This is the second of a two-part post. The first part can be accessed here.
A discussion of diet and nutrition is fundamental to any conversation about hypertension. What you put into your body everyday has a significant impact on your risk of chronic disease, including hypertension. Given its ubiquity, there has been a substantial amount of research done on hypertension and its relation to diet in particular. From these studies patterns have emerged regarding what dietary styles and components increase and decrease risk for hypertension. Generally speaking diets that are high in saturated fat, high in sodium, low in potassium, and low in fiber have been associated with increased risk of hypertension. (1, 2) I will discuss each of these briefly.
To understand the pathophysiology of hypertension, one must be familiar with the endothelium. The endothelium is a lining located on the inner wall of all blood vessels. It has many functions, including regulating the dilation and constriction of blood vessels. Unfortunately, this delicate layer (which is only one cell thick) can be damaged by various substances, resulting in endothelial dysfunction. This is where smoking does much of its damage. Saturated fats also injure the endothelium. Studies have shown that eating a meal high in saturated fat impairs the endothelium’s ability to cause vasodilation (widening of the blood vessels) (3, 4). It also causes cholesterol to build-up in the vessel walls, thereby further contributing to endothelial dysfunction. Saturated fat is primarily found in foods like meats, dairy, and oils (especially coconut oil).
Like saturated fats and smoking, excess sodium also damages the endothelium (5). In addition, it impairs the kidneys’ ability to get rid of extra fluid, which means that when you consume sodium above your normal physiological needs you literally have more volume of fluid in your body. This is why diuretics, or “water pills”, are a mainstay of the pharmacologic treatment of hypertension.
Another possible mechanism by which sodium may increase your risk of hypertension is through its effect on your microbiome. As I have discussed before, the microbiome is the population of microbes (bacteria, viruses, fungi, etc.) that lives on and in your body, mostly in your large intestine. Accumulating research shows that this mass of organisms actually functions much like another organ, producing bioactive metabolites, detoxifying potentially harmful substances, maintaining the health of your gut lining, and much more. Certain species of bacteria have been shown to be harmful to health while others have demonstrated health promoting qualities. A recent study done in mice found that consuming excess sodium killed off a type of good bacteria living in their guts, after which their blood pressure increased (6). This illustrates that the microbiome may have a role in regulating blood pressure which can be mediated by diet. These results were replicated in a small group of men. High sodium foods including those that are processed (foods that come in a package/can) and restaurant foods. Bread and cheese are two commonly consumed, sodium-rich foods that people may not be aware of. A simple rule to remember when it comes to eating foods that come packaged is the sodium-to-calorie ratio rule: avoid foods in which the milligrams of sodium are higher than the calories per serving (ratio <1).
Much like excess sodium can be harmful, inadequate potassium also has deleterious effects on blood pressure (1). Consuming adequate potassium allows your blood vessels to dilate and your kidneys to get rid of excess fluid. Importantly, a diet that is high in sodium is typically also low in potassium and thus exerts a “double whammy” effect. Foods high in potassium include: winter squash, potatoes, tomatoes, beets, bananas, beans (white, kidney, lentils), prunes, raisins, oranges, and avocados. Do NOT try to obtain adequate potassium from supplements; this has not been shown to be protective like a diet high in potassium and consuming too much potassium can be lethal.
Like most other chronic diseases faced in a modern society, fiber has been found to be protective against hypertension (1). While they have not been fully elucidated, there are likely multiple mechanisms by which fiber works to lower your blood pressure including decreasing obesity, promoting the health of blood vessels by decreasing LDL (“bad”) cholesterol, decreasing inflammation, and decreasing insulin resistance. It also promotes a healthy microbiome since fiber acts like “bacteria food” in the colon. The only foods that contain fiber are plant foods. While the USDA’s adequate daily intake is set at 38 grams for men and 25 grams for women, the average American gets about 15 grams per day.
