Salt: More than High Blood Pressure
Sodium is an important mineral that is essential for proper functioning of the human body—however, the American diet contains dangerously high amounts of sodium, almost 80% of which comes from processed and restaurant foods.1 The human diet, for millions of years, did not contain any added salt—only the sodium present in natural foods, adding up to only about 1000 mg sodium per day. The dietary intake of sodium in the U.S. today is about 3500 mg/day—much more than the human body needs.2
Excess dietary salt is most notorious for increasing blood pressure. Americans have a 90% lifetime probability of developing high blood pressure—so even if your blood pressure is normal now, if you continue to eat the typical American diet, you will be at risk. Elevated blood pressure accounts for 62% of strokes and 49% of coronary heart disease.3 Even if you eat an otherwise healthy diet, and your arteries are free of plaque, hypertension late in life damages the delicate blood vessels of the brain, increasing the risk of hemorrhagic stroke. The American Heart Association, recognizing the significant risks of high blood pressure, has recently dropped their recommended maximum sodium intake from 2300 mg to 1500 mg.4
But did you know that salt has several potentially dangerous effects that are not related to blood pressure?
Damage to the cardiovascular system: In the 1990s, it was found that the relationship between salt intake and death from stroke was stronger than the relationship between blood pressure and death from stroke; this suggested that salt had damaging effects on the cardiovascular system other than elevating blood pressure.5 Further research confirmed this observation, showing that long-term excess dietary sodium leads to stiffening of the arteries.6-9 Also, more recent research found that blood vessel function is suppressed within a mere 30 minutes following a high salt meal.10
Damage to the kidneys: Hypertension is an important risk factor for kidney disease, but dietary sodium has other damaging effects on the kidneys. High salt intake leads to oxidative stress in kidney tissue, and is associated with a decline in kidney function.9,11
Calcium loss from bone: High salt intake is a risk factor for osteoporosis because excess dietary sodium promotes urinary calcium loss, leading to calcium loss from bone and therefore decreased bone density.12 Even in the presence of a high calcium diet, high salt intake results in net calcium loss from bone.13
Ulcers & stomach cancer: Salt is the strongest factor relating to stomach cancer 14-16 A high salt diet also increases growth of the ulcer-promoting bacteria H. pylori in the stomach, which is also a risk factor for gastric cancer.9
Asthma: In asthma patients, high dietary sodium may increase severity of the disease.9
Autoimmune disease: There is evidence that excess sodium may increase the inflammation associated with several autoimmune conditions. A certain pro-inflammatory immune cell type that is elevated in people with autoimmune diseases was found also to be elevated in people who eat fast food more often, implying that excess sodium could be involved; studies of these immune cells in different sodium concentrations implied the same. In addition, mice that were predisposed to an autoimmune disease developed the disease more quickly when given a high-salt diet compared to a standard diet.17-19
Avoid added salt! Reducing dietary salt is not only important for those who already have elevated blood pressure—limiting added salt is essential for all of us to remain in good health. It is also important to note that expensive and exotic sea salts are still salt. All salt originates from the sea—it contains over 98% sodium chloride, and it is not health-promoting. Sea salts may contain small amounts of trace minerals, the amounts are insignificant compared to those in natural plant foods. A Nutritarian diet with plenty of G-BOMBS and little or no added salt is ideal.
1. Jacobson MF: Salt: The Forgotten Killer. 2005. Center for Science in the Public Interest. http://www.cspinet.org/salt/saltreport.pdf . Accessed
2. Bernstein AM, Willett WC: Trends in 24-h urinary sodium excretion in the United States, 1957-2003: a systematic review. The American journal of clinical nutrition 2010;92:1172-1180.
3. He FJ, MacGregor GA: A comprehensive review on salt and health and current experience of worldwide salt reduction programmes. J Hum Hypertens 2009;23:363-384.
4. Appel LJ, Frohlich ED, Hall JE, et al: The Importance of Population-Wide Sodium Reduction as a Means to Prevent Cardiovascular Disease and Stroke: A Call to Action From the American Heart Association. Circulation 2011.
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10. 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.
11. Diets High In Sodium And Artificially Sweetened Soda Linked To Kidney Function Decline. 2009. ScienceDaily. http://www.sciencedaily.com/releases/2009/11/091101132543.htm . Accessed
12. Devine A, Criddle RA, Dick IM, et al: A longitudinal study of the effect of sodium and calcium intakes on regional bone density in postmenopausal women. The American journal of clinical nutrition 1995;62:740-745.
13. Teucher B, Dainty JR, Spinks CA, et al: Sodium and bone health: impact of moderately high and low salt intakes on calcium metabolism in postmenopausal women. Journal of bone and mineral research : the official journal of the American Society for Bone and Mineral Research 2008;23:1477-1485.
14. Sonnenberg A: Dietary salt and gastric ulcer. Gut 1986;27:1138-1142.
15. Tsugane S, Sasazuki S: Diet and the risk of gastric cancer: review of epidemiological evidence. Gastric Cancer 2007;10:75-83.
16. D'Elia L, Rossi G, Ippolito R, et al: Habitual salt intake and risk of gastric cancer: A meta-analysis of prospective studies. Clin Nutr 2012.
17. Kleinewietfeld M, Manzel A, Titze J, et al: Sodium chloride drives autoimmune disease by the induction of pathogenic T17 cells. Nature 2013.
18. Harmon K: Salt linked to autoimmune diseases. 2013. Nature News. http://www.nature.com/news/salt-linked-to-autoimmune-diseases-1.12555 . Accessed
19. Wu C, Yosef N, Thalhamer T, et al: Induction of pathogenic T17 cells by inducible salt-sensing kinase SGK1. Nature 2013.