Vitamin D is well known for bone health and preventing osteoporosis, but it also controls the expression of over 1,000 genes in the body. Almost every cell has a receptor for Vitamin D which means it is pretty important! Vitamin D is converted into the active form of Calcitriol in the liver and kidneys.
The sun is the best source of Vitamin D but it is also found in sardines, mackerel, tuna, salmon and cod liver oil. There are also small amounts in grass-fed beef, cheese and pasture raised chicken eggs.
Being a fat-soluble vitamin, you need to make sure you are getting plenty of good quality fats from the diet or you may not absorb Vitamin D very well.
Low vitamin D levels can lead to osteoporosis and increase the risk of falls and fractures. Without vitamin D, bones can become thin, brittle, soft, or misshapen. Other symptoms that may indicate a vitamin D deficiency are muscle weakness, feeling of heaviness in the legs, chronic musculoskeletal pain, fatigue, frequent infections, auto-immune diseases and depression, just to name a few!
People with very low levels of vitamin D (moderate to severe deficiency) are the most at risk of developing health problems.
Vitamin D requirements are highly individual and depend on numerous factors, such as the colour of your skin, your location, and how much sunshine you are exposed to on a regular basis. It is impossible to know what an individual’s needs are without checking the blood levels.
The simplest way to test your Vitamin D levels is with a blood test that measures your levels of 25-hydroxyvitamin D, this is the same type of Vitamin D that you get from the sun, food or supplements. The reference range varies depending on the pathology lab, less than 50 is sub-optimal and ideally you are aiming for around 100.
Who is most at risk of deficiency?
- Naturally dark-skinned people
- Elderly and those that live mostly indoors
- People who cover their skin when outside without getting any sun exposure
- Obesity
- Babies and infants of vitamin D deficient mothers
- Health conditions causing poor absorption of calcium and Vitamin D
- Office and shift workers
- Certain medications can deplete Vitamin D
While it is common for many people to take Vitamin D supplements to help their bones, immune system and improve their overall health, it is important to pair Vitamin D with Vitamin K2. Without Vitamin K2, the body cannot direct calcium to the bones where it is needed; instead, the calcium may reside in soft tissue (like the arteries) which could lead to conditions such as atherosclerosis.
When arteries become narrow, hard, or inflexible due to the calcium lining them, blood pressure increases to push blood through those narrow channels. This can result in high blood pressure, and may actually be the main cause of Hypertension.
If the arteries become sufficiently clogged with calcium, plaque, and fatty deposits, you will have blocked arteries and increase the possibility of a heart attack.
Vitamin D3 allows calcium to be absorbed, once delivered by K2. It you are taking Vitamin D without K2, you could be absorbing calcium in your arteries, kidneys and joints. Not where you want it!
There are two main forms of Vitamin K:
- Vitamin K1 (phylloquinone) is preferentially used by the liver to activate blood clotting proteins and is found in green leafy vegetables including lettuce, broccoli, and spinach.
- Vitamin K2 (menaquinones) is preferentially used by other tissues to deposit calcium in appropriate locations, such as in the bones and teeth, and preventing it from depositing in locations where it does not belong, such as the soft tissues. Vitamin K2 is made by bacteria that line the gastrointestinal tract. It is also made by bacteria, such as Bacillus subtilis, in the process of making natto. Significant amounts of Vitamin K2 are produced during the fermentation process. It can also be found in both hard and soft cheeses and small amounts in egg yolks, butter, chicken and beef.
Other benefits of Vitamin K2 include improved brain health, energy production, oxidative stress as well as helping to prevent cardiovascular disease.
So, bottom line is, get your blood levels of Vitamin D checked via a pathology test. If supplementing with Vitamin D3, it is critical to consider Vitamin K2 as well. Ideally, to optimise absorption, take Vitamin D and K2 after a fat containing meal or snack.