Many people in North America suffer from diabetes, obesity and heart disease. One of the key underlying factors in all of the above conditions is inflammation and damage at the level of the blood vessel lining. The good news is that a diet high in antioxidants such as vitamin C actually protects against these damaging effects. While diet is essential, especially for prevention, it sometimes is not enough to counteract established disease processes. Luckily vitamin C provides a simple solution. Vitamin C is most well-known for its use to combat colds, but a recent large-scale review study confirmed that 500mg of vitamin
Cardiovascular disease (CVD) is the second leading cause of death in Canada, after cancer, and a leading cause of hospitalization.[i] CVD is a broad term that refers to more than one disease of the circulatory system. Amongst them, vascular disease includes any condition that affects your circulatory system, such as peripheral artery disease. This ranges from diseases of your arteries, veins and lymph vessels to blood disorders that affect circulation.[ii]
Besides traditional risk factors such as lipids profile and blood pressure, researchers are investigating newer cardiovascular risk factors, such as inflammation, oxidative stress, endothelial function and conditions which predispose people to cardiovascular events, such as obesity, metabolic syndrome or type 2 diabetes mellitus. This broader, more encompassing view of cardiovascular health is particularly suited for the nutritional modulation of those risk factors through a multifactorial supply of various beneficial substances such as antioxidant, fibers, omega-3 fatty acids, etc. As a result, nutritional interventions are finally gaining their well-deserved seat at the table! (Pun intended)
According to various researchers, promotion of a healthy diet should be given more emphasis in the prevention of cardiovascular disease. A Dutch study published in the European journal of cardiovascular prevention and rehabilitation concluded that, “Broader adherence to recommendations for daily intake of fruit, vegetables, fish and fatty acid composition may take away as much as 20-30% of the burden of cardiovascular disease.” This type of nutritional intervention could also result in approximately one extra life year for a 40-year-old individual.[iii]
But Which Type of Diet?
Our common, western-type diets are characterized by a high intake of red meat, processed foods, refined grains, sugars and saturated fatty acids. All factors known to be pro-inflammatory and detrimental to vascular health. A prospective analysis conducted within the Atherosclerosis Risk in Communities study indicated an 18% greater risk of incident metabolic syndrome for individuals with the highest Western dietary pattern score.[iv]
On the other end of the spectrum, the often-cited Mediterranean diet (MedDiet) with its abundance in minimally processed plant-based foods, rich in monounsaturated fat from olive oil, and lower in saturated fat, meats and dairy products seems to be an ideal nutritional model for cardiovascular health. Indeed, it has been the object of several studies. Indeed, a critical review published in Circulation Research in 2019 concluded that the available evidence supporting the MedDiet is large, strong and consistent. According to the researchers, “Better conformity with the traditional MedDiet is associated with better cardiovascular health outcomes, including clinically meaningful reductions in rates of coronary heart disease, ischemic stroke, and total cardiovascular disease.”[v]
The Lesser Known A-listers
The cardiovascular protective effect of the MedDiet has been mainly attributed to its high content of extra virgin olive oil and increased consumptions of fruits and vegetables. While the health-promoting benefits from an increased consumption of monounsaturated fatty acid, antioxidants and fibers supplied by this diet combined with the concomitant reduction in saturated fats, highly processed and inflammatory foods have been largely discussed, a couple key-factors are often forgotten.
The Role of Phenolic Constituents
Extra virgin olive oil EVOO is known for its nutritional properties and health effects, especially against cardiovascular diseases (CVDs). These properties are due to the presence of high levels of fatty acids (98–99% of its total weight), in particular of monounsaturated acids such as oleic, as well as of other valuable components like phenolics, phytosterols, tocopherols and squalene even if present in low percentages (1–2%).[vi] The phenolic components are relevant for the health effects attributed to EVOO and the main one is oleuropein.
Epidemiological studies indicate that dietary consumption of phenol enriched EVOO has a cardioprotective effect in Mediterranean populations. These data were confirmed in a randomized trial in 200 healthy male subjects that evaluated the effects of olive oil phenol content on lipid oxidative damage and plasma lipid levels. The study confirmed that phenolic content improves lipid oxidative damage and lipid profile.[vii]
The close correlation between inflammation, endothelial dysfunction and CVDs is well known. Several studies showed that a constant consumption of EVOO is associated with a reduction in the molecules involved in inflammatory processes related to atherosclerosis, by the downregulation of the transcription factors NF-kB.[viii]
The Role of Nitrates, Nitrite and Nitric Oxyde
Nitric oxide (NO) has been known as the elusive “endothelium‐derived relaxation factor”, an important biologically active molecule since the 1980s. It was later recognized as a signaling molecule involved in a vast number of physiologic processes, including the regulation of blood pressure and blood flow.[ix] The previous assumption was that the body’s supply of NO was produced solely by the enzymatic action of the NO synthase on the amino acid L‐Arginine. Under that assumption, dietary protein was the ultimate source of NO.
