About Medicine: Vitamin D and heart health
Bradley D. Berry, M.D.
Heart Failure Director
International Heart Institute of Montana
Providence Saint Patrick Hospital
Vitamin D and Heart Health
Vitamin D has long been known to be an important part of good nutrition
to promote healthy bone growth, avoid Rickets, and to avoid bone conditions
such as osteopenia or osteoporosis. Vitamin D leads to increased absorption
of calcium and other minerals from ingested foods. Adequate vitamin D
is necessary to manage the amount of calcium in our blood and bones. Nutritional
sources of vitamin D are traditionally quite poor as a source of adequate
vitamin D. Our bodies get most of its natural vitamin D from exposure
to the sun. Synthesis of vitamin D in our skin from exposure Ultraviolet
(UV) light converts cholesterol into vitamin D3 which is later converted
inside our bodies into an active form.
As a population, we are spending less time in the sun and are more likely
to protect ourselves from the harmful effects of UV light with sunscreen
or clothing which compound the prevalence of deficiency.
Studies indicate that as many as two thirds of healthy volunteers have
low blood levels of active vitamin D and nearly 40% are severely low.
It has been noted that certain populations can run rates of deficiency
at close to 100%. This effect is further compounded by living in northern
latitudes such as western Montana. Risk factors for vitamin D deficiency
include older age, living in northern climates, darker skin pigmentation,
and obesity. Ideal sun exposure to maintain healthy levels of vitamin
D may have harmful side effects, often leading to the need for supplementation.
In recent years, there has been increasing amounts of evidence that low
levels of vitamin D are associated with many health issues and conditions.
Low levels of vitamin D may be associated with conditions ranging from
muscle and joint pain to a variety of cancers including colon, breast,
prostate, esophagus, and the ovaries. Other serious conditions have been
linked to low levels of vitamin D including hypertension (high blood pressure),
diabetes, and immune conditions such as rheumatoid arthritis and multiple
In addition to diseases that increase the risk of heart disease such as
diabetes and hypertension, there is significant evidence related to the
association of low vitamin D levels and actual heart diseases.
Studies have indicated a relationship with vitamin D deficiency and heart
attacks, strokes, congestive heart failure, rhythm disorders, and peripheral
arterial disease. One Harvard study indicated Vitamin D deficient patients
were at twice the risk of similar non-deficient patients for a heart attack.
Studies have also indicated that very low levels may take on higher risk
than mildly low levels. Italian studies have demonstrated a very high
prevalence of vitamin D deficiency in patients suffering heart attacks
throughout all seasons, but in summer months, with increased sun exposure,
the prevalence was less.
Vitamin D may decrease risk through a variety of means including decreasing
inflammation, hypertension and diabetes, arterial wall thickening, and
arterial wall calcification. Normalizing vitamin D levels with supplementation
can normalize parathyroid hormone. This is important because parathyroid
in our blood rises in vitamin D deficiency in response to lower circulating
calcium to maintain normal blood levels of calcium. In addition to weakening
bones and leading to osteoporosis, high parathyroid hormone levels are
inflammatory to blood vessels and are associated with vascular events
such as heart attack and stroke.
The best evidence suggests that avoiding deficiency of vitamin D may decrease
your risk for cardiovascular disease. There are several studies that indicate
treating vitamin D deficiency with supplementation will decrease future
risk, avoid poor outcomes, and decrease complications of cardiovascular
disease. Early studies have shown promising results in treatment of cardiac disease.
Treating vitamin D deficiency with supplements appears to be involved
in preventing and reducing risk of cardiovascular disease. Funding for
such research is difficult, and larger studies has been lacking but some
larger studies are underway. Studies have indicated that the use of vitamin
D supplements has been associated with better tolerance of certain cholesterol
medications common in cardiac patients.
In our own research focusing on patients with congestive heart failure
and vitamin deficiency, we demonstrated dramatic improvement of quality
of life as compared to placebo. This is important as many studies of congestive
heart failure have demonstrated standard or guideline based therapies
will improve survival but may be associated with decreased quality of
life over the course of the study.
Additionally, hormonal markers for heart failure and exercise markers
were improved in our study and demonstrated a marked reduction in parathyroid
hormone in the treatment group. Many studies of vitamin D supplementation
in cardiac disease have had issues with appropriate dosing and often don't
provide sufficient dosing to overcome deficiency. Inadequate dosing is
an issue with current guidelines for vitamin D supplementation in general
as there is evidence that the national daily requirement recommendations
leave many patients deficient, especially the most vulnerable patients.
The appropriate dose for any person should be discussed and decided on
in consultation with their physician. Vitamin D supplementation has been
demonstrated to be very safe. Toxicity occurs only at very high non-recommended
doses and is rare in the absence of other medical conditions. The potential
health benefits are many both for prevention, as well as treatment of
many conditions including cardiac diseases in conjunction with other appropriate
medications. Often, monitoring levels of vitamin D is helpful as people
absorb, convert, and utilize vitamin D at very different rates. Always
discuss supplement additions or dose changes with your healthcare provider
as interactions with existing medications and conditions are possible.
This community health column is brought to you by Marcus Daly Memorial
Hospital, Marcus Daly Cardiology Services and The International Heart
Institute of Montana. For questions and or comments, please contact Bradley
D. Berry, M.D., Heart Failure Director, International Heart Institute
of Montana. Working together to build a healthier community!