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> You could say that this suggests higher sodium increases cardiovascular disease risk but that seems like a stretch when if you'd picked a slightly different s

> You could say that this suggests higher sodium increases cardiovascular disease risk but that seems like a stretch when if you'd picked a slightly different set of CVD-correlated biomarkers you would have got exactly the opposite result. What’s the evidence for this? > Even if the results had been more convincing, the methods are not - it's an extremely short term study and looks only at correlative biomarkers and not at actual health outcomes You're going to have to pick your poison here - when you're after long term data on dietary interventions showing hard outcomes it's highly unlikely you'll ever see this in the form of RCTs that you're looking for (i.e. where you _only_ alter salt consumption). That's why we look for converging lines of evidence - biomarkers/soft outcomes from RCTs and hard outcomes from prospective cohort studies, for example. When we look at this for salt, we consistently see lower salt = lower adverse outcomes. That said, when we meta-analyse RCTs we do actually have sufficient power to see improvements on hard outcomes. In this meta (https://doi.org/10.1016/S0140-6736(11)61174-4 https://doi.org/10.1016/S0140-6736(11)61174-4) we see a 29% reduction in cardiovascular events in the 7 months to 11.5 years in normotensives in RCTs which looked exclusively at salt reduction. I wouldn't call 11.5 years short term, nor cardiovascular disease events a soft outcome. So surely this ticks all your boxes?

lithocarpus 1y ago
> What’s the evidence for this? Exactly what I paraphrased from the study - they chose three biomarkers that correlate with CVD - A increased 19%, B decreased 9%, C stayed the same. If they had chosen some other biomarker D instead of A, that increased say 5% or less, it would give an equally strong but opposite result as the result from the study. Meta analysis is only as strong as the studies it's based on. I looked at quite a few studies before that purport to show sodium causing CVD, and none of them strongly support their conclusion - they all had significant flaws, not that they're not useful research just that they don't show what they are used to say they show. For example, there were studies showing that increased salt increased blood pressure by ~5 mm Hg over long term. I understand that blood pressure can be affected very slightly by salt intake, I would guess because the body is holding more water or some other normal mechanism like that, but this does not suggest it's the long term cause of blood pressures going up from a normal 120 to a chronic 160 or 200 as we're seeing in tons of people. There could be any number of adjustments that would increase blood pressure slightly WHILE the change is in effect and then go back to baseline afterward. The chronic high blood pressure is a disease that doesn't just go back to normal immediately after a change. Anyway, I don't have time at the moment to look through the 11 studies cited in that meta analysis, but if you pick the one or two that give the strongest evidence for salt causing CVD I'd look at them. I'm genuinely trying to figure this out myself as best I can, because I know way too many people close to me dealing with early stage CVD and diabetes. And a lot of them say they're working on it by avoiding meat and dairy and eggs and salt, and instead of that they end up eating more refined oils and refined flour and sugar. It doesn't seem to be helping them any after years of this, and I think this is backwards advice. I'm not saying we need to eat tons of salt, maybe it does have a minor effect, just that it's not the real culprit.
- KempyKolibri 1y ago
  You said: > if you'd picked a slightly different set of CVD-correlated biomarkers you would have got exactly the opposite result. So the evidence I’m looking for is empirics showing CVD correlated biomarkers that suggest a beneficial effect from consuming levels of sodium above recommended levels. Without that evidence then I don’t see why we should believe they would have got the opposite result if they picked other CVD biomarkers. > but this does not suggest it's the long term cause of blood pressures going up from a normal 120 to a chronic 160 or 200 as we're seeing in tons of people I’m not claiming that salt is the single cause of hypertension, but that doesn’t mean that the kind of reductions you see from salt reduction aren’t meaningful or contribute to those very high figures. It’s easy to dismiss 5mmHg as insignificant, but we generally see a 5mmHg reduction in sysBP translate to a ~10% reduction in CVD events. Considering how prevalent CVD is, that’s a pretty large effect size. Chronic diseases are often overdetermined and stack - people have a poor diet which means they consume too much salt, they’re overweight and obesity, have T2DM or prediabetes, sedentary lifestyle, etc etc. The fact that we can’t point to a single one of these and say “this is the thing causing your 160/100 BP doesn’t mean we shouldn’t try to fix the individual factors. So sure, salt reduction seems to offer 5-6mmHg reduction, exercise 4-8, hypertensive drugs 10. But put them all together and that’s a massive change. > Anyway, I don't have time at the moment to look through the 11 studies cited in that meta analysis, but if you pick the one or two that give the strongest evidence for salt causing CVD I'd look at them. It’s just three trials (or four depending on how you count TOHP I & II). I think I’ve met my burden in terms of showing there’s evidence of high salt intake having adverse effects, I have no interest in forcing you to read them. Just trying to provide evidence if that’s something you’re seeking. > I'm genuinely trying to figure this out myself as best I can, because I know way too many people close to me dealing with early stage CVD and diabetes. I’m sorry to hear that. We certainly seem to be struggling with chronic lifestyle-related disease these days, though with GLP-1 RAs I’m a lot more optimistic than I was a few years ago. > And a lot of them say they're working on it by avoiding meat and dairy and eggs and salt, and instead of that they end up eating more refined oils and refined flour and sugar. Yeah depending on the composition of what they’re eating that doesn’t sound great. IMO Replacing butter with refined oils and whole grain flours/carbs - sure, solid move. Replacing meat with plant proteins is also a worthwhile step, and eggs don’t seem to be great for health in many respects. But fermented dairy seems to be a positive as far as CVD risk goes, so ethics aside, seems like a backwards step if they replacing yoghurt and cheese with sugar and white flour! > I'm not saying we need to eat tons of salt, maybe it does have a minor effect, just that it's not the real culprit. I’m very wary of trying to find “the culprit” for public health problems. It’s so rarely the case that a disease has a single aetiology, and in my experience the people who’ll tell you “it was the sugar all along”, “it was the seed oils all along”, “it was the glyphosate all along” have a book to sell. The reality is probably closer to it being a combination of several things. Not as sexy though, no publisher or influencer is interested in that view!

