Vitamin D plays an essential role in various processes in the body, including rickets or bow legs. It is a bone disorder that mainly occurs in young children. Characteristic of this is that there is little bone production and the bones that are made are of poor quality. Vitamin D is made from sunlight and is now added to foods, which makes rickets less common.
Why vitamin D?
Vitamin D, often an underrated vitamin. It is well known that the vitamin is good for you. What exactly he does is still a gray area. It has already been well researched that vitamin D in combination with calcium is good for bone metabolism. We also know that it plays a role in muscle function, immune system, brain function and cell differentiation. This is increasingly reinforced by new research (more below). Despite people’s growing awareness of vitamin D, experts estimate that up to 75% of all adults are deficient in vitamin D. Why is it that so many people have a vitamin D deficiency? A possible answer to that question could be because people spend less and less time outdoors.
Shortages
If the level of vitamin D is too low, it is referred to as a vitamin D deficiency or vitamin D3 deficiency. A deficiency usually causes fatigue, lethargy, muscle pain and/or muscle cramps. A long-term and serious vitamin D deficiency can lead to all kinds of bone complaints, muscle complaints and joint complaints.
What is vitamin D good for?
Vitamin D is a multifunctional vitamin. This means that the body uses it in various processes and needs it to function. It is also an essential vitamin, meaning it is necessary for it to be present in the diet because the body does not produce enough. It is true that the body can produce vitamin D itself under the influence of sunlight, but this does not happen to a sufficient extent for certain groups. The table below indicates which groups are advised to use extra vitamin D.
Bone metabolism
Vitamin D and calcium together ensure strong bones and teeth. Vitamin D is necessary for the absorption of calcium in the body. This has been shown by several studies.
Muscle function
A vitamin D deficiency can cause muscle weakness and muscle cramps. Vitamin D sufficiency ensures a better sense of balance, which reduces the risk of falls. Ultimately, it results in fewer falls and bone fractures. This is a common problem, especially among the elderly. More research is needed to determine the exact role on muscle function.
Immune system
The conversion to the active form of vitamin D triggers a process that stimulates the production of an antimicrobial protein. More research is needed to determine the exact role on the immune system.
Brain function
A number of studies show links between lower vitamin D status and cognitive decline. People with sufficient vitamin D in the blood are less likely to experience depression. More research is needed to determine the exact role on brain function.
Cell differentiation
Several studies link vitamin D and the anti-inflammatory function of (cancer) cells. The KWF has conducted extensive research into vitamin D. One of the most important conclusions is that vitamin D may prevent colon cancer. More research is needed to determine the exact role on (cancer) cells.
A number of products with vitamin D
|
Foodstuff |
Per serving (quantity) |
Micrograms (mcg) of vitamin d |
Mcg/100 grams |
|
Salmon trout, cooked |
1 piece (125 grams) |
11.75 |
9.4 |
|
Mackerel, smoked |
1 piece for 1 slice of bread (40 grams) |
3.2 |
8 |
|
Egg, boiled |
50 grams |
0.8 |
1.6 |
|
Beef tartare, prepared |
1 piece (70 grams) |
0.6 |
1,2 |
|
Margarine/low-fat margarine |
For 1 slice of bread (5 grams) |
0.4 |
8 |
|
Butter, unsalted |
For 1 slice of bread (5 grams) |
0.1 |
2 |
|
Pork fillet steak, prepared |
1 piece (70 grams) |
0.1 |
0.1 |
Research and research
1 International Unit (IU) of vitamin D is equal to 0.025 micrograms (mcg).
A meta-study from August 2014 shows that 4,000 IU/day increases muscle strength in 370 healthy men and women aged 18-40. A number of subjects in these studies were athletes, yet muscle strength was increased. There was no overdose (>375nmol/L (150.2 ng/ml)) in the studies used(1).
In another study, 1000IU/day inhibited muscle breakdown in athletes (3). Korean nutritional scientists published an animal study that vitamin D supplementation inhibits the process of muscle breakdown after heavy exercise. TMF alpha, an inflammatory protein that in small quantities is essential for muscle recovery and in high concentrations inhibits the action of anabolic factors in muscle cells and stimulates muscle breakdown.
A 12-week double-blind randomized clinical trial shows that overweight women (BMI on average 30) benefit from vitamin D supplementation. The women took 1000 IU daily, while the placebo group took a supplement without active ingredients. The women who took the vitamin D lost fat mass and gained lean body mass (4).
Other recommendations
In the Netherlands, the RDA (recommended daily allowance) is 10 mcg/day (400IU/day). The EFSA (European Food Safety Authority) increased the safe upper limit from 50mcg (2,000IE) to 100mcg (4,000IE) in 2012. They even concluded that a daily amount of 250 mcg of vitamin D per day does not cause any complaints. Internationally, the positive effect of vitamin D is better known. In the United States and Canada it is recommended to supplement 600-800IU/day. Research suggests that the true safe upper limit is 10,000 IU/day.
Vitamin D exists in 2 forms: ergocalciferol (D2) and cholecalciferol (D3). Vitamin D2 is isolated from irradiated fats and is often used in fortification of products. Vitamin D3 is formed in the skin and occurs naturally in fish and eggs, for example. This form is also often used in supplements.
When supplementation is involved, it is good to know which form of vitamin D is best absorbed. Vitamin D3 is preferred over vitamin D2, because the active substance is natural and has a stronger effect.
