All plant-based and vegetarian diets are heart-friendly, right? Vegetarian diets combined with exercise and stress management help to reduce the risk of coronary artery disease.1 A higher intake of a more healthful plant-based diet — one rich in whole grains, fruits, vegetables, etc. – has been linked to a substantially lower risk of heart disease.2 Plant-based and vegetarian diets also help other chronic conditions that contribute to coronary artery diseases. 3,4
A plant-based diet, though, can actually increase coronary heart disease (CHD), obesity, and diabetes if they contain refined grains, liberal amounts of sugar, and sugar-sweetened beverages.5 The American Heart Association recommends limiting added sugars to less than 100 calories daily for women and 150 calories daily for men.6 Why this recommended restriction?
Not All Sugars are Created Equally
Sugars that occur naturally in whole fruits and vegetables pose no increased risk for coronary artery disease. The problem is refined sugars, as well as processed foods, contribute to disease risk. Products with added sugars represent 75% of all packaged foods and beverages in the US. These products most commonly contain sucrose or high fructose corn syrup and seem to raise CHD risk even more than other sugars such as glucose.7 A seven year study of half a million Chinese adults found eating a 100g portion of fruit–primarily raw apples and oranges per day– was associated with about one-third less cardiovascular mortality.8 Why? Whole, raw fruits are a rich source of potassium, dietary fiber, antioxidants, and various anti-inflammatory compounds. Additionally, they contain little sodium or fat and have relatively few calories. Our point is how the sugar or fructose is packaged– counts!
More Inflammation and Less HDL Protection
Saturated fats, especially from meat, can spell trouble for the heart. New evidence shows that sugar is more harmful to the heart than saturated fats. Saturated fat, including the vegetable saturated palm oil, increases the bad cholesterol and promotes inflammation 9,10 You heard about the “good” cholesterol HDL. Think of HDL as being a superhero. It pulls cholesterol out of arteries. It exerts antioxidant and anti-inflammatory actions. While some saturated fats do appear to raise the beneficial HDLs, they may reduce the ability of HDLs to protect the inner lining of the blood vessels. Consumption of saturated fats causes the HDLs to lose their anti-inflammatory property.11 The quality of HDL seems as important and perhaps more important than the level of HDL. Any inflammatory agent–sugar, refined grains, or saturated fat—or any inflammatory condition like obesity or diabetes can zap the HDL so that the superhero becomes ineffective.
Added sugars, including high fructose corn syrup, have been found to cause a 3-fold increased risk of death due to cardiovascular disease.12 Liberal sugar consumption, even a few weeks, has been shown to cause numerous abnormalities found in patients with coronary artery disease, elevated total cholesterol, triglycerides, LDL, oxidized LDL, uric acid, insulin resistance and abnormal glucose tolerance, low HDL, and altered platelet function.13 Each one of these is a risk factor for coronary artery disease.
Altered Fat Metabolism in the Liver!
“I am not sick so I can indulge!” Don’t be fooled though. Even healthy people who consumed liberal amounts of sugar still have an elevated risk for coronary heart disease. Healthy men experienced increased levels of fat in their blood and the fat stored in their livers after they had consumed a high sugar diet. After 12 weeks on the high sugar diet, the men with a high level of liver fat — a condition known as the non-alcoholic fatty liver disease (NAFLD) — showed adverse changes in their fat metabolism associated with an increased risk of cardiovascular disease, heart attacks, and strokes.14
Up the Triglycerides, Up the BP, and More…
Sugar raises blood pressure and damages the kidneys. Frequent sugar, not starchy carbohydrates, increases blood fats known as triglycerides.15 Liberal sugar consumption increases blood pressure. Even if a diet consists only of 10% fructose—fructose separated from the fiber and phytochemicals found in whole fruit, sucrose, or high fructose corn syrup—can cause elevated blood pressure and damage to the small vessels of the kidneys.16 Fructose, apart from fiber, increases uric acid which promotes inflammation in the arteries. It also contributes to atherosclerosis by at least five other mechanisms.17
Compromised Blood Flow
Simple sugars like fructose and sucrose, as in table sugar, temporarily impair the ability of blood vessels to dilate. If you are going to eat a sugary treat, engage in moderate exercise afterward as there is some evidence that exercise may ameliorate sugar’s effects on blood flow.18 Always eat a desert with a high fiber, plant-based meal because antioxidants also can lessen this harmful effect of sugar. This might not be the case when high fat is combined with high sugar content. Interestingly, there is some evidence that artificial sweeteners can impair the ability of blood vessels to dilate.19 One caveat here: There might be a sustained or even greater impairment in the capacity of blood vessels to dilate in individuals who have diabetes, obesity, or are exposed to smoke. Additionally, sugar consumption elevates triglycerides which consequently cause red blood cells to clump together. This effect decreases blood flow through small blood vessels.20
Sugar and Risk for Clots
Liberal use of sugar increases triglycerides (blood fats). Elevated blood fats make your platelets hyperactive. This phenomenon is worse in individuals who have higher than normal blood glucose levels for a period of time. Inflammation promotes platelet activation that, in turn, promotes inflammation. High triglycerides can also contribute to platelet clumping and further decrease blood flow. 21,22 Sugar consumption of triglycerides is especially detrimental in people who have hypertension, obesity, depression, diabetes, or who live a sedentary lifestyle, because their platelets tend to clump already. Frequent sugar intake could conceivably raise their risk for an undesirable clot.
Your Gut Health Impacts Your Heart Health!
