Vitamin D - Are your Vitamin D levels right?

Do the test and read all about benefits and tips how to avoid deficiency

Vitamin D deficiency
One third of the Vitamin D you need comes from foods. Worldwide, an estimated 1 billion people have inadequate levels of vitamin D in their blood, and deficiencies can be found in all ethnicities and age groups. Why are these widespread vitamin D deficiencies of such great concern? Because research conducted over the past decade suggests that vitamin D plays a much broader disease-fighting role than once thought. Being “D-ficient” may increase the risk of a host of chronic diseases, such as osteoporosis, heart disease, some cancers, and multiple sclerosis, as well as infectious diseases, such as tuberculosis and even the seasonal flu1. It is not for nothing that reports from across the world indicate that 'vitamin D insufficiency is widespread and is re-emerging as a major health problem globally'2. In the United States, United Kingdom and Germany more than 75% of adults suffer from vitamin D deficiency. In The Netherlands around 50% have a low Vitamin D level according to the British Journal of Nutrition3. Vitamin D deficiency in Children is alarming4. Especially children and adults from a different ethnic background are at risk.

Who are at risk include:
  • infants who are exclusively breast fed (human milk is a poor source of vitamin D)
  • premature and low-birth-weight infants
  • elderly people (reduced capacity to synthesize vitamin D in the skin by exposure to sunlight)
  • people with diseases affecting the liver, kidneys or have impaired fat absorption
  • vegetarians
  • alcoholics
  • overweight or obese people (reduced ability to produce vitamin D in the skin and to absorb it through the intestines)
  • people who are housebound (lack of sunshine exposure)

Studies have shown that low levels of vitamin D and insufficient sunlight exposure (fewer than 20 minutes per day) are associated with osteoporosis. Correctly applied sunscreen reduces our ability to absorb vitamin D by more than 90 percent. And not all sunlight is created equal: The sun’s ultraviolet B (UVB) rays—the so-called “tanning” rays, and the rays that trigger the skin to produce vitamin D—are stronger near the equator and weaker at higher latitudes. So in the fall and winter, people who live at higher latitudes (in the northern U.S. and Europe, for example) can’t make much if any vitamin D from the sun.1

Check your Vitamin D levels!
To make sure that your Vitamin D levels are right, we made a Vitamin D test. Do the test and check your results on your Vitamin D levels.

Benefits of Vitamin D
Why is Vitamin D so important?  Adequate amounts of vitamin D throughout one's life ─ in combination with exercise, proper nutrition, calcium, and magnesium ─ are necessary for building up and maintaining bones and preventing bone loss. Vitamin D is needed to properly absorb calcium.

Calcium, together with vitamin D, has been shown to help heal bone fractures from osteoporosis and decrease the risk of future bone breaks. Moreover, vitamin D is well known to protect against ‘rickets’ and ‘osteomalacia’, diseases of severe vitamin deficiency.

The European Food Safety Authority (EFSA), which provides scientific advice to assist policy makers, has confirmed that clear health benefits have been established for the dietary intake of vitamin D in contributing to:

  • the normal development of bones and teeth among infants and young children;
  • the maintenance of normal bones and teeth;
  • the normal function of the immune system and healthy inflammatory response;
  • the maintenance of normal muscle function;
  • reducing the risk of falling. Falling is a risk factor for bone fractures, especially in men and women 60 years of age and older. In order to obtain the effect, 800 I.U. (20 µg) of vitamin D from all sources should be consumed daily;
  • normal absorption/utilization of calcium and phosphorus and maintenance of normal blood calcium concentrations;
  • normal cell division. 

List of Vitamin D rich foods
Vitamin D found in food is rare. The richest natural sources of vitamin D are:

  • fish liver oils
  • saltwater fish such as sardines, herring, salmon and mackerel.

Eggs, meat, milk and butter also contain small amounts. Plants are poor sources, with fruit and nuts containing no vitamin D at all. The amount of vitamin D in human milk is insufficient to cover infant needs.

Dosage and overdose

Vitamin D toxicity has only been associated with excessive supplemental intake of daily doses greater than 50,000 IU of vitamin D, which is far higher than those necessary to achieve the health benefits. Vitamin D blood levels consistently above 375 nanomoles/liter or higher can induce abnormally high blood calcium levels, which may result in bone loss, kidney stones, and calcification of organs like the heart and kidneys if untreated over a long period of time. Mild symptoms of intoxication are nausea, weakness, constipation and irritability. These symptoms are not associated with overexposure to the sun because a regulating mechanism prevents overproduction of vitamin D in the skin.

Tolerable upper intake level
The European Food Safety Authority and the US health authority have set the tolerable upper intake level for vitamin D at 4,000 IU (100 micrograms) per day for adolescents and adults.

Research and Vitamin D

  • Cancer - Studies in test tubes have indicated that vitamin D may have anti-cancer effects, while clinical study findings on vitamin D and specific cancers such as colorectal cancer have been inconsistent *. However, some studies have shown strong evidence that high doses of vitamin D supplements may reduce the risk of colorectal cancer. In addition, some population studies have suggested that supplementation with vitamin D may improve survival rates in those with a history of breast cancer. Other studies indicated that vitamin D3 supplementation might be effective in treating skin cancer. However, this research is still in the experimental stages.
  • Autoimmune diseases Research suggests that vitamin D deficiency or a low vitamin D status may be linked to an increased risk of developing autoimmune diseases, overactive immune responses of the body attacking its own cells and organs. Clinical studies evaluating the use of vitamin D for some forms of arthritis (e.g. rheumatoid arthritis and osteoarthritis) have found vitamin D to have preventive effects. Observational data has suggested that vitamin D from foods and sunlight may help protect against multiple sclerosis (MS), a disease in which the body's immune response attacks a person's brain and spinal cord. Research has shown that supplementing infants and children with high doses of vitamin D may protect against the development of type 1 diabetes, a disease in which the body’s immune system destroys the insulin-producing cells. 

  • Cardiovascular disease and High blood pressure
    Data from clinical studies have suggested a link between low levels of vitamin D and high blood pressure. Moreover, low vitamin D status (as measured by the 25(OH)-vitamin D plasma level) is thought to be independently associated with all-cause and cardiovascular mortality or a higher risk of a heart attack.

  • Other disorders
    Although the information is limited, studies have suggested that vitamin D supplementation may also be helpful to prevent Seasonal Affective Disorder (SAD), a form of depression that occurs during the winter months because of lack of sunlight, and tuberculosis, an infectious disease.



3 British Journal of Nutrition

4 Journal of Nutrition by the American Society of Nutrion

International Unit (IU)

A unit of measurement for the amount of a substance (e.g., vitamin), based on measured biological activity or effect.

Vitamin A
1 IU is the biological equivalent of 0.3 micrograms (mcg) retinol, or of 0.6 micrograms beta-carotene; 1 nanogram (ng)/ml = 3.5 nanomol (nmol)/l.
Vitamin C
1 IU is 50 micrograms (mcg) L-ascorbic acid; 1 ng/ml = 5.5 nmol/l.
Vitamin D
1 IU is the biological equivalent of 0.025 micrograms (mcg) cholecalciferol/ergocalciferol; 1 ng/ml = 2.5 nmol/l.
Vitamin E
1 IU is the biological equivalent of about 0.667 mg d-alpha-tocopherol, or of 1 mg of dl-alpha-tocopherol acetate; 1 ng/ml = 2.78 nmol/l.