SaltSensibility

For all those who fear the impact of salt on growing crops here is interesting news. Researchers report that growing cherry tomatoes in salty water can make them tastier and richer in antioxidants. Seawater irrigation puts an environmental stress on the the tomato plants that causes them to produce more vitamin C, vitamin E, and dihydrolipoic and chlorogenic acids.in an attempt to cope with the stressful conditions.

It also improves the flavor of the tomatoes.

Riccardo Izzo, a professor of agriculture at the University of Pisaone describes the findings.

Posted by Mort Satin at 04:28 PM | Permalink

In an excellent attempt to provide a balanced view of the salt and health debate, Kevin Lomangino, editor of Clinical Nutrition Insight reviews several sides of the matter in the May 20, 2008 edition of the bulletin. He correctly states that a number of physicians feel strongly that the reduction of salt intake would provide significant benefit to the overall health of the population. However, he immediately follows on to say that there are other well-known physicians that dissent from this point of view.

But while the maneuverings on the political and media fronts would suggest that the science on salt settled, a thorough search of the literature shows that this is not yet the case.

Lomangino goes on to quote Doctor Alexander Logan, professor of medicine at the University of Toronto, Ontario, who stated in an introduction to the 2006 Journal of the American College of Nutrition supplement about dietary salt:

Until better information is available, evidence supports a public-health dietary policy that focuses on improving diet quality in the entire population and recommends a different target intake levels for sodium based on individual susceptibility to salt.

The article describes that several influential medical practitioners would like to see a major study on the impact of sodium restriction on health outcomes while, on the other hand, some believe that it is unnecessary and expensive. Dr. Michael Alderman, professor of medicine at the Albert Einstein College of medicine and Past President of the American Society of Hypertension believes that proceeding to implement a salt reduction policy without such a study is very risky.

To experiment on 300 million people on issues that might cause harm... it's just not sound scientific policy.

The article went on to say that Dr. Alderman was very concerned that people have stopped looking at the paucity of evidence supporting salt reduction policy and that they are simply looking at the means of implementing one.

Posted by Mort Satin at 04:40 PM | Permalink

In the article, "Technological issues associated with iodine fortification of foods," authors Winger, Konig and House describe some of the potential interactions of iodine compounds with foods. This article is of considerable interest because it goes into a range of possible problems associated with high-level iodine fortification - that is, the addition of iodine compounds directly to the finished foods.

Although the authors attempt to make it clear that the negative consequences of iodine fortification of foods would only occur at high levels of fortification and would never be the result of using iodized salt, they do not unequivocally state that, for all intents and purposes, whole formulated food products would never be iodized at levels that would impact the color, flavor or functionality of those foods.

If whole, formulated foods will never be iodized to those levels which can impact on the quality of the food, then the whole issue becomes moot and should not be confused with the use of iodized salt in food products.

Iodized salt can be used in formulating all food products without any fear of reducing quality.

Perhaps it would have been useful for the authors to have made that simple statement of fact.

Posted by Mort Satin at 10:26 AM | Permalink

With the US presidential campaign focusing so much on character (Obama's embrace of his racist preacher, Clinton's embellished "experience," McCain's unpredictable "maverick" tendencies), one can lose track of some very real issues that divide the candidates. These aren't limited to the economic issues, but that's today's focus. This week Congressional Democrats tied themselves squarely to the anti-free trade crowd with Speaker Pelosi refusing a vote on the Columbian free trade agreement (which Bill was for before Hillary was against). Hovering just under the radar is, aguably, the biggest divide: the Bush tax cuts. Democrats only accepted the cuts because they included in the package a provision that automatically restores the original tax rules and rates at the end of 2010 unless another law supersedes the one on the books. Democrats have loudly proclaimed the tax cuts as a Republican give-away of the federal treasury while Republicans crow that the cuts ended the recession that began in the last year of the Clinton presidency and is needed to sustain our economic growth.

