Salt: What Is It Good For?       

Image may be NSFW.
Clik here to view.Other  than saturated  fat, I can’t think of a nutrient that’s been so universally maligned and  demonized as salt.  All the experts hate it and recommend that we get as little of it as possible.  They even all seem to have their own little anti-salt slogans. The American  Diabetes Association recommends between 2300 and 1500 mg of sodium per day (“Be Sodium Savvy“). The American Heart Association wants you  eating less than 1500 mg per day (“Shaking the Salt Habit“) and claims that 97% of young people  already eat way too much salt. The other ADA – the American Dietetic Association  – also recommends between 2300 and 1500 mg, but their slogan is far inferior  (“Slice Your Sodium Intake“). It’s quite the pile-on, isn’t  it?

Why does salt strike mortal terror into the hearts of so  many?

Back in the 1980s, a massive global study of salt intake and blood pressure  called INTERSALT was undertaken. Overall, it showed a modest association between  the two, but some groups, particularly the undeveloped, non-industrial peoples  who had very little access to salt (and other trappings of industrialization),  had blood pressure that was generally extremely low. Foremost among these groups  were the Yanomami of  the Amazon rainforest. The Yanomami have very low sodium excretion, which  indicates very low sodium intake, and very low blood pressure. Even the elderly  Yanomami enjoyed low blood pressure. This was convincing. I mean, it sounds  convincing, right? Low salt intake, low lifelong incidence of hypertension – how  much more cut and dry can you get? This low salt/low blood pressure connection  seemed to also apply to other groups who happened to be living more traditional  ways of life.

Except that there’s another non-industrialized group (and you only need one)  whose slightly different results kinda muck up the Yanomami argument: the Kuna  of Panama.

Among the Kuna, a tribe native to Panama, both salt intake and blood pressure  were also historically low well into old age. To study whether the two variables  were linked, researchers examined a group of “acculturated”  Kuna with ample access to salt and an otherwise strict adherence to  their traditional way of life. Little changed but the salt intake, in other  words. But, despite consuming an average of 2.6 daily teaspoons of salt  (and sometimes up to 6 teaspoons), the Kuna did not have hypertension, not even  in old age. There was no change between the hypertensive statuses of 20  year old Kuna and 60 year old Kuna.

All in all, drastic reduction of sodium can reduce blood pressure by  a few points. The evidence is pretty consistent on that. But the example of the  Kuna shows that there’s way more to blood pressure than how much salt you eat,  like how much potassium you eat.

Consider two recent Cochrane meta-analyses. The first, on  sodium restriction and blood pressure, found that for people with  hypertension the mean effect of sodium restriction was -5.39 mm Hg for systolic  blood pressure and -2.82 mm Hg for diastolic blood pressure. In normotensive  people, the figures were -2.42 mm Hg and -1.00 mm Hg, respectively. Decent  reductions, I suppose, but what about potassium and  blood pressure?

The upper intake of potassium was  associated with over a 7-point drop in systolic blood pressure and a  2-point drop in diastolic blood pressure, but only in people with hypertension  (the people who actually should lower blood pressure). Unfortunately, the  official recommendations for sodium and  potassium intake cannot be met simultaneously. Yep – the experts want you to  eat in a way that is literally impossible to accomplish. Inspires confidence,  doesn’t it?

Let’s forget about blood pressure for a second, because there’s also way more  to health than the meager drops in blood pressure afforded by sodium  restriction. Recent evidence suggests that for many people, all out salt  reduction has an overall negative impact on several other aspects of  health:

In 2011, one study showed that seven days on a low salt diet increased insulin resistance in  healthy men and women when compared to a higher-salt diet.

Another study showed that while reducing salt moderately improved the blood pressure of  hypertensive patients by a mere 4.18 and 1.98 points for systolic and diastolic,  respectively (but not of people with normal blood pressure), it also had  negative effects on multiple other health markers, including increased triglycerides and  LDL and elevated stress hormones.

Another 2011 study found that eating a low salt diet (under 3 grams of sodium per day, or just over  a teaspoon of salt) and a high salt diet (from 6-7 grams of sodium per day, or  well over two teaspoons of salt) both increased the risk of stroke and heart  attack, while eating between four and six grams of sodium, or about two  teaspoons of salt, each day was associated with the lowest risk of  cardiovascular incidents.

A recent study found that salt intake followed a J-curve, with low and high intakes increasing  arterial plaque formation and a medium intake decreasing it.

Sodium depletion due to “low-sodium nutrition” has been  shown to trigger overtraining-like symptoms, including hypertension and  sleeping disorders.

The greatest health marker of all – being alive – also has an interesting  association with salt intake. It seems that, time and time again, folks with a “medium” salt intake live longer than people  who eat too little salt or too much salt. That amounts to roughly 4000 mg of  sodium, or close to two teaspoons of regular salt.

