Experts refer to a vitamin D level below 20 micrograms per liter as vitamin D deficiency. Between 20 and 30 micrograms per liter also still represents too low a vitamin D level. When winter ends, more than half of Germans have a vitamin D deficiency of 20 micrograms per liter. The reason for this finding is that the vitamin D balance naturally depends only on sunlight. Only a few foods supply the organism with larger amounts of vitamin D.
The vitamin D level and its effect on calcium metabolism
Scientists confirm that an optimal vitamin D level is between 30 to 70 micrograms per liter. Below 30 micrograms per liter, intestinal calcium absorption decreases significantly and parathyroid hormone production increases. If the vitamin D in the organism increases from 20 to 32 micrograms per liter, the calcium absorption in the intestine increases by half. This effect has a long-term impact on bone density.
People living near the equator almost consistently have more than 30 micrograms of vitamin D per liter. Yet one billion people worldwide suffer from a vitamin D deficiency of less than 20 micrograms per liter. In European and U.S. nursing homes, this emergency is making itself severely felt. A large meta-analysis showed the direct relationship between the amount of vitamin D in the body and bone density. At levels above 40 micrograms per liter, study participants had maximum bone density. Osteoporosis is therefore significantly more common in female residents of northern latitudes. In Oslo and Stockholm, 3,500 out of 100,000 women have a femoral neck fracture. In Singapore, only 300 out of 100,000 women suffer from this fracture.
Vitamin D level and its effect on the immune system
Vitamin D has an antiproliferative effect and positively strengthens the immune system. People from northern climes are at increased risk for certain cancers such as pancreatic, prostate, ovarian, mammary, Hodgkin’s disease and others. If vitamin D falls below 20 micrograms per liter, it increases the risk of colon, breast and prostate cancers. The incidence probability increases by 30 to 50 percent. The mortality rate also increases. Participants in the Women’s Health Initiative study with less than 12 micrograms per liter showed a greatly increased risk. They were significantly more likely to develop colorectal cancer within eight years.
The vitamin D level and diabetes
In a Finnish study of more than 10,000 babies, vitamin D therapy with 2,000 International Units daily reduced the risk of type I diabetes. Treatment in the first year of life reduced the risk by 80 percent in the following 31 years. Vitamin D also has a positive effect against insulin resistance and type II diabetes. 800 International Units of vitamin D and 1,200 milligrams of calcium a day reduced the risk of type II diabetes. Compared to a dose of 400 International Units and 600 milligrams of calcium a day, it was 33 percent less.
Increase vitamin D for health
The American Academy of Dermatology recommends increasing vitamin D through supplements rather than more sunlight. For prophylaxis, researchers advise the following doses:
- In children and adolescents in winter and lack of sunlight, 400 to 1,000 International Units daily,
- in adults in winter and with insufficient sunlight exposure 800 to 1,000 International Units,
- in persons over 50 years of age, 800 to 1,000 International Units at all times
- during pregnancy and lactation 1,000 to 2,000 International Units
- in the case of renal insufficiency, 1,000 international units at all times. Dialysis patients have vitamin D deficiency despite frequent vitamin D intake. The level in these patients is ideally above 30 micrograms per liter. Therefore, the administration of vitamin D proves necessary.
If the patient has a proven vitamin D deficiency of less than 20 micrograms per liter, doctors advise:
- 20,000 International Units of vitamin D once a week for eight weeks,
- if the vitamin D deficiency persists, another eight weeks of 20,000 International Units once a week,
- when a vitamin D level of 32 micrograms per liter or more is reached, take 20,000 International Units every two to three weeks on a permanent basis. In the event of increased exposure to sunlight, the attending physician will adjust the therapy.
A vitamin D level lower than 20 micrograms per liter increases the risk of osteoporosis, cancer, and type I and type II diabetes. The level increases permanently with prophylactic or therapeutic use of vitamin D preparations.