Minerals Flashcards
Describe the ways and forms that minerals are found in food
- Minerals present in different chemical forms in foods
- Free ions – water soluble
- Complexes – bound to other minerals
(Information about minerals X8)
- 90 naturally-occurring elements in earth’s crust
- ~25 known to be essential to life and present in living cells
- Minerals are elements other than C, H, O, and N
- Minerals in food
- Plants and animals accumulate minerals from environment
- Minerals enter food as contaminants
- Minerals present in food additives
- Present in fairly low concentrations
Major Minerals x7
- We need more than 100 mg/day (going to be found in higher concentrations in food)
- Calcium
- Phosphorus
- Magnesium
- Sodium
- Potassium
- Chloride
- Sulfur
Trace Minerals x9
- We need less than 100 mg/day
- Iron
- Iodine
- Zinc
- Selenium
- Copper
- Fluoride
- Chromium
- Manganese
- Molybdenum
Other minerals found in food x9
- Ultra trace minerals - such low concentrations; no RDAs, but are in food and still have chemical and functional properties
- Aluminum
- Bromine
- Nickel
- Silicon
- Vanadium
- Arsenic
- Boron
- Cobalt
- Tin
Explain how the mineral composition of food is determined
- Ash
- Determined by weighing residue left following complete combustion of organic matter in food
- Estimates total mineral content > but cannot tell you much of it is iron, magnesium, calcium or specific minerals
- Ash is total mineral content (everything else but the minerals will combust)
- Individual minerals
- Determined by dissolving ash in acid and measuring mineral concentrations in resulting solution
- – Take ash and dissolve it in acid and then take that solution and measure the amount of each individual mineral
- Atomic absorption spectroscopy – measures one mineral at a time
- Inductively coupled plasma spectrometers – measures several minerals simultaneously
Recognize factors that affect mineral composition in plant foods and minerals that may be found in low concentrations in plant foods
Mineral composition depends on:
- Plant genetics – will determine how much of a mineral the plant will take from soil
- Soil composition and pH – pH depends on plant, and soil = typically what is high in soil is high in plant
- Environment – how much sun, how much water, etc.
- – Fertilizer – depends on fertilizer and the plant
Fluoride, selenium and iodine not necessary for plants
- Plants don’t need these minerals to sustain life
- Plants that may be low in these minerals may lead to deficiencies in the human diet
Concentrations may be too low to meet human needs
- I.e. calcium is taken up by plants but it is I low concentrations that humans cannot meet calcium needs without difficulty
Minerals may be present in forms not efficiently utilized by humans
- I.e. iron – heme iron is much better absorbed in non-heme irons; heme iron is only found in animal foods and not plant foods
Identify minerals found in animal food sources
Mineral composition less variable
- In animal foods it is not as variable > like humans, animals will regulate the levels of minerals in the body
- If intake is low in animal, It will adjust for higher absorption of minerals > regulation of mineral levels
- If body level is high, Body will restrict absorption, and vice versa
Meat, fish and poultry
- Iron
- Zinc
- Phosphorus
Dairy products
- Calcium
- Phosphorus
Marine fish/shellfish
- Iodine (saltwater fish and shellfish)
- (Freshwater fish and shellfish are not good sources of iodine)
Recognize factors that affect the bioavailability of minerals
Solubility – more soluble the mineral = more bioavailable
Chemical form
- I.e. iron – non heme iron > ferric and ferr ous > ferrous is more soluble
- Ferrous is more bioavailable
Food ligands – ligand is a molecule that binds to a mineral
- Some ligands enhance bioavailability, others may reduce
- Some binding makes mineral more soluble, or less
- I.e. EDTA > binds to iron and copper and makes them more soluble/bioavailable
Redox activity – sometimes the reduced form or the oxidized form is more bioavailable
Mineral-mineral interactions –when two minerals from a complex, can make more or less bioavailable
- I.e. when calcium and iron bind, both less bioavailable
Physiological state of consumer
- If person is deficient in a certain mineral, the bioavailability of that mineral will increase
- If consumer has malabsorption problem, bioavailability is decreased
- Some minerals are absorbed better in the presence of acid – people with low or high levels of acid (lower stomach acid can decrease bioavailability)
- Infants, children, and pregnant women > iron is more bioavailable because needs are higher (iron is good for growth) »_space; pregnancy or growing will increase bioavail
Substances that enhance mineral absorption
- Organic acids – ascorbic, citric, lactic
- When they bind to minerals, they make that complex (chelate) more soluble
(Complexes are more soluble) - Ascorbic acts as an antioxidant and keeps iron in its reduced form
- Meat factor
- Meat fish and poultry > iron sources better
- Non heme iron, if eaten with MFP Is better absorbed than when eaten alone
- Meat factor, just for iron (while organic acids are for most minerals)
Substances that inhibit mineral absorption
- Phytic acid a whole grains, legumes > iron, zinc, and ca, Mg)
- Phytates form insoluble chelate
- Tannins – coffee and tea
- Inhibit iron absorption (decrease bioavailability or iron)
- Form insoluble chelate
- Oxalates – spinach and nuts (high in calcium but aren’t good sources of calcium because they bind to oxaOxalates)
- Decrease bioavailability of calcium
Fortification and Enrichment - Iron
- Enrichment of white flour
- Fortification of infant formulas and cereals (I.e. with iron)
- Ferrous sulfate – most common form that is used to fortify or enrich products because it is more bioavailable than some other forms (ferrous form is reduced and is more BA than ferric)
- – Fairly bioavailable but not stable
- – Heme – animal foods; better absorbed
- – Non-heme – plants > heme and non heme
- – More BA = more soluble but more soluble means more unstable
- Elemental iron powders – stable but not highly bioavailable
- Chelated forms of iron – more soluble and is also fairly stable, but more expensive to use in food
- – Ferric sodium EDTA – can be to iron and make more BA
- – Ferrous bis-glycinate – more BA and fairly stable, but is expensive
Fortification and Enrichment - Zinc
- Fortification of infant formula and cereals
- Zinc oxide – less BA, less soluble, more stable, longer shelf life
- Zinc sulfate – more BA, more soluble, but less stable (shorter shelf life)
Fortification and Enrichment - Iodine
- Iodized salt
- Sodium iodide
- Sodium iodate – more stable, preferred form to use for iodizing salt, helps prevent clumping of salt in humid environments
- – Don’t worry about BA for iodine
Effects of processing on minerals
Not destroyed by: heat, light, water, oxidizing agents, or extreme pH
Can be removed by: by leaching or physical separation
- (not destroyed but removed from their food)
- i.e. could be moved/transferred into the cooking water
Methods causing mineral loss
- Milling (of wheat, corn, rice, grains/cereals) – iron, zinc, manganese, copper and selenium
- – Just iron is added back with enrichment (enrichment, remove a lot of nutrients and only add some)
- Cheese making (acid coagulation) – calcium
- – Acid coagulated cheeses are lower in calcium – pH doesn’t destroy minerals but at a lower pH, calcium is more soluble > when we make cheese, we drain the whey and since calcium is more soluble, when we drain the whey we drain the calcium
- —-If we use that whey to make cheese, that cheese will be high in calcium
- –Cottage cheese is much lower in calcium compared to other cheeses – you have two consume two cups of cottage cheese for it to be same amount of calcium in a cup of milk
- Cooking in water
- –Depending on the form, but most minerals are more soluble, so they tend to be lost in the cooking water
