Think Beets, Not Meat! Vegetarian Diets and Cardiovascular Health

 In Cardiopulmonary Medicine

STEPHEN W. PARCELL, ND 

There is good scientific data supporting the role of diet in the prevention of disease, especially cardiovascular disease. Many of the foods we grew up eating – foods that are a part of our cultural food heritage – are not good for our health. It’s an inconvenient truth. In my practice of over 20 years, I have seen all manner of damage done by the diet and lifestyle choices (though they so often are not really “choices”) of my patients. I have also been fortunate enough to see how changes in diet can have measurable, positive impacts on blood chemistry, arterial health, and disease prevention. Eating foods implicated in the causation and progression of hypertension, coronary artery disease, and heart failure is the main reason that heart attacks occur. But, with all of the various diets out there and all of the information floating around about which ones actually work, how can we best inform our patients on which diet is right for them? My experience is that trendy diets can be good! It all depends on how they are applied. 

Vegetarian, Vegan, or Plant-Based? 

It’s trendy to refer to vegetarian diets as “plant-based” now, instead of “vegan” or “vegetarian.” The term “vegan” can have political and philosophical connotations that may be difficult for some patients, so I have generally just used “vegetarian.” Vegetarian means no animal foods. If people are eating cheese, eggs, and fish, they are not eating a vegetarian diet. A “plant-based” diet may look a lot like a vegetarian or vegan diet, but it is not well-defined. For patients, it can be open to the problems of misinterpretation and unhealthy substitutions. What I do like about the term “plant-based,” is that people seem to easily understand it (as a starting point), and it has become as ubiquitous in marketing as the word “organic.” During nutritional consultations, I like to use what patients know about popularized diets in order to help them understand the specific benefits, and potential pitfalls, of their nutritional decisions. 

Another diet growing in popularity is the more specific, “whole-foods, plant-based diet” (WFPBD). A WFPBD does not just avoid animal products though; advocates of this diet have raised the bar by including an emphasis on eating “whole” foods and avoiding anything that is considered “processed.” A processed food is anything that does not look like the food in its natural state. As companies try to meet new demands, the emphasis now is on adequate plant protein, healthy fats, and minimally processed plant foods. The reason this raises the bar is because whole foods are much higher in vitamins, minerals and phytonutrients. Beyond their relative nutrient deficits, processed foods tend to contain less fiber, and typically contain more sugar, salt, and other additives than unprocessed foods. Any diet that relies heavily on plant-based nutrition can fall short unless a wide variety of whole foods are incorporated. I tell my patients, “It’s not just what you don’t eat, it’s what you do eat that matters.”  

Eat Real Food 

Animal food replacement products, such as plant-based meat and plant-based cheese, are becoming more readily available. These foods are still highly processed, are typically high in salt and polyunsaturated fats, and are not inherently healthy.1 Plant-based meats can be comparable, or even higher, in fat and sodium content when compared to beef.1 The main difference, however, is that they do not contain cholesterol, are lower in saturated fat, and do contain fiber. Furthermore, unwanted disease promoters such as heterocyclic amines (HAs), advanced glycated end products (AGEs), accumulated pesticides, growth hormones, and antibiotics are also avoided by eating a meat-substitute burger. But patients should not rely on convenience foods in order to succeed in following a WFPBD. Easy to prepare foods like bread, pasta, nut butter (in excess), meat and cheese replacement products, granola, and sweets will satisfy the “plant-based” part of the diet, but are relatively poor choices nutritionally. I tell my patients to, “Eat foods that look like food in their natural state.” 

Why Is Meat Bad For Us Anyway? 

Advanced Glycated End Products (AGEs) 

More than 500 foods have been tested for advanced glycated end products.2 AGEs occur when proteins and fats are exposed to sugar and become glycated. This reaction is accelerated with heat. AGEs cause disease to both large and small arteries, primarily by affecting the integrity of the arterial walls.3 AGEs also promote aging of all tissues.4 There is a receptor for these dangerous molecules. It’s called the receptor for advanced glycation end products (RAGE). RAGE interacts with AGEs, resulting in chronic inflammation and oxidative stress.3 RAGE signaling has been implicated in multiple human illnesses, including diabetes, atherosclerosis, arthritis, and Alzheimer’s disease.5 

Cooking methods matter in the production of AGEs. High heat, especially in the presence of marinades or other sauces that contain sugar, are the biggest offenders.2 High heat alone, like flame broiling, is also bad. In general (regardless of preparation), meat, cheese and highly processed foods contain the highest content of AGEs; while grains, beans, bread, vegetables, fruits and milk have the least.2 The two worst foods (in terms of AGE content) are fried bacon and barbecued chicken (with skin left on).2 Pharmaceutical companies are even working on drugs to counteract damage done by AGE compounds … but what if people could just stop putting them into their bodies? If a patient must eat meat, I always recommend they eat it steamed, not roasted or barbecued. 

