One of the big complaints processed food companies, physicians in clinical practice, and the great gourmet media all have in common is that cutting back on salt would make food taste flat, and you as an individual wouldn’t necessarily get a big drop in your personal blood pressure from doing it. They argue that only “salt-sensitive” people have to worry about their intake, and anyway, a few points lower, they all say, isn’t really impressive enough to give up your 300-mg serving of sodium in a bowl of Kellogg’s raisin bran or 390 in a slice of La Brea sourdough. And don’t, for g-d’s sake, ask your favorite name brand celebrity chefs to stop salting early and often in each dish!
A big statistical modeling study in the New England Journal of Medicine this week knocks all this wishful thinking on the head, and does it very nicely. The study looked not at individual blood pressure drops but the health and cost benefit of dropping average salt intake by 3 grams a day over the entire U.S. population.
The researchers found that if everyone drops their salt intake back down, the benefits start to look like the ones from quitting smoking, cutting cholesterol and saturated fat, and losing weight to get to a normal BMI.
That’s because even when individual blood pressures drop by only a few points, they’re not going up (as they are today), and when a small average drop happens in a very large group, the big bell curve of disease shifts toward lower risk of consequences and later starts for developing heart disease and high blood pressure. After the first national cholesterol lowering guidelines were issued in the late 1960s, the nation’s heart disease and stroke risk dropped by about a third, and at least until obesity and blood pressure started to cause a back-reaction, the average age for a first heart attack went from 50 to 60 in men. That’s a huge kind of benefit.
The combined drop in heart disease and stroke deaths from cutting salt would be something like 200-400,000 people per year, a lot more than can be saved by simply putting everyone on blood pressure medications–the study made that comparison directly.
Altogether, a solid recommendation for dropping sodium levels in processed and restaurant foods, which make up about 80% of today’s sodium intake. And for not imitating processed food and chain restaurant thinking in your professional or home cooking, as Francis Lam seems to in his Salon.com commentary on the new NYC Department of Health initiative. And if there was any doubt that the Culinary Institute of America has been training restaurant chefs to salt, salt, and salt some more, Lam really dispels that–without realizing the impact of what he’s revealing.
In any case, three groups who would benefit most strikingly from a nationwide drop in salt: women, African Americans, and children. More than half the adults living today, and all of the future ones.
Current salt intake levels are almost 11 g/day for men and 8 for women, or about double the current HHS recommended levels of 5-ish grams of salt (2300 mg sodium) for people under 40 and about 3 g (1500 mg sodium) for people 40 and older (ahem!) and those with high blood pressure, heart or kidney disease, etc. Men’s salt intakes have increased by half in the past 20-30 years, but women’s have increased by two-thirds–a faster, sharper increase for a population more vulnerable to stroke.
African Americans still have a higher risk of stroke, heart disease, diabetes, and kidney disease than the general population even after accounting for dietary factors, smoking, and socioeconomic status.
As for kids…Children’s current intake levels are a bit trickier to assess than adults’, and solid recommendations for daily maximum intakes in different age and weight groups have been established only in the past 5 years or so. The UK is ahead of the US on this, as it is on a national program of sodium reduction.
Parents and pediatricians have both assumed for years that kids don’t really need to worry about salt, that they’ll make up for it as they grow. But the study demonstrated just the opposite: kids are more vulnerable to future heart disease if they eat a high-salt diet while they’re young, so there’s a possibility of preventing future blood pressure and cardiovascular problems from developing if kids eat less salt in their early years.
And for the salt-sensitive issue? Ask not for whom the bell curve tolls: blood pressure is controlled by at least 6 different known genes, so it’s not a yes/no question. There’s very little way to know your exact genetic vulnerability and no fool-proof way to identify salt sensitivity for anything but Dahl rats, which were bred specifically for the extremes of blood pressure response to salt over more than 3000 generations of rats (easier to do than in humans; a generation for rats is only about 6 weeks). If you knew your family’s exact blood pressure pedigree for more than 3 generations, it would be astonishing: blood pressure cuffs were only invented in the 1890s.
So arguing that you personally are “not salt-sensitive” even while the population curve shows that most people are is idiotic. The truth is you don’t have any way to know how much your personal blood pressure depends on your salt intake unless you’re personally willing to show up to a lab for daily diet reports, BP measurements and urine samples over months. Better, for a rule of thumb, to assume you’re somewhere in the great lump of humanity, not one of the rare exceptions at the far tail of the bell curve, and figure your blood pressure is at least partially sensitive to salt, even if your fingers don’t swell up every time you eat take-out. Or three-star tasting menus replete with amuses-bouches.
Filed under: breads, cooking, DASH Diet, Eating out, Food Blogs, Food Politics, kid food, nutrition | Tagged: cardiovascular disease, Culinary Institute of America, Food Politics, food porn, Francis Lam, heart disease, hypertension, low-salt, National Salt Reduction Initiative, processed food industry, public health, Regina Schrambling, salt, stroke |