Doctors automatically suggest that anyone with high blood pressure cut down drastically on salt. But I have read that only somewhere between ten and twenty percent of people are even salt sensitive. Now if I knew for certain that I was one of those ten to twenty percent, it wouldn't bother me so much to cut out my beloved salt. But I can't help but think I just don't want to sacrifice that much in taste for the next ten, twenty, forty years if I'm not one of those affected by it anyway.

But how can one really test if one is salt sensitive or not? My doctor said try taking blood pressure readings after eating salt and without salt. But it just isn't that easy! For me, and I'm sure for many others, differences in stress and other factors would throw off those readings completely. I'd probably have to go at least a month of no salt, then a month on exactly the same meals and snacks but with salt to get enough readings to average out other factors and make it at all meaningful.

Has anyone had any experience in determining if you really are salt sensitive?

Hi Uff-Da,

GREAT topic!

Funny you should bring that up- it's been on my mind too. I've been reading that as many as 1/3 of people are low-renin hypertensives. For this lot, the drugs that work by lowering renin are not useful. That includes beta-blockers, ACE inhibitors and ARBS.

This minority owes hypertension to salt-sensitivity and so diuretics (and maybe calcium-channel blockers <not sure>) are the way to go, and of course the horrid and difficult no-salt diet. ;)

Obviously, if one's goal is monotherapy (one drug rather than 16:D), one MUST determine what's causing the hypertension.

Some clues I am putting together:
1. I retain MUCH more water weight than other people from a big salty day...as much as 7 pounds.
2. My BP soars when my weight does.
3. Thiazide diuretics lower my BP best and give brisk diuresis WHEN I'm full of water (not otherwise)
4. ARB's don't do much for me.

I've started experimenting first with a diuretic...then I'll do only an ARB.

I'll keep you posted, but things are pointing me towards being in the minority.

There's some good stuff on the net about non-renin hypertension.

Keep in mind that for the other 2/3 that are high renin, ACE inhibitors and ARBs will block the renin-angiotensin system - essentially turning them into low-renin salt senisitive individuals as well.

Pal

Keep in mind that for the other 2/3 that are high renin, ACE inhibitors and ARBs will block the renin-angiotensin system - essentially turning them into low-renin salt senisitive individuals as well.

Pal
I'm on Lisinopril. So, if I understand you correctly, on that medication I'm salt-sensitive whether I was originally or not. No! I am not liking this! I was hoping for a way out! :(

Pal,

So to follow your statement to it's logical conclusion, treating the angiotensin II-renin (and ultimately aldosterone) system really benefits nobody if the 2/3 high renin hypertensitives become low-renin salt sensistives.

Thus only the low renin, sodium sensitives have any hope for monotherapy.
Do I read you correctly?

Do you have any guesses on what the mechanism might be for hypertension in the "salt-sensitives": genetic, pituitary, adrenal, other:D?

So to follow your statement to it's logical conclusion, treating the angiotensin-renin system really benefits nobody if the 2/3 high renin hypertensitives become low-renin salt sensistives.
Thus only the low renin, sodium sensitives have any hope for monotherapy.
Do I read you correctly?
I don't believe that is the logical conclusion. I believe the "first-line" for a high renin person should be an ACEI, ARB or the new and upcomming class called "Renin Inhibitors" (i.e. Aliskiren). Otherwise, you are fighting an uphill battle with the renin-angiotensin system.

A more logical conclusion is that your ACEI or ARB will give you a certain level of control. However, a low-sodium diet will give you even better BP control.

Here are some interesting articles:

http://www.stress.org/Hypertension.htm - This is a very good read as it challenges ALLHAT and JNC-7.

http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=372606 - This experiment from the 1970's shows much of the forgotten science behind these drugs. You can see some real data on how sodium and the renin-angiotensin system interact under a highly controlled environment. Also, you can also see that ACEIs and ARBs have been around a while. It just took them some time to synthesize these into marketable drugs.

http://www.findarticles.com/p/articles/mi_m0CUH/is_4_25/ai_85170977/pg_1 - This is a little study done on diabetics using lotarsan. It noted a high sensitivity to sodium. But, only in the losartan treated group. I wish someone would do (or I could find) a similar study with a non-diabetic population. I suspect the results would be similar.

