Food must have a limited amount of salts because excess sodium (Na⁺) from salt causes serious health problems including high blood pressure (hypertension), kidney damage, water retention (edema), and increased risk of heart disease and stroke. The World Health Organization (WHO) recommends a maximum intake of 5 grams of salt (about 2 g of sodium) per day for adults.
Excess salt causes hypertension (high blood pressure), kidney damage, edema, and osteoporosis.
WHO recommends: less than 5g salt (2g sodium) per day for adults.
Excess Na⁺ increases blood volume → raises blood pressure → risk of heart attack and stroke.
Kidneys overworked by excess salt may develop chronic kidney disease.
High salt diet increases calcium loss in urine → weakens bones (osteoporosis).
Salt is essential in small amounts for nerve impulse transmission and muscle contraction.
Most processed and packaged foods contain high amounts of hidden salt.
Potassium (from fruits and vegetables) helps counteract the blood pressure effects of excess sodium.
Common salt (sodium chloride, NaCl) provides sodium (Na⁺), which is essential in small amounts for nerve function and fluid balance. However, excess sodium causes:
High Blood Pressure (Hypertension): • Excess Na⁺ in blood increases osmotic pressure • Body retains water to dilute the salt → blood volume increases • Higher blood volume → greater pressure on blood vessel walls → hypertension • Hypertension is the leading risk factor for heart attack and stroke
Kidney Damage: • Kidneys must filter excess sodium • Overworked kidneys lose efficiency over time • May lead to chronic kidney disease
Water Retention (Edema): • Excess Na⁺ causes the body to retain water • Results in swelling of hands, feet, and ankles
Osteoporosis: • Excess salt increases calcium loss in urine • Leads to weaker bones over time
Stomach Cancer Risk: • High salt diet is linked to increased risk of stomach cancer (H. pylori bacteria thrive in high-salt environment)
Essential functions of salt (small amounts):
Nerve impulse transmission: Na⁺/K⁺ ions maintain the electrochemical gradient needed for nerve signals
Muscle contraction: Na⁺ is involved in the action potential that triggers muscle fibres
Fluid balance: Na⁺ regulates osmotic balance between cells and extracellular fluid
Acid-base balance: Chloride (Cl⁻) from salt helps maintain blood pH
Stomach acid: Cl⁻ is used to produce HCl in the stomach for digestion
Recommended intake (WHO, 2023): • Adults: < 5 g salt/day (< 2 g sodium/day) • Children: lower (based on caloric needs) • Most people consume 9–12 g/day — twice the recommended amount
Note: 1 teaspoon of salt ≈ 5 g (contains ~2 g of sodium)
Much of the salt in our diet comes from processed and packaged foods:
High-salt foods to limit: • Processed/packaged snacks (chips, crackers) • Fast food and restaurant meals • Pickles and chutneys • Canned soups and vegetables • Sauces (soy sauce, ketchup) • Bread and baked goods • Cheese and processed meats
Healthy habits:
Food must have limited salt because excess sodium causes: (1) High blood pressure (hypertension) — increasing risk of heart disease and stroke; (2) Kidney damage — kidneys are overworked filtering excess Na⁺; (3) Water retention (edema); (4) Calcium loss leading to osteoporosis. WHO recommends less than 5g salt per day.
The World Health Organization (WHO) recommends a maximum of 5 grams of salt (about 2 grams of sodium) per day for adults. Most people consume 9–12 g/day — about twice the safe limit.
Excess sodium (Na⁺) increases the osmotic pressure in blood. The body retains water to dilute the salt, which increases blood volume. Greater blood volume exerts more pressure on blood vessel walls, causing hypertension (high blood pressure).
Yes. Salt (NaCl) is essential in small amounts for nerve impulse transmission (Na⁺/K⁺ pump), muscle contraction, fluid balance, and producing stomach acid (HCl from Cl⁻). The problem is excess salt, not salt itself.
Hidden salt is found in processed foods: packaged snacks, bread, canned soups, sauces (soy sauce, ketchup), cheese, processed meats, and fast food. These contribute the most to daily sodium intake even without added table salt.
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