AGT: whether salt actually moves your blood pressure

• GenesAGT (angiotensinogen) and GNB3 (G-protein beta-3)
• Variants testedAGT rs699 (M235T), GNB3 rs5443 (C825T)
• What they controlBlood pressure and fluid balance, and cellular sodium handling
• If salt-sensitiveThe blood-pressure response to sodium is roughly twice as steep
• What changesHow hard your report pushes on sodium, and potassium emphasis

What the genes do

AGT encodes angiotensinogen, the starting substrate of the renin-angiotensin-aldosterone system, which is the main hormonal control on blood pressure and fluid balance. GNB3 sits in a different place, affecting the G-protein signalling behind sodium-proton exchange at the cell membrane.

Different mechanisms, same visible outcome: how much your blood pressure moves when your sodium intake moves.

What the variants change

The M235T variant in AGT is associated with higher circulating angiotensinogen. In a population study using urinary sodium as the measure rather than food questionnaires, the slope between systolic blood pressure and sodium intake was around twice as steep in risk-allele carriers as in reference-allele homozygotes.

The DASH trial found genotype groups separated clearly on blood-pressure response to a low-sodium diet, and an earlier hypertension-prevention trial pointed the same way.

What it means for you

If you're salt-sensitive, sodium reduction is one of the highest-value things you can do, and it's worth being systematic about it. Processed and packaged food is where the sodium actually is, not the salt cellar, so that's where the reduction has to happen.

The other half is potassium, which counterbalances sodium at the kidney. Fruit and vegetables are the practical route.

If you're not salt-sensitive, sodium is a smaller lever for you than it is for the average person. That's useful to know, because effort spent on the wrong lever is effort not spent on the right one.

What your formula does

This chapter shapes the dietary side of your report more than the sachet. Where the genotype says salt-sensitive, your report says so directly rather than repeating the general advice everyone already ignores.

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