The April 21 edition of National Review (subscription required) examines the historic tax take of the national governments of the US and its OECD partners. An excerpt illustrates, but please keep reading because I'd like to draw a parallel to an issue regarding salt. NR's Kevin Hassett wrote:

As reporters sort through these debates, they must write at a far lower level of sophistication than that of the studies in question. Since New York Times readers don’t know econometrics, they are instead offered pseudo-analysis. The economists who agree with supply-side economics are generally described in terms to suggest that they are nut jobs. Those who disagree with supply-siders are “distinguished professors” or “senior fellows” at “nonpartisan” institutes. We are invited to judge, not the arguments, but the reasonableness of those who make them — and it is clear what our judgment is supposed to be. But interestingly enough, it’s possible to determine with some precision whether a policy has been formulated by nut jobs. To see how, consider the following statement: “U.S. fiscal policy in recent years has deviated wildly from fiscal policy in other developed nations.” If that’s true, one can presumably make the case that U.S. policymakers have ignored policy norms. (This is of course just what one would expect nut jobs to do.) If the claim is false, however, then it’s rather harder to claim that American fiscal policy is in the hands of kooks.

Let’s apply that method to the question of income-tax cuts. The nearby chart depicts recent trends in the share of GDP that governments collect through income taxes. The purple line represents the U.S.; the blue line represents the average for large developed nations in the OECD, excluding the U.S. And the story is clear: For most of recent history, the U.S. share was about equal to that of the OECD generally. It did deviate wildly at one point — in the second term of President Clinton, when the U.S. was collecting a markedly higher percentage of its GDP in income-tax revenue than were its fellow OECD members. But the Bush tax cuts returned us to normalcy.

The "salt" issue? The policy debates over whether the entire population should be encouraged to reduce dietary salt often comes across as a debate with an empty chair. Proponents of this intervention are content to point to their accepted "expert" status and insist that their informed opinion should determine the policy question. These are the "distinguished professors" etc of Mr. Hassett's narrative. By no means all, but some of these activists have tried to marginalize the equally-distinguished experts who argue that no evidence shows low salt diets will improve public health. They duck the issue and try to dismiss opposing scientists as somehow less informed or, surely, more biased -- in short, akin to the "nut jobs" Mr. Hassett describes (though none of them have stooped that far to date).

The parallel? Mr. Hassett graphs the data. That's what we should be doing too: looking at the data. Those data can tell us a lot more than the "expert" opinion of those who cannot or won't deal with the real evidence. Let's stop talking with the empty chair. The public deserves better.

Posted by Dick Hanneman at 03:36 PM | Permalink

The April 10 issue of the Harvard Medical School's HealthBeat offers "diet tips for lower blood pressure." We wish they'd wake up that the real issue isn't "blood pressure," but "improved health." Still, the glimmerings of awakening are discernible. Let me add boldface to the relevant parts of the complete text for the tip: "Consume less salt":

Doctors first noticed a link between hypertension and sodium chloride — the most common form of dietary salt — in the early 1900s, when they found restricting salt in patients with kidney failure and severe hypertension brought their blood pressures down and improved kidney function.

Federal guidelines advise people to limit sodium intake to 2,300 milligrams (mg) per day — about the amount in 1 teaspoon of table salt. Yet Americans typically consume 1 to 3 teaspoons, or as much as 7,200 mg a day. This fact, coupled with the high prevalence of hypertension in the United States, led researchers to assume that salt overload was the culprit.

As it turns out, this may or may not be true. Nearly 50% of people who have hypertension are salt-sensitive, meaning eating too much sodium clearly elevates their blood pressure and puts them at risk for complications. In addition, people with diabetes, the obese, and older people seem more sensitive to the effects of salt than the general population. However, the question of whether high salt consumption also puts generally healthy people at risk for hypertension is the source of considerable debate. Regardless of whether high salt intake increases blood pressure, it does interfere with the blood pressure–lowering effects of antihypertensive medications.

Baby steps forward.

