Are there documented cases of nutritional sodium deficiency? I'm curious what the symptoms are, and if it's possible to achieve them through dietary restrictions alone. I could only find examples of hyponatremia with causes other than nutritional deficiency.
Two case reports of hyponatremia in infants fed exclusively with almond, nut, chestnut and soy milk or a homemade sesame seed emulsion were identified. These cases appear to be due to inadequate sodium in the diet.
Fourreau D, Peretti N, Hengy B, et al. Complications carentielles suite à l'utilisation de « laits » végétaux, chez des nourrissons de deux mois et demi à 14 mois (quatre cas) [Pediatric nutrition: Severe deficiency complications by using vegetable beverages, four cases report]. Presse Med. 2013;42(2):e37-43. French. doi: 10.1016/j.lpm.2012.05.029. Epub 2012 Sep 28. PMID: 23021957.
Shohat M, Levy I, Levy Y, Nitzan M. Nutritional complications in an infant fed exclusively on homemade sesame seed emulsion. J Am Coll Nutr. 1989;8:167-9. doi: 10.1080/07315724.1989.10720291. PMID: 2708731.
According to Sterns, hyponatremia is not a disease but rather a pathophysiologic process indicating disturbed water homeostasis.
Sterns RH. Disorders of plasma sodium--causes, consequences, and correction. N Engl J Med. 2015;372:55-65. doi: 10.1056/NEJMra1404489. PMID:25551526.
Maximal dilution of urine prevents hyponatremia unless water intake is extraordinarily large (>1 liter per hour) (e.g., in patients with schizophrenia who drink water compulsively) or the rate of urinary solute excretion is extremely low (e.g., in beer drinkers who eat very little).
There are numerous case reports of a condition called “beer potomania”—excessive consumption of beer—which is characterized by hyponatremia. Lodhi et al. explain “beer potomania” as follows:
Beer potomania, a unique syndrome of hyponatremia, was first reported in 1972. It is described as the excessive intake of alcohol, particularly beer, together with poor dietary solute intake that leads to fatigue, dizziness, and muscular weakness. The low solute content of beer, and suppressive effect of alcohol on proteolysis result in reduced solute delivery to the kidney. The presence of inadequate solute in the kidney eventually causes dilutional hyponatremia secondary to reduced clearance of excess fluid from the body.
Lodhi MU, Saleem TS, Kuzel AR, et al. "Beer Potomania" - A Syndrome of Severe Hyponatremia with Unique Pathophysiology: Case Studies and Literature Review. Cureus. 2017;9(12):e2000. doi: 10.7759/cureus.2000. PMID: 29507848; PMCID: PMC5832394.
Published case reports of beer potomania up to 2018 are cited in Joshi and Chou, who also explain the pathophysiology.
Joshi R, Chou S. Beer Potomania: A View on the Dynamic Process of Developing Hyponatremia. Cureus 2018;10(7): e3024. DOI 10.7759/cureus.3024
Pica is a condition in which patients crave and chew substances with no nutritional value. Ice pica (pagophagia) is seen in patients with iron deficiency. A case report of hyponatremia due to excessive consumption of water because of ice pica (pagophagia) was identified.
Bedanie G, Tikue A, Thongtan T, et al. Pica/Pagophagia-Associated Hyponatremia: Patient Presenting With Seizure. Cureus 2020;12(7): e9330. DOI 10.7759/cureus.9330 https://pubmed.ncbi.nlm.nih.gov/32742885/
Tea and Toast syndrome is a well-known cause of hyponatremia due to a diet with restricted salt/protein intake but abundant fluids ("tea and toast"), usually occurring among elderly who are unable to cook or feed themselves properly. This is especially dangerous when taking other salt-wasting medication such as diuretics.
symptomatology of acute hyponatremia (developed in <48 h) such as nausea, vomiting, headache, stupor, coma and seizures, as well as manifestations (even mild) associated with chronic hyponatremia, such as fatigue, cognitive impairment, gait deficits, falls, adverse effects on bone quality (eg, osteoporosis) and fractures, are more frequent and severe in elderly patients
Filippatos TD, Makri A, Elisaf MS, Liamis G. Hyponatremia in the elderly: challenges and solutions. Clin Interv Aging. 2017;12:1957-1965. Published 2017 Nov 14. doi:10.2147/CIA.S138535