Low Levels of Vitamin D Indicate Much Higher Risk
for Heart Attack, Early Death
Large study funded by Danish Heart Foundation used
blood samples from 10,000 Danes
Sept. 24, 2012 - Low levels of vitamin D are
associated with a markedly higher risk of heart attack and early death
in a large study that involved more than 10,000 Danes. The researchers
say those with the lowest levels of vitamin D have at least an 81
percent higher risk of death from heart disease than those with the
Vitamin D deficiency has traditionally been linked
with poor bone health. However, the results from several population
studies indicate that a low level of this important vitamin may also be
linked to a higher risk of ischemic heart disease, a designation that
covers heart attack, coronary arteriosclerosis and angina.
show that vitamin D deficiency may increase blood pressure, and it is
well known that high blood pressure increases the risk of heart attack.
"We have now examined the association between a low
level of vitamin D and ischemic heart disease and death in the largest
study to date. We observed that low levels of vitamin D compared to
optimal levels are linked to 40% higher risk of ischemic heart disease,
64% higher risk of heart attack, 57% higher risk of early death, and to
no less than 81% higher risk of death from heart disease," says Dr.
Peter Brøndum-Jacobsen, Clinical Biochemical Department, Copenhagen
The scientists have compared the 5% lowest levels
of vitamin D - less than 15 nanomol (amount of substance) vitamin per
liter serum - with the 50% highest levels (more than 50 nanomol vitamin
per liter serum). In Denmark, it is currently recommended to have a
vitamin D status of at least 50 nanomol vitamin per liter serum.
The higher risks are visible, even after adjustment
for several factors that can influence the level of vitamin D and the
risk of disease and death. This is one of the methods scientists use to
Facts About Vitamin D
The average person gets 1/5 of his or her need for
vitamin D covered through diet and 4/5 through sunlight.
Vitamin D is produced in the skin. The
amount of sunlight needed to cover the body’s requirement for vitamin D
corresponds to 5-30 minutes of sunlight on arms, neck and head several
times a week in spring, summer and early fall in most countries.
However, in late fall and winter in
Northern countries/states and in
countries closer to the South Pole, the sun is so low in the sky that it
does not provide enough light to initiate vitamin D production in the
skin. Therefore, in such countries diet and possibly vitamin D
supplements are extremely important as sources of vitamin D in the
winter half of the year.
National health authorities often recommend on intake
of vitamin D. For example, the Danish Health and Medicines Authority
recommends a daily consumption of 7.5 mcg of vitamin D. Most Danes
receive from 2-4 mcg of vitamin D from diet.
With the exception of
certain mushrooms, only animal products contain vitamin D (fish, meat,
eggs and dairy products). In Denmark, it is recommended to eat 200-300
of fish every week. Fatty fish in particular is rich in vitamin D.
Vitamin D is important for good bone health, and
vitamin D deficiency is a risk factor for the development of
osteoporosis. Whether vitamin D can have a protective effect on the
development of heart disease and certain types of cancer is not yet
known, which is why recommendations for vitamin D supplementation are
aimed primarily at preventing osteoporosis.
Supplements are most often
not recommended for healthy individuals who eat a varied diet.
However, vitamin D supplementation is often
recommended for pregnant women, children under the age of two, people
with dark skin, women who are veiled in the summer half of the year and
for people over the age of 70.
Blood samples from more than 10,000 Danes
The population study that forms the basis for
this scientific investigation is
the Copenhagen City Heart Study, where levels of vitamin D were measured
in blood samples from 1981-1983. Participants were then followed in the
nationwide Danish registries up to the present.
"With this type of population study, we are unable
to say anything definitive about a possible causal relationship. But we
can ascertain that there is a strong statistical correlation between a
low level of vitamin D and high risk of heart disease and early death.
The explanation may be that a low level of vitamin D directly leads to
heart disease and death. However, it is also possible that vitamin
deficiency is a marker for poor health generally," says
Børge Nordestgaard, clinical
the Faculty of Health and Medical Sciences,
University of Copenhagen and senior physician at Copenhagen University
Long-term goal is prevention
The scientists are now working to determine whether
the connection between a low level of vitamin D and the risk of heart
disease is a genuine causal relationship.
If this is the case, it will potentially have a
massive influence on the health of the world population. Heart disease
is the most common cause of adult death in the world according to the
World Health Organization (WHO), which estimates that at least 17
million people die every year from heart disease.
"The cheapest and easiest way to get enough vitamin
D is to let the sun shine on your skin at regular intervals. There is
plenty of evidence that sunshine is good, but it is also important to
avoid getting sunburned, which increases the risk of skin cancer. Diet
with a good supply of vitamin D is also good, but it has not been proven
that vitamin D as a dietary supplement prevents heart disease and
Very few foods in nature contain vitamin D. The flesh of fatty fish
(such as salmon, tuna, and mackerel) and fish liver oils are among the
best sources. Small amounts of vitamin D are found in beef liver,
cheese, and egg yolks. Vitamin D in these foods is primarily in the form
of vitamin D3 and its metabolite 25(OH)D3. Some mushrooms provide
vitamin D2 in variable amounts. Mushrooms with enhanced levels of
vitamin D2, from being exposed to ultraviolet light under controlled
conditions, are also available.
Fortified foods provide most of the vitamin D in the American diet. For
example, almost all of the U.S. milk supply is voluntarily fortified
with 100 IU/cup. (In Canada, milk is fortified by law with 35–40 IU/100
mL, as is margarine at ≥530 IU/100 g.) In the 1930s, a milk
fortification program was implemented in the United States to combat
rickets, then a major public health problem. Other dairy products made
from milk, such as cheese and ice cream, are generally not fortified.
Ready-to-eat breakfast cereals often contain added vitamin D, as do some
brands of orange juice, yogurt, margarine and other food products.