- Ultraviolet-B (UVB) light from the sun may reduce the risk of coronary heart disease.
- Higher vitamin D levels are associated with a lower risk of coronary heart disease.
- Vitamin D appears to reduce risk of diabetes and high blood pressure. These disorders contribute to risk of coronary heart disease.
Coronary heart disease (CHD) is one of several cardiovascular diseases. The others include stroke, congestive heart failure, and peripheral artery disease.
CHD occurs when the blood supply to the heart is cut off.
CHD is usually caused by a condition called atherosclerosis. This occurs when fatty material and other substances form a plaque build-up on the inner walls of the coronary arteries. The arteries narrow, and blood flow to the heart slows down or even stops. This can cause chest pain (stable angina), shortness of breath, and a heart attack. A heart attack is an acute form of CHD. These and other symptoms usually occur during activity.
CHD is a leading cause of death in the United States and many other countries. Each year, it affects about 14 million U.S. men and women and kills about 425,000.
The most important risk factors for CHD include:
- High alcohol consumption
- Diets high in sugar and fatty meat
Other risk factors include:
- Diabetes, high blood pressure, and chronic kidney disease
Fruits and vegetables reduce the risk of CHD. Vitamin C reduces inflammation in the blood vessels.
Sunlight exposure and CHD risk
The effects of sunlight exposure on CHD risk can be seen in the few studies of location and seasons:
- People living at higher elevations or altitudes for long periods of time may have lower rates of CHD. Solar ultraviolet-B (UVB) doses increase with higher elevations.
- People living farther from the equator have higher risk of CHD. Countries with the most sunshine are closer to the equator.
- CHD rates are generally higher in winter than in summer. This is true for countries with cold winters. It is also true for countries with warm winters such as Australia. Similar findings are well known for influenza. Solar UVB doses are lowest in winter, and vitamin D levels are lowest in late winter.
Vitamin D and coronary heart disease
Vitamin D levels
There is modest evidence that higher vitamin D levels are associated with a lower risk of CHD. However, few studies have researched CHD as a separate disease entity from cardiovascular disease. Two related studies are of interest:
- A Harvard study found that people with low vitamin D levels had twice the risk of developing a heart attack compared to those with adequate vitamin D levels.
- A study in a Utah healthcare system found that people with lower vitamin D levels were more likely to have CHD. This study did not look for the effect of vitamin D levels on CHD risk, however.
How vitamin D works
Vitamin D may lower the risk of CHD incidence and death by reducing:
- Metabolic diseases such as diabetes and high blood pressure
- Thickening of the arterial walls
- Risk of respiratory infections
- Risk of arterial calcification or hardening
Higher vitamin D levels may lower the risk of CHD. However, this has not been proven in vitamin D supplement trials.
Based on general findings for vitamin D and CHD, in addition to cardiovascular disease rates, keeping vitamin D levels above 30–40 ng/mL (75–100 nmol/L) may reduce the risk of CHD.
Vitamin D and calcium
A few studies determined that calcium supplements were associated with an increased risk of CHD. Calcium supplements may increase the risk of arterial hardening. However, when calcium and vitamin D supplements were both given, there was little change in CHD risk.
There is mounting evidence that vitamin D may be associated with reduced risk of CHD. However, there is insufficient evidence that increasing vitamin D levels can reduce the severity of CHD
Find out more…
Do you want to find out more and see the research upon which this summary is based? Read our detailed evidence summary on Coronary heart disease.
Page last edited: 21 May 2011