health.
Low and insufficient levels of vitamin D have been associated with a higher risk of heart disease [R].
Vitamin D has been found to regulate blood pressure and prevent cardiac enlargement in mice [R].
Low vitamin D has been associated with calcium deposits within arteries. This calcification can lead to poor heart hearth. The right balance of just enough vitamin D may be needed to reverse this process [R].
Vitamin D has been found to prevent atherosclerosis in mice by preventing oxidation of immune cells [R].
Blood Sugar Regulation
Higher levels of vitamin D were associated with better blood sugar regulation [R].
Supplementation has also been shown to improve blood sugar levels in those who are deficient [R].
Those with higher vitamin D levels had a lower risk for diabetes [R].
Vitamin D is needed for calcium absorption to improve the health of bone.
Low vitamin D may cause bone fractures even in healthy young men and women. Stress fractures of the tibia and fibula may be prevented with blood levels of 40 ng/mL or greater. This can be accomplished with intakes of 2,000 to 4,000 IU of vitamin D3 [R, R].
Sleep disorders can be cause by vitamin D deficiency. Supplementation may help elsseon these condtions [R].
Veterans deficient in vitamin D trouble were found to have longer sleep durations after taking 50,000 IU per week for six months [R].
Those with sleeping disorders had longer and better quality sleep when supplementing with 50,000 IU once every two weeks for two months [R].
Increased risk of illness and infection has been seen with low levels of vitamin D [R].
Immune cells need vitamin D to function. Autoimmunity and inflammation may be prevented with vitamin D3 [R].
A supplement of 1,200 IU of vitamin D per day for four months reduced the flu infection in children when compared with a placebo [R].
K2 Health Benefits
Vitamin K2 health benefits include cardiovascular health, bone health, and immune function
Vitamin K2 may protect from heart disease risk.
Higher intake of K2 was associated with a lower risk of coronary heart disease, death, and arterial calcifications [R].
Vitamin has been associated with better bone health and reduced fractures.
MK-7 from fermented soybeans stimulates bone growth and remineralizes bone [R].
Vitamin K2 may improve bone quality and reduce fractures in conjunction with calcium and vitamin D. One fracture is reduced by 25% with the daily intake of 800 IU of vitamin D, 45 micrograms vitamin K2, and 1200 mg calcium [R].
K2 is thought to increase bone strength. Taking 45 mg of K2 per day significantly reduced hip, vertebral, and non-vertebral fractures [R].
K2 is thought to reduce markers for inflammation related to disease and aging
When added to cell cultures MK-7 had immunoprotective effects by producing immune fighting cells and preventing the production of inflammatory markers [R].
Vitamin D3 As a Performance Vitamin
Muscle mass is critical for performance. Adequate levels of vitamin D are needed for optimal muscle function [R].
Levels between 30 and 50 ng/mL have been shown to increase muscle protein synthesis, ATP concentration, strength, jump height, jump velocity, jump power, exercise capacity, and physical performance. Inflammation, pain and weakness are also reduced at this level [R].
Supplementation of vitamin D improves blood levels of 25OHD in deficient athletes and trainers. Especially those living in northern climates and practice indoors during winter months [R].
Doses of 2,000 and 5,000 IUs of vitamin D3 given over two and four month periods were found to improve muscle function and prevent injury in vitamin D deficient athletes when compared with a placebo [R, R, R].
Other studies found doses between 20,000 and 40,000 IUs were not effective for improving muscle function. [R].
Athletes and trainers may benefit from a D3 supplement if they are deficient in this vitamin.
Vitamin K2 As a Performance Vitamin
Endurance relies on cardiac output [R]. Vitamin K2 has been shown to improve cardiovascular function and prevent injury in active individuals.
Skeletal and cardiac muscle function may be improved with K2 supplements. Male and female athletes given K2 supplement over an 8 week period (300 mg per day for the first four weeks, then 150 mg for the last four weeks) had a 12% increase in cardiac output than those receiving a placebo [R].
Other research on vitamin K2 and performance has been focused on the correlation between injury and low vitamin levels.
Lower intakes of nutrients important for bone health like K2 were found to be lower in all but one of the 16 collegiate athletes who sustained sports fractures [R].
Nine out of 71 professional Japanese baseball players aged 18 to 39 year old were found to have low levels of phylloquinone despite getting an adequate daily intake of vitamin K [R].
The full benefits of Vitamin K2 and perfrance are still unknown.
Benefits of Taking Vitamin D3 and K2 Together
Separately vitamin D3 and K2 provide an abundance of nutrition and benefits for health. Together their benefits may be enhanced due to the synergy of their effects on both cardiovascular and bone health [R].