NO is rapidly oxidized to nitrite and nitrate. These products were considered metabolically inactive and destined for excretion in the urine. Research in recent decades has demonstrated that there is an endogenous pathway – the nitrate‐nitrite‐NO pathway – that recycles these anions back into NO within the body.[x] Nitrate (NO3−) is also supplied through the diet. It is an essential plant nutrient found in soil after the fixation of atmospheric nitrogen by the action of soil microbes.[xi] The body can use this exogenous nitrate to produce NO through the same nitrate‐nitrite‐NO pathway.[xii] Since the NOx pathway uses nitrate to produce nitrite and then nitric oxide, we now know that dietary nitrate, obtained mostly through dietary vegetable content, is an important source of the body’s supply of NO.[xiii]
Currently, evidence suggests that a diet naturally rich in fruits and vegetables may offer the cardiovascular benefits of enhanced NO production. Since nitrate constitutes a reservoir for NO, it exhibits many of the important roles played by NO including its antithrombotic and immune modulatory effect and its role in cytoprotection and vasodilation.[xiv]
Epidemiological studies have consistently found that fruit‐and‐vegetable–rich diets to be associated with lower blood pressure (BP) and decreased risk of ischemic stroke and ischemic heart disease.[xv] Although the exact mechanism of this protection remains unknown, studies that examined the protective effects of various categories of fruits and vegetables find that green leafy vegetables appear to confer the highest degree of protection against cardiovascular disease.[xvi]
Your first source of nitrate should consist in a diet rich in leafy green and root vegetables but for additional benefits, potassium nitrate supplements can give you the extra NOx boost that you need. As for EVOO, tree cultivars, their growing conditions, and the techniques used for its production, are key factors for the quality of the final product, affecting both its qualitative and quantitative characteristics. Make sure to use only the best quality of EVOO, purchased from a reputable producers. For added protection, you can supplement your diet with olive leaf extract standardized to contain 20% oleuropein.
[i] Report from the Canadian Chronic Disease Surveillance System: Heart Disease in Canada, 2018. Government of Canada. https://www.canada.ca/en/public-health/services/publications/diseases-conditions/report-heart-disease-Canada-2018.html#s1-2
[ii] Cleveland Clinic. Vascular Disease. https://my.clevelandclinic.org/health/diseases/17604-vascular-disease#:~:text=Vascular%20Disease%20includes%20any%20condition,blood%20disorders%20that%20affect%20circulation.
[iii] Engelfriet P, Hoekstra J, Hoogenveen R, Büchner F, van Rossum C, Verschuren M. Food and vessels: the importance of a healthy diet to prevent cardiovascular disease. Eur J Cardiovasc Prev Rehabil. 2010;17(1):50-55. doi:10.1097/HJR.0b013e32832f3a76
[iv] Lutsey PL, Steffen LM, Stevens J. Dietary intake and the development of the metabolic syndrome: the Atherosclerosis Risk in Communities study. Circulation. 2008;117(6):754-761. doi:10.1161/CIRCULATIONAHA.107.716159
[v] Martínez-González MA, Gea A, Ruiz-Canela M. The Mediterranean Diet and Cardiovascular Health. Circ Res. 2019 Mar;124(5):779-798. doi: 10.1161/CIRCRESAHA.118.313348. PMID: 30817261.