Pal

Here's a couple more articles supporting the fact that you become sodium sensitive while on an ACEI or ARB:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=retrieve&db=pubmed&list_uids=3103761&dopt=Abstract - This one is from 1987. It was a little study that clearly shows that sodium restriction helps out an ACEI.

http://hyper.ahajournals.org/cgi/content/full/25/5/1042 - And, here is very good article from 1995. It compares a low sodium diet to HCTZ while on an ACEI. It concludes that the two yeild similar blood pressure control. But, it prefers the low sodium diet because it doesn't affect potassium levels.

Pal

Thanks Pal, I'll digest the links in the wee hours. One thing seems certain, though: to treat a low renin hypertensive with ARB's and ACE's and Beta Blockers seems a disastrously wrong approach and can only make matters worse.

I guess the first order of business seems to test the plasma renin in the absence of meds. I gather, from the little I've gleaned, that the testing is neither cheap nor common.

There's a long interview with a Dr. Joseph Laragh (qualifications too many to mention) floating around the web. That sheds lots of light on the subject.

I did read (well ok scan) the stress.org article and found it interesting. How can one determine if renin is the underlying cause? Are there tests that can be performed? If so, what are the treatment options?

I am going to try to get my plasma renin measured the next time I see my GP. I'm presuming that a week beforehand without the meds will be a sufficient "wash out" period.
I know the article talks about the difficulty of the two applicable tests, but I think the science is good enough so that my insurance company will pick up the tab.
My take on the treatment is that high renin people should continue to block angiotensin the best way they can: ACES<cough cough> and $$ARBS$$. The low renin hypertensives should go with the thiazides or other diuretics.

I am going to try to get my plasma renin measured the next time I see my GP. I'm presuming that a week beforehand without the meds will be a sufficient "wash out" period.

I remember reading somewhere that it took 2-4 weeks washout. And, your sodium intake had to be controlled for a few days before the test. And, it said something about needing to take an initial blood draw after resting for a couple hours. Then, another after standing for a couple hours. I can see why this test is seldom done. Dr. Laragh makes it sound like it's just a simple blood test that everyone should have done. This is a lot more involved than the traditional 8-12 hour fasting rule for most other tests.

Pal

This website describes the renin test http://my.webmd.com/hw/hypertension/hw203228.asp

I'm editing the part about drawing blood.

Renin

Test Overview

Renin is an enzyme produced by specific cells in the kidneys. Renin interacts with aldosterone (a hormone produced by the adrenal glands) and several other substances to help regulate sodium and potassium in the blood, fluid levels in the body, and blood pressure.

A renin test, or plasma renin activity (PRA) test, is done to determine the cause of high blood pressure (hypertension). It is usually done at the same time as an aldosterone test (see the medical test Aldosterone). In some situations, it may be normal to have high blood levels of both renin and aldosterone. However, if renin levels are low and aldosterone levels are high, an aldosterone-producing tumor of the adrenal glands may be present.

This test is usually done on a blood sample taken from a vein.

Why It Is Done

A plasma renin activity test is done to determine the cause of high blood pressure (hypertension), especially when potassium levels in the blood are low.

How To Prepare

For about 2 to 4 weeks before the test, you will have to stop taking medications that can interfere with the test, such as diuretics, birth control pills, and high blood pressure medications (especially beta-blockers and ACE inhibitors ). Talk to your doctor about which medications you need to stop taking. Your doctor may substitute your medications with others that will not interfere with the renin blood test results.

Do not eat natural black licorice for at least 2 weeks before the test, and avoid eating or drinking foods containing caffeine the day before the test. Natural licorice and caffeine can interfere with test results.

Recent diagnostic imaging procedures that required the use of a radioactive tracer (such as a thyroid scan or bone scan) can interfere with renin test results. Inform your doctor if you have undergone any test within 3 days that used a radioactive tracer.

For 3 days before a renin test, you may be required to follow a special diet that contains known amounts of sodium.

