Vitamin D: Supplement for success

It has long been known that Vitamin D assists the absorption and metabolism of calcium and phosphorous in the body, making it essential for building strong bones. However, recent evidence now suggests that it also plays a major role in the prevention of cardiovascular disease (CVD). 

Vitamin D is a fat-soluble vitamin obtained from sun exposure, certain foods, and supplements. Unfortunately, vitamin D deficiency and its related health risks are highly prevalent across the globe. 

It has been estimated that approximately one billion people worldwide are affected by low levels of vitamin D. Frequently, people experience vitamin D deficiency and CVD together. ¹

Insufficient levels of the ‘sunshine vitamin‘ have been documented in patients with myocardial infarction, stroke, heart failure, diabetic CVD, and peripheral arterial disease. With the ageing global population and soaring obesity levels, vitamin D deficiency is an increasingly important public health issue.

There is a growing body of evidence indicating that middle aged and older people with high levels of vitamin D could significantly reduce their chances of developing heart disease.

Making the link

UK researchers carried out a review of studies examining vitamin D and cardiometabolic disorders, such as cardiovascular disease, type 2 diabetes and metabolic syndrome.² They looked at 28 studies involving almost 100,000 men and women across a variety of ethnic groups.

They found a significant association between high levels of vitamin D and a lower risk of developing cardiovascular disease (33% compared to low levels of vitamin D), type 2 diabetes (a 55% reduction) and metabolic syndrome (a 51% reduction).

“We found that high levels of vitamin D among middle age and elderly populations are associated with a substantial decrease in cardiovascular disease, type 2 diabetes and metabolic syndrome. Targeting vitamin D deficiency in adult populations could potentially slow the current epidemics of cardiometabolic disorders,” explained lead researcher of the study, Dr Oscar Franco of the University of Warwick.

Meanwhile, the Framingham Offspring Study found a link between vitamin D deficiency and subsequent major heart problems.³ More than 1,700 people took part in the study; all participants were free of CVD at the beginning, but were tracked by researchers for a period of more than five years. 

At the end of the study, the rate of cardiovascular problems (including fatal or non-fatal myocardial infarction, ischemia, stroke or heart failure) was 53-80% higher in people with low vitamin D levels. 

Furthermore, the increased risk of CVD associated with vitamin D deficiency was magnified in the people who had high blood pressure (hypertension).

Sources of Vitamin D

Vitamin D is also naturally produced in the body when ultraviolet (UV) rays from sunlight strike the skin. Vitamin D is naturally present in a very limited amount of foods. The main sources are the flesh of oily fish (such as salmon, tuna and mackerel) and fish liver oils. Small amounts of vitamin D are also found in beef liver, cheese and egg yolks. 

A growing body of evidence suggests that, for those not getting enough vitamin D in their diet, adding supplements can help to reduce the risk of CVD. Dietary supplementation is simple, safe and inexpensive and there are various types that are available over-the-counter.

Two forms of vitamin D are used in these supplements: ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3). Vitamin D2 is commonly considered a vegetarian source of vitamin D because it is derived from plants. Vitamin D3 can be obtained from synthetic or animal sources. 

Many healthcare professionals prefer vitamin D3 as it is better absorbed and closer to the naturally occurring form of the vitamin in humans. However, both forms can be effective in increasing vitamin D levels in the blood.

References

1. Manson JE, Bassuk S, Lee, I-M et al. The VITamin D and OmegA-3 TriaL (VITAL): Rationale and design of a large randomized controlled trial of vitamin D and marine omega-3 fatty acid supplements for the primary prevention of cancer and cardiovascular disease. Contemporary Clin Trials 2012; 33: 159-171
2. Vitamin D cuts heart disease risk. Available at: www.irishhealth.com
3. Lee JH, O’Keefe JH, Bell, D et al. Vitamin D Deficiency: An Important, Common, and Easily Treatable Cardiovascular Risk Factor? J Am Coll Cardiology 2008; 52 (24): 1949-56