As we gather our family today for Thanksgiving (ten of us together this year, spanning four generations), we have much to be thankful for.
TV network sports have been touting "Feast Week" football and basketball and today's Thanksgiving meal will probably have most of us leaving the table the same way the turkey arrives - stuffed.
Certainly on Thanksgiving, few will be following the DASH eating plan advocated by both the Salt Institute and the Dietary Guidelines for Americans. The DASH Diet is high in fruits, vegetables and dairy products (and, by implication, low on turkey, stuffing, mashed potatoes and gravy). While the American Council for Science and Health has used the "traditional" Thanksgiving meal to illustrate the dose-determines-toxicity arguments about carcinogens in our foods, so far I haven't seen a Thanksgiving DASH Diet. That's something to be thankful for, anyway.
The DASH Diet gained immediate national prominence in 1997 when it demonstrated that, holding salt constant, enormous blood pressure lowering could be achieved - fully as much as taking any single medication. The most responsive group were people who already had hypertension (>140 mmHg systolic blood pressure, the "top number" thought to be the most accurate predictor of the risk of cardiovascular events). This group averaged an 11.4 mmHg SBP reduction.
Some complained that the common-sense DASH Diet, consistent with diets advocated for years to reduce the risk of cancer and other maladies, didn't also include evidence showing the "politically correct" results for low-salt diets, or the Mediterranean diet or other favored interventions. With all the favorable publicity around the DASH Diet, others wanted to get on board. So new studies were launched to "improve" the DASH Diet.
First came the anti-salt folks. They produced a version of the DASH Diet that also cut salt by 60% and found, voila!, that the hypertensives in their study reduced their average SBP by 11.5 mmHg. They proclaimed that "everyone" would benefit by reducing dietary salt even though this unachievable salt reduction contributed, at best, marginally to the blood pressure benefit (after all, the DASH Diet produced 11.4 mmHg lowering so we're going to attempt a massive salt reduction to get that additional 0.1 mmHg instead of putting our energies into boosting consumption of fruits, vegetables and dairy products?).
Earlier this month came a second round: "DASH Diets" that were also "improved" by making them Atkins/South Beach-like "low carb DASH Diets" and "DASH Diets" with added amounts of monosaturated fats like the Mediterranean diet or high in protein.
If this keeps up, the dilution factor will soon destroy the strong effort of the 2005 Dietary Guidelines for Americans to encourage eating the original DASH Diet. That would be nothing to be thankful for. Let's make sure our Thanksgiving plates have some green and yellow veggies and include a glass of milk with our fruit pie for dessert.
Last month, the Journal of the American Medical Association published an issue that featured the revelation that gastric bypass (bariatric or stomach stapling) surgery raises the risk of early death "considerably higher than previously suggested." Those who had their stomachs stapled were promised lower risk of health problems and longer lives because their obesity equated to more adverse health outcomes. Public health campaigns have bombarded us all with the strong message that excess weight is unhealthy.
Excess weight is unhealthy. So why didn't this dramatic surgery that consistently reduces obesity work out as planned?
The research addresses the broader question: does everyone who loses weight lower their risks of the adverse outcomes associated with obesity? Or, put another way: does it matter how someone reduces weight or just that they reduce excess weight?
But that's not the question I want to answer. You'll have to read JAMA for that answer.
What I wanted to point out is the strong parallel here with another recommended intervention which, its advocates promise, will reduce health risks, improve health and extend lives. That intervention isn't bariatric surgery; it's salt reduction.
Consumers are bombarded with public heath messages telling them that cutting back salt will save their lives.
Is that true or is it more like stomach stapling? Consider the parallels.
A gastric bypass will result in the patient eating less and losing weight. Salt reduction, for a significant minority of the population, will reduce blood pressure. Obesity is strongly correlated with adverse health problems and increased mortality. Elevated blood pressure, likewise, is correlated with increased risk of heart attacks and strokes.
The simplistic answers of bariatric surgery or salt reduction rest on the assumption that it makes no difference how a person loses weight or lowers high blood pressure - Just do it! The JAMA papers suggest that this isn't true for obesity. A dozen papers examining salt intakes and comparing them to health outcomes reach the same conclusion: it matters a great deal how blood pressure is lowered. Salt restricted diets do not reduce adverse health outcomes; in fact, some of the studies show elevated risks, just as the JAMA papers find for stomach stapling. Read more about salt and health on the Salt Institute website .
Today's Tech Central Station has a great article by author John Luik entitled "A Grain of Salt " that summarizes the ongoing salt and health controversy admirably. Luik points out: "That's why across the board salt reductions such as the MRC and CSPI call for make no scientific sense. Instead, the science, taken in its entirety, suggests that population-wide dietary salt reductions do not improve health outcomes, such as the number of strokes, heart attacks or the risk of premature mortality. In fact for some groups they actually increase certain risks. For example, analysis of the MRFIT (Multiple Risk Factor Intervention Trial), which followed the lives and deaths of 12,866 American males for an average of 12 years, found there were no health benefits from low-sodium diets." It's worth a read.
Unfortunately, today's news also includes the assertion that cutting back salt would cut health care costs in Britain by 6 billion pounds, based on assumed reduced incidence of cardiovascular events. In an online response, I pointed out that "Anyone can build a model and project an outcome (6bn pounds a year), but the model depends on the assumptions of its creators and NHS' model reflects is the triumph of hope over the realities of the scientific data." I further observed:
"Reducing dietary salt is promoted to reduce blood pressure on the assumption that however blood pressure is reduced will lower the risk profile for heart attacks and cardiovascular deaths. That's where the "savings" NHS projects originate. But there are no data confirming this hope. In fact, only a dozen studies have examined the health outcomes of people on lower sodium diets and they show, if anything, that there is a HIGHER RISK of heart attacks. How can that be? When salt is reduced, the body compensates with other metabolic changes: insulin resistance is increased, sympathetic nervous system activity increases and, most of all, the body secretes vastly more renin, a hormone produced in the kidney that has been shown by the president of the International Society of Hypertension to cause four times more heart attacks."
