Whether you are taking the Holiday Challenge for the first time or you are a veteran nutritarian, rich holiday foods packed with oils, animal products, white flour, and sugar may look tempting to you. Maybe tempting enough for you to say to yourself “It’s just for today, just this one meal. I’ll go back to my healthy nutritarian diet tomorrow – one unhealthy meal can’t possibly harm me.” Is that true?
Aside from the fact that a single low-nutrient meal may awaken old addictive drives that could then lead to many more low-nutrient meals, a single meal is enough to cause damage to your cardiovascular system. As Dr. Fuhrman mentioned in his recent Twitter chat, there are more cardiac deaths on December 25, 26, and January 1 than any other days of the year.1 This sobering observation suggests that overindulging at a holiday meal can be extremely hazardous to your heart.
First, I’d like to define the phrase “endothelial function,” which will be used frequently in this post: The endothelium is a specialized layer of cells that forms the inner lining of all blood vessels. Endothelial cells produce nitric oxide and other substances that regulate blood pressure, maintain balance between pro-thrombotic (blood clotting) and anti-thrombotic mechanisms, and act as a selective barrier between the blood and surrounding tissues. The functions of the endothelium are crucial; endothelial dysfunction is an early event in atherosclerotic plaque development and cardiovascular disease.2
Now let’s take a look at the traditional components of a holiday meal, and how they affect our cardiovascular system…
Meat, cheese, and oils. Fifteen years ago, a study reported that eating a high saturated fat, high animal product meal impaired endothelial function for four hours following the meal, and this effect has been confirmed in the literature over and over.3,4 For example, a study presented earlier this year reported the detrimental effects of a sausage, egg and cheese breakfast sandwich on endothelial function.5 In addition to impaired endothelial function, single low-nutrient, high fat meals have been reported to induce insulin resistance, increase circulating adhesion molecules (which allows excess LDL and inflammatory cells to enter the vessel wall – a contributor to atherosclerosis), induce oxidative stress, and deplete the body’s circulating antioxidants.6-8 The detrimental effects of a high saturated fat meal on endothelial function are believed to occur via oxidative stress and activation of pro-inflammatory pathways.4,9 Although most of the studies have focused on high saturated fat meals, there is also evidence that animal protein and excess oils (high in omega-6 fatty acids) may also negatively affect the endothelium and induce oxidative stress.10,11
Bread, pasta, and sugary desserts. For a refresher on some of the harms of added sugar, revisit Dr. Klaper’s post from last year’s Holiday Challenge. In addition to those effects, refined carbohydrate is just as harmful to endothelial function as saturated fat. Refined carbohydrates cause dangerous spikes in blood glucose – repeated spikes over time promote diabetes and other chronic diseases, but what about a single high glycemic meal? Acute hyperglycemia (short term elevated blood glucose after a single refined carbohydrate-rich meal) has been shown to impair endothelial function, promote blood clotting (which increases heart attack risk), induce oxidative stress and deplete circulating antioxidants, increase blood pressure, increase circulating adhesion molecules, impair the body’s ability to fight infection, and decrease blood flow to the heart.7,12-17
Salty snacks, beer, and wine. A single high salt meal impairs endothelial function, just like high saturated fat or high sugar meals, and alcohol magnifies the increase in blood glucose from a refined carbohydrate-rich meal.18,19
The point: A SINGLE unhealthy holiday meal inflicts damage on the cardiovascular system, contributes to atherosclerotic plaque development, and in susceptible individuals may even provoke a cardiac event.
When I see a fatty, sugary dessert, I try to think up some scary images to deter myself from indulging – here are some examples:
- Sugar crystals floating around in my bloodstream, scratching up the delicate surface of my endothelium.
- All the circulating antioxidants from my previous nutritarian meals being used up and destroyed.
- My vessels constricting, failing to deliver adequate blood to my heart muscle.
- My blood pressure rising, and my heart becoming fatigued from pumping against that extra pressure.
- LDL cholesterol and inflammatory cells pouring through the gaps in my compromised endothelial barrier and building the beginnings of atherosclerotic plaque.
…and I stick with my G-BOMBS. But that doesn’t mean that I have to choose between excellent health and tasty food. I get the best of both worlds - I enjoy preparing and serving a special dish for the holidays, while sharing health-promoting foods with my friends and family. And if I bring a nutritarian dessert, I don’t have to conjure up scary images of what an unhealthy dessert will do to my body; the nutritarian option is always far more appetizing! For the past few family holidays, I’ve made apple pie, key lime pie, raw chocolate pudding pie, and pumpkin chai ice cream. Trust me – no one missed the sugar, oil, or white flour!
This year I’m excited to share a new main dish recipe I created: Layered Sweet Potatoes with Rosemary Cream Sauce. Seasonal winter squash and rosemary make it perfect for the holidays!
