Effect of diet on arterial stiffness.
Vascular aging is associated with an increase in collagen, ground substance and calcium deposition that cause a progressive deterioration in vessel elasticity. Other than structural characteristics, arterial stiffness is influenced by functional mechanisms such as vascular tone and the release of vasoactive mediators by the endothelium.
The most straightforward, valid and reliable measure of arterial stiffness is pulse wave velocity (PWV) which is predictive of future cardiovascular events, mortality and even dementia. Although blood pressure (BP) is a major determinant of arterial stiffness, indexes of arterial stiffness have additional predicative values over and above that of brachial BP.
This systematic review examined the current evidence regarding the efficacy of dietary and nutrient interventions on arterial stiffness. Relevant, randomised controlled clinical trials (RCTs) were selected and conducted with >15 adult participants investigating the effects of common dietary and nutrient interventions as a monotherapy for arterial stiffness and associated wave reflections. Thirty eight RCTs were included in the review and divided into three groups: animal food based interventions, nutrient interventions and plant food derived interventions.
The current evidence suggested that long term fish oil supplementation with the long chain omega-3 polyunsaturated fatty acids (PUFAs), eicosapentaenoic acid (EPA) and DHA provided an efficacious means of reducing PWV and increasing arterial compliance. The lowest daily dosage of long chain PUFAs that yielded an effect on arterial stiffness relative to that of a control was 540 mg EPA combined with 360 mg DHA. The largest clinical effect was shown with this dosage.
Consumption of Lactobacillus helveticus fermented milk that contained the bioactive tripeptides isoleucylprolyl-proline and valyl-prolyl-proline was shown to be effective in reducing arterial stiffness in hypertensive patients with small to moderate effects.
Plant derived polyphenols have been shown to enhance the production and synthesis of nitric oxide which influences large artery dispensability thereby reducing arterial stiffness. One study on black tea flavonoids offered promising results for reducing arterial stiffness, attributed to the high polyphenol content.
The researchers found evidence for the use of vitamins and micronutrients was lacking and the majority of studies reported no effect of treatment relative to that of placebo intake. Evidence from four trials suggested a benefit of intake of soy and related isoflavones on arterial stiffness measured through PWV and arterial compliance. Consistent evidence from two studies of high scientific quality suggested that salt supplementation increases arterial stiffness at doses ranging from 10 to 140 mmol NaCl/d in hypertensive subjects.
Current evidence from a number of small trials suggested that supplementation with omega-3 PUFAs and soy isoflavones offers a scientifically supported means of reducing arterial stiffness. Consistent evidence from two studies of high methodologic quality suggested that salt restriction is important in the management of arterial stiffness. Similarly consistent but preliminary evidence from two studies suggested that the consumption of fermented milk products that contained bioactive peptides decreases arterial stiffness.
Although fish oil and soy supplementations were shown to be effective in reducing arterial stiffness, it is unclear how these reductions in arterial stiffness affect cardiovascular risk. Future research is required to longitudinally investigate how such reductions in arterial stiffness affect future cardiovascular events.
Kathleen Murphy mnhaa
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|Publication:||Australian Journal of Medical Herbalism|
|Date:||Mar 22, 2011|
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