So, when considering what to eat to lower your blood pressure you should consider the following: which foods are low in saturated fat and sodium while being high in potassium and fiber? Answer: whole plant foods!! These are the only foods that check all of the boxes and should thus form the bulk of your diet. Furthermore, when you emphasize these protective foods you are naturally displacing the potentially harmful foods, like animal products and processed foods. There are likely a few more reasons that plant foods are beneficial to blood pressure. They are good sources of magnesium and calcium, which may be protective against hypertension (7, 8), as well as antioxidants, which down regulate inflammation and promote endothelial health. In addition, many plant foods contain nitrates, which are converted to nitric oxide by the endothelium. Nitric oxide is a strong vasodilator and thus can lower blood pressure.
If you’re looking to add an extra blood pressure-lowering boost to your diet, there are certain plant foods that have been shown to be particularly effective at lowering blood pressure. These include ground flaxseed (9), beet juice (10) (feel free to eat the whole beet), and hibiscus (11), such as hibiscus tea. Don’t make the mistake of “supplementizing” these foods. That is, don’t consume large quantities of these foods in an effort to offset an otherwise poor diet. Eating these hypertension superfoods in the context of an overall healthy, plant-based diet is where you will see the most benefit.
I hope these posts have left you with the impression that, while common, hypertension is almost always preventable, often reversible, and thus usually optional. While medications can help lower the risk of secondary complications like heart disease and strokes, they are not curative and come with added costs and potential side effects. True healing is achieved by understanding that hypertension is a lifestyle disease and approaching it accordingly. If you suffer with hypertension and would like help in addressing it, please do not hesitate to schedule an appointment at your earliest convenience.
1. Nguyen, H., Odelola, O. A., Rangaswami, J., & Amanullah, A. (2013). A review of nutritional factors in hypertension management. International Journal of Hypertension, 2013.
2. Alexander, S., Ostfeld, R. J., Allen, K., & Williams, K. A. (2017). A plant-based diet and hypertension. Journal of geriatric cardiology : JGC, 14(5), 327-330.
3. Vogel, R. A., Corretti, M. C., & Plotnick, G. D. (1997). Effect of a single high-fat meal on endothelial function in healthy subjects. The American Journal of Cardiology, 79, 350-354.
4. Hall, W. L. (2009). Dietary saturated and unsaturated fats as determinants of blood pressure and vascular function. Nutrition Research Reviews, 22(1), 18-38.
5. Edwards, D. G., & Farquhar, W. B. (2015). Vascular effects of dietary salt. Current opinion in nephrology and hypertension, 24(1), 8-13.
6. Wilck, N., Matus, M. G., Kearney, S. M., Olesen, S. W., Forslund, K., Bartolomaeus, H.,…Müller, D. N. (2017). Salt-responsive gut commensal modulates TH17 axis and disease. Nature, 551(7682),
7. Houston, M. (2011). The role of magnesium in hypertension and cardiovascular disease. Journal of Clinical Hypertension, 13, 843-847.
8. Jayedi, A., & Sadat Zargar, M. (2018). Dietary calcium intake and hypertension risk: A dose–response meta-analysis of prospective cohort studies. European Journal of Clinical Nutrition.
9. Rodriguez-Leyva, D., Weighell, W., Edell, A. L., LaVallee, R., Dibrov, E., Pinneker, R., . . . Pierce, G. N. (2013). Potent antihypertensive action of dietary flaxseed in hypertensive patients. Hypertension, 62(6), 1081-1089.
10. Asgary, S., Afshani, M. R., Sahebkar, A., Keshvari, M., Taheri, M., Jahanian, E., . . . Sarrafzadegan, N. (2016). Improvement of hypertension, endothelial function and systemic inflammation following short-term supplementation with red beet (Beta vulgaris L.) juice: a randomized crossover pilot study. Journal of Human Hypertension, 30, 627-632.
11. Hopkins, A. L., Lamm, M., Funk, J., & Ritenbaugh, C. (2013). Hibiscus sabdariffa L. in the treatment of hypertension and hyperlipidemia: A comprehensive review of animal and human studies. Fitoterapia, 85, 84-94.