Now that we've just about resigned ourselves to salt as a no-no, here is a clutch of medical experts and nutritionists to tell us to wait a minute.
It isn't that salt (sodium-chloride) hasn't been implicated in certain forms of hypertension -- even the fiercest salt supporters agree that as many as 30 percent of hypertensives may be "sodium sensitive," and may require a sodium-restricted diet to keep blood pressure under control.
But the current campaign by the federal government, heart associations and high blood pressure groups to get most of the salt out of the general American diet may be going too far, according to a number of reputable experts.
Indeed, the salty stew has been simmering for some time in that part of the medical community dealing with cardiovascular illnesses and especially with hypertension, the leading indicator for heart disease and stroke, as well as kidney and heart failure.
Some experts, like Dr. John Laragh of the Cornell Medical Center in New York, have been saying for some years that in certain forms of hypertension salt reduction can actually cause blood pressure to rise.
Several factors are behind the opposition to a wholesale effort to move the entire country below the salt.
One is a long-overdue but now burgeoning awareness about the complicated relationships between health and nutrition on the part of physicians. Another is a sharper awareness of the infinitely complicated nature of human physiology, cellular biology and genetic coding.
Finally, in the vast majority of cases, the experts simply do not know why this person is hypertensive and that one isn't, what basic mechanisms are at work and why hypertensives react differently to treatments.
A lot of the controversy surfaced during salt talks at a recent seminar here on Nutrition and Blood Pressure Control sponsored by the National Kidney Foundation, the Department of Health and Human Services and the International Life Sciences Institute.
Dr. David A. McCarron, chief of the Hypertension Program of the University of Oregon Health Sciences Center is a leader among those who suggest that indiscriminate salt reduction could have as yet unknown fallout on other nutrients -- and health -- down the line.
At the seminar, and later at a smaller conference sponsored by the local chapter of the National Dairy Council, McCarron discussed research suggesting that a calcium deficiency is an even more likely culprit in hypertension than sodium.
McCarron made public some of his findings in a report in July's Science. Predictably it caused immediate controversy, although he has had support from studies at a number of other reputable research laboratories.
In the article, he described a survey of the calcium intakes of 46 people with hypertension and 44 with normal blood pressures. The hypertensives "reported significantly less daily calcium ingestion." He said, "The data suggest that inadequate calcium intake may be a previously unrecognized factor in the development of hypertension."
McCarron's research is underwritten, in part, by grants from the National Dairy Council, but his interest in the calcium connection was triggered by a patient -- a black man with hypertension and poor calcium metabolism -- he saw in the course of his medical training at Tufts-New England Medical Center. Recently he re-analyzed major nutritional studies and found that in groups known to be at high risk for hypertension -- young black men, older blacks and all women over 50 -- calcium intake is markedly lower. (Estrogen deficiency, he speculates, may play as much a role in hypertension as in osteoporosis--loss of bone calcium--in the latter group.)
Indeed, in all groups studied, calcium intake was significantly lower among hypertensives.
Other participants at the nutrition seminar also suggested potassium deficiency as a factor in hypertension. Dr. James W. Anderson, chief of Medical Services at the Veterans Administration Hospital, Lexington, Ky., suggested that high-fiber, high-carbohydrate diets lowered the blood pressures of patients on the regime.
Admittedly the fiber findings are very preliminary, in a very small sample -- 12 people -- but they suggest new avenues of research. Anderson noted that the high-fiber diets were actually lower in calcium than in the control subjects and he still advocates some cutback in general sodium consumption.
"Of course," McCarron says, "if you have high blood pressure and it goes down when you restrict your sodium intake, then that's what you should do, but what do we know about the people who make up the other 80-some-percent of our society who don't have high blood pressure? What happens to them when they restrict their sodium intake?"
This is not to suggest, he says, that calcium is the answer. "There may never be a single answer because the problem is not that simple . . . It's not an issue that sodium is not the culprit and something else is, it is simply that there may be other culprits, and we better make sure we know who the cast of characters are before we make global recommendations."