What is the daily vitamin D requirement for humans? By what means do people cover their requirements? Which people need the intake of additional vitamin D? Is the daily requirement covered by sunlight?
People who spend time outdoors every day cover their daily vitamin D requirement through exposure to the sun’s UV rays. The organism produces 80 percent of the required daily dose on its own through the effect of the sun’s rays. Only ten to 20 percent of vitamin D is absorbed through food.
Daily requirement of vitamin D for all age groups
Since 2012, the following recommendations have been in effect for daily vitamin D intake when production falters due to lack of sunlight:
- Infants aged zero to twelve months ten micrograms,
- Children from one to 15 years 20 micrograms,
- Adults from 15 to 65 years 20 micrograms,
- Pregnant and nursing women 20 micrograms,
- Adults over 65 years 20 micrograms.
The daily vitamin D requirement for people in northern climes over the age of one is 20 micrograms. For infants under one year of age, ten micrograms of vitamin D daily is sufficient. However, infants require vitamin D supplements despite the relatively low daily requirement.
Vitamin D for infants and children
They absorb small amounts of vitamin D through their mother’s milk. These are not sufficient to meet the daily vitamin D requirement. Therefore, doctors recommend one vitamin D tablet daily for all children who receive breast milk or substitute products, regardless of the amount of sunlight. The tablet contains the required daily dose of ten to 12.5 micrograms.
Parents avoid deficiency symptoms by administering vitamin D products, even if the sun does not shine long enough. Parents continue this prophylactic measure for children in their second year of life during the darker months. The vitamin D tablets ensure that children meet their daily vitamin D requirements and develop healthy bones. Lack of vitamin D in children may lead to the bone disease rickets.
Cover daily requirement of vitamin D for adults
All other age groups in northern climes also have a high probability of not naturally meeting their daily vitamin D requirement. Adults reach the recommended dose of 20 micrograms through the body’s own production after exposure to the sun’s rays. The second option is to take vitamin D tablets. Especially in the winter months, people resort to the second option to cover their daily vitamin D requirement. Frequent exposure to the sun is enough to balance the budget.
Dark-skinned people living in northern climes are advised by doctors to take supplemental vitamin D. Their skin prevents exposure to UV rays compared to light skin. As a result, they do not produce enough vitamin D. Dark-skinned people cover their daily vitamin D requirement with supplements or by increasing their diet with products containing vitamin D.
Vitamin D requirement in seniors
In recent years, doctors and nutrition experts are increasingly recognizing the importance of vitamin D for the human metabolism. An adequate supply prevents diseases and improves well-being. There are different opinions about the optimal vitamin D level in the blood.
What is certain is that special population groups, such as pregnant women, small children and senior citizens, benefit from additional vitamin D supplements. Studies have frequently found an undersupply of vitamin D, especially among seniors in Central Europe. A study by the Robert Koch Institute, for example, shows that almost 60 percent of the population in Central Europe suffers from vitamin D deficiency. Among 65-year-old women, the figure is 75 percent.
Need for vitamin D in old age
The German Nutrition Society (DGE) provides reference values for the daily vitamin D requirement for seniors. Since 2012, this value recommends a daily intake of 20 micrograms of vitamin D. This applies when the body’s own synthesis via sunlight does not occur – especially in the winter months.
20 micrograms correspond to 800 International Units (I. E.), the more common indication on package inserts. It is interesting to note that prior to 2012, the reference values for vitamin D requirements for seniors were half of what they are now. This shows a rethinking of the effect of this vitamin on health.
What is the importance of vitamin D for the health of older people?
Vitamin D increases mineralization, the incorporation of calcium into the bones. It thus prevents bone softening and bone loss. These diseases occur especially in older women. Lack of bone density leads to increased fractures of the neck of the femur in falls. If the vitamin D requirement is met in seniors, muscle mass is maintained into old age.
In addition, vitamin D has a positive effect on cognitive brain function and thus coordination ability. This helps to reduce the risk of falls. Vitamin D has an anti-inflammatory effect, contributes to the improvement of heart failure and helps to lower blood pressure. High levels of vitamin D reduce the risk of diabetes and counteract the development of breast and colon cancer. The same applies to dementia and Parkinson’s disease.
