Widespread media coverage on the dangers of salt, and recent public-health efforts to reduce it in foods, seem to make salt the bad guy of nutrition. Is salt harmful for people who have hypertension, and can they still consume it? What about those without high blood pressure? And can you get too little salt in your diet?
Martica Heaner, who has a doctorate in behavioral nutrition, is an NASM-certified trainer and is the coauthor of Cross-Training for Dummies (IDG Books 2000), sheds light on the topic.
People with existing hypertension are generally advised to aim for low sodium, both by avoiding processed and restaurant foods and by salting less. But salt’s effect on blood pressure depends on the individual. “A person with normal kidneys excretes excess sodium and can handle very wide variations,” says Michael Alderman, MD, professor of epidemiology and population health and of medicine at the Albert Einstein College of Medicine in New York City. But some people respond to sodium differently than others. “Restricting salt can control blood pressure in those people who are salt-sensitive.” People who have hypertension or prehypertension and have been diagnosed as sodium-sensitive should consult a physician regarding salt as an added ingredient in the daily diet, advises Kristine Clark, PhD, RD, director of sports nutrition at Penn State University in State College, Pennsylvania.
Other lifestyle modifications—including reducing alcohol intake, eating more plant foods and getting more exercise—also affect hypertension. Consuming a more nutritious diet all around, rather than simply eating lower-sodium versions of processed foods, may be the healthiest approach. Fruits and vegetables are high in potassium, an electrolyte that helps balance out sodium levels. Some studies have shown that vegetarian diets or diets that emphasize potassium-rich fruits and vegetables can lower high blood pressure even if dietary sodium is not limited (Nowson, Morgan & Gibbons 2003).
Whether people with normal blood pressure, especially if they are regular exercisers, should risk lowering their blood pressure by minimizing sodium intake is unclear. “Too little sodium can be a real hazard,” says Alderman, who believes that universally lowering sodium in the food supply is a rash—and potentially risky—approach. Lowering sodium intake can lead to dizziness and can lower blood pressure, sometimes to levels that are too low. Lowering intake has been shown to decrease insulin sensitivity as well (Alderman 2010), and insulin resistance is a precursor to diabetes, another serious health risk.
“Most added sodium comes from processed foods, so if you are eating out a lot or eating lots of packaged foods, you may be getting more sodium than you need,” says Karen Dolins, EdD, RD, a board-certified specialist in sports dietetics and a professor at Columbia University in New York City. However, if you eat lots of fruits, vegetables, grains, nuts and legumes and cook at home, you are likely already following a low-sodium diet.
Note: If you sweat a lot doing extended cardio workouts, you may want to avoid low salt intake and needn’t worry too much about salting food.