The Blood Pressure Fix That Costs Almost Nothing – And Nobody Uses

Iran signals openness to ending the war. Markets have their best day since May.

The quick scan: Tuesday delivered the sharpest single-day rally in months, driven by two sequential catalysts. First, the Wall Street Journal reported Trump told aides he was willing to wind down military hostilities even if the Strait of Hormuz remains closed. Then Iranian President Pezeshkian signalled openness to ending the war with guarantees – and markets surged. All three indices posted their best session since May. It wasn't enough to salvage March: the S&P 500 still closed the month down 5.3%, its worst monthly performance since 2022.

S&P 500: +2.91% to 6,528.52 – broad-based gains with 441 of 500 stocks higher; ten of eleven sectors rose, with consumer discretionary, communication services and technology leading
Dow Jones: +2.49% to 46,341.51 – best single-day gain since May, with Caterpillar, Amazon and Nvidia among the leaders
NASDAQ: +3.83% to 21,590.63 – tech's sharp reversal from Monday's semiconductor sell-off; Nvidia +5.6%, Microsoft +3.1%, Meta +3%; VIX fell to 25.12.

What's driving it: The session had two distinct catalysts arriving in sequence. The WSJ report gave markets an initial boost – the idea that Trump might de-escalate without waiting for the strait to reopen removed a key sticking point. Then Pezeshkian's signal added the second leg. Energy stocks sold off as oil edged lower on WTI – though Brent settled higher at $118 after a separate strike on a Kuwaiti tanker, a reminder that the conflict is not over. Warren Buffett, appearing on CNBC's Squawk Box, said he sold Apple too soon and would consider buying more if the price were right. Quarter-end portfolio rebalancing also contributed to the move's magnitude.

Bottom line: The Ken Fisher argument from yesterday's article – that the wall of worry is bull market fuel – looked prescient on Tuesday. The biggest single-day gains tend to arrive without warning, embedded in the worst stretches. For L-Plate Retirees who stayed invested through five weeks of losses, Tuesday was the session that validated the discipline. The war isn't over. The strait isn't open. But the market priced the possibility of resolution, and it moved fast.

The Cheapest Blood Pressure Trick Most People Have Never Tried

The scoop: Here is a fact that should probably bother us more than it does. Nearly half of all American adults – about 122 million people – have high blood pressure. It's a condition that contributes to over 130,000 deaths a year, and that quietly raises the risk of heart attack, stroke and kidney disease over time. Most people with it know they have it. Many are on medication for it.

And yet, according to new research presented at the American Heart Association's Hypertension Scientific Sessions, fewer than 6% of American adults use one of the simplest and cheapest tools available to help manage it.

That tool is a salt substitute.

Not a supplement. Not a prescription. A product that sits on the supermarket shelf next to regular salt, costs roughly the same, and works by replacing some or all of the sodium in ordinary salt with potassium – a mineral that does the opposite of sodium when it comes to blood pressure.

What the research found.

The study is the first to track long-term trends in salt substitute use across a nationally representative group of US adults. Researchers at UT Southwestern Medical Center in Dallas analysed data from the National Health and Nutrition Examination Survey spanning 2003 to 2020 – nearly two decades – covering 37,080 adults.

The findings are striking not for what changed, but for what didn't. Salt substitute use peaked at 5.4% of the population in 2013–14, then fell to 2.5% by 2017–2020. There has been no meaningful improvement in uptake across almost 20 years.

Among people specifically eligible to safely use salt substitutes – those with normal kidney function and not on medications that affect potassium levels – only 2.3% to 5.1% reported using them. Even among people whose blood pressure was uncontrolled despite medication, most were still reaching for regular salt.

"Salt substitute use remained uncommon over the last two decades including among people with high blood pressure," said lead author Yinying Wei, a PhD candidate in hypertension and cardiology at UT Southwestern. "Even among individuals with treated and poorly managed or untreated high blood pressure, most continued to use regular salt."

Amit Khera, a professor of medicine and director of preventive cardiology at UT Southwestern – who was not involved in the research – called the findings "eye-opening." The study, he said, highlights "an important and easy missed opportunity to improve blood pressure in the US."

Why sodium matters – and what potassium does.

The American Heart Association recommends keeping sodium intake to no more than 2,300mg per day, with an ideal target of under 1,500mg for most adults, especially those with high blood pressure. Most people in developed countries consume significantly more than that – and the majority doesn't come from a salt shaker. It comes from processed foods, packaged items and restaurant meals, where sodium is essentially invisible.

