Trace elements are ubiquitous
Each time you take a bite of an apple, or take a sip of water, you provide your body with the trace elements it needs. Not all foods, however, provide the same amounts of zinc, manganese, selenium, etc., hence the benefits of a varied diet.
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Zinc • Oysters, crab, mussels, egg yolk, poultry, fish, seaweed, wholegrain cereals, pulses, squash seeds, cocoa, etc.
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Manganese • Seaweed, almonds, pineapple, dried fruit, walnuts, wholemeal cereal, cocoa, tea, blackcurrants, egg yolk.
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Copper • Seafood, fish, liver, poultry, oil seeds, garlic, broccoli, oranges, green vegetables, soya, pulses, cocoa, tea.
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Magnesium • Magnesium-rich mineral water (>50 mg/l), pulses, dried fruit, oil seeds, wholemeal cereals, dark green-leaved vegetables, seafood, spices.
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Iron • Blood sausage, liver, shellfish, fish, poultry, egg yolk, pulses, almonds, beetroot, cocoa and wholemeal cereals.
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Molybdenum • Celeriac, garlic, coconut, dried beans, split peas, dark green-leaved vegetables.
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Selenium • Seafood, fish, poultry, Brazil nuts, dried mushrooms, eggs, garlic, seaweed, broccoli, wholemeal cereals.
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Chromium • Seaweed, wholemeal cereals, wheat germ, broccoli, green beans, asparagus, walnuts, potato, veal liver, egg yolk.
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Sources: all marine produce: fish, seafood, cod liver oil, seaweed, iodized salt.
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Not all mixtures are equal
The devil is in the details, as we say in nutrition. This is probably truer than elsewhere. Trace element absorption, and hence food efficiency, will vary according to the presence of other nutrients.
For example, iron absorption is enhanced by so-called reducing nutrients such as vitamin C, amino acids (cysteine, lysine, histidine) synthesized from animal or plant proteins, other organic acids (citric or lactic) such as berries, citrus fruit, dairy products, fruit and vegetables. It is significantly reduced by calcium and phosphates, along with tannins found in stimulants (coffee, tea) and red wine.
Magnesium absorption is limited by the simultaneous ingestion of large doses of iron, calcium, zinc and phytates from plant foods and fibres.
Dietary chromium absorption is very low. It is promoted by vitamin B3, found in nutritional yeast for example, vitamin C and amino acids. It is reduced however by the absorption of large quantities of zinc, iron, magnesium and calcium.
Selenium absorption decreases significantly in the elderly, even when active.
What should I remember of these limitations in terms of my daily diet?
Remember to limit or eliminate stimulants, pollutants such as tobacco smoke or alcohol, along with trace elements taken in isolation as dietary supplements. Advice from a healthcare professional is always welcome.
*CREDOC, **SUVIMAX study, Arnaud et al.2006
