Development and application of phenolic-rich oats for the maintenance of cardiovascular health

Lead Research Organisation: Rothamsted Research
Department Name: Plant Sciences

Abstract

UK products composed of >51% whole grains can claim, "People with a healthy heart tend to eat more whole grains foods as part of a healthy lifestyle". A number of components present in wholegrain have been hypothesised to contribute to the beneficial cardiovascular effects associated with wholegrain consumption, including phenolic acids. Recent dietary interventions in humans using phenolic acid-rich foods (blueberry, coffee, champagne) are capable of improving the function of the circulatory system. Oats are a rich source of phenolic acids, although the degree to which they contribute to the human health benefits associated with wholegrain intake has not been investigated in humans. We hypothesise that phenolic acid-rich oats will be effective at inducing acute, beneficial improvements in circulatory function in humans thus contributing to a healthy cardiovascular function.
Building on existing human work conducted in our laboratory, this study is designed to determine how phenolic acids may enhance human vascular function by focussing on how they modulate the function of the human circulatory system. The proposal will provide crucial information in three areas. Firstly, it will provide information regarding the variation in phenolic content that exists in both commercial varieties of oat products and newly developed ones. Secondly, we will test the ability of phenolic acid-rich oat intake to produce improvements in circulatory function in healthy humans using established, gold standard, clinical measures of blood flow around the body. Thirdly, we will strive to determine the processes in the body by which these beneficial effects on blood vessel function are mediated. The outcomes of this proposal have implications for exploiting the potential beneficial health effects of phenolic acids of the diet, particularly with relation to oat and other wholegrain intake. Oats are a sustainable, relatively cheap, UK product that offers an alternative to more expensive and less sustainable foods/beverages such as cocoa and berries, also shown to exert such biological effects on the circulation.
The concept of healthy ageing is rooted at the core of this proposal through the application of sound dietary recommendations. Data emanating from the proposal are necessary before academia/industry may work to exploit such public health properties of foods in the future. There has been a large growth in the desire for such functional foods (21% market growth in the USA) and cause-and-effect data are essential for the development of EFSA/FDA health claims on specific oat products. The impact of bad diet/lifestyle and obesity on blood vessel health/disease is well reported and whilst wholegrain oat intake is recommended for the maintenance of a healthy circulation and heart, no studies to date have provided evidence for the health effects of the polyphenols in oats. Over three million Britons currently suffer from cardiovascular-related problems in the UK, with annual costs for the health system exceeding £30billion. Yet it has been estimated that 80%-90% of premature cardio-vascular events are preventable, and a healthy diet is paramount in this. We aim to work with a major food company, PepsiCo, to design and test a novel oat food/beverage with the potential to counteract the loss of correct blood vessel function. Understanding more about how specific diets may promote healthy cardiovascular aging will help us to define more effective public health advice and reduce the cost of services, by encouraging the population to make more informed healthy food choices.

Technical Summary

The intake of dietary-derived phenolic acids, including ferulic acid, caffeic acid and p-coumaric acid have been shown to improve microvasculature blood flow and large artery function in humans. These beneficial effects have been attributed to their potential to improve endothelial function by increasing NO availability. This proposal is designed to test the hypothesis that phenolic acids found within oat-based diets may promote vascular function via their potential to enhance NO bioavailability to the vascular endothelium, through effects on NADPH oxidase activity and NO production.

Initially, we will analyse various oat varieties for their polyphenols profile, selecting low and high containing ones for the clinical work. Acute blood flow changes in response to oat intervention will be assessed by conducting a randomised, controlled, crossover intervention study to assess vascular function in healthy human volunteers: Vascular function will be assessed by flow mediated dilatation (FMD) and laser Doppler imaging (LDI). In order that we can make causal relationships between the phenolics in the oats and vascular outcomes, we will also assess plasma levels of phenolic metabolites by using established analytical methods (HPLC with UV-visible, fluorescent and mass detection). We will also assess the modulation of endothelial NO levels by measurement of the circulating NO pool using gas-phase chemiluminescence and the activity of NAPDPH oxidase (enzymatically and by flow cytometry). Metabolic phenotyping/profiling will be undertaken on urine samples (baseline and 24 h) and blood (3 time points) using 1H nuclear magnetic resonance (NMR) spectroscopy. Lastly, the modulation of NO cell signalling (PI3 kinase/Akt and downstream eNOS levels) will be assessed in cultured endothelial cells exposed to physiological phenolic acid metabolites by Western immunoblotting.

