Himalayan Pink Rock Salt. Bolivian Rose Sea Salt. Celtic Sea Salt.
Rock and Sea Salts are marketed to us as a more natural and healthy alternative. But are they any
different than table salt?
Yes and No.
What is Sea Salt and Rock Salt, anyway?
Sea Salt is produced through evaporation of seawater. Depending on the region, the seawater imparts trace minerals and elements to the salt, giving it a distinct color and texture.
Rock Salts form from old, dried lakes and river beds in Earth's rocky sublayers. If we are getting technical (my first major was Geology), rock salt is a sedimentary rock called 'halite', primarily composed of NaCl (sodium chloride). Like sea salt, each type of rock salt has specific impurities - trace minerals and elements - that give it
For example, Himalayan Pink Rock Salt typically contains a bit of iron oxide, which gives it a pinkish huge. Hawaiian Alaea Sea Salt gets its brownish-pink color from a Hawaiian clay called ‘alaea', which again is rich in iron oxide. Black Sea Salt actually has activated charcoal added to it primarily for visual effects.
But aren’t the minerals and trace elements in these salts good for me?
If there were enough, sure. Unfortunately, minerals and trace elements account for less than 2% of the average sea salts. This means that if we’re only supposed to consume 1 teaspoon of salt total per day (which equals about 2,300 mg), you’d have to eat around a quarter of a cup of sea salt a day to get enough of the trace elements to make an impact on your health.
Talk about high blood pressure!
The other 98% of sea salt is made of NaCl, which is chemically identical to table salt.
This leads me to a myth:
Sea Salt does not have less sodium than table salt.
Gram for gram, sea salt has the same amount of sodium as table salt.
However, because the salt crystals are bigger, less of it can fit in a teaspoon. So per teaspoon, sea salt has less sodium.
(This is similar to whipped butter. It’s still plain ol’ butter, but since there’s more air, less butter fits in a teaspoon – and therefore has fewer calories).
** A Note on Purity: Sea Salt is often considered a healthy alternative, but the fact is that it can contain pollutants. Years ago the seas may have been relatively clean, but now they’re increasingly contaminated from oil spills, water traffic, garbage, and other pollutants. Newer studies have found even found microplastics in it. Because sea salt is harvested on coastlines, potential pollution from the land is also a concern.
Table Salt Basics
Table salt is a finely ground rock salt mined from underground salt deposits, or dried salt lakes, such as out in Utah. This type of salt is a bit more processed to eliminate extra minerals and may contain an additive to help prevent the clumping of small crystals.
Iodine fortification
Most table salt also has added iodine, hence 'iodized salt'. Iodine fortification is considered one of the most successful and effective public health initiatives in the United States.
In the 1920s iodine deficiency was endemic in some areas of the U.S., causing thyroid issues in an estimated 26-70% of all children in this 'goiter belt'. At the same time, up to 30% of all draft registrants for World War I had large enough thyromegaly (goiter) to disqualify them from serving.
After doctors found that iodine helped to successfully eliminate goiter, in 1924 the US Food and Drug Administration began recommending fortifying salt with iodine to help with the persistent problem of goiter.
The rise of hypothyroidism
& iodine insufficiency
For a while, thyroid issues had been greatly reduced, however low thyroid hormones and hypothyroid have begun to increase. In 2009 the prevalence of hypothyroid in the United States was around 4.6%. In 2019 that number has grown to between 11 and 14%.
While researchers and clinicians are still determining exactly why, many have hypothesized that the change is due to an increase in insufficient iodine intake.
Other than iodized salt, seafood, fish, sea vegetables, enriched grains (such as white bread and pasta), and dairy* are the best sources of iodine. Most of these foods aren't necessarily eaten in adequate amounts by everyone.
Additionally, sea salt has become more popular, along with processed foods that use non-iodized salt, which is likely a big contributor to iodine insufficiency and the increase in the prevalence of hypothyroidism.
