Medical School

Postgraduate research profiles

Contact

Lauren Blekkenhorst

Phone: (+61 8) 9224 0381


Supervisors

Start date

Feb 2014

Submission date

Feb 2017

Lauren Blekkenhorst

Thesis

An investigation into the potential health benefits of dietary nitrate on hypertension-related outcomes

Summary

In Australia, one person dies approximately every 10 minutes from cardiovascular disease (CVD). Hypertension is a leading risk factor for CVD affecting approximately one-third (~7.7 million) of all Australians over the age of 18 years and approximately half (~11.5 million) of all Australians by age 55 years.

Diet and lifestyle modification is an effective population-based approach for addressing hypertension. It has the potential to reduce the need for costly anti-hypertensive medications and potentially reduce the risk of mortality. Randomized controlled trials have demonstrated blood pressure lowering effects of lifestyle modifications which are equivalent to drug therapy, such as diets rich in vegetables. However, more than 90% of Australian adults do not consume their daily recommendation of 5 serves of vegetables. This may be partly contributing to the large prevalence of CVD in Australia.

Dietary nitrate has previously been considered as a toxic constituent in our diet due to the ability to form nitrosamines. However, recent research has demonstrated consistent and convincing evidence of the potential benefits on blood pressure and cardiovascular health through the nitrate-nitrite-nitric oxide metabolic pathway. Nitric oxide (NO) plays a vital role in supporting vascular homeostasis, and a decreased production of NO has been demonstrated in hypertensive individuals.

Vegetables, such as celery, beetroot and leafy greens, are a major source of dietary nitrate in humans, contributing to 60-80% of an individual’s total intake of dietary nitrate. Randomized controlled trials have demonstrated beneficial effects of diets rich in vegetables. However, to date there is no direct evidence from randomized controlled trials demonstrating an increase in vegetable intake alone results in lower blood pressure and if the type of vegetables consumed is an important determinant of any effect on blood pressure. The type of vegetables consumed may be important for blood pressure and focused advice to consume nitrate-rich vegetables may have the potential for acceptability by the wider community as current general recommendations relating to vegetable intake are not widely followed within Australia.

Why my research is important

CVD is a leading cause of morbidity and mortality in Australia and its large prevalence may be in part due to more than 90% of Australian adults not meeting their daily recommendation of 5 serves of vegetables. This PhD project will potentially establish target advice to increase the consumption of nitrate-rich vegetables as a means of decreasing risk of CVD, which may be more effective than more general advice of increasing overall vegetable intake, as current recommendations relating to vegetable intake are poorly followed within Australia.