Why eat a low sodium paleo diet?
You can go all over the internet and find arguments for eating paleo, or other variations on ancestral diets. Some good places to start are Whole9 or Mark's Daily Apple. But if you read deeper into some of these websites, you'll find some debate about whether the "conventional wisdom" on low salt diets is actually wisdom or just poppycock. (I love that word, poppycock!) Looking from the low sodium side of the fence, I'm going to lay out why (and why not) you might want to take a lower sodium approach to paleo(ish) eating.
1. You have a medical condition that can truly be helped by eating a lower sodium diet.
There's a bunch of these. Meniere's disease. Various kidney (renal) conditions. An aortic aneurysm. Yes, these are big high stakes diseases. If you have one of these issues, you want to limit your sodium. The details are different for each condition, but generally speaking these are conditions where the fluid balance in the body is out of whack and limiting sodium can either restore appropriate fluid levels, or reduce the strain on the kidneys as they try to balance fluids. Personally, I have Meniere's disease which is an inner ear disorder causing severe intermittent vertigo and restricting my sodium intake to 1000-1200mg a day keeps me mostly off medication (for now).
A note on renal diets: There are a lot of other dietary issues at play for people who have renal failure. I know some people need to restrict potassium, phosphorous or other minerals, or sometimes manage their protein intake. I still believe that a diet based around whole foods is ideal, but if you have renal disease and want to make changes in your diet, it's best to consult with a dietician who's familiar with your labs.
2. You have a medical condition that can cause renal or blood pressure issues downstream.
Diabetes is the big one here, uncontrolled diabetes can result in kidney failure. A reduced carbohydrate paleo(ish) diet may help a diabetic control blood sugar, but they're probably dealing with some level of diminished kidney function. It just makes sense to me, in this case, to moderately reduce sodium intake to reduce the load on the kidneys. A much rarer situation, that unfortunately runs in my family, is a structural heart issue that can raise the risk of aortic aneurysm. In this case, keeping sodium moderate can help keep blood pressure low, which consequently reduces the long term strain on the aorta. There are also autoimmune diseases (like lupus) that can result in renal damage, and I'm sure there are a number of other conditions that I don't even know about. If you're dealing with one of these issues but don't have frank kidney or heart problems, you should think about a moderate sodium intake, maybe around 2000mg... unless your doctor is already telling you to go very low sodium.
3. You are overweight, obese or have a binge eating disorder and you're working to reduce food reward.
Now we step away from people with clear medical indication for going low sodium and start talking about the general public. First of all, I don't believe that going paleo(ish) is only about getting lean, but for a lot of people that's where they're coming from. There are a lot of competing ideas (within and without the paleo-verse) about how and why people become overweight. One of those theories is the "food reward" hypothesis or the "hyperpalatability" hypothesis. Basically that many processed foods are engineered to be more stimulating to the brain than real whole foods found in nature. Proponents of this argument would include neurobiologist Stephan Guyenet and public health policy expert Dr. David Kessler. One of the specific factors in Kessler's hyperpalatability argument is salt (the other two are fat and sugar). Based on my experience with a low sodium diet (which I will go into later), I truly think that they're onto something here. I don't know that this is driving the obesity epidemic, but certainly hyperpalatable foods are sitting shotgun and handing the driver can after can of Red Bull.
If you're concerned about this, if you think this theory explains some issues you're having with food or your body, I really think you should consider a trial of low sodium paleo eating. Despite what many people think, it doesn't have to be bland or boring (as I'll demonstrate), but dropping the sodium in your diet may well decrease the stimulating effect food has on your brain. And when you modify your sugar or fat intake you need to make other adjustments to be sure you're getting sufficient calories and nutrition... when you drop salt to a low (but adequate) level, you don't need to make a lot of other adjustments. Here I think you'd want to aim somewhere in the 1500-2000mg range... but possibly as low as 1000mg.
Why NOT eat a low sodium paleo diet?
1. You don't have to.
As someone who really does need to watch my sodium, this makes it's own case. If you don't have any good need to watch your sodium, DON'T! It's easier and you can enjoy bacon, cold cuts, bleu cheese and thai food without worry. If you just go paleo(ish) and base your diet around real whole foods, you're probably going to drop your sodium intake to a reasonably healthy level. A recent CDC report indicates that the top 10 types of food that contribute the most sodium to the American diet include bread and rolls, pizza, sandwiches, pasta mixed dishes, meat mixed dishes, and savory snacks. All things you won't eat if you go paleo(ish). Yes, there are some higher sodium paleo foods like cold cuts, cured meats, and cheeses. But avoiding bread alone is going to drop your sodium intake substantially! Take out processed fast food and snack foods and it drops even further. As long as you're not eating an everyday diet of bacon for breakfast, cold cuts for lunch and thai curries for dinner, you're probably OK.
2. You get a lot of exercise in the hot sun.
If you're sweating out a lot of salt, you need to take in salt. I live in California and I love exploring our local desert wilderness. But desert hiking means I need to up my sodium a little bit, or I get dizzy and weak. If you work outside in the summer or are very active in the outdoors, your body has an increased need for sodium. Period. Even if you have a good reason to limit salt overall, you may want to bump up your intake when you're sweating out a lot of it. (Again, renal folks talk to a dietician on this one.)
3. You have really low blood pressure.
If you have postural hypotension (you get faint when standing up from a seated or lying position), or if you find yourself dizzy or lightheaded eating a diet of all whole foods, you might want to look at your sodium intake and intentionally add some salt. I've found that a really strict paleo(ish) eating plan can sometimes drop sodium too low for good health. Even for me, I sometimes need to salt my food, lest I drop below 800mg.
OK... next to come in the series... understanding salt & sodium: how much sodium is really in the foods you eat.