Vitamin D, derived from sunshine, diet and supplements, is essential for normal growth and development of bones and teeth. When you lack this essential nutrient, it's not only your bones that may suffer. According to new research from the University of South Australia, your cardiovascular health can, too.
In the first study of its kind, Australian researchers have identified genetic evidence for a role of vitamin D deficiency in causing cardiovascular disease.
About the study
This large-scale study used a new genetic approach that allowed the research team to assess how increasing vitamin D levels could affect cardiovascular risk based on how high the participants actual vitamin D levels were. The study used information from up to 267,980 individuals.
The researchers found that people with vitamin D deficiency were more likely to suffer from heart disease and higher blood pressure compared to those with normal levels of vitamin D*. For participants with the lowest concentrations of vitamin D, the risk of heart disease was more than double that seen for those with sufficient concentrations.
By increasing vitamin D-deficient individuals to levels of at least 50 nmol/L, the researchers estimated that 4.4 per cent of all CVD cases could have been prevented.
How common is low vitamin D?
Low blood concentrations of vitamin D are common in many parts of the world, with data from the UK Biobank showing that 55 per cent of participants have low levels of vitamin D (<50 nmol/L) and 13 per cent have severe deficiency (<25 nmol/L).
Low levels of vitamin D are recorded by an estimated 23 per cent of people in Australia, 24 per cent of people in the US, and 37 per cent of people in Canada.
Vitamin D sources
Foods that provide vitamin D naturally, which are few and far between, include salmon (447 IU per 3 ounces), tuna (154 IU per 3 ounces), eggs (41 IU per yolk) and cheese (14 IU per 2 ounces of cheddar). Fluid milk, many non-dairy beverages and some brands of orange juice are fortified with vitamin D (100 IU per one cup).
An otherwise healthy diet does not typically contain enough vitamin D. For people who don’t get vitamin D through the sun, a daily supplement is needed to maintain a sufficient blood concentration.
How much vitamin D?
Health Canada’s daily recommended intakes (RDAs) for vitamin D, based on bone health, are 400 international units (IU) for infants, 600 IU for children aged one to adults aged 70, and 800 IU for adults over 70. The safe upper limit is 4,000 IU per day.
Osteoporosis Canada advises healthy adults aged 19-50 consume 400-1,000 IU daily, and those over 50, or younger adults who have or are at high risk for osteoporosis, get 800-2,000 IU daily.
*The Australian and New Zealand Bone and Mineral Society (ANZBMS) and Osteoporosis Australia (OA) guidelines (2012) classify vitamin D results as follows:
- 25-hydroxy-vitamin D of less than 30 nmol/L is deficient
- 25-hydroxy-vitamin D of 30-50 nmol/L is mildly deficient
- 25-hydroxy-vitamin D of greater than 50 nmol/L is sufficient for the health of bones
All research on this web site is the property of Leslie Beck Nutrition Consulting Inc. and is protected by copyright. Keep in mind that research on these matters continues daily and is subject to change. The information presented is not intended as a substitute for medical treatment. It is intended to provide ongoing support of your healthy lifestyle practices.