Minerals Flashcards
What are macrominerals?
Minerals required in large quantities.
How are minerals different from vitamins?
Minerals maintain their chemical structure; vitamins are broken down and transformed.
What affects mineral absorption and utilisation?
Binding with other compounds (e.g., phytates), interactions with other minerals, and certain dietary components.
What makes minerals more stable than vitamins?
They’re not easily destroyed by heat or food processing, though they can leach into cooking water.
What minerals are important for structural function?
Calcium, Magnesium, and Phosphorus.
What minerals are important for fluid and electrolyte balance?
Sodium, Potassium, and Chloride.
Where is most calcium stored in the body?
In bones and teeth (99%).
What is hydroxyapatite?
The bone structure formed from calcium and phosphorus.
How is calcium homeostasis regulated?
By vitamin D, parathyroid hormone, and calcitonin.
List some calcium-rich foods.
Green leafy veg (e.g., kale, broccoli), dairy, seeds (chia, sesame), tofu, tinned fish with bones.
What inhibits calcium absorption?
High iron/phosphorus, fats, fibre (phytates).
What are the symptoms of calcium deficiency?
Hypocalcaemia (seizures), stunting, osteoporosis, tetany.
What are signs of calcium toxicity?
Constipation, kidney stones, calcium deposits in soft tissues.
What functions is magnesium involved in?
> 300 enzymatic reactions, nerve/muscle function, bone formation, ATPase activity, vitamin D hydroxylation, insulin production.
What are food sources of magnesium?
Legumes, nuts, seeds, mineral water, leafy greens, cocoa.
What increases magnesium requirements?
Chronic stress.
Symptoms of magnesium deficiency?
Hypertension, cramps, twitching, heart issues, lethargy, nervous tension.
Magnesium toxicity symptoms?
Diarrhoea, alkalosis, hypotension, dehydration (mainly from supplements).
Where is phosphorus stored and with what mineral?
Bones and teeth, with calcium as hydroxyapatite.
What are the key roles of phosphorus?
ATP production, enzyme activation, component of phospholipids.
What affects phosphorus absorption?
Phytates in seeds/cereals and interactions with other minerals.
Food sources of phosphorus?
Dairy, legumes, sunflower seeds, eggs, meats (especially liver).
Symptoms of deficiency?
Bone pain, muscular weakness.
Symptoms of toxicity?
Calcification of soft tissues (lungs, heart, kidneys).
What are electrolytes?
Mineral salts that dissociate in water into ions, affecting water movement.
What are the main intracellular and extracellular ions?
Intracellular: K+ (potassium), HPO₄²⁻ (phosphate); Extracellular: Na+ (sodium), Cl⁻ (chloride).
Key functions of sodium?
Fluid balance, nerve function (Na/K pump), blood pressure regulation (RAAS).
Common sodium food sources?
Meats, processed foods, salts (97-99% sodium chloride).
What contributes more to sodium intake: table salt or processed foods?
Processed foods.
Symptoms of sodium deficiency?
Cramps, confusion, appetite loss (especially in athletes).
Sodium toxicity symptoms?
Hypertension, oedema, seizures, coma (in acute toxicity).
Functions of chloride?
Fluid/pH balance, protein digestion (HCl), secretions (mucus), immune support.
Chloride food sources?
Same as sodium – no separate NRV.
Deficiency/toxicity symptoms?
Same as sodium.
Key functions of potassium?
Na/K pump, heart and nerve function, fluid balance, gastric acid secretion, bone density, vasodilation.
Food sources of potassium?
Unprocessed fruits and veggies (bananas, potatoes, legumes, squash).
Symptoms of potassium deficiency?
Hypertension, kidney stones, bone issues, arrhythmia, weakness.
Potassium toxicity?
Only from IV injection — can stop the heart.
Where is most of the body’s iron found?
Over 65% is in haemoglobin; the rest is in myoglobin, enzymes, circulation, and storage.
What are the two dietary forms of iron?
Heme (animal foods, better absorbed) and non-heme (plant foods, less absorbed).
What factors inhibit iron absorption?
Polyphenols (tea, coffee), oxalates (spinach), phytates (legumes), calcium, zinc, manganese.
Why is iron carried on transferrin in the body?
Free iron causes oxidative damage; transferrin transports it safely.
What enzyme functions require iron?
Energy metabolism, neurotransmitters, antioxidants, DNA synthesis, phase I liver detox, thyroid function, collagen formation.
What is microcytic hypochromic anaemia?
A condition from iron deficiency where red blood cells are small and pale.
What are symptoms of iron deficiency?
Fatigue, breathlessness, mood problems, poor immunity.
What condition results from iron toxicity due to genetic issues?
Haemochromatosis – leads to iron overload and oxidative damage.
Where is copper found in the body?
All tissues and secretions (saliva, gastric juice, bile, etc.).
What nutrient interferes with copper absorption?
Zinc (especially in high doses).
What are key functions of zinc?
Spermatogenesis, insulin synthesis, digestive enzyme production, smell/taste, immunity, thyroid hormone synthesis, bone mineralisation.
What factors reduce zinc bioavailability?
Phytates, low stomach acid, food processing.
What nutrients can compete with zinc for absorption?
Copper and iron.
What are signs of zinc deficiency?
Skin rash, poor wound healing, frequent infections, loss of taste.
What are effects of zinc toxicity?
Nausea, vomiting, copper/iron deficiency, impaired immunity.
Where is most iodine in the body stored?
70–80% is in the thyroid gland.
What are the richest dietary sources of iodine?
Seafood and seaweed.
What are the effects of iodine deficiency?
Goitre, hypothyroidism, infertility, cretinism.
What are goitrogens?
Compounds that reduce iodine uptake or interfere with thyroid hormone production (found in soy, brassicas, almonds).
What nutrients are needed for thyroxine synthesis?
Tyrosine, iodine, vitamin C, zinc, iron.
What is the key cofactor for thyroxine activation?
Selenium.
What affects selenium content in foods?
Soil selenium levels (e.g., low in NZ and parts of China).
What are rich food sources of selenium?
Brazil nuts, shellfish, brewer’s yeast.
What enzymes use selenium?
Mitochondrial antioxidant enzymes (especially in sperm).
What are signs of selenium deficiency?
Poor growth, muscle pain, white nail beds, depigmented skin/hair.
What are signs of selenium toxicity?
Hair/nail loss, nausea, vomiting, multi-organ damage (lethal dose ~1g).
Where is manganese mainly stored in the body?
Bones, liver, kidneys, pancreas, and mitochondrial membranes.
What is the absorption rate of manganese?
Less than 5% – it’s required only in tiny amounts.
What are risks of manganese toxicity?
From dust exposure in industrial settings (e.g., smelters).