[vi] Romani A, Ieri F, Urciuoli S, et al. Health Effects of Phenolic Compounds Found in Extra-Virgin Olive Oil, By-Products, and Leaf of Olea europaea L. Nutrients. 2019;11(8):1776. Published 2019 Aug 1. doi:10.3390/nu11081776
[vii] Covas M.I., Nyyssonen K., Poulsen H.E., Kaikkonen J., Zunft H.J., Kiesewetter H., Gaddi A., de la Torre R., Mursu J., Baumler H., et al. The effect of polyphenols in olive oil on heart disease risk factors: A randomized trial. Ann. Int. Med. 2006;145:333–341. doi: 10.7326/0003-4819-145-5-200609050-00006. https://pubmed.ncbi.nlm.nih.gov/16954359/
[viii] Souza P.A.L., Marcadenti A., Portal V.L. Effects of Olive Oil Phenolic Compounds on Inflammation in the Prevention and Treatment of Coronary Artery Disease. Nutrients. 2017;9:1087. doi: 10.3390/nu9101087
[ix] Dietary Nitrate and the Epidemiology of Cardiovascular Disease: Report From a National Heart, Lung, and Blood Institute Workshop. Amrita Ahluwalia , PhD , Mark Gladwin , MD , Gary D. Coleman , PhD , Norman Hord , PhD, MPH, RD , George Howard , DrPH , Daniel B. Kim‐Shapiro , PhD , Martin Lajous , MD, PhD , Filip J. Larsen , PhD , David J. Lefer , PhD , Leslie A. McClure , PhD , Bernard T. Nolan , PhD , Ryszard Pluta , MD, PhD , Alan Schechter , MD , Chia‐Yih Wang , PhD , Mary H. Ward , PhD , and Jane L. Harman , DVM, MS, PhD https://www.ahajournals.org/doi/10.1161/JAHA.116.003402
[x] Lundberg JO, Weitzberg E, Gladwin MT. The nitrate‐nitrite‐nitric oxide pathway in physiology and therapeutics. Nat Rev Drug Discov. 2008; 7:156–167 https://www.nature.com/articles/nrd2466?is_widget=1
[xi] EFSA . Nitrate in vegetables: scientific opinion of the panel on contaminants in the food chain. EFSA J. 2008; 689:1–79. https://seguridadalimentaria.elika.eus/wp-content/uploads/articulos/Archivo291/CONTAM_NitratosVeg08.pdf
[xii] Butler AR, Feelisch M. Therapeutic uses of inorganic nitrite and nitrate: from the past to the future. Circulation. 2008; 117:2151–2159. https://www.ahajournals.org/doi/10.1161/circulationaha.107.753814
[xiii] Dietary Nitrate and the Epidemiology of Cardiovascular Disease: Report From a National Heart, Lung, and Blood Institute Workshop. Amrita Ahluwalia , PhD , Mark Gladwin , MD , Gary D. Coleman , PhD , Norman Hord , PhD, MPH, RD , George Howard , DrPH , Daniel B. Kim‐Shapiro , PhD , Martin Lajous , MD, PhD , Filip J. Larsen , PhD , David J. Lefer , PhD , Leslie A. McClure , PhD , Bernard T. Nolan , PhD , Ryszard Pluta , MD, PhD , Alan Schechter , MD , Chia‐Yih Wang , PhD , Mary H. Ward , PhD , and Jane L. Harman , DVM, MS, PhD https://www.ahajournals.org/doi/10.1161/JAHA.116.003402
[xiv] Dietary Nitrate and the Epidemiology of Cardiovascular Disease: Report From a National Heart, Lung, and Blood Institute Workshop. Amrita Ahluwalia , PhD , Mark Gladwin , MD , Gary D. Coleman , PhD , Norman Hord , PhD, MPH, RD , George Howard , DrPH , Daniel B. Kim‐Shapiro , PhD , Martin Lajous , MD, PhD , Filip J. Larsen , PhD , David J. Lefer , PhD , Leslie A. McClure , PhD , Bernard T. Nolan , PhD , Ryszard Pluta , MD, PhD , Alan Schechter , MD , Chia‐Yih Wang , PhD , Mary H. Ward , PhD , and Jane L. Harman , DVM, MS, PhD https://www.ahajournals.org/doi/10.1161/JAHA.116.003402
[xv] Bhupathiraju SN, Wedick NM, Pan A, Manson JE, Rexrode KM, Willett WC, Rimm EB, Hu FB. Quantity and variety in fruit and vegetable intake and risk of coronary heart disease. Am J Clin Nutr. 2013; 98:1514–1523. https://pubmed.ncbi.nlm.nih.gov/24088718/
[xvi] Joshipura KJ, Hu FB, Manson JE, Stampfer MJ, Rimm EB, Speizer FE, Colditz G, Ascherio A, Rosner B, Spiegelman D, Willett W. The effect of fruit and vegetable intake on risk for coronary heart disease. Ann Intern Med. 2001; 134:1106–1114. https://pubmed.ncbi.nlm.nih.gov/11412050/