Sodium - Information and Sources
Sodium is an electrolyte which is essential for regulating the body's water balance and acid-base balance, nerve stimulation, muscle contraction and the uptake of nutrients by cells in the intestines and kidneys.
Dietary reference values for sodium are 1.6g per day for adults. In the West there is over-consumption of sodium through people having too much sodium chloride (salt) in their diet. It is rare for there to be sodium deficiency without an underlying medical condition, except in severe heat dehydration from perfuse sweating causing loss of fluid and sodium. Symptoms include weakness, apathy, nausea and muscle cramps. Taking additional salt in tablet form is a preventive measure, and increased use of table salt is also recommended to replace sodium lost during dehydration and sweating. In rare cases, sodium deficiency can lead to systemic shock due to decreased blood pressure.
High sodium diets, common in modern society, may lead to water retention and high blood pressure. However, sodium is generally nontoxic for healthy adult individuals because it is excreted readily in the urine. Government campaigns are focused on getting people to consume less salt (sodium).
Sodium occurs naturally in a wide range of foods and it is also present in drinking water, although the amount varies deepening on the source. Salt is added to various food products as it helps flavour and is a food preservative.
Sodium is also found added to food as part of food additives including monosodium glutamate, sodium nitrite, sodium saccharin, baking soda (sodium bicarbonate) and sodium benzoate. These additives are ingredients in condiments and seasonings such as Worcestershire sauce, tomato ketchup, soya sauce, garlic salt and gravy granules, and processed and fast food take aways (which are typically very high in sodium).
Processed meats, such as bacon, sausage and ham, and canned soups and vegetables are all examples of foods that contain added sodium. Many prescription and OTC drugs are also significantly high in sodium (check labels).
Marmite, Bovril and pickles are also high in salt. Snack foods like crisps and salted nuts are very high in sodium due to salt content.
Natural food sources which contribute to sodium intake include:
- Red meat
- Fish, especially sea fish
- Dark green leafy vegetables
- Runner beans
- Kelp (seaweed)