Salt substitutes address the sodium side of the equation by swapping it for potassium, which supports healthier blood pressure. The taste is similar to regular salt, though potassium-based substitutes can develop a slight bitterness when heated – the main reason some people try them once and don't go back.

Even a reduction of 1,000mg of sodium per day, the research notes, can lead to meaningful improvements in blood pressure and overall heart health. That's a number a salt substitute can help achieve without changing much else.

The important caveat – who should not use them.

Because potassium-based substitutes increase potassium intake, they can be problematic for people with kidney disease – kidneys that aren't functioning well may not clear excess potassium efficiently, and high potassium levels can cause abnormal heart rhythms. They are also not suitable for people taking certain medications or supplements that raise potassium levels, including some common blood pressure medications.

The research defined the safe-use group as people with normal kidney function (an eGFR of 60 or above) who are not on potassium-affecting medications. If you fall into that group, the risk profile looks quite manageable. If you're not sure, the answer is simple: ask your GP before switching.

The researchers and cardiologists involved in the study are not suggesting everyone make the swap independently. They are suggesting that clinicians start having the conversation with patients, particularly those with persistent or hard-to-manage high blood pressure.

A note on the research itself.

This study was presented as a preliminary abstract at a scientific conference – it has not yet been published as a full peer-reviewed paper. The scale of the dataset (37,080 participants, 17 years of national data) and the institutional source give it credibility, but preliminary findings can shift before publication.

What is well established – from prior peer-reviewed research – is that salt substitutes work, and that reducing sodium intake improves blood pressure. This study's contribution is documenting how few people are actually doing it.

The practical upshot.

You probably don't need another supplement. You probably don't need another prescription. If you have high blood pressure and your kidneys are functioning normally, the conversation worth having with your GP at your next check-up is a simple one: "Is a salt substitute appropriate for me?"

It costs almost nothing. It requires no significant behaviour change. And according to nearly 20 years of national data, almost nobody is asking the question.

Actionable takeaways for L-Plate Retirees:

• Check whether you're in the safe-use group. Salt substitutes are appropriate for people with normal kidney function and who aren't on medications that affect potassium. If you don't know your kidney function status, ask your GP – it's a standard blood test result. This is the first step before anything else.

• Raise it with your doctor at your next blood pressure appointment. The research specifically recommends that clinicians initiate this conversation with patients who have persistent or hard-to-manage hypertension. If your doctor hasn't raised it, you can – especially if your blood pressure has been difficult to control on medication alone.

• Understand the mechanism, not just the product. Salt substitutes reduce sodium and increase potassium simultaneously – which is why they work. Eating more potassium-rich foods (leafy greens, bananas, legumes, potatoes) while cutting processed food sodium applies the same principle without a product at all.

• The 1,000mg reduction target is achievable. The AHA's ideal target of under 1,500mg sodium per day is ambitious. But even cutting 1,000mg from your daily intake produces meaningful blood pressure benefits. A salt substitute used at the table is one way to get there; reducing restaurant meals and processed food is another.

• Don't use potassium-based substitutes if you have kidney disease or relevant medication. This is the non-negotiable caveat. High potassium is dangerous if your kidneys can't clear it. If you have any kidney condition or take ACE inhibitors, ARBs, potassium-sparing diuretics or potassium supplements, speak to your doctor before making this change.

• The taste adjustment is real but manageable. Potassium-based substitutes can taste slightly bitter when used in cooking at high heat. Many people find them indistinguishable from regular salt when used at the table. If bitterness is the reason you stopped, try using it cold rather than cooked.

Your Turn:
If you have high blood pressure – or someone in your household does – have you ever discussed salt substitutes with your GP? If not, what's the reason?
Most people consuming excess sodium don't get it from a salt shaker – they get it from packaged and restaurant food. How much of your sodium intake do you think comes from sources you actually control?
The study found that usage hasn't improved in 20 years despite the evidence being well established. What does that say about the gap between what we know is good for us and what we actually do?

👉 Hit reply and share your thoughts – your answers could inspire fellow readers in future issues.

If this issue gave you a useful nudge toward the grocery aisle rather than the supplement shelf, consider shouting L-Plate Retiree a coffee on Ko-fi.