Heterocyclic Amines (HCAs) 

HCAs are a major class of toxic compounds commonly found in cooked meat. They are produced by the reaction of amino acids, sugar, and the creatine or creatinine found in muscle, at very high temperatures.6 Grilling, broiling, and frying of meat tend to produce the greatest amount of HCA’s.6 Because they are genotoxic (able to interact directly with DNA), HCA’s can eventually foster mutagenicity (gene damage), and cancer.7  

Polycyclic Aromatic Hydrocarbons (PAHs) 

Ubiquitous in the environment, the majority of exposure to PAHs occurs through the diet. High-heat cooking methods, such as roasting, grilling, barbecuing, and smoking, generate the highest levels of these compounds.8 Once ingested, PAH’s contribute to cardiovascular disease through oxidative stress and endothelial injury.8  

Nitrites, Nitrosamines, and Nitrosamides 

Preserved meats often contain nitrites. They are added to meat products to prevent the growth of bacteria and maintain color.9 Nitrites are also found in plants, but are only harmful when they are converted into nitrosamines or nitrosamides.10,11 These reactions occur in the presence of amines and amides, which are found in much greater abundance in animal products than in plants. Some uncured bacon products say “nitrite free,” but manufacturers are instead adding concentrated plant nitrates to their products. While naturally occurring nitrates can be beneficial, in high concentrations, they can also be converted into nitrites (and subsequently nitrosamines and nitroamides), so preserving cured meats using plant-based nitrates is a clever workaround, but it is not necessarily a healthier option.9,11 Deli meat is another convenience food that is high in nitrites. Convenience foods can be difficult to give up. I generally recommend patients avoid cured meats altogether, and try to let go of convenience foods as much as possible. 

Insulin-like Growth Factor 1 (IGF-1) 

Meat eaters have higher blood levels of IGF-I.12 Adults with higher IGF-I numbers compared to those with lower numbers have a higher risk of cancer.12 IGF-I acts like growth hormone in the body and may promote the growth of tumors.12 

Endotoxins 

The bacterial load in raw or cooked meats contributes to endotoxemia, which causes a spike in inflammation within an hour after a meal.13 Diets high in fruit and vegetable intake have shown correspondingly lower serum lipopolysaccharide (LPS) levels.14 Saturated animal fats can be especially problematic for LPS absorption.13  

How Do Vegetarian Diets Improve Cardiovascular Health? 

Saturated Fat 

Saturated fat intake typically goes down on a vegetarian diet. Saturated fat of animal origin is pro-inflammatory and can act like an arterial toxin, causing constriction within hours of a high fat meal.15 Saturated fat is also the main driver of cholesterol production by the liver. The monounsaturated and polyunsaturated fats in raw nuts, olives, and avocado, are neutral on cholesterol; whereas saturated fats increase cholesterol production. 

Cholesterol 

Dietary cholesterol reduces hepatic low-density lipoprotein (LDL) receptor function. This leads to decreased clearance of LDL and increased production of LDL by the liver. Because plants typically do not contain cholesterol, avoiding animal products typically results in decreased cholesterol intake, decreased cholesterol production in the liver, and decreased serum LDL. Individuals with familial hypercholesterolemia will still have increased cholesterol production, even on a plant-based diet; however, they will be reducing their total intake of cholesterol significantly. Additionally, some individuals are more sensitive to dietary cholesterol than others because of different rates of sterol absorption from the small intestine.16 Not everyone will respond in the same way to a low-cholesterol diet, and it is important to monitor changes closely. 

Sodium 

Processed meats, cheeses, deli meats, and even raw chicken are high in salt (chicken is typically injected with saltwater to improve cooking and increase its weight). Avoiding these foods (and others like them) can result in a drastic decrease in dietary sodium intake. In addition to raising blood pressure through fluid retention, sodium contributes to vasoconstriction and endothelial dysfunction.17 Excess salt in the diet can also impair arterial function and cause damage to vessel walls prior to the onset of hypertension.18 

Phosphates 

Added phosphates are avoided with a plant-based diet. Industrial meats (also colas and other processed foods) have phosphates added to enhance or preserve color. Phosphates are also used help prevent seepage, (that weird juice found at the bottom meat packages). Phosphates are vascular toxins and cause arterial calcification.19 

Trimethylene-N-Oxide (TMAO) 

Intake of the amino acid carnitine and the nutrient choline also decrease by avoiding animal products. This is important because these nutrients can be converted into an unpleasant substance called trimethylamine-N-oxide or TMAO.20 The research on TMAO and atherosclerosis suggests this metabolite contributes to cardiovascular disease by promoting an inflammatory response, and may contribute directly to atherogenesis.20 Drug companies are examining medications that interrupt TMAO synthesis in the gut to prevent cardiovascular disease;20 vegetarian diets decrease TMAO formation by simply limiting its constituents. 

