Low vitamin D doubles the risk of cardiovascular disease in diabetics
Added 02.10.2009
Cardiovascular disease - the leading cause of death
Cardiovascular disease is the leading cause of death in the UK, claiming the lives of more than 190,000 people each year. Cardiovascular disease is also the leading cause of death among people with type II diabetes, a condition which affects approximately two million people. Last year a study established that low levels of vitamin D were linked to an increased risk of heart disease. This year, a study has gone a step farther: researchers found out how vitamin D may play a role in cardiovascular health.Vitamin D helps to process cholesterol
People with type II diabetes have a higher risk of developing cardiovascular disease. One reason could be explained by the findings of a study published this year in the journal Circulation: diabetics with low levels of vitamin D are unable to process cholesterol correctly, resulting in its accumulation in artery walls. In turn, excess cholesterol in the arteries increases the risk of atherosclerosis and cardiovascular disease.Researchers found out that vitamin D prevents macrophages from ingesting cholesterol. A macrophage is a type of white blood cell - part of the immune system - that has the ability to recognise and ingest excess amounts of cholesterol that can't be eliminated. Inevitably, the macrophages become saturated with cholesterol and develop into foam cells - cells which scientists believe are an early marker of atherosclerosis.
The Scientific Study
Background information
The study aimed at investigating the effects of active vitamin D (25-hydroxyvitamin D3) on macrophage cholesterol deposition (culture dish). For this purpose macrophages were obtained from 76 obese, diabetic, hypertensive participants with low levels of vitamin D (<80 nmol/L). Macrophages were also obtained from four different control groups:
- Obese participants with diabetes, hypertension and normal vitamin D blood levels.
- Obese participants without diabetes, but with hypertension and low levels of vitamin D.
- Non-obese, non-diabetic and non-hypertensive participants with low vitamin D levels.
- Non-obese, non-diabetic and non-hypertensive participants with normal levels of vitamin D.
Results
Macrophage cells taken from participants with low levels of vitamin D were turned into foam cells more quickly. Also, vitamin D's action of inhibiting macrophages resulted in improved insulin signalling, down regulated SRA1 (steroid receptor RNA activator 1) expression and prevented the uptake of oxidised LDL cholesterol.
Conclusion
Low levels of vitamin D accelerated the development of macrophages into foam cells and increased the risk of heart disease in diabetic patients.
Sun or supplements?
The vast majority of people do not get enough vitamin D throughout the year; in order to generate enough of this vitamin, one would have to expose the entire body to the sun every day for about 20 to 30 minutes. This of course is virtually impossible, especially during the winter months. Most scientists agree that supplements adequately and safely provide daily levels of vitamin D needed to avoid many chronic illnesses. How much vitamin D should you take? Many scientists suggest at least 2,000 IU to obtain health benefits. Whether you are diabetic or not, vitamin D is a vital nutrient that not only protects against heart disease and keeps bones strong and healthy; it has been shown to offer protection against many of today's diseases.References:
British Heart Foundation
Oh, J. & all. "1,25(OH) vitamin D inhibits foam cell formation and suppresses macrophage cholesterol uptake in patients with type 2 diabetes mellitus." Circulation. 2009.
Wang, T. & all. "Vitamin D deficiency and risk of cardiovascular disease." Circulation. 2008.
Oh, J. & all. "1,25(OH) vitamin D inhibits foam cell formation and suppresses macrophage cholesterol uptake in patients with type 2 diabetes mellitus." Circulation. 2009.
Wang, T. & all. "Vitamin D deficiency and risk of cardiovascular disease." Circulation. 2008.
Dr. Bo Nielsen's comments:
Atherosclerosis is the most common cause of death in this part of the world. Reducing the risk of atherosclerosis is naturally of major importance for millions of us. This study proves yet another major benefit of taking vitamin D supplements, BUT in significantly higher dosages - yet still totally safe - than the current RDA. This study demonstrates that vitamin D has a direct impact on the ingestion of LDL cholesterol by macrophages, which we know is an important part of the development of atherosclerosis. In other words, take a daily supplement with at least 2000 IU of vitamin D3 and help prevent osteoporosis, certain types of cancer and cardiovascular disease.