Signs of vitamin D deficiency in seniors
If the vitamin D requirement is met in seniors, this helps to prevent, delay or mitigate diseases. Therefore, it is advisable to check for a possible vitamin D deficiency if the following symptoms occur:
- Optic nerve inflammation (possible sign of multiple sclerosis),
- general decrease in performance,
- headaches after physical exertion,
- joint pain,
- muscle tremors and cramps,
- poor sleep,
- decreasing concentration,
- brittle fingernails
One or more of the symptoms do not necessarily mean a vitamin D deficiency. However, cholecalciferol influences a number of metabolic processes that are necessary for a healthy organism. In addition, the positive effect with regard to various age-specific diseases has been proven for a long time. It is therefore worth investigating – especially since vitamin D deficiency is a problem among seniors in Europe.
Determine the level of vitamin D
Doctors determine the vitamin D level by means of a blood test. If the amount of vitamin D is 30 nanograms per milliliter (ng/ml) of blood or above, the supply is good. There is a low risk of disease. At 20 ng/ml, the supply is no longer optimal and below that there is a deficiency. Doctors and experts agree that vitamin D deficiency promotes the development of a wide variety of diseases.
The amount that optimally meets the vitamin D needs of seniors is a matter of debate. 30 ng/ml blood is too little for many experts. Accordingly, 40 – 80 ng/ml guarantee optimal protection against diseases. Studies show that vitamin D deficiency is present in many sections of the population in mid-latitudes. This is particularly true for women beyond the menopause and for residents of old people’s homes.
What are the options to ensure sufficient vitamin D supply?
Seniors meet their vitamin D needs in three ways:
- endogenous production through sunlight,
- through vitamin D in foods,
- through vitamin D-containing food supplements.
The body forms most of the vitamin D it needs by converting sunlight in the skin. Excess amounts are stored in fat and muscle tissue and in the liver. For this purpose, it is necessary to expose larger areas of skin to the sun for longer periods of time every day. Long stays in the fresh air are an effective way to boost vitamin D production. This natural way of meeting the vitamin D needs of seniors does not correspond to the reality of life in Central Europe. Bad weather and cold often make it impossible to spend time outdoors.
The body compensates for part of the resulting vitamin D deficiency through food. In particular, fatty fish, mushrooms, cream and butter contain vitamin D. 100 grams of herring contain 27 micrograms of vitamin D, the same amount of anchovies 20 micrograms and salmon 16 micrograms. An egg yolk contains 5.5 micrograms, and porcini mushrooms 3.5. In any case, it is worthwhile to find out more about the vitamin content of foods. However, a maximum of 20 percent of the requirement can be covered in this way.
Overall, the lifestyle and dietary habits in Central Europe and the USA lead to a vitamin D deficiency in many seniors. For this reason, additional vitamin D administration is necessary.
Special features on vitamin D requirements in seniors
Especially in older people the possibility of too low cholecalciferol levels is high. In addition to bad weather and poor diet, the skin’s ability to produce vitamin D decreases. A young adult produces enough cholecalciferol during a one-hour sunbath every day. An older person makes a quarter in the same amount of time. A four-hour stay in the sun is rather unrealistic. Apart from skin damage caused by sun exposure, clouds or rain counteract vitamin formation.
Special attention should be paid to diseases that hinder the absorption of vitamin D. These include Crohn’s disease and liver and kidney disorders. In such cases, a higher dose of cholecalciferol as a dietary supplement is necessary after consulting a doctor.
Daily vitamin D dose for vegetarians
An increased daily vitamin D requirement also exists in the case of vegetarians. They absorb up to 50 percent less vitamin D through their diet than people who eat meat and fish. In the winter months, they additionally lack the main source of sunlight for vitamin D production. Helpful foods include:
- avocados and
On average, the daily vitamin D requirement of a Central European is 20 micrograms, and ten micrograms for children under one year of age. Adults cover their requirements through daily exposure to sunlight and by eating foods rich in vitamin D. For children, physicians advise the use of dietary supplements to prevent serious deficiency symptoms.