Posted by Dick Hanneman at 12:32 PM | Permalink

Newspapers today reported on work being carried out at Glasgow University on the relationship of aldosterone to blood pressure. The research was presented at the annual Society for Endocrinology BES meeting in Harrogate, UK. The initial research indicates that in older people, higher levels of aldosterone in the bloodstream are associated with high blood pressure.

In a paper entitled, “Aldosterone and cardiovascular function: a lifetime of damage,” Dr. John Connell, who is Professor of Endocrinology at the University of Glasgow and Head of the of the Medical Research Council’s Blood Pressure Group, based in the British Heart Foundation’s Cardiovascular Research Centre in Glasgow described how an excess of aldosterone greatly increases the risk of stroke and heart failure, thus explaining the results of several previous research studies that revealed more cardiovascular patients dying on low salt diets than on regular diets.

Professor Connell said:

“Aldosterone is a key cardiovascular hormone. The higher the level of aldosterone in your blood, the more likely it is that you will suffer from high blood pressure, which will increase your risk of suffering a heart attack or a stroke.”

The research revealed that in older people, higher levels of aldosterone in the extracellular fluid are associated with high blood pressure. In young adults, high aldosterone levels predict that they will be more likely to develop hypertension later in their lives. There are a number of factors that determine elevated aldosterone levels in humans, including low birth weights, genetics and diet. More specifically, insufficient salt intakes will stimulate the renin-angiotensin-aldosterone system (RAAS) to produce more aldosterone in order to conserve the body's cache of sodium in order to retain osmotic balance.

Elevated aldosterone levels mean that throughout life, certain individuals will be more prone to developing high blood pressure, arterial stiffness and cardiovascular disease. Connell’s previous research indicated that aldosterone may be a causal factor in 10% of UK patients with high blood pressure*.

It is difficult to understand why the UK Food Standards Agency, the EU Commission and the Health Canada are all deliberately ignoring this research in their drive to reduce the levels of salt consumed. The mechanistic research work on the malignant role of elevated aldosterone levels upon the cardiovascular system brings far more weight to the salt and health outcomes question than the highly promoted, yet scientifically flawed epidemiological studies on salt and blood pressure.

The human body is an organism governed by biological mechanisms and no amount of bias, hype or imprudent policies will change this.
______
*Connell, J.M.C., Davies, E. 2005. Journal of Endocrinology, 186, 1-20.

Posted by Mort Satin at 12:01 PM | Permalink

Aldosterone is the primary mineralocorticoid hormone in humans. The mineralocorticoids are those steroid hormones, secreted by the adrenal cortex that regulate the balance of water and electrolytes in the body. Working at the distal tubule and collecting ducts of the kidney, aldosterone increases the permeability of their inner membranes to sodium and potassium and is responsible for reabsorbing sodium (Na+) ions and water from the urine back into the blood, while secreting potassium (K+) ions into the urine. Aldosterone is responsible for the reabsorption of virtually all the sodium content in human blood under normal kidney filtration function. Aldosterone also acts on specific receptors in the brain to conserve water and salt by controlling renal tubular resorption.

Unfortunately, chronic high levels of aldosterone in the blood can have major negative consequences for the cardiovascular system, including to induce myocardial fibrosis, renal damage and stiffening of the arteries.

After its discovery more than 50 years ago, the medical interest in aldosterone has been dramatically renewed because of it’s immense impact on the cardiovascular system. Aldosterone is now considered to be the most important cardiovascular hormone in the human body.

As an integral part of the renin-angiotensin-aldosterone system (RAAS), a key function of aldosterone is to conserve salt (sodium chloride), when an insufficient amount is consumed. The latest research published in Clinical Endocrinology indicates that for most healthy humans, anything less than 6 g/day of salt (2300 mg sodium) will be insufficient to prevent the RAAS system from kicking in. That’s right – anything less than 6 grams of salt a day!

But the Dietary Reference Intakes recommends that an adequate intake of salt is 3.8 g/day of salt – not 6 g/day. In fact, the dietary reference intakes state that 6 g/day of salt is the tolerable upper limit of salt intake. How can one recommendation state one figure for a maximum intake while the scientific research indicates that very same figure is a minimum intake?