As previously mentioned, too much sugar spells inflammation. Let’s spell it out more. Sugary drinks can spike inflammation for over 2 hours! Advanced glycation end products (AGEs) are harmful compounds that form when protein, fat, or DNA combine with sugar in the bloodstream. Too many AGEs lead to oxidative stress and inflammation.23 Sugar enhances gut permeability so that bacteria, toxins, and undigested food particles can more easily move out of the gut and into the bloodstream, potentially eliciting an immune response and consequentially inflammation.24 Inflammation underlies each stage in the development of atherosclerosis.
Poor Sleep & Your Heart Health
Sugar hurts the quality of your sleep. There is increasing recognition of the role of sleep in the development of chronic disorders such as hypertension, diabetes, and cardiovascular disease. The good news? The practice of eating less fiber, more saturated fat, and more sugar has been linked to lighter, less restorative, and more disrupted sleep. Greater fiber intake predicted more time spent in the stage of deep, slow wave sleep. In contrast, a higher percentage of energy from saturated fat predicted less slow wave sleep. Greater sugar intake also was associated with more arousals from sleep (sleep fragmentation). Studies show that sleep fragmentation significantly increases the risk of coronary artery disease even after other possible confounding factors are adjusted for.25
- Limit sugary sweets to one or two servings a week.
- Do not exceed 6 teaspoons of sugar a day.
- Organic, whole cane sugar is superior to the regular table sugar.
- Dark honey is preferable to sugar as it has antioxidants.
- Grogan SP. A vegetarian diet reverses coronary artery disease. www.mdmag.com/journals/family-practice-recertification/2015/january2015/vegetarian-diet-reverses-coronary-artery-disease
- Esselstyn CB Jr. A way to reverse CAD? J Fam Pract. 2014 Jul;63(7):356-364b.
- Wright N. The BROAD study: A randomized controlled trial using a whole food plant-based diet in the community for obesity, ischaemic heart disease or diabetes. Nutr Diabetes. 2017 Mar 20;7(3):e256. doi: 10.1038/nutd.2017.3.
- Institute of Food Technologists (IFT). “Plant-based diets can remedy chronic diseases.” ScienceDaily. ScienceDaily, 17 October 2012. www.sciencedaily.com/releases/2012/10/121017131546.htm
- American Medical Association (AMA). “Study examines consumption of added sugar, death from cardiovascular disease.” ScienceDaily. ScienceDaily, 3 February 2014. www.sciencedaily.com/releases/2014/02/140203163432.htm
- Rocha DM. Saturated fatty acids trigger TLR4-mediated inflammatory response. Atherosclerosis. 2016 Jan; 244:211-5.
- Du Huaidong. Fresh Fruit Consumption and Major Cardiovascular Disease in China. New England Journal of Medicine, 2016; 374 (14): 1332 DOI: 10.1056/NEJMoa1501451
- University of Surrey. “Too much sugar? Even ‘healthy people’ are at risk of developing heart disease.” ScienceDaily. ScienceDaily, 4 October 2017. www.sciencedaily.com/releases/2017/10/171. 004202008.htm
- Lin Mu. Erythrocyte Saturated Fatty Acids and Systemic Inflammation in Adults. Nutrition. 2014 Nov-Dec; 30(0): 1404–1408.
- Nicholls S. Consumption of Saturated Fat Impairs the Anti-Inflammatory Properties of High-Density Lipoproteins and Endothelial Function. www.sciencedirect.com/science/article/pii/S0735109706013386
- DiNicolantonio JJ. The Evidence for Saturated Fat and for Sugar-Related to Coronary Heart Disease. Progress in Cardiovascular Diseases, 2015; DOI: 10.1016/j.pcad.2015.11.006
- DiNicolantonio JJ, ibid.
- Elsevier. “Sugar consumption plays a greater role in heart disease than saturated fat.” ScienceDaily. ScienceDaily, 13 January 2016. www.sciencedaily.com/releases/2016/01/160113103318.htm
- Johnson RJ. The potential role of sugar (fructose) in the epidemic of hypertension, obesity and the metabolic syndrome, diabetes, kidney disease, and cardiovascular disease. academic.oup.com/ajcn/article/86/4/899/4649308
- Sanchez-Lozada. Fructose-induced metabolic syndrome is associated with glomerular hypertension and renal microvascular damage in rats. Am J Physiol Renal Physiol 2007; 292: F423–9.
- Johnson RJ. Ibid.
- Varsamis P. Transient endothelial dysfunction induced by sugar-sweetened beverage consumption may be attenuated by a single bout of aerobic exercise. Microvasc Res. 2018 Jan; 115:8-11.
- Loader J. Effects of Sugar-Sweetened Beverage Consumption on Microvascular and Macrovascular Function in a Healthy Population. Arterioscler Thromb Vasc Biol. 2017 Jun;37(6):1250-1260.
- Newman T. Artificial sweeteners may damage blood vessels. April 23 2018.Medical News Today.
- Cicha I. Effects of dietary triglycerides on rheological properties of human red blood cells (abstract). Clin Hemorheol Microcirc. 2004;30(3-4):301-5.
- David J. Schneider, MD. Factors Contributing to Increased Platelet Reactivity in People With Diabetes. Diabetes Care. 2009 Apr; 32(4): 525–527.
- Frazier TH. Gut microbiota, intestinal permeability, obesity-induced inflammation, and liver injury. JPEN J Parenter Enteral Nutr.2011 Sep;35(5 Suppl):14S-20S.
- Courtney L Millar. Effects of Dietary Flavonoids on Reverse Cholesterol Transport, HDL Metabolism, and HDL Function. Adv Nutr. 2017 Mar; 8(2): 226–239.
- Hall E.J. “Can’t Sleep, Check Your Diet!” March 28, 2018. wildwoodhealth.com/blog/cant-sleep-check-your-diet/