Sodium isn’t inherently bad for you. Your body requires it to function, using it to regulate blood pressure, blood volume, nerve signaling, and muscle contraction. The problem is quantity: the global average adult consumes about 4,310 mg of sodium per day, more than double the World Health Organization’s recommendation of less than 2,000 mg. At those levels, sodium does real, measurable harm to your cardiovascular system, kidneys, and more.
Why Your Body Needs Sodium
Sodium is an essential mineral. Without it, your nerves can’t fire properly, your muscles can’t contract, and your body can’t maintain the right balance of fluids inside and outside your cells. You lose sodium constantly through sweat and urine, so you need a steady intake from food to replace it.
The issue has never been whether you need sodium. You do. The issue is that almost no one in the modern world is at risk of getting too little from food alone. The real question for most people is how much is too much.
How Excess Sodium Raises Blood Pressure
The traditional explanation is straightforward: eat more salt, retain more water, increase blood volume, raise blood pressure. That’s partly true, but the full picture is more nuanced. Research published by the American Heart Association shows that in people who are “salt-sensitive,” the core problem is that their blood vessels fail to relax properly in response to higher salt intake. Normally, when you eat more salt and your blood volume ticks up, your arteries widen to compensate. In salt-sensitive people, that compensation doesn’t happen adequately, so pressure climbs.
This matters because it explains why sodium affects people differently. About 30% of otherwise healthy people are salt-sensitive, meaning their blood pressure responds more dramatically to changes in sodium intake. Among people who already have high blood pressure, that figure rises above 50%. Salt sensitivity is more common in women than men and becomes more prevalent with age in both groups.
What Cutting Back Actually Does
Reducing sodium intake lowers blood pressure in the majority of people, not just those with hypertension. A study highlighted by the National Institutes of Health found that nearly 75% of participants had lower systolic blood pressure on a low-sodium diet compared to a high-sodium diet, with an average drop of about 7 mmHg. Even compared to their usual diets (not a deliberately high-sodium one), 72% of participants saw a drop, averaging 6 mmHg.
A 6 to 7 point drop might not sound dramatic, but at a population level it’s significant. That kind of reduction is comparable to what some blood pressure medications achieve, and it lowers the long-term risk of heart attack and stroke.
Effects on Your Kidneys
High sodium doesn’t just affect your heart. A study in the American Journal of Physiology found that just 10 days of high salt intake (around 3,900 mg of added sodium per day) increased markers of kidney stress in healthy young adults, even though their blood pressure didn’t change. The kidneys had to work harder to filter the extra sodium, and a biomarker associated with kidney injury rose significantly. This suggests that sodium can strain your kidneys before any blood pressure changes show up on a reading, particularly over years of consistently high intake.
Can Sodium Be Too Low?
Yes. A condition called hyponatremia occurs when blood sodium levels drop dangerously low. Symptoms range from nausea, headaches, and fatigue to muscle cramps, confusion, seizures, and in severe cases, coma. When sodium drops gradually over 48 hours or more, symptoms tend to be milder. A rapid drop is a medical emergency that can cause brain swelling.
Hyponatremia is most often caused by drinking excessive water without replacing electrolytes, certain medications, or underlying health conditions. It’s rarely caused by simply eating less salt. Premenopausal women appear to be at the greatest risk of serious complications, possibly due to the effects of sex hormones on sodium balance. Endurance athletes are another group at risk: heavy sweating can deplete sodium quickly, and replacement of about one gram per hour is recommended during long, intense exercise with heavy sweat losses.
Where All That Sodium Comes From
Most of the sodium in your diet isn’t coming from the salt shaker. According to CDC data, 44% of sodium consumed in the U.S. comes from just 10 food categories:
- Breads and rolls (7.4%)
- Cold cuts and cured meats (5.1%)
- Pizza (4.9%)
- Poultry (4.5%)
- Soups (4.3%)
- Sandwiches (4.0%)
- Cheese (3.8%)
- Pasta dishes (3.3%)
- Meat dishes (3.2%)
- Savory snacks (3.1%)
Bread being the top contributor surprises most people. A single slice doesn’t contain much sodium, but because bread is eaten so frequently and in so many forms, it adds up fast. The same logic applies to poultry: it often comes pre-brined, injected with salt solutions, or seasoned during processing. The sodium in your diet is largely invisible, built into foods before they reach your plate.
How Much You Should Aim For
The WHO recommends less than 2,000 mg of sodium per day for adults, which works out to about one teaspoon of table salt. U.S. guidelines are slightly more lenient at 2,300 mg. Both figures are well below what most people actually consume.
The most effective way to reduce sodium isn’t to stop salting your food, though that helps at the margins. It’s to shift the balance of what you eat. Cooking more meals from whole ingredients gives you control over sodium in a way that choosing between packaged products doesn’t. Reading nutrition labels matters too. Two cans of soup that look nearly identical on the shelf can differ by over 500 mg of sodium per serving. When eating out, soups, sauces, and anything described as “crispy” or “smoked” tend to be the highest-sodium items on a menu.
If you’re currently eating the average of 4,000+ mg per day, you don’t need to cut to 2,000 overnight. Even a partial reduction delivers measurable blood pressure benefits. The goal is a sustained downward shift, not perfection.