Salt is often used as a flavoring and preservative in food, and has been since before recorded history. We take salt for granted now, but it was once so esteemed it was used as currency and was equivalent to gold in value. Salt was used in trade, and the difficulty in obtaining salt was initially responsible for it’s high value. Later, its availability to the market was highly regulated, thereby keeping the value high. Salt was also an important part of religious rituals across different faiths. And wars have even been fought over it! The word “salt” comes originally from “Salus,” a Roman goddess seen as the protector of health. “Sal” referred to the “salubrious” (health-promoting) nature of salt (1).
Why Salt?
Many natural dog treats and foods employ salt as a simple, non-toxic and natural preservative. Other natural preservatives include vitamin E (aka tocopherols) and vitamin C (ascorbic acid), which are used to prevent fats and oils in food from going rancid. Salt acts as a preservative via a different mechanism — it prevents the proliferation of microbes such as bacteria and mold. How does salt do this? In a high enough concentration, salt “sucks” water out of cells. Bacteria are individual cells, while mold is made of multiple cells. Salt also dries the food itself, by absorbing water, and making the food too dry an environment to allow microbial growth. You will usually see salt, vitamin E and vitamin C in a natural dog treat.
Does My Dog Need Salt?
Both sodium and chloride are heavily involved in cellular function, acid-base balance, fluid balance and nerve signal transmission. Salt deficiency may cause abnormalities in heart rhythm, restlessness, dry mucus membranes, excess fluid intake and excess urination, among other issues (2).
What About Salt and High Blood Pressure?
While excessive salt intake over time can contribute to high blood pressure in people, this isn’t necessarily so for dogs. Some pooches do suffer from high blood pressure, but many are generally resistant to it (3), and there is not much evidence that sodium levels in the diet of a healthy dog correlates with blood pressure (2). In fact, dogs appear quite resistant to wide fluctuations in the amount of salt in their diet (2). Problems in dogs related to salt are associated mainly with very high intake (2) or from being put on a salt-restricted diet (4). Indeed, salt is a necessary part of the canine diet, with the minimum daily requirement to avoid disease of 5 mg per kg of dog weight (2). Commercial dog foods generally contain similar levels of salt as that found in the prey animals eaten by wild dogs (2).
References
- Time Staff (1982) A brief history of salt. Time. March 15.
- Watson, T (2010) Sodium – chloride, tripolyphosphate, or nitrite: do dogs really need salt? Veterinary Times
- Michell, AR, et al (1994) Salt, hypertension and renal disease: comparative medicine, models and real diseases. Postgrad Med J. 70(828):686-94.
- Suematsu, N, et al (2010) Potential mechanisms of low-sodium diet-induced cardiac disease: superoxide-NO in the heart. Circ Res. 106(3):593-600.
