The FastDay Forum

"Salt is not an issue in normotensive subjects" as someone once wrote in a very detailed review paper.

In plain language you don't need to worry about salt at all unless you have high blood pressure. Your kidneys came supplied with the ability to regulate sodium in your body.

Thanks Phil. So now I've started looking around and the prevailing view seems to be that salt raises blood pressure as well as increasing the risk of cardiovascular disease and that we should keep it low. See 2012 WHO report which recommends keeping salt intake below 5g per day (the UK target is currently 6g/day).

These recommendations apply to all individuals, with or without hypertension (including pregnant and lactating women), except for individuals with illnesses or taking drug therapy that may lead to hyponatraemia or acute build-up of body water, or require physician-supervised diets (e.g. patients with heart failure and those with type I diabetes).

There's also a UK paper about the 6g/day target and the science behind it here. (And there's an NHS page but we all know how much credence we should give those!)

Clearly lowering salt intake lowers blood pressure, but if your blood pressure is already normal or even better optimal is there a benefit in reducing it further? Is the effect of high salt intake long-term or reversible? So if someone with normal BP has high salt intake and later develops raised BP, can they just reduce their salt intake to get back to the BP they would have had if they had not eaten all that salt, or is some of the damage non-reversible?

Makes a lot of sense to me now why certain said fast meals make me feel crook within about 15 minutes. you know when you are all packed back into the car and on your way again.

Also I feel so fabulous on fast days and again not so flash on feeds days and my GIT not a happy camper. I have been mainly having veg dishes on fast days so that ties in with article too.

While I want to keep on with this WOE I would also like to develop an optimum diet which is nutritious and enables me to have confidence I am eating well. So in that sense this WOE is only a step on the journey and only part of my solution.

Clearly lowering salt intake lowers blood pressure

Not clear at all unfortunately. Setting aside broad sweeping generalisations based on epidemiology....

There are people who have blood pressure sensitive to salt, and those who don't. There may even be a third group where extra salt reduces blood pressure. The biggest group doesn't respond to extra salt intake (two thirds ?)

http://hyper.ahajournals.org/content/22/3/331.full.pdf

"The present and previous studies demonstrate that
the blood pressure response to salt restriction is heterogeneous and not uniformly a depressor one"

This RCT switched subjects from a salt intake of 20 to one of 300 mmol/day.

Here's a Cochrane review of RCTs - http://onlinelibrary.wiley.com/doi/10.1 ... 2/abstract
"Intensive interventions, unsuited to primary care or population prevention programmes, provide only minimal reductions in blood pressure during long-term trials. Further evaluations to assess effects on morbidity and mortality outcomes are needed for populations as a whole and for patients with elevated blood pressure."


there are others, with broadly similar conclusions.

http://www.theatlantic.com/health/archi ... ad/275888/

"This week experts warned against the dangers of overdoing low-sodium diets."

I've always suspected this. I have lowish blood pressure, love salt, eat loads of it, and never had an ill effect.

I had my doubts about high salt raised by the Pala Nomads of central Tibet. I was doing a cultural paper for my nursing, it was early in 2000. These people eat on average 11g of salt per day yet suffer no cardiovascular ill effects. They were studied because they were a medical mystery.

Diet and food interaction are far to complex for a simple broad sweep solution. Unless you are thinking of the 5:2 diet

I have had a raised BP since it went up during a difficult pregnancy many years ago. One thing I have always noticed is that I have a specific trigger weight and things go out of control even on medication if I go above that point. I asked my GP about salt and was old that reducing intake only works for some people. The advice was to give it a try and see if it makes a difference. It never has for me. As part of our healthy eating I use a sensible amount in cooking but don't actually add salt at the table.

I've always been more of a sugar fiend than a salt addict but since starting 5:2 I do sometimes crave salt on a fast day but thats sorted with a cup of bouillon.

I have no idea as yet what effect 5:2 might have had on my BP. I'm due a medication revue next month which will be interesting. At the moment I'm sleeping better and have more energy. My weight loss is very slow but I can cope with that now I'm feeling better in myself.

The US Institute of Medicine (disclaimer: I used to work there, though not on this study) indicates there is no clear benefit to major restrictions on salt intake: http://www.nytimes.com/2013/05/15/healt ... d=all&_r=0

The recommendation in the US is about 2000 mg, though most people eat around 3500 mg. The IOM study did not set an upper limit.

Thanks badtzmaru5 for that link. But although they are critical of the max 1500mg/day sodium recommendation, they seem implicitly to endorse 2300mg/day (= 5.75g salt I think or very close to the 6g/day level that UK is supposed to be aiming for) - below the current average levels in typical US/UK diet. From the article:

But the new expert committee, commissioned by the Institute of Medicine at the behest of the Centers for Disease Control and Prevention, said there was no rationale for anyone to aim for sodium levels below 2,300 milligrams a day.

Here is a better link - press release from the NAS itself: http://www8.nationalacademies.org/onpin ... rdID=18311

The implicit endorsement comes from the NYT, I think. The IOM committee was not asked to set an upper limit, only look at the evidence for current guidelines (2300 mg max sodium per day; 1500 mg for susceptible groups). They found no evidence for benefits in reducing the rec to 1500 for general population, and also some evidence that low consumption is harmful even for high-risk populations. They didn't look at the evidence for above 2300 mg so did not weigh in on whether higher levels are good or bad. Next study, perhaps.

Institutions don't find it easy to say "we were wrong" so I expect to find this sort of meally mouthed response to this and other issues where the current public position cannot be justified with evidence.

Cholesterol, saturated fat, salt and other issues have strong "these things are bad" messages in the public domain which are very dubious in their substance.

Similar postive messages about fruit, carbohydrates etc ar ein a similar position, especially when it comes to diabetics.

One of the effects of climate change is that weather at the extreme ends of the range are more intense, the biggest tornadoes are bigger, the strongest hurricane are stronger, and when heat waves hit the worst ones are longer and hotter. When you sweat you lose salt as well as water, which is why people travelling in the desert take salt tablets. So what happen to vulnerable people in heat waves who are on 'healthy' low salt diets?

When you sweat you lose salt as well as water, which is why people travelling in the desert take salt tablets. So what happen to vulnerable people in heat waves who are on 'healthy' low salt diets?

I imagine they get headaches, light headed, dizziness etc and blame it on lack of water / dehydration.

I've had no reduction in salt intake but recently posted some excellent results in lowering my persistently high bp without meds...thanks to IF in my opinion.