Salt: Don't Ban It Entirely
Salt is bad for blood pressure but good for brain development, researchers say.
Truth About Iodized Salt continued...
In fact, Americans now get one-third less iodine than they once did, he notes.
Both newborns and toddlers are affected by iodine deficiency. A recent study showed lower IQ scores among children with mild iodine deficiency -- proof that the problem exists in developed countries, writes researcher Piedad Santiago-Fernandez, MD, an endocrinologist at the Complejo Hospitalario Carlos Haya in Malaga, Spain.
It's true, says Michael Karl, MD, an endocrinologist with the University of Miami School of Medicine. "You can certainly see even subtle changes in iodine can affect IQ," Karl tells WebMD. "Iodine is critical in the first years of life, extraordinarily important up to 3 or 5 years of age."
Children in financially stressed families are likely at highest risk. They rarely take multivitamins, he tells WebMD. "Iodine deficiency is not an epidemic yet, but it's serious enough that it should be watched."
Sea salt and most salt substitutes are not iodized. Unless fruits and vegetables are grown in iodine-rich soil, they will not contain iodine. Restaurants usually order salt in bulk, and often it's not iodized salt.
However, anything from the sea - such as seaweed (kelp) or fish -- can be a good source of iodine, says Maberly. A cup of cow's milk contains nearly 100 micrograms of iodine. Some breads contain iodine, but not all.
The normal requirement for iodine, according to World Health Organization standards: Adults need 150 micrograms a day. Women trying to get pregnant should increase their intake to 200 to 300 micrograms a day.
"We certainly should make pregnant and lactating women aware of this deficiency," says Karl. "I don't think most primary care doctors are aware of it."
Salt and Your Blood Pressure
The link between sodium and blood pressure has been rocky in recent years. Two decades ago, the landmark study known as Dietary Approaches to Stop Hypertension (DASH) showed that a low-sodium, low-fat diet -- high in calcium, fruits, and vegetables -- had a direct impact on lowering blood pressure.
But a study last year challenged that dictum. It indicated that high-sodium intake is a marker for a poor-quality diet. It wasn't the sodium that affected blood pressure, but the lack of other important vitamins and minerals. That study was funded by the salt industry.
David McCarron, MD, a longtime paid consultant for the salt industry, presented these findings at the American Heart Association's 57th annual high blood pressure research conference last year.
However, a new report from the DASH research group shows -- once again -- that cutting sodium improved blood pressure, especially as people hit their 40s and 50s.
"In general, people who are older benefit more from lowering their sodium. Around age 40, 50, we begin to see a real difference," says Daniel W. Jones, MD, a hypertension expert with the University of Mississippi, and spokesman for the American Heart Association.