Vitamin D

What is Vitamin D?

Vitamin D is an important fat-soluble vitamin. Every cell in your body has vitamin D receptors. Vitamin D is especially important for bone formation, immune health, muscles, heart, lung, and brain function. Recent research suggests that optimal vitamin D levels may help to prevent several long-term health problems.  Your body synthesizes vitamin D from sunlight.

In the northern hemispheres, it is difficult to get enough vitamin D from the sun. However, even those from hot and sunny countries are often vitamin D deficient. You can also supplement vitamin D and get a small amount from some foods.  Calcium, phosphorus, and vitamin K2 are essential for developing the structure and strength of your bones and you need vitamin D to absorb them. Recent research suggests that optimal vitamin D levels may help to prevent several long-term health problems.

Why test vitamin D?

Unless this is ordered as a retest or for a specific reason, we recommend ordering this as part of a health test.

Limited sun exposure
If you don’t get enough sun exposure, always cover up, or have dark skin, you are at risk of vitamin D deficiency - even if you live in a hot country.

Genetics
Some people have genetic risk factors that reduce their absorption of vitamin D.

Monitoring
Monitor a low value or track it over time as you make lifestyle changes or undergo treatments.

Pregnancy
Vitamin D is very important for maternal and fetal health. It is your baby’s sole source of vitamin D and is required for good health, particularly teeth, bones, and immune function.

50+
Those aged 50+ are most vulnerable to a lack of vitamin D. Synthesis of vitamin D decreases with age.

Medications
You take a drug, such as hydrocortisone or antacids, which increases the need for vitamin D.

What causes low vitamin D?

A low level of 25-hydroxyvitamin D means that you do not have enough vitamin D in your bloodstream and probably need to supplement and/or expose yourself to more sunlight, depending on your levels. It may mean that you do not absorb vitamin D well from the intestines. Drugs used to treat seizures, particularly phenytoin (Dilantin), can interfere with the production of 25-hydroxyvitamin D in the liver.

Vitamin D deficiency is defined as a 25(OH)D level of 20 ng/mL or less, and vitamin D insufficiency as 21 – 29 ng/ML. This is based on the observed physiological changes in calcium absorption and parathyroid hormone levels that occur with changes in vitamin D levels.

Studies have linked blood 25(OH)D levels between 30 ng/mL and 60 ng/mL with lower risks of health conditions, including autoimmune conditions, cardiovascular disease, and some cancers. These include lack of sun exposure, place of residence, atmospheric conditions (air pollution, clouds), dark skin, which affects the skin’s ability to produce vitamin D, clothing choices, including headscarves, sunscreen, malabsorption, gut conditions like inflammatory bowel disease, celiac disease, liver disease, low intake, veganism, kidney disease, old age, obesity, pregnancy, and certain medications. 

Vitamin D deficiency tends to be caused by inadequate sun exposure, although genetic factors and diet can contribute. Nordic Wellth’s nutritional therapists are university-qualified and are trained and insured to address any dietary and lifestyle factors, including supplementation advice, considering any health conditions and medications used. We work alongside a doctor when required and can help you to find the right doctor. 

What causes high vitamin D?

A very high level* may indicates toxicity and is most often caused by excessive supplementation, but can also be due to health conditions such as sarcoidosis. There is little consensus about reference ranges, however currently a level between 75 and 150 nmol/l is considered optimal and at least one study concluded that a level of 90-120 nmol/l may be optimal for cancer prevention (1)(2).

*The Swedish laboratories we use for this test have set the upper limit for toxicity at >250nmol/l, although based on its understanding and review of relevant research, the vitamin D Society has set a higher level of 375 nmol/l. The Vitamin D Council recognizes that there are not enough controlled trials to support or oppose their recommendations.

More information

Your body synthesizes vitamin D from sunlight and in the northern hemisphere it is difficult to get enough vitamin D from the sun. However, even those from hot and sunny countries are often Vitamin D deficient. Some people do not absorb vitamin D well for genetic reasons. Severe vitamin D deficiency causes rickets in children and osteomalacia in adults. Both conditions cause soft, thin, and brittle bones.

The best way to get sufficient vitamin D is from sunlight, but you can also supplement vitamin D and get a small amount from some foods. Calcium, phosphorus, and vitamin K2 are essential for developing the structure and strength of your bones and you need vitamin D to absorb them. Recent research suggests that optimal vitamin D levels may help to prevent several long-term health problems.

Instructions
No preparation is needed for this test.

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