A large McDonald's chocolate shake doesn't taste particularly salty. But would it surprise you to learn that it contains about as much salt as Macca's large-size fries? That's one of the issues with salt (aka sodium) – it can be hidden in food and difficult to detect. And considering that around 70% of our processed meats, cheeses and sauces contain unacceptably high levels of sodium, the difference between a reasonable sodium intake and a dangerous one isn't always obvious if you're just using your taste buds to check.

Sweet deceit

Biscuits, cakes and pastries can be stealth suppliers of sodium, as sodium bicarbonate (bi-carb soda or baking soda) is used as a raising agent - and one teaspoon of baking soda contains 1000mg of sodium (we need just 460mg a day for good health). It's also used as a filling agent for fizzy or dissolvable sweets. Some breads and breakfast cereals, as our reports consistently show, contain alarming amounts of salt too.

A 2009 survey by the Australian Division of World Action on Salt and Health (AWASH) of major fast food chains KFC, Hungry Jack's, Oporto, Red Rooster, Subway and McDonald's, showed 75% of burger and sandwich-style products provided more than 50% of an adult's recommended daily sodium limit.

Food Standards Australia New Zealand (FSANZ) has found foods that contain the highest levels of sodium per 100g are sauces, spreads and condiments, potato crisps, processed meat and meat products, including sausages, meat pies, sausage rolls and chicken nuggets, cheese and pizza.

How much salt should you have?

To prevent chronic disease, the National Health and Medical Research Council (NHMRC) has set 1600mg as the daily Suggested Dietary Target (SDT) for sodium for adults, with 2,300mg the maximum daily upper limit, and 460-920mg an adequate adult intake for good health. Children should have much less.

It's estimated we munch through twice the SDT, despite the significant health risks.

How much salt should children have?

A 2007 Australian National Children's Nutrition and Physical Activity survey found that sodium intake in two- to 16-year-olds exceeds their upper daily limits. It also found sodium intake in two- to three-year-olds was 167% of their daily maximum. Average sodium intake by nine- to 16-year-olds even exceeded the upper daily limit set for adults.

Salt health risks

High blood pressure (anything approaching around 140 over 90) and cardiovascular disease (CVD) are two risk factors associated with a high-salt diet. In fact, even with fairly low blood pressure, the risk of stroke, heart attack and heart failure will increase with a raise in blood pressure.

CVD is Australia's biggest killer and the second-largest contributor to our burden of disease after cancer. CVDs have a highly preventable and treatable group of diseases risk factors – one being high blood pressure.

Over the past decade salt consumption has fallen in England by 15% and this has been linked to a 40% fall in deaths from heart disease and 42% from stroke over the same period, according to a study published in the British Medical Journal.

Be salt aware

Here is how you can cut down on hidden salts:

  • Avoid processed, prepared and pre-packaged foods.
  • Eat more fresh fruit and vegetables, and limit buying high sodium soups, sauces and condiments, canned and preserved goods and prepared mixes. Keep takeaways and fast foods such as burgers, fried chicken and pizza to an occasional treat.
  • Check nutritional information labels. Compare products, brands and varieties and choose lower sodium options (120mg/100g or less) where possible and avoid high sodium (>600mg/100g) foods.
  • Consider serving sizes. How much are you eating? Even low sodium products can supply a lot of sodium if eaten in large amounts.
  • Read ingredients lists. Salt (rock, sea, celery, garlic), baking soda, sodium bicarbonate, celery salt, garlic salt and monosodium glutamate (MSG, additive 621) are all high sodium ingredients.
  • Remove the salt shaker from the table and don't add salt to your children's food when cooking.
  • Avoid sodium heavyweights such as packaged stock, Asian sauces - like soy, oyster and fish sauce, mustard, pickles and mayonnaise; at the very least, choose low-salt varieties.
  • Use alternatives. Lemon juice, garlic, vinegar or herbs and spices instead of salt when cooking.
  • Retrain your taste buds - research shows that our sensitivity to 'saltiness' increases when we cut back, so less salt is needed.
  • Check your meds. Some over-the-counter and prescription drugs may contain sodium. Ask your doctor or pharmacist about yours if you need to reduce your dietary sodium.