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OCTOBER 2022 TABLEHOPPING

I wrote about sodium several months ago but because I continue to see a low salt diet mentioned in every consult note I get from other doctors and even in my own literature we give out to patients I am compelled to bring even more evidence that limiting your salt intake is not the most important component to improve your health. I happen to think that if you take diuretics to lower your blood pressure or if you sweat a lot via activity or sauna that you should replace your lost electrolytes. That’s not very controversial. Luckily, you can have the major electrolytes measured anytime you want. Unluckily , the measurement reflects plasma levels of the electrolytes not the true total body amount but it’s better than nothing.

I reviewed three articles that point out that low-sodium intakes are not associated with lower blood pressure . The first study was the Framingham Offspring study. Framingham is the longest and largest longitudinal study ever done in America …….Their conclusion from following 2362 adults aged 30-64 was

“Sodium intake was not associated with CVD risk within the range of intakes generally consumed by these participants. In contrast, higher intakes of both potassium and magnesium were inversely associated with risk of CVD.” See the details here.

https://academic.oup.com/cdn/article/4/Supplement_2/1476/5845928

The next nail in the sodium is bad for you coffin comes from this study PMID: 33314019 “Effects of low sodium diet vs. high sodium diet on blood pressure reading aldosterone catecholamines cholesterol triglyceride” In this study the differences in blood pressure between the groups were minuscule, not tiny, miniscule. Their exact number was ,in white participants, sodium reduction resulted in mean arterial pressure reduction of 0.4 mL of Mercury and 4 mm of mercury in people with hypertension. So if your blood pressure is 200/100 and you adopt a low sodium diet you will now have 196/98. Is that going to prevent a stroke or heart attack? As the authors conclude there is “weak evidence indicates these effects may be a little greater and black and Asian people”. They further point out that the effect of sodium reduction on potential side effects or among the lipids were more consistent than the effect on blood pressure.”
Translation = the negative side effects were more consistent than the benefits. Yes, there are dangers to a low sodium diet see August 2022 Tablehopping for that run through.

Next up is a study called INTERSALT…an International study of electrolyte excretion in blood pressure results for 24 hour urinary sodium and potassium excretion. Type PMID: 3416162 into your browser to be brought directly to the study.

In this large study body mass index and heavy alcohol intake has a strong significant independent relationship with blood pressure in individual subjects The INTERSALT group studied 10,079 men and women aged 20 to 60 from 52 centers around the world. The results are a bit dense “Sodium excretion ranged from 0.2 mmol/24 h (Yanomamo Indians, Brazil) to 242 mmol/24 h (north China). In individual subjects (within centres) it was significantly related to blood pressure. Four centres found very low sodium excretion, low blood pressure, and little or no upward slope of blood pressure with age. Across the other 48 centres sodium was significantly related to the slope of blood pressure with age but not to median blood pressure or prevalence of high blood pressure. Potassium excretion was negatively correlated with blood pressure in individual subjects after adjustment for confounding variables. Across centres there was no consistent association. Bottom line is the last line…across centres there was no consistent association between salt excretion and blood pressure. Salt excretion is a measure of salt intake. Different slants in this study have been used by both sides of the argument and if that’s possible that means the argument for salt restriction cant be that compelling.

Finally , from the Cochrane Review , a respected independent reviewer of the medical literature…..after collating all available data they concluded…..”Despite collating more event data than previous systematic reviews of randomized controlled trials, there is insufficient power to confirm clinically important effects of dietary advice and salt substitution on cardiovascular mortality in normotensive or hypertensive populations.”

If you want to lower your blood pressure, the science says lose weight and stop drinking heavily, add more potassium and magnesium to your diet and cut the carbs and you will have better health and a lower risk for heart disease and stroke. The easiest intervention is to get “lite” salt or “lo-salt” which replaces some of the sodium with potassium . The addition of the potassium is much more important than taking the sodium away. Of course check with your doctor blah blah….but don’t feel so guilty putting that salt on the corn on the cob.

Until next month …get well and stay well

JT BARRY MD