A new, very large study just published in the Journal of Clinical Endocrinology & Metabolism shows chronic low sodium concentration in the blood (hyponatremia) increases risk of osteoporosis, fragility fracture 390%!¹
Normal serum sodium levels are between approximately 135 and 145 mEq/liter (135 – 145 mmol/L). Hyponatremia is a serum sodium level of less than 135 mEq/L. Sodium loss can lead to a state of low blood volume, which triggers the release of anti-diuretic hormone, which leads to water retention and dilution of the blood resulting in a low sodium concentration.
Too little sodium in the diet is rarely the key cause of hyponatremia, but avoiding salt entirely may contribute.
Normally, we need about ½ teaspoon of salt per day, but for many of us, since summer means we’re sweating more, we may need a wee bit more – say just ¾ teaspoon of salt per day.
Sweat contains electrolytes, which include not just magnesium, potassium and calcium, but also sodium. Whatever makes you sweat – be it salsa or swing dancing, Zumba or a BodyPump class (my favorites), a hike or a couple of hours working outside in your garden – will make you need to replace the electrolytes you’ve sweated out. Another good reason to be sure you are taking your 2 capsules of AlgaeCal Plus in the morning and again at night to ensure your calcium and magnesium needs are being met. If you’re working up a sweat most days – a great way to build healthy bones – then your chances of being chronically hyponatremic are not insignificant. Exercise-associated hyponatremia is common in marathon runners and participants of other endurance events. 13% of the athletes who finished the 2002 Boston Marathon were in a hyponatremic state, that is, the salt levels in their blood had fallen below 135 – 145 mmol/L levels. ²
Many conditions including kidney and liver disease, are associated with a low sodium concentration in the blood.
Hyponatremia can be caused by:
- Overhydration from drinking too much water because of excess thirst.
- Other causes include hypothyroidism, adrenal insufficiency (both thyroid hormone and cortisol are required to excrete free water), and
- Drugs: particularly SSRIs (~ 30% of depressed patients on SSRIs have hyponatremia); tricyclic antidepressants; antipsychotics; anti-epileptics; glucocorticoids; thiazide & loop diuretics. If you have any of these conditions or are taking any of these drugs, have your doctor run a lab to check your blood levels of sodium next time you go in for a checkup.
¹Miriam Rachel Usala G, Fernandez SJ, Mete M, et al. Hyponatremia is Associated with Increased Osteoporosis and Bone Fractures in a Large U. S. Health System Population. J Clin Endocrinol Metab. 2015 Jun 17:jc20151261. [Epub ahead of print] PMID: 26083821
²Almond CS, Shin AY, Fortescue EB, et al. Hyponatremia among runners in the Boston Marathon. N Engl J Med. 2005 Apr 14;352(15):1550-6. PMID: 15829535
Add New Comment