Fiber 

Fiber intake goes up as a result of eating more plant foods. Among other health benefits, fiber improves the distribution of friendly microbes, potentially reducing inflammation. Eating more fiber also lowers glycemic load, improves insulin sensitivity, helps obese people lose weight, lowers cholesterol, and lowers blood pressure.21 

Beneficial Nutrients 

When adopting a healthy whole-foods, plant-based diet, beneficial nutrient intake tends to increase. Here are some of the most important nutrients and my favorite food sources: 

  • Beta-Carotene – is important for bone health, skin health, vision, and the immune system;22 food sources include apricots, squash, carrots, sweet potato, collard greens, spinach, kale, and broccoli. 
  • Lycopene – is associated with less cardiovascular disease and reduction of prostate cancer risk.23 Food sources are red peppers, pink grapefruit, tomatoes, and watermelon. 
  • Lutein – helps with eye health, heart health, and may lower cancer risk.24 Food sources are broccoli, spinach, kale, collard greens, brussels sprouts, and artichoke. 
  • Resveratrol – is particularly important for its cardioprotective effects, for improving lung function, and for reducing inflammation.25 Food sources are red wine, peanuts, and grapes. 
  • Anthocyanidins – are especially important for heart and blood vessel health.26 Food sources are strawberries, blueberries, blackberries, plums, cranberries, raspberries, red onions, red potatoes, and radishes. 
  • Isoflavones – act as selective estrogen receptor modulators and help with the prevention of breast cancer, improve bone health, lower joint inflammation, and help lower cholesterol.27 The main source is soybeans. 
  • Lignans – have a weak estrogen-like effect. Lignans bind to estrogen receptors and prevent stronger estrogens from entering the cell. An exceptionally good source is ground flaxseeds. Approximately 40 g/day of ground flax seeds has been shown to reduce serum LDL, total cholesterol, triglycerides, apolipoprotien A1, and apolipoprotein B.28 
  • Nitrates – can be great for blood pressure (as long as they are naturally occurring).11 The body converts nitrates to nitric oxide (NO), which helps to relax blood vessels, improve circulation, and lower blood pressure.11 Athletes sometimes even use a shot of beet juice to improve performance! My top 10, naturally occurring, plant sources of nitrates are arugula, rhubarb, cilantro, butter leaf lettuce, beet greens, oak leaf lettuce, swiss chard, and beets. 

Just Do It 

In 2019, the Journal of the American Heart Association published a review based on data from the Atherosclerosis Risk in Communities study. Evaluating health information collected from 1987 through 2016, the authors concluded that predominantly plant-based diets were “associated with a lower risk of incident cardiovascular disease, cardiovascular disease mortality, and all cause mortality.”29 The benefits of a vegetarian diet are numerous, and the current emphasis on whole-foods, plant-based diets further promotes healthy eating habits within the meat-free diet spectrum. Helping a patient change their diet is never an easy task; however, with time, care, and simple instructions, patients often learn how to give up foods they never thought possible. Furthermore, as they start to feel their health improve, they are even more motivated to continue their healing process. 

References: 

