Salt sensitivity and the AGT / GNB3 genes

“Eat less salt” is given to everyone, but salt raises blood pressure dramatically in some people and hardly at all in others. The difference is called salt sensitivity, and it is partly genetic.

Salt and blood pressure are not the same for everyone

In salt-sensitive people, sodium causes the body to hold on to more water, raising blood pressure measurably. In salt-resistant people, the same intake barely moves the needle. Generic low-salt advice therefore over- or under-shoots depending on who follows it.

AGT and GNB3 set your sensitivity

Two genes are central: AGT (variant rs699), part of the system that regulates blood pressure and fluid balance, and GNB3 (variant rs5443), involved in cellular signalling that influences sodium handling. Together they tilt how strongly salt affects your blood pressure.

Why it matters

For the salt-sensitive, reducing sodium is one of the highest-impact, lowest-cost things they can do for long-term heart health. For the salt-resistant, the effort is better spent elsewhere. Knowing which you are turns a blunt rule into a targeted one.

What actually helps

Salt-sensitive carriers benefit from lowering sodium (processed foods are the main source) and increasing potassium-rich fruit and vegetables, which counterbalance sodium. Everyone benefits from knowing where they stand rather than guessing.

The science, in depth

AGT rs699 (M235T) influences angiotensinogen levels in the renin-angiotensin-aldosterone system, while GNB3 rs5443 (C825T) affects G-protein signal transduction linked to sodium-proton exchange. Both associate with salt-sensitive blood-pressure responses, supporting genotype-personalised sodium recommendations.