Studies have not established the effect of salt on breast cancer

Last updated:
Effect of salt on breast cancer not established
Although salt is a necessity, U.S. consumers are unlikely ever to be deficient in salt (sodium). Our diets are heavily loaded with salt, the majority of which is derived from processed food, fast food, and restaurant meals. Increasing salt consumption is correlated with higher blood pressure in the majority of people, so that high salt consumption serves to promote heart disease and stroke.
Salt consumption is also suspected of contributing to insulin resistance and metabolic syndrome, which themselves may be associated with increased risk of breast cancer.
High salt consumption has been found to be associated with increased risk of pancreatic cancer. Consumption of highly salted foods (including fermented soybean products, pickled vegetables, preserved salted vegetables, and salted fish) has also been found to be associated with increased risks of ovarian and prostate cancer in China. Consumption of salted fish has been shown in several studies to increase the risks of nasopharyngeal and colorectal cancers, as well as stomach cancer. One South American study found the risk of esophageal cancer to increase with increasing consumption of salt.

Breast cancer-related effects of consuming salt

The relationship between salt and cancer is related to two types of salt intake: high overall intake and high intake of very salty foods. The relatively high overall level of salt in the average U.S. diet contributes to cancer risk indirectly by promoting metabolic syndrome and reducing the potassium/sodium ratio in the diet, both of which are thought to increase the risks of various cancers.
The second type of cancer-promoting salt intake occurs when people consume highly salted specialty foods, condiments and snacks. These foods act directly on the digestive track and have been shown in numerous studies to cause stomach (gastric) cancer. Implicated foods include dried and salted fish and seafood, fermented/pickled vegetables, fish sauce, kimchi, salted preserved vegetables, salted and fermented soybean paste, salted fish preserves, salted fish roe, salted meat, salted shrimp paste, salty snacks, and salty soups. Many of the foods listed above are Asian; since the rate of stomach cancer is relatively high in Asia, there has been great interest in investigating the causes. Note however, that European and South American studies also have found associations between heavily salted foods and stomach cancer.
One study hypothesized that a high salt diet might result in an earlier onset of puberty, which in turn would increase subsequent breast cancer risk. Another study reported that hormone receptor positive (ER+/PR+) and triple negative (ER-/PR-/HER2-) breast cancer cells exerted higher tumorigenicity when exposed to high levels of salt. The same study found that high salt induced resistance to the chemotherapy drug Taxol in breast cancer cells. A 2020 study described a mechanism of action by which a high salt diet could promote breast cancer metastasis and accelerate its progression.
There is some evidence that breast cancer survivors are at increased risk of developing stomach cancer and lobular breast cancer survivors in particular are vulnerable to gastric metastases.

Additional comments

Sodium nitrite and related compounds are routinely added to processed meat and some other salty foods to preserve their freshness and coloring. Sodium nitrite has been shown to react with chemicals in the stomach to produce nitrosamines, which are known to be cancer-promoting. However, the cancer-related effects of salt consumption are not dependent on the presence of sodium nitrite; this carcinogen simply worsens the cancer profile of salty foods that contain it.
Iodine deficiency is a major cause of preventable mental retardation found worldwide. Iodized salt is designed to prevent this deficiency.
Note that while we are continually searching for new evidence specifically concerning this food, there is not much interest in it among breast cancer researchers, so few studies are available.

