This weekly commentary piece by Anthony Fletcher in foodnavigator.com contends that the public may loose a proper focus on the iinherent danger of dietary salt in the current debate in the UK over sodium reduction targets in various foods. Mr. Fletcher is right to worry about missing the forest for the trees -- but, overall, is only half right.

I totally agree with him that it would be a dangerous public policy mistake to re-focus the "salt debate" on the UK Food Safety Agency's targets for foods away from the scientific rationale for reducing dietary salt. The public deserves to know what medical science informs us of the prospective benefits that achieving compliance with these targets will deliver, not just how hard it will be to accomplish.

Where we part company becomes apparent in his cheery contention: "The vital important message that salt consumption must be reduced will be lost in detail and voluntary detail at that." Wrong. The vital important message that would be lost in detailing the FSA target debate is the crucial and paramount question of whether reducing dietary salt will improve public health. You jump too quickly to the conclusion that "everyone knows" salt should be reduced.

In fact, there have been only thirteen studies reported which examine the amount of salt in the diet with relation to the incidence of cardiovascular events or mortality. All of them are observational studies; none is a controlled trial. If all thirteen were consistent in finding a health benefit for lower-salt consuming populations, perhaps we would have a strong argument that we should do a controlled trial of salt reduction to confirm that the postulated benefits would be realized. Recent trials of hormone-replacement therapy, calcium supplementation and low-fat diets have failed to confirm benefits suggested by observational studies of these questions even though the hypotheses were eminently plausible. Not only is there no controlled trial of the health outcomes of salt reduction, but all thirteen observational studies that have been reported turn out to be consistent in their findings -- but consistently find that there is no health benefit of reducing dietary salt. Four of the thirteen studies, including the Scottish Heart Health Study, have shown that low-salt consuming populations, in fact, showed a higher risk of adverse cardiovascular outcomes. The current, March edition of the American Journal of Medicine, for example, contains the latest of these studies. That research, by the current president of the International Society of Hypertension, documents that those on low-sodium diets have a 37% greater cardiovascular mortality.

So I agree with the commentary that "The current debate about the levels at which the UK's food regulator has set its salt reduction targets misses the point about how healthier eating habits can be achieved." "Healthier eating" will not be achieved by reducing dietary salt. We believe that the "healthier eating habits" should be based on the Dietary Approaches to Stop Hypertension (DASH Diet) with greater emphasis on consumption of fruits, vegetables and dairy products and which is salt-neutral. Let's not let the "details" of the scientific underpinning for the entire enterprise be lost in the discussion to the detriment of both consumers' understanding and, more importantly, improving consumers' health.

We know salt masks bitter flavors. The reason for the bitter taste of the salt debate is the lack of a crucial, missing ingredient -- mixing in a generous portion of health outcomes data. For more, see http://www.saltinstitute.org/28.html.

BestSyndication.com just ran an article with this title authored by Dan Wilson. Wilson argues that the proper test of a dietary intervention is not its affect on an intermediate factor like blood pressure, but whether the dietary change has been shown to extend life.

We agree.

Unfortunately, Wilson makes a few errors and omissions that undermine the argument. He compares a low-calorie diet to the DASH Diet. The only tests of the DASH Diet are for blood pressure; longevity was not measured -- it was, after all, a 30-day trial of a special population (e.g. 60% African American). He states that a "goal (of the DASH Diet) was to reuce sodium intake." This is an error. The DASH Diet held sodium constant -- a major distinguishing feature of this from other interventions. Thus, he concludes in puzzlement asking why advocates of a purportedly low-sodium DASH Diet would continue to recommend sodum reduction in the face of evidence "that showed people who said they limited their salt intake were 37% more likely to die from coronary heart disease or stroke when compared with those who ate more than the US recommended daily allowance of 2,300 milligrams a day (of sodium, he forgot to add)."

We have no quarrel with advocates of calorie restriction. But let's not set up straw men. And let's play square with the facts. The facts are: the DASH Diet is not sodium restricted and the DASH Diet never claimed to reduce mortality (although some of its advocates would have you believe that).

Bottom line: The headline is correct: Aim at extending life, not any intermediate risk factor like blood pressure (or insulin resistance, plasma renin activity, etc.).

This story in the March 14 Washington Post captures pretty well the issues underlying the discussion about whether American consumers should believe the massive new federal study that found no health outcome benefit of reducing dietary fat.

Authors Lisa Schwartz, Steven Woloshin and Gilbert Welch capture public anxiety over what to believe when headlines trumpet stories that diet can prevent cancer and counter-punch with other stories saying just the opposite.

In the recent Women's Health Initiative (WHI), researcher reported "the latest apparent flip-flop...about low-fat diet and breast cancer. The story describes the new 50,000, eight-year WHI trial and the 2005 Women's Intervention Nutrition Study (WINS) with about 5% that number. Helpfully, the authors point out that the two studies "differed in two major ways. First, they studied different groups of women: one with prior breast cancer (WINS) and one without (WHI). Women with breat cancer are substantially more likely todevelop a new breast cancer than women without breast cancer....And this is exactly what happened....The second major difference ...was in how statisticians judged the findings. This difference was profound. Based on conventiaionl statistical practices, the effect of the low-fat diet in women with breast concer was deemed to be real--the result of more than chance. But in women without breast cancer, the effect of diet was judged to be statistical noise."

The authors go on to explain the importance of statistical significance, the difficulty of compliance -- especially by the subgroup that derives no benefit and, importantly, the crucial difference between observational studies (that show diet affecting cancer risk) and intervention trials which don't.

"In fact, most of the diet flip-flops come from observational studies that suggest a benefit (or harm) from diet that is not subsequently confirmed in randomized trials." See where I'm headed? With regard to salt, we have policy based on an intermediate variable (blood pressure) and only observational studies of health outcomes. While the observational studies offer no comfort to low-salt interventionistsl, we can only insist on a controlled trial of low sodium diets to see if they will reduce risk. The early betting is that they won't.

For more, see the author's website, the VA Oucomes Group .

Yesterday and today, many of the nation's leading scientists and experts on women's health met at the National Institutes of Health (NIH) in Bethesda, MD to celebrate the legacy and probe the findings and future directions of the Women's Health Initiativve, the largest and most comprehensive study of postmenopausal women's health ever conducted in the United States.

And not only the largest, the WHI is aguably the most far-reaching in terms of documenting flaws in our understanding of accepted medical "knowledge" on everything from the effects of a low-fat diet and calcium/vitamin D supplements to the dangers of hormone replacement therapy. In all these cases, WHI reseachers have turned on their head logical hypotheses supported by at least some observational studies. We now know that low-fat diets don't make much difference, nor do calcium/vitamin D supplements, and that hormone replacement therapy creates an increased risk of breast cancer and that, overall, risks from use of the hormones outweighed the benefits.

"The WHI has replaced conventional wisdom about women's health issues with evidence-based research findings, and reminded us that there aren't always simple, universal answers to complex questions," said Elias A. Zerhouni, M.D., director of the NIH, announcing the celebration. Hopefully, NHLBI director Elizabeth G. Nabel, M.D., who also spoke to the gathering, recognized the application of Dr. Zerhouni's comments to the salt and health research funded by her agency. Several days earlier, yet another study of a massive federal nutrition and health database found risks of low-salt diets outweigh any health benefit.

NIH has more on WHI on its website .