Pink salt may have traces of iron not found in grey salt, but this difference is not significant. Photo Credit Janet Rhodes/iStock/Getty Images
All salts share a similar chemical makeup -- they're made primarily from sodium chloride and serve as a concentrated source of sodium in your diet. Specialty salts, such as pink or grey sea salts, also contain trace amounts of minerals that affect the appearance and flavor of the salt. While pink and grey sea salts have minor differences in mineral content, they're both roughly nutritionally equivalent to table salt.
Pink and grey salts' colors come from their trace mineral content. Pink salt's hue is likely a result of its iron content, according to the University of Texas at San Antonio. Grey Celtic sea salt, on the other hand, has trace amounts of magnesium. While both iron and magnesium offer health benefits -- they're both important for energy production, for example -- the amount in sea salt isn't nutritionally significant.
The main difference between pink salt and grey salt is their textures. Pink salt is harvested from mines, has drier grains and is typically sold in larger grains with a texture similar to coarse sea salt. Pink salt works well sprinkled over roasted or grilled vegetables, chicken or fish, and the larger grains give bursts of salty flavor without the need to use much salt. Pink salt also works well as a crunchy and flavorful seasoning for air-popped popcorn.
Grey salt, which is made from seawater, has a higher natural water content than pink salt, so it has a more moist, crumbly texture that melts easily into your food. It retains some of its marine flavor, which makes it a good seasoning for bolder dishes, like lean cuts of beef, cheese and lamb.
Although salt has a bad reputation, it's not all bad as long as you enjoy any salt you use – grey, pink or other salt – in moderation. Sodium plays a key role in nerve communication, which is essential for brain function, muscle contraction and healthy digestion. Salt is also responsible for controlling blood pressure, and having enough sodium can protect you from low blood pressure. However, unless you're doing intense endurance exercise -- like competing in an Ironman triathlon -- it's unlikely that you'll develop a sodium deficiency as a result of low sodium in your diet.
It's more likely that you'll overdo it on sodium without meaning to. Too much sodium disrupts the mineral balance in your body, leaving you short of heart-healthy potassium and facing a higher risk of high blood pressure. Sodium also increases calcium excretion, so following a low-sodium diet might retain your body's calcium levels, promoting bone health. Because they're both very high in sodium, pink and grey sea salts can both boost your sodium intake to unhealthy levels if you're not careful.
You should treat both sea salts the same you would table salt -- as a concentrated source of sodium that should be used in moderation. Your total sodium intake, which includes the salt you add to your foods as well as the sodium found in breads and processed foods, should not exceed 1.5 grams daily. That's the equivalent of a little less than 4 grams of salt, or less than a teaspoon. Reduce your sodium intake by focusing on whole foods -- fresh produce, unsalted legumes and nuts, and lean meats -- and practicing moderation when you season your food with salt.