According to the National Center for Biotechnology Information:
"Vitamin D deficiency is a global public health issue. About 1 billion people worldwide have vitamin D deficiency."
Vitamin D3 deficiency is a growing concern amongst modern day society. In general, people are spending more time indoors than ever before which limits their body's exposure to natural sunlight. Studies show that between 50% and 90% of vitamin D is absorbed through the skin via sunlight while the rest comes from the diet. People are also using more sunscreen now more than ever before. Obviously there is a fine line between protecting your skin and avoiding sunburn, however, this is an added barrier of entry for sunlight. Anything that blocks UVB rays (such as sunscreen) will prevent your skin from making a sufficient amount of vitamin D3.
The obesity epidemic has also played a huge role in vitamin D deficiency. Vitamin D3 is fat-soluble, which simply means it is stored in our fat. A higher body fat percentage leads to less bioavailable vitamin D throughout the body. Excessive fat constrains vitamin D and limits its ability to to travel to other tissues. Put simply, overweight and obese individuals have less vitamin D available in their body.
The natural aging process also plays a factor in limited vitamin D bioavailability. One study suggests that a seventy-year-old makes about four times less vitamin D3 from the sun when compared to a twenty-year old.
To many people’s surprise, Vitamin D actually acts more like a hormone than it does a vitamin. Vitamin D2 and vitamin D3 are the two forms of vitamin D found in the human body. Vitamin D3 is simply the most common form of intake via the sun, food, and supplements. Vitamin D3 is found primarily in animal sources while vitamin D2 is primarily found in plant sources. Surprisingly, vitamin D2 and D3 actually have a lot in common even though their chemical makeup and sources differ. Studies show that the type of vitamin D you get is less important than getting the right dose and making sure your levels are in the right range to avoid any deficiencies.
Once vitamin D is broken down and turned into this active form (a steroid hormone), it becomes present throughout the body and plays an integral role in various functions including building bones and muscles. It also has anti-inflammatory effects and even assists in making the proteins that prevent disease and aging. Proficient levels of vitamin D have been linked to stronger immune systems, while low levels have been linked to a higher risk of heart disease, diabetes, and various types of cancer.
According to Dr. Rhonda Patrick, vitamin D is shown to affect around 5% of the human protein-encoding genome. That is over 1,000 different genes in the body!
According to the NCBI, the immune system defends the body from foreign, invading organisms, promoting protective immunity while maintaining tolerance to self. The implications of vitamin D deficiency on the immune system have become clearer in recent years and in the context of vitamin D deficiency, there appears to be an increased susceptibility to infection and a diathesis, in a genetically susceptible host to autoimmunity.
Various studies have now shown that vitamin D deficiency is associated with increased susceptibility to infection, oftentimes because this deficiency impairs the growth of healthy white blood cells whose function is to fight infection and outside invaders.
Many autoimmune diseases have been linked to vitamin D deficiency as well. Some of which include Crohn’s disease, diabetes, multiple sclerosis (MS), asthma, and rheumatoid arthritis.
When individuals lack proper amounts of vitamin D and calcium in their diets, it often leads to diminished bone health. These deficiencies often result in a condition called osteoporosis which unfortunately millions of older men and women suffer from daily. Muscle health is also an important aspect of healthy bones and joints because they help create stability, maintain balance, and prevent falls. A shortage of vitamin D may lead to weakened muscles.
In more technical terms, vitamin D plays a vital role in cellular metabolism. Vitamin D facilitates intestinal calcium absorption and reduces calcium excretion by the kidneys, providing the calcium necessary for bone mineralization. Vitamin D is vital for normal growth and development in children and adolescents with peak bone mass occurring in the late teenage years, increasing about 40 times from birth to adulthood.
What are the health benefits of vitamin K? Both K1 and K2 are important to health: vitamin K1 (the naturally-occurring form of vitamin K in vegetables) and vitamin K2 as MK-7, which is a product of fermentation and has the special property of metabolizing slowly throughout the day. Vitamins D and K are essential for optimal bone and arterial health and for maintaining the immune system in proper balance. A balanced formula of vitamin D and K may help correct the deficiencies of a majority of people that do not get adequate sun exposure and/or dietary sources of these vitamins.
Vitamin K is vital for directing the transport of calcium into bone and teeth for optimal strength. Increasing the amount of vitamin D, via supplementation, in the presence of inadequate levels of vitamin K, can increase the risk of calcium deposition in arteries and soft tissue and have a very negative effect on artery elasticity. Therefore, it is crucial to have proper levels of vitamin K accompany vitamin D in order to ensure the intended benefits.
We always recommend testing biomarkers first and foremost in order to fully understand how much supplementation (if any) is necessary. Vitamin D can be tested easily through a routine blood panel.
According to Dr. Rhonda Patrick, data compiled from several different vitamin D supplementation studies reveal that vitamin D toxicity is obtained at doses higher than 10,000 IU. Toxic doses of vitamin D can result in exceedingly high serum levels of calcium, known as hypercalcemia and have been reported at doses higher than 50,000 IU.