lithocarpus 1y ago

> What’s the evidence for this? Exactly what I paraphrased from the study - they chose three biomarkers that correlate with CVD - A increased 19%, B decreased 9%, C stayed the same. If they had chosen some other biomarker D instead of A, that increased say 5% or less, it would give an equally strong but opposite result as the result from the study. Meta analysis is only as strong as the studies it's based on. I looked at quite a few studies before that purport to show sodium causing CVD, and none of them strongly support their conclusion - they all had significant flaws, not that they're not useful research just that they don't show what they are used to say they show. For example, there were studies showing that increased salt increased blood pressure by ~5 mm Hg over long term. I understand that blood pressure can be affected very slightly by salt intake, I would guess because the body is holding more water or some other normal mechanism like that, but this does not suggest it's the long term cause of blood pressures going up from a normal 120 to a chronic 160 or 200 as we're seeing in tons of people. There could be any number of adjustments that would increase blood pressure slightly WHILE the change is in effect and then go back to baseline afterward. The chronic high blood pressure is a disease that doesn't just go back to normal immediately after a change. Anyway, I don't have time at the moment to look through the 11 studies cited in that meta analysis, but if you pick the one or two that give the strongest evidence for salt causing CVD I'd look at them. I'm genuinely trying to figure this out myself as best I can, because I know way too many people close to me dealing with early stage CVD and diabetes. And a lot of them say they're working on it by avoiding meat and dairy and eggs and salt, and instead of that they end up eating more refined oils and refined flour and sugar. It doesn't seem to be helping them any after years of this, and I think this is backwards advice. I'm not saying we need to eat tons of salt, maybe it does have a minor effect, just that it's not the real culprit.

KempyKolibri 1y ago
You said: > if you'd picked a slightly different set of CVD-correlated biomarkers you would have got exactly the opposite result. So the evidence I’m looking for is empirics showing CVD correlated biomarkers that suggest a beneficial effect from consuming levels of sodium above recommended levels. Without that evidence then I don’t see why we should believe they would have got the opposite result if they picked other CVD biomarkers. > but this does not suggest it's the long term cause of blood pressures going up from a normal 120 to a chronic 160 or 200 as we're seeing in tons of people I’m not claiming that salt is the single cause of hypertension, but that doesn’t mean that the kind of reductions you see from salt reduction aren’t meaningful or contribute to those very high figures. It’s easy to dismiss 5mmHg as insignificant, but we generally see a 5mmHg reduction in sysBP translate to a ~10% reduction in CVD events. Considering how prevalent CVD is, that’s a pretty large effect size. Chronic diseases are often overdetermined and stack - people have a poor diet which means they consume too much salt, they’re overweight and obesity, have T2DM or prediabetes, sedentary lifestyle, etc etc. The fact that we can’t point to a single one of these and say “this is the thing causing your 160/100 BP doesn’t mean we shouldn’t try to fix the individual factors. So sure, salt reduction seems to offer 5-6mmHg reduction, exercise 4-8, hypertensive drugs 10. But put them all together and that’s a massive change. > Anyway, I don't have time at the moment to look through the 11 studies cited in that meta analysis, but if you pick the one or two that give the strongest evidence for salt causing CVD I'd look at them. It’s just three trials (or four depending on how you count TOHP I & II). I think I’ve met my burden in terms of showing there’s evidence of high salt intake having adverse effects, I have no interest in forcing you to read them. Just trying to provide evidence if that’s something you’re seeking. > I'm genuinely trying to figure this out myself as best I can, because I know way too many people close to me dealing with early stage CVD and diabetes. I’m sorry to hear that. We certainly seem to be struggling with chronic lifestyle-related disease these days, though with GLP-1 RAs I’m a lot more optimistic than I was a few years ago. > And a lot of them say they're working on it by avoiding meat and dairy and eggs and salt, and instead of that they end up eating more refined oils and refined flour and sugar. Yeah depending on the composition of what they’re eating that doesn’t sound great. IMO Replacing butter with refined oils and whole grain flours/carbs - sure, solid move. Replacing meat with plant proteins is also a worthwhile step, and eggs don’t seem to be great for health in many respects. But fermented dairy seems to be a positive as far as CVD risk goes, so ethics aside, seems like a backwards step if they replacing yoghurt and cheese with sugar and white flour! > I'm not saying we need to eat tons of salt, maybe it does have a minor effect, just that it's not the real culprit. I’m very wary of trying to find “the culprit” for public health problems. It’s so rarely the case that a disease has a single aetiology, and in my experience the people who’ll tell you “it was the sugar all along”, “it was the seed oils all along”, “it was the glyphosate all along” have a book to sell. The reality is probably closer to it being a combination of several things. Not as sexy though, no publisher or influencer is interested in that view!