*Interesting nutritional tidbit: Dairy is a source of iodine not because it naturally contains it (it does contain a little depending on the cow's diet), but because of how the milking equipment is sanitized. Many places use an iodine solution to clean the equipment, and some of that is then transferred into the milk. For these reasons, the iodine content of dairy is highly variable.
Salt Recommendations
The bottom line is that you have to look at your entire dietary picture to know what you need.
If your diet is full of seaweed, seafood, dairy, and enriched grains - then you are likely getting enough iodine. Feel free to keep using that sea and rock salt!
If, however, your diet does not have much food from the sea, is low in dairy, and is without many enriched grains - you may want to consider using iodized salt a couple times per week. Yes, you can use sea or rock salt the other days.
Who is most at risk for iodine insufficiency?
There seems to be a higher percentage of women of childbearing age who are iodine-insufficient.
Iodine needs increase during pregnancy to help meet both mom and baby's needs, so women should choose a prenatal that includes iodine, or be more aware of their iodized salt intake to help bridge the gap.
Additionally, women who are breastfeeding have even higher iodine needs than when they were pregnant. These women should chat with their healthcare provider about taking a supplement - or be vigilant about their diet - to ensure they and their babies are getting the nutrients required for health, growth, and development.
Bottom Line
Using sea salt over table salt is a matter of preference, not healthfulness.
Adding salt while cooking can enhance the flavors, making them more well-rounded. But be aware that you may only need a pinch to jazz up your meal. And note that much of our salt consumption may come from the processed foods we are eating.
Consuming too much during the day may lead to high blood pressure, so experiment with herbs, spices, and citrus zest to help add a delicious zing to your food.
Sources:
American Heart Association. How Much Sodium Should I Eat Per Day? Heart.org. Accessed 13 September 2024.
Di Fiore C, Sammartino MP, Giannattasio C, Avino P, Visco G. Microplastic contamination in commercial salt: An issue for their sampling and quantification. Food Chem. 2023 Mar 15;404(Pt B):134682. doi: 10.1016/j.foodchem.2022.134682. Epub 2022 Oct 20. PMID: 36279784.
Leung AM, Braverman LE, Pearce EN. History of U.S. iodine fortification and supplementation [published correction appears in Nutrients. 2017 Sep 05;9(9):E976. doi: 10.3390/nu9090976]. Nutrients. 2012;4(11):1740-1746. Published 2012 Nov 13. doi:10.3390/nu4111740
COUNCIL ON ENVIRONMENTAL HEALTH, Walter J. Rogan, Jerome A. Paulson, Carl Baum, Alice C. Brock-Utne, Heather L. Brumberg, Carla C. Campbell, Bruce P. Lanphear, Jennifer A. Lowry, Kevin C. Osterhoudt, Megan T. Sandel, Adam Spanier, Leonardo Trasande; Iodine Deficiency, Pollutant Chemicals, and the Thyroid: New Information on an Old Problem. Pediatrics June 2014; 133 (6): 1163–1166. 10.1542/peds.2014-0900
Chiovato L, Magri F, Carlé A. Hypothyroidism in Context: Where We've Been and Where We're Going. Adv Ther. 2019;36(Suppl 2):47-58. doi:10.1007/s12325-019-01080-8
Wyne KL, Nair L, Schneiderman CP, et al. Hypothyroidism Prevalence in the United States: A Retrospective Study Combining National Health and Nutrition Examination Survey and Claims Data, 2009-2019. J Endocr Soc. 2022;7(1):bvac172. Published 2022 Nov 10. doi:10.1210/jendso/bvac172
Roseland JM, Phillips KM, Patterson KY, et al. Large Variability of Iodine Content in Retail Cow's Milk in the U.S. Nutrients. 2020;12(5):1246. Published 2020 Apr 28. doi:10.3390/nu12051246
NIH Office of Dietary Supplements. Iodine. ODS.od.nih.gov. May 2024. Accessed 13 September 2024.
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