In response to last week’s canned soup post , reader Dave offered this comment: “I’d just like to point out that just as many Apple readers believe in literature that debunks the lipid hypothesis, there’s a camp that says there is minimal effect on blood pressure from salt. There are two sides to many stories!”
We couldn’t agree more that nutritional (or general health) debates are rarely so simple as they’re made out to be. As long-time readers have probably noticed, we’ll mention salt recommendations now and then and generally try to keep our recipe suggestions fairly low in salt. We do tend to follow general salt recommendations. Blood pressure issue aside, high salt intake (as we mentioned last week) has been associated with osteoporosis, asthma, kidney disease and stomach cancer.
But what about the salt and blood pressure issue? Does it really hold water (pun intended)? We’d say it has enough bearing to figure into our choices, and for some people, research suggests, it’s crucially significant.
For years, scientists have researched the possibility of a “salt sensitive hypertension” that was the general result of a person’s genetic profile. In other words, salt sensitive peoples’ blood pressure is impacted more than the average person’s. To be precise, their blood pressure rises 10% or more in response to a salty meal.
In 2006, researchers at the University of Virginia Health Center announced  that they had traced the “sensitive” salt response to particular gene variations and that they were in the process of completing a genetic test for the salt sensitive profile. Salt sensitivity, researchers say, whether it accompanies chronic high blood pressure, negatively impacts the vascular system in the same way high blood pressure itself does. African-Americans are more likely to be salt-sensitive than people of other races in the U.S. The test, once it becomes readily available, will hopefully be a useful tool for people who want to learn more about steps essential for their individual health.
But as for the rest of us, does salt matter for blood pressure? It’s true that many studies in this area, as in all areas, have their failings. And, it’s true that salt is just one piece (albeit an important one) involved in the process of fluid retention and its link to higher blood pressure.
Yet, there seems to be enough suggestion that salt can have a significant or at least measurable impact on blood pressure. A unique look into the connection was found in a recent study  that compared blood pressure in groupings of salt mine workers in India, dividing those who worked directly with the processing of salt and those that worked away from the milling plant and its processing steps. The group that worked directly with the salt and had opportunity for inhalation of salt on a daily basis showed higher blood pressure (average of 4 points higher for the systolic measurement) than the group that didn’t work in the mill. After a group of mill workers used face masks and goggles for just four days, their blood pressure dropped an average of ten points in the systolic measurement.
While the above study examines a mode of salt intake other than ingestion, there is no shortage of studies  that measure the effects of reducing dietary salt intake. Follow up research on two study groups from the 1990s help strengthen the argument for lower salt intake as helpful in preventing heart disease. Former subjects that had been part of the intake “intervention” group and were given the low salt diet, 10-15 years later had a “25% reduction in the risk of cardiovascular disease.”
Another study out in 2006 showed significant and positive impact of salt substitute use in Northern rural China, which is known to have especially high rates of hypertension as well as high salt intake. The salt substitute, researchers said , “demonstrated that it could reduce blood pressure to about the same extent as single drug therapy.”
And, ultimately, what does a low salt diet look like? First off, it should mean pretty much no processed food. We definitely support that! Up to ¾ of American’s salt intake comes from processed foods – those curious boxed creations you find in the middle of the grocery store, cured meats, etc. Cut those out, and you’re already in good shape. We certainly don’t begrudge anyone reaching for the salt shaker. We do, but we also don’t rely on it for taste. The more people moderate (yes, moderation is the key here, not elimination) their salt intake, the more likely they are to turn to other sources of flavorings, hopefully healthful ones like herbs and more varied, flavorful ingredients like peppers, onions and other vegetables and fruits. At least, that’s what we’d suggest.
This is one of those fascinating discussions that we love to continue. We’re always on the lookout for research from both sides of the issue. Keep your comments coming!