Sodium intake affects other markers of vascular health beyond just  blood pressure, too:

Greater sodium excretion in the urine (a common marker of sodium intake) may  be positively associated with large arterial compliance. Large  arterial compliance is a measure of arterial elasticity, or the ability of one’s  arteries to handle fluctuations in pressure. Stiffer arteries are more prone to  damage.

Low sodium status (whether dietarily-induced or caused by increased sodium  loss) can also increase aldosterone, an adrenal hormone that seeks to preserve  sodium in the body when it’s perceived to be scarce. High aldosterone levels are  associated with insulin  resistance, and aldosterone  blockers are being explored as potential treatments of vascular  disease and hypertension.

Well, what is salt good for?

That question honestly isn’t asked very often in the literature, but we can  surmise some of the benefits just by looking at what happens in people on a  low-sodium diet. If that connection persists, then adequate (not excess) salt  probably helps prevent some of those problems, like insulin resistance,  plaque formation, increased stress hormones, worsened blood lipids, and elevated  aldosterone.

There are, however, outright positive effects of salt consumption, too:

Salt supports hydration, especially during exercise.

Of the electrolytes, potassium gets all the attention, even though sodium is  just as important. Studies show that sodium  loading before exercising in the heat increases fluid volume and reduces the  physiological strain of the subsequent training. In other words, consuming  sodium before training “involved less thermoregulatory and perceived strain  during exercise and increased exercise capacity in warm conditions.” You can  workout harder, longer, and more effectively with sufficient sodium in your  diet. Salt loading also boosts  performance in thermoneutral conditions, not just hot weather.

I remember drinking so much plain water during one race that I actually  became dehydrated from pissing out all my electrolyte stores and almost passed  out. From that point on, a few teaspoons of salt would solve the problem and  prevent it from occurring again. The much ballyhooed bananas didn’t do it. Only  pure, unmitigated salt did the trick. Hardcore ketogenic athlete/doctor Peter  Attia does the same with his bullion cubes, which he credits for maintaining his  performance.

Salt may help you cope with stress.

This is a guess on my part, based on several lines of evidence. First, salt  has been shown to speed up cortisol clearance from the blood. The faster you  clear cortisol, the quicker you recover from a stressor. If cortisol lingers,  you “stay stressed.”

Second, there’s evidence that stress increases salt appetite. In lab mice, activation of  the sympathetic nervous system by a stressor causes them to prefer salt water to  plain water. Similar findings have been observed in rats  subjected to stress. In humans, acute bouts of stress don’t seem to increase  salt appetite, but chronic  stress does increase intake of salty, processed junk food. Obviously, eating  McDonald’s fries doesn’t help improve your health, but I find it highly  plausible that salting your healthy Primal food to taste could be an important  ally against stress. It’s just that when most people need “something salty,”  they reach for potato chips, not a couple soft boiled eggs dipped in sea  salt.

Third, as I mentioned above, low sodium diets are often associated with  elevated stress hormones.

Personally, I’m drawn to salty foods – often jerky or macadamia nuts  sprinkled with some sea salt – when I’m up against a deadline, and it seems to  help.

It makes food taste better.

Yes, some people would claim this attribute as a negative. Adding salt to  food will make you more likely to overeat and gain weight and develop the  diseases associated with weight gain and so on and so forth. But I’ve always  held that eating good food is one of life’s highest, purest pleasures. If your  food doesn’t taste good, there’s no point in eating it. We’re not machines  concerned only with fuel. We are sensory, sensual beings with the capacity for  appreciation of thousands of flavors. To deny the pleasure of food is to deny  our humanity.

Salt can also make otherwise unpalatable – but healthy – food somehow  palatable. A plate of steamed kale is boring and bitter. A plate of steamed kale  with sea  salt and olive  oil is delicious and inspiring. Plain broccoli? Kids everywhere are spitting  it into napkins and stuffing them into their pockets. Broccoli stir-fried with  soy sauce (or tamari, if you please)? Kids everywhere are mailing in their dues  (and signing up for auto-pay) for the clean plate club.

You could drop your salt intake to half a teaspoon and get a three or four  point drop in your blood pressure. Of course, you might not enjoy your food  anymore, your performance in the gym or on the trail would likely suffer, your  stress hormones might be elevated, you might start feeling overtrained without doing any actual training, you could become insulin resistant, and you  may have trouble clearing (the elevated) cortisol from your blood. But, hey: your blood  pressure readings will likely improve by a few points! Or, you could keep  your salt intake up around two teaspoons, give or take, simply by salting your  food to taste, and avoid all that other stuff.

Your choice.

What do you think, readers? Do you fear salt? Do you relish it? Do  you find your salt appetite increases under certain conditions? Let me know in  the comment section!