Salt linked with stubborn blood pressure problems

Last Wednesday I wrote about ‘mindful eating’, and mentioned I was in the process of reducing my own weight. Actually, I don’t really care about my weight, it’s fat I’m attempting to lose. My aim is to improve my body composition, and to this end weight is relatively irrelevant. However, I confess that I have been weighing myself daily, along with taking other measurements, to get as complete a picture of my changing body as possible.

I’ve plotted my weight loss on a graph, and after a rapid drop, my loss appears to have been quite consistent with, obviously, a bit of wavering from day-to-day. Except for one day, when my weight jumped up a pound and a half, but came down to ‘normal’ the following day.

When I look at the graph, this day sticks out like a sore thumb. What happened? Well, the evening before I was at a Portuguese barbeque (the Portuguese may be relevant, as you’ll see). I ate nothing different and no more than normal. I had barbequed chicken and pork, and green leafy salad. There was a lot of my favourite beer around, and I didn’t want to be tempted due to thirst, so I drank a lot of water. So, how come the following day my weight was up a pound and a half?

I think the answer is most likely to be ‘salt’. The Portuguese put a lot of salt in and on their food. One potential risk of excessive salt consumption is raised blood pressure, which itself is a risk factor for cardiovascular disease, particularly stroke. When I’m in Portugal, I am amazed at the number of not-so-elderly people who have been affected by ‘thrombosis’ (the common expression for stroke in Portugal). My brother-in-law, an expert in stroke, informs me that Portugal is regarded as the stroke capital of Europe. Salt, I suspect, has a lot to do with it.

So, one thing I remember about the food at the barbeque is that it tasted really salty. When salt levels in the body are high, the body tends to retain fluid (in an effort to dilute the salt). My suspicion is that my little blip in weight was down to this and nothing more.

The relationship between salt, fluid levels in the body and blood pressure was highlighted recently in a study published on-line in the journal Hypertension [1]. In this study, individuals were put at different times on low and high sodium diets, each for a period of a week. These individuals were all suffering from what is termed ‘resistant’ hypertension. Which means that despite multiple medications, the blood pressure remains high. The average number of medications taken by participants in this trial was 3-4. Average blood pressure was 146/84 mmHg.

The high sodium diet contained 5.75 grams of sodium (about 14.5 grams of salt) a day. The low sodium diet contained 1.15 grams of sodium (about 2.9 grams of salt) a day.

Compared to the high salt diet, the low-salt diet reduced blood pressure significantly: the systolic (higher) and diastolic (lower) blood pressure dropped by about 23 and 9 mmHg respectively. Chemical analysis of the blood revealed that this was most likely due to a reduction in blood (plasma) volume.

Those with raised or borderline raised blood pressure may like to consider cutting back on salt. 80-90 per cent of the salt consumed in the Western diet comes from processed foods, some of which are extremely salty but don’t necessarily taste it. For example cornflakes, gram for gram, contain as much salt as seawater. Processed food is the place to look to effectively cut down on salt intake. After that, we might consider limiting what we add during cooking and at the table too.

Another nutritional approach to combating high blood pressure is to increase intake of potassium (found, for example, in fruits and vegetables). For more on this, see here.


1. Pimenta E, et al. Effects of Dietary Sodium Reduction on Blood Pressure in Subjects With Resistant Hypertension. Results From a Randomized Trial. Hypertension 2009 Jul 20. [Epub ahead of print]

6 Responses to Salt linked with stubborn blood pressure problems

  1. Jake 11 August 2009 at 2:48 am #

    Here is my blood pressure history over the last 6 months which shows that there are a lot of factors affecting blood pressure.

    1. Without treatment my blood pressure was 148/95. I took blood pressure medicine (ACE inhibitor)and my blood pressure dropped to 135/85 at the beginning of this year.

    2. I cured my Vitamin D deficiency by raising my Vitamin D level to 70. My blood pressure dropped to 125/75.

    3. I went on a low carb diet eating less than 30 grams of carbs a day. My blood pressure dropped to 112/72.

    4. I drank the hot chocolate drink made of two tablespoons of pure Cocoa (or cacao powder), 100% and not “dutched” (i.e. not washed with an alkalai wash). I sweeten with Splenda to kill the bitter taste. Within a month my blood pressure dropped to 102/69.

    I do use plenty of salt on my food and it does not affect my blood pressure although I do not eat any processed food.

  2. Sam Mac 11 August 2009 at 3:46 pm #

    I think that salt has been unfairly labeled as a killer. The evidence just is not there. Also basing general advice on treatments for people with specify diseases is not good practice. And using anecdotal evidence is even worse. Salt is a very simple molecule that our bodies are very familiar with (think millions of years of exposure) and healthy people are able to control effectively.

    try this:

  3. Trinkwasser 12 August 2009 at 12:53 am #

    It’s my understanding that only a relatively small percentage of the population are actually sodium sensitive WRT blood pressure.

    Having said which, many of the rest of us can find improvements not through reducing salt but through increasing potassium (CARE if you are on certain BP meds or diuretics!) and possibly magnesium and calcium.

    In your case it could well have caused water retention, most people seem to find various blips in weight loss and often major stalls, probably when your body cottons on to the fact that it’s losing all its hard won fat, and turns down its metabolic rate.

    Odd things can happen, for me Seroxat (Paxil) made me retain water and after switching to Venlafaxine I was peeing more than I drank for days. SSRIs are notorious for causing weight gain and this may be one mechanism.

  4. salt and hypertension 13 August 2009 at 1:40 pm #

    Too much salt is not good for you – I agree. Not enough salt is not good for you too.

    They say that we get enough (or even too much) salt in processed foods. That may be true but what if you don’t eat processed foods like me?

    The recommended amount for salt intake a day is between .5 to 4 grams.

    I use only natural sea salt from France – unprocessed and still full of natural nutients. My blood pressure has dropped some30 points in the past few months.
    If you like salt get this stuff. Here’s a link:

  5. Margaret Wilde 14 August 2009 at 7:05 pm #

    Shop-bought bread is a major source of avoidable salt intake.

    I make my own bread, without salt, using a breadmaker.

    This has the added benefit of having no strange chemicals in the ingredients.

  6. Hilda Glickman 15 August 2009 at 1:20 am #

    In the natural state where would we get salt? We are programmed to store salt as it is in short supply in nature whereas potassium is everywhere in natural food. The sodium/ potassium ratio is important. Processed food is laden with sodium and those low in zinc find it gard to taste food so may crave salty food. If people eat processed food with few fruits or vegatables they will get far too much salt. The body tries to dilute this by increasing water in the tissues.

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