Layered Sweet Potatoes with Rosemary Cream Sauce
1 medium sweet potato
1 small winter squash, such as butternut or dumpling
1 large red onion
16 ounces cremini mushrooms
1.5 cups cooked white beans
2 tablespoons raw tahini or cashew butter
5 cloves garlic
1/3 cup nutritional yeast
1 cup water
2 teaspoons dried rosemary (or 1-2 Tablespoons fresh rosemary)
1/2 teaspoon dried sage
1/4 teaspoon black pepper
1. Preheat oven to 350 F
2. Slice the sweet potato, squash, red onion, and mushrooms thinly (preferably with a mandoline).
3. Combine the remaining ingredients in a high-power blender and blend until creamy.
4. Spread a thin layer of rosemary cream sauce on the bottom of a 9x13 pan.
5. Layer one-third of each ingredient, and repeat to make three layers.
6. Bake at 350 for 40 minutes, then turn down heat to 300 and bake an additional 30 minutes.
1. Kloner RA. The "Merry Christmas Coronary" and "Happy New Year Heart Attack" phenomenon. Circulation 2004;110:3744-3745.
2. Higashi Y, Noma K, Yoshizumi M, et al. Endothelial function and oxidative stress in cardiovascular diseases. Circ J 2009;73:411-418.
3. Vogel RA, Corretti MC, Plotnick GD. Effect of a single high-fat meal on endothelial function in healthy subjects. Am J Cardiol 1997;79:350-354.
4. Hall WL. Dietary saturated and unsaturated fats as determinants of blood pressure and vascular function. Nutr Res Rev 2009;22:18-38.
5. Lacroix S, Des Rosiers C, Gayda M, et al: Abstract 752: Baseline Triglyceridemia Influences Postprandial Endothelial Response to a Single Mixed Mediterranean-type Meal Compared to a High-saturated fat meal. In Canadian Cardiovascular Congress. Toronto, Canada; 2012.
6. Ramirez-Velez R. [Postprandial lipemia induces endothelial dysfunction and higher insulin resistance in healthy subjects]. Endocrinol Nutr 2011;58:529-535.
7. Ceriello A, Quagliaro L, Piconi L, et al. Effect of postprandial hypertriglyceridemia and hyperglycemia on circulating adhesion molecules and oxidative stress generation and the possible role of simvastatin treatment. Diabetes 2004;53:701-710.
8. Tsai WC, Li YH, Lin CC, et al. Effects of oxidative stress on endothelial function after a high-fat meal. Clin Sci (Lond) 2004;106:315-319.
9. Lacroix S, Rosiers CD, Tardif JC, et al. The role of oxidative stress in postprandial endothelial dysfunction. Nutr Res Rev 2012;25:288-301.
10. Mohanty P, Ghanim H, Hamouda W, et al. Both lipid and protein intakes stimulate increased generation of reactive oxygen species by polymorphonuclear leukocytes and mononuclear cells. Am J Clin Nutr 2002;75:767-772.
11. Hennig B, Toborek M, McClain CJ. High-energy diets, fatty acids and endothelial cell function: implications for atherosclerosis. J Am Coll Nutr 2001;20:97-105.
12. Lemkes BA, Hermanides J, Devries JH, et al. Hyperglycemia: a prothrombotic factor? J Thromb Haemost 2010;8:1663-1669.
13. Mohanty P, Hamouda W, Garg R, et al. Glucose challenge stimulates reactive oxygen species (ROS) generation by leucocytes. J Clin Endocrinol Metab 2000;85:2970-2973.
14. Turina M, Fry DE, Polk HC, Jr. Acute hyperglycemia and the innate immune system: clinical, cellular, and molecular aspects. Crit Care Med 2005;33:1624-1633.
15. Fujimoto K, Hozumi T, Watanabe H, et al. Acute hyperglycemia induced by oral glucose loading suppresses coronary microcirculation on transthoracic Doppler echocardiography in healthy young adults. Echocardiography 2006;23:829-834.
16. Rammos G, Peppes V, Zakopoulos N. Transient insulin resistance in normal subjects: acute hyperglycemia inhibits endothelial-dependent vasodilatation in normal subjects. Metab Syndr Relat Disord 2008;6:159-170.
17. Lee IK, Kim HS, Bae JH. Endothelial dysfunction: its relationship with acute hyperglycaemia and hyperlipidemia. Int J Clin Pract Suppl 2002:59-64.
18. Hatonen KA, Virtamo J, Eriksson JG, et al. Modifying effects of alcohol on the postprandial glucose and insulin responses in healthy subjects. Am J Clin Nutr 2012;96:44-49.
19. Dickinson KM, Clifton PM, Keogh JB. Endothelial function is impaired after a high-salt meal in healthy subjects. The American journal of clinical nutrition 2011.