Long-Term Effects of Too Much Salt

Video 1.  Sodium and Arterial Function: A-salting our Endothelium (YouTube link)

The Western diet is rich in salt, which poses various health risks.  For example,  too much sodium in the diet can lead to high blood pressure, stomach cancer, kidney stones, bone loss, obesity and even cause direct damage to our kidneys, arteries, and heart.

According to the WHO’s recommendations, the maximum amount of salt individuals should consume every day is 5 grams, which is about 1 level teaspoon. In reality most of us are exceeding this amount considerably.

Long-Term Effects of Too Much Salt

• Bad for cardiovascular systems^[5]
• Consume one salty meal, and not only does our blood pressure go up, but our arteries literally stiffen
• Sodium in our blood stiffens the artery lining within minutes and reduces nitric oxide release
• Whereas potassium, concentrated in fruits and vegetables, softens the cells that line our arteries and increases the release of nitric oxide that allows our arteries to relax
• Bad for immune system^[6,8]
• Human volunteers consuming an extra 6 grams of salt a day experienced pronounced immune deficiencies. This amount is equivalent to the salt content of 2 fast food meals.
• A high-salt diet compromises antibacterial neutrophil responses through hormonal perturbation
• High salt diet → overactivation of Th17 cells → autoimmune diseases
• Salt appears to drive autoimmune disease by the induction of disease-causing Th17 cells, which includes but not limited to:
• Multiple sclerosis, psoriasis, type I diabetes, Sjögren’s syndrome, asthma, and rheumatoid arthritis
• It turns out there’s a salt-sensing enzyme which is responsible for triggering the formation of these Th17 cells.
• Bad for bone
• It can cause calcium losses, some of which may be pulled from bone.
• Higher stomach cancer risk
• The pickled foods (i.e., kimchi and the like) may explain why Korea appears to have the highest stomach cancer rates in the world.^[17]
• In a study, it showed that the importance of nitrate as risk factor for stomach cancer mortality increased markedly with higher sodium levels. However, the relationship of stomach cancer mortality with sodium was always stronger than with nitrate.^[15]

Some Salt-Rich Foods

Dietary salt intake is directly associated with the risk of stomach cancer.^[15]  And, the higher the intake, the higher the risks. In a meta-analysis study,  it went further looking at specific salt-rich foods: 

• Pickled foods
• Salted fish
• Processed meat
• Miso soup

to see their effect on the cancer rate.  Here are its findings:

• Habitual consumption of pickled foods, salted fish,  and processed meat were associated with about a 25% greater risk of stomach cancer. 
• But, there was no significant association with the consumption of miso soup.^[18] 
• This may be because the carcinogenic effects of the salt are counteracted by the anti-carcinogenic effects of the soy, effectively canceling out the risk. 
• And, if we made garlicky soup with some scallions thrown in, it may drop our cancer risk even lower.

Video 2.  Is miso health? (YouTube link)

References

1. Association Between Sodium Excretion and Cardiovascular Disease and Mortality in the Elderly: A Cohort Study
2. 老人吃盐太少，很危险，国外最新研究发现
3. Sodium & Arterial Function: A-Salting our Endothelium
4. Sodium Skeptics Try to Shake Up the Salt Debate
5. Why We Should Cut Down on Salt Independently of Blood Pressure (Dr. Greger)
6. A high-salt diet compromises antibacterial neutrophil responses through hormonal perturbation
7. Salt and Sodium 
8. Sodium and Autoimmune Disease: Rubbing Salt in the Wound?
9. Mickleborough TD, Lindley MR, Ray S. Dietary salt, airway inflammation, and diffusion capacity in exercise-induced asthma. Med Sci Sports Exerc. 2005 Jun;37(6):904-14.
10. Javaid A, Cushley MJ, Bone MF. Effect of dietary salt on bronchial reactivity to histamine in asthma. BMJ. 1988 Aug 13;297(6646):454.
11. van der Meer JW, Netea MG. A salty taste to autoimmunity. N Engl J Med. 2013 Jun 27;368(26):2520-1.
12. Zhou X, Zhang L, Ji WJ, Yuan F, Guo ZZ, Pang B, Luo T, Liu X, Zhang WC, Jiang TM, Zhang Z, Li YM. Variation in dietary salt intake induces coordinated dynamics of monocyte subsets and monocyte-platelet aggregates in humans: implications in end organ inflammation. PLoS One. 2013 Apr 4;8(4):e60332.
13. Wu C, Yosef N, Thalhamer T, Zhu C, Xiao S, Kishi Y, Regev A, Kuchroo VK. Induction of pathogenic TH17 cells by inducible salt-sensing kinase SGK1. Nature. 2013 Apr 25;496(7446):513-7.
14. Yi B, Titze J, Rykova M, Feuerecker M, Vassilieva G, Nichiporuk I, Schelling G, Morukov B, Choukèr A. Effects of dietary salt levels on monocytic cells and immune responses in healthy human subjects: a longitudinal study. Transl Res. 2015 Jul;166(1):103-10.
15. Joossens JV, Hill MJ, Elliott P, Stamler R, Lesaffre E, Dyer A, Nichols R, Kesteloot H. Dietary salt, nitrate and stomach cancer mortality in 24 countries. European Cancer Prevention (ECP) and the INTERSALT Cooperative Research Group. Int J Epidemiol. 1996 Jun;25(3):494-504.
16. Boutron-Ruault MC, Trichopoulou A, Psaltopoulou T, Roukos D, Lund E, Hemon B, Kaaks R, Norat T, Riboli E. Meat intake and risk of stomach and esophageal adenocarcinoma within the European Prospective Investigation Into Cancer and Nutrition (EPIC). J Natl Cancer Inst. 2006 Mar 1;98(5):345-54.
17. Stomach cancer statistics
18. Is Miso Healthy?
19. What Are the Best Foods for Kidney Health?
• A renal diet is a diet that becomes increasingly more restrictive as your kidney function declines. It starts out with having you limit your salt and the amount of protein you eat.