Salt: Benefits, Risks and How Much Is Too Much

Salt (sodium chloride) is the world’s most common seasoning. It improves flavor, preserves food and has been used for thousands of years; in ancient Persia and Rome salt was even used as money. The body needs some sodium to work, but most people eat much more than they need, and this is one of the biggest dietary risks for heart disease and stroke worldwide.

Salt and sodium: what is the difference?

Salt is about 40% sodium and 60% chloride. Health guides talk about both salt and sodium: 5 g of salt (about a level teaspoon) contains 2 g (2,000 mg) of sodium. To convert sodium to salt, multiply by 2.5.

What salt does in the body

Fluid balance: sodium helps control the water inside and outside cells.
Nerves and muscles: it is needed to send nerve signals and contract muscles, including the heart.
Blood pressure and volume: sodium helps maintain blood volume.
Nutrient absorption: sodium helps absorb glucose and amino acids in the gut.
Iodine: iodized salt provides iodine, which the thyroid needs to make hormones; this has prevented goiter in many countries.

The risks of too much

High blood pressure, a major cause of heart disease, stroke and kidney disease.
Kidney strain and a higher risk of kidney stones.
Water retention and swelling in the feet, hands and face.
Stomach problems: very salty and pickled foods are linked with a higher risk of stomach cancer.
Bone calcium loss in some people, because the kidneys excrete more calcium with sodium.
Headaches and thirst after very salty meals.

The risks of too little

True sodium deficiency is rare in people eating normal food. It can happen with severe vomiting or diarrhea, heavy sweating over many hours, some medicines (diuretics) and some illnesses, causing weakness, cramps, confusion and, in severe cases, seizures. This needs medical care.

How much is right?

The World Health Organization recommends less than 5 grams of salt a day (about one level teaspoon), which equals about 2 grams of sodium. The American Heart Association suggests an ideal limit of 1,500 mg of sodium for most adults, and not more than 2,300 mg. Many people eat double the recommended amount, mostly from processed foods and restaurant meals rather than from the salt shaker (in many countries, about 70%).

Where hidden salt comes from

Bread and baked goods, which are a major source because we eat them often
Cheese (feta and brined cheeses), processed meats, sausages and deli meats
Pickles, olives and salted nuts
Soups, stock cubes, instant noodles and sauces (soy sauce, ketchup, ready pasta sauces)
Chips, crackers and snacks
Restaurant and fast food

Easy ways to eat less salt

Cook with herbs, lemon, garlic, sumac, pepper and spices, such as garlic or cardamom in rice dishes.
Read labels (see how to read a nutrition label) and choose lower-sodium bread, cheese, canned foods and sauces. “Low sodium” means 140 mg or less per serving.
Limit pickles, salted nuts, chips, processed meats and instant soups.
Add salt at the end of cooking, and taste first. Salt on the surface tastes stronger than salt mixed in, so you need less.
Rinse canned beans and vegetables to remove up to 40% of the salt.
Use stock cubes sparingly and skip extra salt when using them.
Eat more potassium-rich foods such as bananas, potatoes, beans, spinach and tomatoes, which help balance sodium.
Let your taste adapt: after 2 to 4 weeks, a lower-salt diet tastes normal.

Types of salt: are some healthier?

Table, sea, rock, Himalayan pink and kosher salt all have about the same amount of sodium by weight (about 40%). Trace minerals in sea or pink salt are too small to matter.
Iodized salt is useful if your diet is low in iodine.
Low-sodium salt substitutes contain potassium chloride; they help many people but are not safe for those with kidney disease or on certain medicines, so ask your doctor.
Coarse salt has less sodium per teaspoon than fine salt because of air gaps, but not by weight.

Who needs extra care?

People with high blood pressure, heart or kidney disease, or fluid retention should follow their doctor’s limit, which may be lower. Older adults, African-heritage people and those with diabetes are more sensitive to salt. On the other hand, athletes who sweat heavily for hours, and people with certain illnesses, may need extra sodium; ask your doctor.