Selected breast cancer studies

  • Liking for foods high in salt and fat is associated with a lower diet quality but liking for foods high in sugar is not – Results from the PREDISE study Cite
    Carbonneau E, Lamarche B, Provencher V, Desroches S, Robitaille J, Vohl M, et al. Liking for foods high in salt and fat is associated with a lower diet quality but liking for foods high in sugar is not – Results from the PREDISE study. Food Quality and Preference. Elsevier BV; 2021; 88:104073 10.1016/j.foodqual.2020.104073
  • High salt diet may promote progression of breast tumor through eliciting immune response Cite
    Chen J, Liu X, Huang H, Zhang F, Lu Y, Hu H. High salt diet may promote progression of breast tumor through eliciting immune response. International Immunopharmacology. Elsevier BV; 2020; 87:106816 10.1016/j.intimp.2020.106816
  • High salt induces P-glycoprotein mediated treatment resistance in breast cancer cells through store operated calcium influx Cite
    Babaer D, Amara S, Ivy M, Zhao Y, Lammers PE, Titze JM, et al. High salt induces P-glycoprotein mediated treatment resistance in breast cancer cells through store operated calcium influx. Oncotarget. Impact Journals, LLC; 2018; 9:25193-25205 10.18632/oncotarget.25391
  • High Salt Intake Attenuates Breast Cancer Metastasis to Lung Cite
    Xu Y, Wang W, Wang M, Liu X, Lee M, Wang M, et al. High Salt Intake Attenuates Breast Cancer Metastasis to Lung. Journal of Agricultural and Food Chemistry. American Chemical Society (ACS); 2018; 66:3386-3392 10.1021/acs.jafc.7b05923
  • Does salt have a permissive role in the induction of puberty? Cite
    Pitynski D, Flynn FW, Skinner DC. Does salt have a permissive role in the induction of puberty?. Medical Hypotheses. Elsevier BV; 2015; 85:463-467 10.1016/j.mehy.2015.06.029
  • Lower Breast Cancer Risk among Women following the World Cancer Research Fund and American Institute for Cancer Research Lifestyle Recommendations: EpiGEICAM Case-Control Study Cite
    Castelló A, Martín M, Ruiz A, Casas AM, Baena-Cañada JM, Lope V, et al. Lower Breast Cancer Risk among Women following the World Cancer Research Fund and American Institute for Cancer Research Lifestyle Recommendations: EpiGEICAM Case-Control Study. PLOS ONE. Public Library of Science (PLoS); 2015; 10:e0126096 10.1371/journal.pone.0126096
  • Diet and Cancer Risk in the Korean Population: A Meta-analysis Cite
    Woo HD, Park S, Oh K, Kim HJ, Shin HR, Moon HK, et al. Diet and Cancer Risk in the Korean Population: A Meta-analysis. Asian Pacific Journal of Cancer Prevention. Asian Pacific Organization for Cancer Prevention; 2014; 15:8509-8519 10.7314/apjcp.2014.15.19.8509
  • Estimated Amount of 24-Hour Urine Sodium Excretion Is Positively Correlated with Stomach and Breast Cancer Prevalence in Korea Cite
    Park JH, Kim YC, Koo HS, Oh SW, Kim S, Chin HJ. Estimated Amount of 24-Hour Urine Sodium Excretion Is Positively Correlated with Stomach and Breast Cancer Prevalence in Korea. Journal of Korean Medical Science. Korean Academy of Medical Sciences; 2014; 29:S131 10.3346/jkms.2014.29.s2.s131
  • USDA Monitors Levels of Added Sodium in Commercial Packaged and Restaurant Foods Cite
    Holden J, Pehrsson P, Nickle M, Haytowitz D, Exler J, Showell B, et al. USDA Monitors Levels of Added Sodium in Commercial Packaged and Restaurant Foods. Procedia Food Science. Elsevier BV; 2013; 2:60-67 10.1016/j.profoo.2013.04.010
  • Salt, processed meat and the risk of cancer Cite
    Hu J, La Vecchia C, Morrison H, Negri E, Mery L. Salt, processed meat and the risk of cancer. European Journal of Cancer Prevention. Ovid Technologies (Wolters Kluwer Health); 2011; 20:132-139 10.1097/cej.0b013e3283429e32
  • Body composition, dietary salt and sugar intake as determinants of breast cancer: a case-control study Cite
    Bernardi JLD, Gomes JCN, McLellan KCP, Merhi VAL, de Souza MC. Body composition, dietary salt and sugar intake as determinants of breast cancer: a case-control study. Proceedings of the Nutrition Society. Cambridge University Press (CUP); 2011; 70 10.1017/s0029665111001996
  • Gastric malignancies in breast cancer survivors: Pathology and outcomes Cite
    Ellis MC, Mason T, Barnett J, Kiesow LL, Vetto JT. Gastric malignancies in breast cancer survivors: Pathology and outcomes. The American Journal of Surgery. Elsevier BV; 2009; 197:633-636 10.1016/j.amjsurg.2008.12.015
  • Diet and cancer of the stomach: A case-control study in China Cite
    Hu J, Zhang S, Jia E, Wang Q, Liu S, Liu Y, et al. Diet and cancer of the stomach: A case-control study in China. International Journal of Cancer. Wiley; 1988; 41:331-335 10.1002/ijc.2910410302
  • Consumption of Salted Fish and Other Risk Factors for Nasopharyngeal Carcinoma (NPC) in Tianjin, a Low-Risk Region for NPC in the People's Republic of China Cite
    Ning J, Yu MC, Wang Q, Henderson BE. Consumption of Salted Fish and Other Risk Factors for Nasopharyngeal Carcinoma (NPC) in Tianjin, a Low-Risk Region for NPC in the People's Republic of China. JNCI Journal of the National Cancer Institute. Oxford University Press (OUP); 1990; 82:291-296 10.1093/jnci/82.4.291