What to Look for in a Vitamin D3 and K2 supplement
Vitamin supplements are not regulated so looking for a supplement that is from a reputable company and is third-party tested. Look for a product that is free of contaminants, additives, and fillers.
Sources of Vitamin D3 and K2
If you are looking for other ways to amp up your intake of vitamin D3 and K2 you can also get these natural sources.
Vitamin D3 Sources
Vitamin D can be found in food and also can be made by the sun.
Vitamin D3 and the Sun
The sun is the best source of vitamin D. Getting 10 to 15 minutes of sunlight with no sunscreen will give you a day’s worth of Vitamin D. Thanks to our bodies’ ability to convert it into its active form.
Vitamin D3 In Food
Food is also where you will find vitamin D. Recently a lot of foods have been fortified with vitamin D to address the problem of deficiency within the population.
Take caution with these foods. Often they contain D2 and may not be as effective. They can also be overly processed and high in sugar or unhealthy fats.
The best foods to get vitamin D include the following:
- Beef liver
- Cod and cod liver oil
- Egg yolk
- Swiss cheese.
Vitamin K2 Sources
Vitamin K2 can be made in the body from K1 but it may not be enough to meet the needs of this nutrient. Luckily, some foods contain this vitamin that can be added to the diet. They include animal products and fermented foods:
- High-fat dairy products from grass-fed cows
- Egg yolks
- Organ meats
- Hard cheeses
- Soft cheeses
- Dark Chicken Meat
How to Take Vitamin D3 and K2
Vitamin D3 Dosage
Research shows a dose of 1,000 to 2,000 International Units (IU) of D3 per day should meet the needs of most people. Vitamin D is better absorbed when taken with a source of dietary fat [R].
Vitamin D3 supplements come in both liquid and pill form. Liquid D3 is often mixed with olive oil for better absorption. Those with digestive issues may benefit from taking a liquid form of this vitamin.
Vitamin D has been known to cause toxicity when taken in high doses. That is why an upper limit has been imposed. It is recommended not to exceed 4,000 IU a day.
Newer research indicates 10,0000 IU of vitamin D had no signs of toxicity in healthy individuals. Unless under the direction of a health professional it is best to not exceed the recommended upper-level intake. [R, R].
Vitamin K2 Dosage
The MK-7 appears to be more readily absorbed in humans when compared with the MK-4 form of K2.
MK-4 was found to be effective in healthy subjects at higher doses of at least 1500 micrograms per day [R].
Dosages of MK-7 increased K2 at levels between 45 and 90 micrograms a day [R].
MK-7 may induce blood clotting in some individuals with excessive blood clotting at doses as little as 10 micrograms [R].
It may be best to start with a lower dose of MK-7 or consult with a specialist who can help you find the right dose.
Side Effects of D3 and K2 Supplements
Like any supplements there can be side effects when taking vitamin D3 and K2.
Side Effects of D3
Side effects are rare unless the intake is excessive. It usually occurs in those taking high dosing for long periods. Side effects include the following [R]:
- Loss of appetite
- Dry Mouth
- Metallic taste
- High calcium levels
- High blood pressure
- Digestive issues (stomach pain, constipation, diarrhea)
Side Effects of K2
Upset stomach or diarrhea may occur but most people have not had any adverse side effects when taking the recommended doses.
No toxic effects were seen in mice given lethal doses of MK-7 (greater than 2000 mg per kg of body weight). Other research indicates there is no adverse effect on humans so no limit has been posed [R, R].
Contraindications of D3 and K2 Supplements
For some individuals, there are risks to taking vitamin D3 and K2 supplements. If you have medical issues it is best to check with your healthcare provider before taking these supplements.
Contraindications of D3 and K2 Supplements
Supplementation of vitamin D is not recommended for those with [R] :
- Elevated phosphate levels
- High calcium levels
- High vitamin D levels
- Kidney stones or decreased kidney function
- Artery blockages (arteriosclerosis obliterans)
Medications that have been found to interact with vitamin D3 and K2 include:
Final Thoughts on Vitamin D3 and K2 Vitamins
Low levels of vitamins D and K2 can negatively affect overall health. Decreased levels have also been tied to poor muscle function which can impact performance. Athletes and high endurance trainers deficient in these vitamins may benefit from supplementation. Though side effects are rare it is best to start with a low dose to prevent toxicity and side effects. Those with health issues or on medications should ask their doctor before taking vitamin D3 and K2.
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