Vitamin D

PROF. DR. MED. VERENA BRINER, FRCP
PROF. DR. MED. VERENA BRINER, FRCP
Body & Mind
 Our skin produces vitamin D when exposed to the sun, however to prevent skin cancer we limit sun effect with sun screens. The consequence is we often have low vitamin D level, this can weaken bones and increase the risk of fractures.

 


 

Generally vitamins have to be ingested with the food and cannot be produced by the body. In medicine there are always exceptions. The skin is able to produce vitamin D when exposed to the sun. However, to prevent development of skin cancer, as little as possible sun exposure and sun screen is recommended. A disease which has disappeared more than 70 years ago, returns.

Older generations remember that years back, small children frequently had O-shape deformity of the legs. As soon as the cause of this was elucidated: Vitamin D deficiency, new borne babies routinely receive vitamin D supplements to prevent rickets. Vitamin D is important for calcium and phosphate uptake from the food. The molecule must be activated first by the liver and the kidney to the active metabolite 1,25-dihydroxycholecalciferol. Severe diseased liver or kidney may impair vitamin D activation and cause bone disease also in adults.

Nowadays body lotions and sun cream protect against UV light (280-320nm) and skin cancer and accelerated aging of the skin. On the other hand, in our area more than 60% of people show low concentration of vitamin D in the blood (25-hydroxy-vitamin D <50nmol/l in the blood) and therefore an increased risk of a weakening bone and increased risk for fractures after little trauma. Bone is not a static organ. Osteoclasts brake bone down and osteoblast build it up. Normal bone metabolism requires calcium and phosphate to ossify the matrix of the bone. In addition, vitamin D also has a direct effect on the function of the muscle fibres. Thus, low level of vitamin D rises the risk of falls and also of fractures of the vertebral bones and the hip. X-ray may show spontaneous pseudo-fractures of the pelvis, the ribs and leg.

Waldhotel offers bone density scanning (DEXA Scanning) to assess your risk of bone fracture.

Many organs demonstrate specific receptors for vitamin D. This finding suggests many more effects of vitamin D than on the muscles and skeletal. Scientific studies address the relationship between vitamin D deficiency and increased risk of rheumatoid arthritis, the development and acceleration of autoimmune diseases, postoperatively more frequently irregular heart rhythm (atrial fibrillation), prolonged bleeding, increased risk of infection and impaired renal function in patients with low vitamin D level in the blood. Vitamin D modulates the immune system by proliferation and differentiation of lymphocyte and monocytic blood cells and has anti-inflammatory effects. Cytokines seem also to be involved. Of course, to much vitamin D is not healthy either. Increased concentration of vitamin D results in high level of calcium in the blood and that may damage the kidney, impair gut and brain function.

Within the Waldhotel Checkup, in addition to other parameters, we routinely measure the calcium and vitamin D concentration in the blood.

Our body is a complex system depending on numerous small units that are coordinated with each other. Generally there is a substance inducing some effect and another inhibiting to balance the system. Calcium metabolism is regulated by vitamin D to increase calcium from the gut. A rise in calcium level in the blood inhibits parathyroid hormone (PTH). Low calcium in the blood enhances PTH concentration from the parathyroid gland to remove calcium from the bone. Thus, calcium concentration in the blood stabilises and tetanic muscle reaction are prevented. However, the mineralisation of the bone will decreases when PTH is rising. PTH is suppressed when vitamin D level is at least 70nmol/l in the blood.

We carry out a variety of blood tests, including hormone concentrations to identify under and over functioning glands, electrolyte or trace element deficiencies.

Vitamin D in the food is not sufficient to keep the blood concentration of 25-0H-vitamin D in the preferred range (>100nmol/l). Fat fish such as salmon, sardines and mackerel have high concentration of vitamin D but one regular portion per day is rarely enough to cover the need. Some food products therefore, are enriched with vitamin D (e.g. margarine, milk, cereals). The daily requirement for adults: 800U vitamin D. Calcium intake has to be normal (1000mg/day) too. In the average population older than 65 years the supplement of vitamin D and calcium (800U and 1000mg calcium) reduces the number of falls and hip fractures by 30%.

Preventative healthcare is our philosophy and we recommend a basic check up to detect any risks of disease. This can forestall the onset of an illness or reduce the severity. Nutrition is integral to preventative healthcare, if you would like to learn which foods could have a positive influence on your personal health we recommend our Cooking Lab with our nutritionist chef.

Osteomalacia is also seen in persons with low calcium intake (adults: 1000mg/day). In the skin, the sun stimulates the production of endogenous vitamin D. That’s in contrast to other vitamins, which have to be supplemented and therefore vitamin D is now named hormone.