  1. Curtain F, Grafenauer S. Plant-Based Meat Substitutes in the Flexitarian Age: An Audit of Products on Supermarket Shelves. Nutrients. 2019;11(11):2603 
  1. Uribarri J, Woodruff S, Goodman S, et al. Advanced glycation end products in foods and a practical guide to their reduction in the diet. J Am Diet Assoc. 2010;110(6):911-16.e12. 
  1. Stirban A, Gawlowski T, Roden M. Vascular effects of advanced glycation endproducts: Clinical effects and molecular mechanisms. Mol Metab. 2014;3(2):94-108. 
  1. Solway J, McBride M, Haq F, et al. Diet and Dermatology: The Role of a Whole-food, Plant-based Diet in Preventing and Reversing Skin Aging–A Review. J Clin Aesthet Dermatol. 2020;13(5):38-43. 
  1. Lin L, Park S, Lakatta EG. RAGE signaling in inflammation and arterial aging. Front Biosci (Landmark Ed). 2009;14:1403-1413. 
  1. Sugimura T, Wakabayashi K, Nakagama H, Nagao M. Heterocyclic amines: Mutagens/carcinogens produced during cooking of meat and fish. Cancer Sci. 2004;95(4):290-299. 
  1. Weisburger JH. Lifestyle, health and disease prevention: the underlying mechanisms. Eur J Cancer Prev. 2002;11(Suppl 2):S1-S7. 
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  1. Tricker AR, Preussmann R. Carcinogenic N-nitrosamines in the diet: occurrence, formation, mechanisms and carcinogenic potential. Mutat Res. 1991;259(3-4):277-289. 
  1. Karwowska M, Kononiuk A. Nitrates/Nitrites in Food-Risk for Nitrosative Stress and Benefits. Antioxidants (Basel). 2020;9(3):241. 
  1. Allen NE, Appleby PN, Davey GK, et al. The associations of diet with serum insulin-like growth factor I and its main binding proteins in 292 women meat-eaters, vegetarians, and vegans. Cancer Epidemiol Biomarkers Prev. 2002;11(11):1441-1448. 
  1. André P, Laugerette F, Féart C. Metabolic Endotoxemia: A Potential Underlying Mechanism of the Relationship between Dietary Fat Intake and Risk for Cognitive Impairments in Humans?. Nutrients. 2019;11(8):1887. 
  1. Ahola AJ, Lassenius MI, Forsblom C, et al. Dietary patterns reflecting healthy food choices are associated with lower serum LPS activity. Sci Rep. 2017;7:6511. 
  1. Vogel RA, Corretti MC, Plotnick GD. Effect of a single high-fat meal on endothelial function in healthy subjects. Am J Cardiol. 1997;79(3):350-354. 
  1. Mashnafi S, Plat J, Mensink RP, Baumgartner S. Non-Cholesterol Sterol Concentrations as Biomarkers for Cholesterol Absorption and Synthesis in Different Metabolic Disorders: A Systematic Review. Nutrients. 2019;11(1):124. 
  1. Dickinson KM, Clifton PM, Burrell LM, et al. Postprandial effects of a high salt meal on serum sodium, arterial stiffness, markers of nitric oxide production and markers of endothelial function. Atherosclerosis. 2014;232(1):211-216. 
  1. Edwards DG, Farquhar WB. Vascular Effects of Dietary Salt. Curr Opin Nephrol Hypertens. 2015;24(1):8-13. 
  1. Lau WL, Festing MH, Giachelli CM. Phosphate and Vascular Calcification: Emerging Role of the Sodium-Dependent Phosphate Cotransporter PiT-1. Thromb Haemost. 2010;104(3):464-470. 
  1. Yang S, Li X, Yang F, et al. Gut Microbiota-Dependent Marker TMAO in Promoting Cardiovascular Disease: Inflammation Mechanism, Clinical Prognostic, and Potential as a Therapeutic Target. Front Pharmacol. 2019;10:1360. 
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  1. Leermakers ET, Darweesh SK, Baena CP, et al. The effects of lutein on cardiometabolic health across the life course: a systematic review and meta-analysis. Am J Clin Nutr. 2016;103(2):481-494. 
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  1. Kimble R, Keane KM, Lodge JK, Howatson G. Dietary intake of anthocyanins and risk of cardiovascular disease: A systematic review and meta-analysis of prospective cohort studies. Crit Rev Food Sci Nutr. 2019;59(18):3032-3043. 
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  1. Rodriguez-Leyva D, Dupasquier CM, McCullough R, Pierce GN. The cardiovascular effects of flaxseed and its omega-3 fatty acid, alpha-linolenic acid. Can J Cardiol. 2010;26(9):489-496. 
  1. Kim H, Caulfield LE, Garcia-Larsen V, et al. Plant-Based Diets Are Associated With a Lower Risk of Incident Cardiovascular Disease, Cardiovascular Disease Mortality, and All-Cause Mortality in a General Population of Middle-Aged Adults. J Am Heart Assoc. 2019;8(16):e012865. 

Stephen W. Parcell, ND earned his doctorate in naturopathic medicine from Bastyr University in 2002. Dr Parcell worked as a freelance medical researcher at U of WA Medical School. He has done additional trainings through the ACAM, the National Lipid Association (NLA), AAEM, and the American Academy for Anti-aging Medicine (A4M). He is board-certified in anti-aging medicine through A4M. He is a past vice president of the Colorado Association of Naturopathic Doctors (COAND). Dr Parcell is a paid speaker and educator, has been a contributing writer, published peer-reviewed articles, and authored a book titled Dare to Live. He is co-owner of NatureMed Integrative Medicine, in Boulder, CO. Email: drparcell@naturemedclinic.com 

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