Twice in the past two weeks, the Food and Drug Administration has shown why it may have the second toughest and important job in America (after the job of parenting, of course). On November 2, FDA announced its ruling that "there is no credible evidence to support qualified health claims about calcium and breast cancer or calcium and prostate cancer . " Then this week, on November 9, the agency ruled that "there is very limited credible evidence for qualified health claims for tomatoes and/or tomato sauce, and prostate cancer ." In short, FDA is denying qualified health claims, not describing them as its rules seemed to promise.
Pity the FDA! On the one hand, the public expects approval of life-saving medicines double-quick and food labels that inform but don't mislead consumers. On the other, the courts have ruled against FDA's efforts to prevent food manufacturers from making certain claims about the healthfulness of their products -- "commercial free speech."
FDA sought a way to navigate between the Scylla of unrestrained commercial hype and the Charybdis of suffocating hyper-regulation. After the courts invalidated as too restrictive its "health claims" rules for foods with nutrients where "significant scientific agreement" supports a relationship to a "disease or condition," FDA came up with a scheme of "qualified health claims" that manufacturers could make based on FDA's determination about the amount of evidence supporting the claim. So, worst case for a manufacturer, a food would have the right to claim a diet/disease relationship and also be required to carry an FDA warning that there is no evidence to support the claim.
With these two decisions, however, FDA seems to have lost its nerve and reverted to denying claims. Rather than require ketchup manufacturers who want to say their product prevents prostate cancer to affix a warning that the scientific evidence for such a claim is very weak, or make sellers of dairy products warn consumers that medical scholars dispute their claims that their high-calcium product cuts the risk of breast cancer or prostate cancer, FDA is denying the claims entirely (or, in the case of tomato products, largely). Preserving the integrity of health claims is virtually a no-win situation.
This blog is salt-related. How does this tie in?
FDA has yet to consider or approve a health claim that low-salt foods reduce the risk of heart attacks and strokes, though lots of ink is spilled alleging that case. Such a claim about salt and heart attacks, according to my review of the evidence , would have to be judged entirely lacking in scientific support. What is clearly justified in science is the conclusion that "salt is an essential nutrient." Scientific, yes, but politically-incorrect.
The nutrition nannies at the gratuitously-self-named Center for Science in the Public Interest are at it again. Denied in court, they today petitioned the FDA to declare that salt should forfeit its "Generally Recognized As Safe" status and that food manufacturers should use less of it in the foods they make.
The petition doesn't pass the sniff test. It badly needed a fact-checker. I opened the petition randomly and didnt' have to read beyond the first paragraph to find an error. There were plenty more.
But worse, CSPI persists in trying to foist off extrapolations and projections in the place of data. They allege salt is killing 150,000 people a year (nearly four times the number that die in traffic crashes and 75 times more than the number of Americans killed in Iraq since Sadaam's fall). The huge number is a statistical construction based on blood pressure only and ignores the fact that lowering dietary salt has other impacts -- No, not just that the food tastes bad. The other impacts of lowering dietary salt are that it triggers the production of the kidney hormone renin, it activates the sympathetic nervous system and it increases insulin resistance, a key risk factor for diabetes.
What we need to look at is the NET EFFECT of lowering dietary sodium. Will it make people healthier or not? If so, then we should address the very real problems of implementing such a change with food manufacturers and try to convince the public to forego their salt. But in the absence of evidence of harm, why expend all these resources? In fact, the evidence shows no benefit and some studies even show people on low-sodium diets suffer more heart attacks and die more often -- not a figure you'll find in the CSPI petition.
Today's Washington Post carries a reminder that the DASH Diet, high in fruits, vegetables and dairy products, provides vital potassium to blunt salt-sensitive hypertension. True, as far as it goes.
The DASH Diet, released in 1997, promotes a food consumption pattern, although it does clearly make the most striking changes in overcoming mineral deficiencies. Those under-consumed minerals include not only potassium, but also calcium and magnesium. There is strong medical consensus that these essential nutrients are under-consumed in today's diet.
The focus here is on blood pressure. When the DASH Diet was announced, the Salt Institute endorsed it strongly, since it focuses properly on enhanced mineral intake; it does not reduce dietary sodium/salt. For example, hypertensive subjects in the DASH Study population reduced their systolic blood pressure (SBP, the top number) by an impressive 11.4 mmHg. In a later study that also featured cutting salt by 60% (it was, after all, only a 30-day study), hypertensive patients on the DASH Diet with this drastically-reduced salt intake reduced their SBP by 11.5 mmHg. Salt restriction in 6 of the 8 subgroups reported (important because the sample represented particularly a salt-sensitive universe) no significant differences of blood pressure even when salt was reduced by more than half for those on the DASH Diet.
We should all keep in mind that blood pressure is only one of several relevant health impacts. The key is to understand the net health outcome of any dietary change. As outlined on the Salt Institute website ( http://www.saltinstitute.org/28.html ), the limited studies on health outcomes of salt-reduced diets show no health benefit because other systems in the body are adversely affected by salt reduction (e.g. insulin resistance, plasma renin activity).
So, eat those fruits and veggies -- and dairy products (dairy contributed more than half the blood pressure-lowering effect) -- but don't get too hung up on what our prehistoric ancestors ate. After all, they didn't live long enough to worry about blood pressure.