Perhaps the answer lies in the paper given at the Institute of Medicine workshop “The Development of DRIs 1994-2004: Lessons Learned and New Challenges” held in Washington September 18-20, 2007 by Dr. Peter Greenwald, Director of Cancer Prevention at the National Cancer Institute of the National Institutes of Health. Dr Greenwald described how most of the figures behind the recommended dietary intakes were based upon expert opinion (the lowest quality evidence) rather than randomized controlled double blind clinical trials (the highest level of evidence).

“Little research of the most useful type (randomized clinical trials) is available, whereas there is an enormous amount of information that is not very meaningful. This needs to be reversed.”

Later Dr. Greenwald goes on to say:

“To underscore the importance of “getting the science right,” we need only turn to a recent article in the New York Times Magazine written by a respected science reporter. It was entitled “Why can’t we trust much of what we hear about diet, health and behavior-related diseases?” (Taubes, 2007). The reporter includes several examples, many in nutrition epidemiology, where there is so much conflicting evidence that people do not believe it. Clearly, we have a serious problem, and we must push for the conduct of definitive studies before we make pronouncements on public health.”

As noted in an earlier article, the latest evidence reported by Shapiro, Boaz et al from the Tel Aviv University Medical School reveals that healthy young adults who have been asked to limit their salt intake to 6 g/day (2300 mg sodium) were found to have elevated aldosterone levels indicating that their bodies were in a salt conservation mode. Unfortunately, these elevated levels of aldosterone quickly led to stiffening of the arteries. The conclusion was that for healthy young adults, the Dietary Guideline tolerable upper limit for salt was insufficient to prevent stimulation of aldosterone production. What would happen if the population actually consumed the level of salt recommended by the Guidelines? Would we be condemning an entire population to premature arterial stiffening? Would the government take responsibility for this or would it somehow contrive to blame the food industry for this problem?

In Europe, the EU Commission, led in large part by the UK and its Food Standards Agency has decided that public policy to reduce salt intake will trump basic human physiology. Charging forward pell-mell, the EU Commission, deliberately ignoring the latest scientific evidence, believes that they could not possibly go wrong on this issue because of the support of medical advocates, who have long ago given up any pretence of scientific objectivity.

The world has seen, time and again, that we ignore the science at our peril and as usual, consumers will end up being the victims.

The EU Commission has set the stage for the largest nutrition experiment ever carried out in history with the half billion citizens of the European Union expected to serve as the guinea pigs. When the compulsion to be seen as a driving force for change grabs policy makers by the throat, there is little left to do but allow that change to take place, regardless of the potentially disastrous consequences.

Not wanting to be perceived as being left out of this salt-reduction policy wave, Canada is set to follow suit – again totally ignoring the science and putting Canadian citizens at an elevated risk. One would think that some caution would be in order, but once again, backed by medical advisors and institutions that have done far more advocacy than homework, the government believes it cannot lose on this issue. Since when does ignoring the science and putting a population at an elevated risk give the Government a free pass?

So here we are, in the early part of 2008, with the drumbeat of scientific evidence piling up that the dietary guideline recommendations for sodium are largely irrelevant for the general population and insufficient to prevent production of elevated levels of aldosterone. For the majority of the people, salt, like water is a self-limiting nutrient. We know that aldosterone, chronically maintained at elevated levels as a result of reduced salt intake, will have major negative consequences on the integrity of our cardiovascular system. Like the mythical lemmings that march inexorably over the cliffs to their watery demise, it appears that the EU and Canada are on a track guided by what they don’t know, rather than by what they know – by urban myth and prejudice rather than science.

It is hoped that the new Committee selected to establish the Dietary Guidelines for 2010 will not feel obliged to make poor quality, knee-jerk decisions based upon subjective opinion and search out the most current scientific data upon which to establish their recommendations. Our health is at stake here.

Posted by Mort Satin at 06:51 PM | Permalink