Planned Impact

This proposal will further our understanding of the impact of diet on human cardiovascular function. The proposal will make available underpinning science to provide the world's growing population with a sustainable, secure supply of safe, nutritious, and affordable high-quality food. The outcomes of our research will encourage the development of a variety of new, healthy oat-based food products relevant to the UK market. The proposal addresses the strategic priority: Global Food Security: sustainable, healthy and safe diets and has relevance to the strategic grand challenge 1 within the BBSRC delivery plan (2012-2015): "Food security". The proposal will also impact on the BBSRCs Fundamental bioscience focus area in that it will provide underpinning science for the understanding and prevention of cardiovascular disease throughout a healthy diet.
Industry: There is a huge, and growing, demand for novel functional foods that provide health benefits and this is particularly the case with those designed for cardiovascular health. In the US alone (the largest market for functional foods) a 21% growth in the functional foods market is expected in the coming years owing to the growing demand for functional foods, expected to reach $8.62 billion by 2015. PepsiCo agreed to part-fund our research because of its potential to determine cause-and-effect data relating to polyphenols intake and cardiovascular efficacy. Our research will provide industry with the confidence to invest in new polyphenols-containing products aimed at vascular enhancement and will provide a foundation for the development of EFSA/FDA health claims on specific polyphenol containing products. Thus, the proposal will be applicable to a variety of companies manufacturing wholegrain-based products. The proposal will provide fundamental data to aid in the development of a wide array of novel products over the next 5-10 years. The requirement for novel dietary approaches designed to improve cardiovascular health has never been greater given the increased incidence of CVD. This proposal will provide the scientific basis for the design, and manufacture of novel phenolic acid containing products for future exploitation.
General Public: The ability of polyphenols to enhance human vascular function has the potential to benefit the whole population. Understanding more about how specific diets may promote healthy cardiovascular aging and improve endothelial function will have important societal and economic impacts to the general public, encouraging the population to make more informed healthy food choices. Over three million Britons currently suffer from CVD and healthy food choices will improve quality of life and address issues of sustainability and food security. There is wide support for this type of research, as previous BBSRC surveys have shown. Although the study findings have most relevance to those at greatest risk of vascular disfunction, the proposed research will have relevance for all individuals. Whilst mortality from CVD has fallen, an increasing older population over the next decade will create further demands on services, with cost of prescriptions for all circulatory disease fast approaching £2 billion per annum. Our proposal is designed to help in the long-term planning of prevention and treatment services to tackle CVD head on. Lastly, the public interest in such science is high, thus the proposal will be highly applicable for wide dissemination through public engagement events.
Government agencies involved in promotion of public health (FSA, DOH, and DEFRA): Understanding more about how specific diets may promote healthy aging and modulate disease progression will help agencies inform the public and encourage them to make more informed and healthy food choices. We anticipate being able to make recommendations about which foods may be most beneficial in promoting healthy cardiovascular aging.

Publications

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Description We have made the following novel Key Findings to date:
1) A full profile of oat phenolic absorption, metabolism and excretion has been detailed ranging from baseline to 48 h;
2) Pure beta gluten and pure ferulic acid (the main polyphenol in oats) do not influence the growth of the microbiota, however, ferulic acid bound to the arabinoxylan fibre backbone within oats significantly modulates favourable growth and diversity of the bacteria;
3) Acute administration of a high polyphenol oat intervention leads to improvements in vascular function measured by flow-mediated dilatation and laser Doppler imaging;
4) Oat phenolics may act to improve human vascular function via activation of the nitric oxide system, specifically activation of Akt, eNOS and downstream signalling partners;
5) The intake of phenolic containing oats leads to reductions in blood pressure that are linked to the renin-angiotensin system (a secondary route aside from eNOS activation that induces reductions in blood pressure. Further Key Findings regarding longer term intake will follow towards the middle to end of 2019.
6) Different types of commercial oat products vary in their contents of avenanthramides and phenolic acids, but products in the same category (such as oat cakes) have similar contenmts
Exploitation Route Providing advice on diet and health to consumers, food industry, health professionals and regulatory authorities.
Underpinning the development of novel processing technologies to increase the contents of beneficial phenolic components in oat-based foods.
Sectors Agriculture, Food and Drink,Healthcare

 
Description The data have been provided to our Industry partners (PepsiCo) to inform their strategy for developing oat products with improved health benefits
Sector Agriculture, Food and Drink