In home care, saline solution is widely used for nasal irrigation and wound cleaning due to its osmotic pressure being identical to that of the human body. However, using iodized salt instead of medical-grade non-iodized salt to prepare solutions, a seemingly simple operation, can lead to multiple health risks.
Osmotic Pressure Imbalance
The core standard for saline solution is a sodium chloride concentration of 0.9%, a ratio that perfectly matches the osmotic pressure of human extracellular fluid. When using iodized salt, if the amount of salt cannot be precisely controlled, concentration deviations are very likely to occur. For example, the commonly used rough ratio of "one spoonful of salt to 500 ml of water" may result in an actual salt amount error of 30%-50% due to differences in spoon size. If the concentration is too high, nasal mucosal cells will lose water due to the osmotic pressure difference, causing dryness, stinging, and even tiny cracks, creating conditions for bacterial invasion; if the concentration is too low, it will lead to mucosal edema, worsening symptoms such as nasal congestion and runny nose.
A clinical case illustrates how a patient's self-prepared saline solution with iodized salt for nasal irrigation resulted in severe dehydration of the nasal mucosa due to improper concentration control, ultimately leading to sinusitis that required antibiotic treatment for relief. This case demonstrates the direct threat of osmotic imbalance to nasal health.
The Dual Role of Iodine
While potassium iodate or potassium iodide in iodized salt is an essential trace element, it plays a contradictory role in nasal irrigation. On one hand, iodine has broad-spectrum bactericidal properties, inhibiting the growth of bacteria, viruses, and other microorganisms; on the other hand, its strong oxidizing properties directly irritate the nasal mucosa. Studies indicate that when the iodine concentration exceeds 0.01%, it can cause denaturation of mucosal cell proteins, leading to stinging, burning sensations, and even triggering allergic rhinitis.
More importantly, the nasal mucosa contains a rich network of capillaries. If there are minor breaks in the mucosa during irrigation, iodine may be rapidly absorbed into the bloodstream. Long-term excessive iodine intake may interfere with thyroid function, especially for patients with hyperthyroidism or pregnant women, potentially leading to serious consequences such as palpitations and metabolic disorders.
Risk of Impurities
Medical saline solution undergoes multiple processes including distillation, filtration, and sterilization to ensure the solution is free of microorganisms, heavy metals, and other impurities. While household iodized salt meets food standards, it may contain additives such as anti-caking agents (e.g., potassium ferrocyanide) and minerals. These components may deposit in the nasal cavity during rinsing, damaging the mucosal barrier and even becoming a culture medium for bacteria.
Comparative experiments have shown that rinsing the nasal cavity with saline solution prepared with iodized salt resulted in a 2.3 times higher detection rate of bacteria in nasal secretions compared to using physiological saline. This data suggests that the risk of impurities may negate the bactericidal effect of iodine, actually increasing the probability of infection.
Safe Alternative Solutions
If you need to prepare your own nasal irrigation solution, please follow these principles:
Use non-iodized salt: Prioritize purchasing medical-grade non-iodized salt, or use table salt labeled "anti-caking agent-free";
Precise weighing: Prepare the solution by adding 4.5 grams of salt to every 500 ml of water (with an error of no more than ±0.5 grams);
Sterilization: Boil the prepared solution for 15 minutes, or sterilize it in a microwave oven for 1 minute;
Temperature control: The temperature of the irrigation solution should be close to body temperature (36-38℃) to avoid cold or hot stimulation that could cause mucosal spasms.
For special populations such as children, pregnant women, and patients with thyroid diseases, it is recommended to use commercially available saline solution, as its sterility and concentration stability are more guaranteed. For example, a certain brand of children's nasal irrigation solution uses micron-level filtration technology to control the impurity content to below 0.001%, significantly reducing the risk of allergies.
From osmotic pressure balance to component purity, the preparation of saline solution is far more than a simple combination of "salt + water". Misuse of iodized salt can trigger multiple risks, ranging from local irritation to systemic metabolic disorders. This is especially true in the care of the nasal cavity, a sensitive organ, where any deviation in composition can be amplified into health hazards. Following medical guidelines and choosing compliant products is the first line of defense for protecting respiratory health.