How It Is Done

You may need to sit or lie down for 1 to 2 hours before your blood is collected. In addition, a second blood sample may be collected after you stand for 2 hours.

edited here-------

Results

The results depend upon the time of day and your position (standing, sitting, or lying down) before the blood sample is collected, your age, and the level of sodium in your blood.

Normal
Normal values may vary from lab to lab.

Plasma renin activity Adult (upright position, normal sodium diet):
1–6 nanograms per milliliter per hour (ng/mL/hr)


Greater-than-normal values may mean
A high renin value can indicate kidney disease, blockage of an artery leading to a kidney, Addison's disease, cirrhosis, excessive bleeding (hemorrhage), or malignant high blood pressure.

Lower-than-normal values may mean
A low renin value can indicate Conn's syndrome.

What Affects the Test

A diet high in natural black licorice can lower renin values.
Many medications used to treat high blood pressure can raise or lower renin levels.
Your position (standing, sitting, or lying) before the test is done or the time of day when the blood sample is drawn, as well as recent salt intake, can affect renin levels.
Very high doses of corticosteroids can lower renin values.
Pregnancy causes renin levels to increase.
Rough handling, contamination, or inadequate refrigeration of the blood sample can cause inaccurate test results.
What To Think About

Many factors can affect renin test results. Therefore, only a doctor who has experience with renin tests should interpret the results.
A renin stimulation test may occasionally be done if blood renin levels are low. To prepare for this test, you will follow a low-sodium diet for 3 days. A blood renin level will then be drawn and a diuretic, usually furosemide (Lasix), will be injected through an IV. Normally, blood renin levels will increase, whereas in Conn's syndrome blood renin levels will not change.
A plasma renin activity (PRA) test measures renin indirectly by measuring an enzyme called angiotensin I rather than renin itself. Many hospitals now measure renin activity directly through a test called the renin direct immunoassay, which measures the amount of renin in the blood. A renin direct immunoassay is easier to do and can generally be substituted for the PRA test. However, in some situations (such as pregnancy), PRA results may be more accurate than the renin direct immunoassay.

Well, I guess that makes up my mind for me. There is no way in Hades that my GP will ever be able to get the testing for renin right. I routinely get lab results that say something like: Unable to test for <balh blah> because the sample was not centrifuged properly, or the red blood cells remained in contact with <blah blah> too long, or the sample wasn't properly refrigerated.

I clearly need a new <blah blah!> because mine is vaguely incompetent!:D:D:D

I was just sitting here watching an old war movie, & i had a bag of ACT II diet popcorn, figured not much fat

I took my blood pressure when the movie was over, still sitting relaxed, and my bp was 157/109, 10 minutes later i checked & it was 156/102, its been 145/low 90's all day

this is probably 30 - 45 minutes after i finished the popcorn

i looked at the box & each bag has 680 mg of sodium

maybe it does make a difference, but then i havent had any salt that i know of all week, ive been eating mostly food i made from scratch myself

If it were me, I'd be inclined to think the movie would probably have a greater influence than the salt. I know for a fact that my blood pressure is greatly influenced by stress. And watching a war movie would do it. Even watching the news, which is usually bad, does it.

Just eating anything tends to raise the blood pressure, too, so I'd think one would have to compare eating foods with salt and eating the same food without salt.

Come to think of it, I have one bag of ACT II diet popcorn left in the cupboard that I bought a long time ago. One of these days I'm going to see what it does to me.

I'm amazed the popcorn is ONLY 680 mg sodium. Are you sure it's not 680 PER SERVING with several servings per bag?
I've had a can of soup with nearly 3000 mg sodium in it.
A good way around this is to pop your own and add NO-SALT or NU-SALT to it...you can get sodium down to near zero that way! It doesn't taste as good but it's good enough and doesn't pump our arteries full of water.

the popcorn was 340 mg per serving, 2 per bag

i was sick last week & had some canned chicken soup, my bp was swinging all over then, i didnt think anything of it at the time, but i sure didnt feel like cooking then

regarding the comment about black licorice & renin levels, i was taking licorice for years to control stomach problems (later diagnosed as acid reflux), the licorice controlled it as good as prevacid does now, but i found the licorice was raising my bp (at least when i had been off it for a couple of weeks my bp was lower at the dr's office, that was before i was monitoring it myself)