Minerals

Question 1

Minerals Facts:

Answer 1

• Minerals are inorganic elements that originate in the Earth and cannot be made by living organisms.
• For humans to absorb and use minerals they must first be bound to organic compounds (containing carbon).
• Plants obtain minerals from the soil and most of the minerals in our diet come directly from plants (or indirectly from animal sources).
• Inorganic minerals may also be present in the water we drink (not useable by the body).
• Mineral levels from plants also vary depending on the mineral content in soil.
• Minerals represent 4-5% of total body weight.
• Calcium and Phosphorus make up the majority (approx. 75%).

Question 2

Minerals:

Answer 2

Macro-minerals exist in the body (and in food) mainly in the ionic state (as Cations or Anions):

• Cations: K+ (Potassium), Mg2+ (Magnesium), Ca2+ (Calcium), Na+ (Sodium).
• Anions: Cl- (Chlorine as chloride); S- (Sulphur as sulphate); P- (Phosphorus as phosphate).

• Minerals also exist as components of organic compounds such as:

• Phosphoproteins (a protein attached to a phosphate group); phospholipids (i.e. cell membranes); metalloenzymes (e.g. zinc is required for ‘alcohol dehydrogenase’, which breaks down
  alcohol) ; metalloproteins (e.g. haemoglobin – a protein with iron).

Question 3

Minerals:

Answer 3

Mineral Absorption and Functions:
• Minerals are absorbed in the GIT (mostly in the small intestine) in their ionic state (with the exception of iron) and must be unbound from the organic compound with the help of digestive secretions (e.g. stomach acid) before being utilised by the body.
• Any unabsorbed minerals are excreted in the faeces.

• Key functions of minerals include:

• Building tissues; e.g. skeletal system, teeth
• Nerve and muscle function
• Thyroid health (supporting metabolism)
• Supporting immune health
• Components of enzymes

Question 4

Minerals:

Answer 4

Several factors can affect mineral bioavailability, including:
1. Mineral status in the body - in mineral deficiency states, the body upregulates absorption of the mineral. In excess states, it downregulates absorption.

2. Substances present in food – can enhance (e.g. ascorbic acid and Fe) or inhibit (e.g. phytates & Fe) absorption.
3. Other minerals present in food (or supplements) - can compete for absorption: (e.g. iron supplements reduce Zn absorption; Zn antagonises Cu absorption)

Question 5

Minerals:

Answer 5

Minerals in supplements:

• Minerals in supplements are rarely found as pure minerals - they’re bound to carrier molecules, also called ligands.
• Each carrier has unique characteristics that facilitate absorption.
• The challenges with mineral supplementation include tolerability, bioavailability and chemical reactivity.
• Mineral supplements come in various forms: e.g. mineral salts, ionic & colloidal minerals, food-state minerals and amino acid chelates.
• Common mineral carriers include:
- Organic: Citrate, Ascorbate, Gluconate, Glycinate
- Inorganic: Oxide, Carbonate, Sulphide, Chloride

Question 6

Calcium

Answer 6

• Calcium (Ca) is the most abundant mineral in the body accounting for 2% of body weight and 39% of the body’s mineral content❗️
• 99% of Ca in the body is found in mineralised connective tissues (bones and teeth).
• The rest (1%) is found in extra-cellular fluid, muscle and other tissues.
• Ca levels in blood are tightly regulated by Parathyroid hormone (PTH), Vitamin D and Calcitonin (at the expense of the skeleton when dietary intake is inadequate).

Question 7

Calcium: Food Sourcss

Answer 7

• Calcium is found mostly in plant and dairy foods.
• Vegetable sources have the highest bioavailability – e.g. Ca from cruciferous vegetables is absorbed 2x as efficiently as Ca from dairy.

Dark green & cruciferous veg.; e.g. kale, Nuts & seeds; e.g. sesame, almonds, Beans; e.g. edamame, haricot, Herbs & spices; e.g. sage, coriander leaf, Sardines including the tiny bones, Dairy foods: e.g. cow’s milk full fat

Question 8

Calcium Functions:

Answer 8

Question 9

Calcium

Answer 9

Absorption:
• Ca is absorbed by all parts of the small intestine, but especially in the duodenum, where conditions are more acidic due to the acidic chyme that enters from the stomach, which increases absorption.

• Ca is absorbed both actively and passively:
- Active absorption is controlled by Vitamin D (calcitriol), which binds to the enterocyte Vitamin
D Receptor (VDR) and increases the transcription
of calcium transporters called calbindins, which increase calcium movement from the GIT to the blood.
- Passive absorption occurs without Vitamin D, when Ca is consumed.

• 50%-70% of ingested Ca is not absorbed and lost in the faeces.

Question 10

Calcium

Answer 10

Deficiency:
• Calcium deficiency is extremely rare as blood levels are typically maintained even with inadequate intake at the expense of bones❗️
• Unlike other diseases, loss of bone mineral density is asymptomatic.

Question 11

Calcium

Answer 11

Supplementation:
• Studies mostly show that Calcium supplementation is ineffective at preserving bone density when dietary intake is sufficient and it can present risks: e.g. kidney stones; soft tissue calcification- especially when vitamin D and K levels are inadequate.
• Although calcium carbonate is often recommended, calcium citrate is far easier to absorb.

Question 12

Calcium 🚩

Question 13

Magnesium

Answer 13

• Mg serves many body functions, and is a cofactor in over 300 enzymatic reactions❗️
• Haemoglobin and chlorophyll are almost identical in their structure, with haemoglobin having iron at its core, and chlorophyll (the green plant pigment) - magnesium

Food Sources:
• Magnesium is found mostly in plants (especially seeds, nuts, wholegrains, legumes and dark green leafy vegetables).
Eg. Green leaves; e.g. swiss chard, spinach, Nuts & seeds; e.g. pumpkin seeds, flax, Beans; e.g. soy beans, haricot, pinto, Whole grains; e.g. amaranth, buckwheat, Cacao powder

Question 14

Magnesium Functions:

Answer 14

Question 15

Magnesium

Answer 15

Absorption and Excretion:
• In healthy adults 30-50% of dietary magnesium is absorbed, mostly in the distal small intestine (ileum).
• Phosphate (especially from high-phytate containing foods) and Ca may be inhibitors of Mg absorption, whilst protein and fructose may enhance Mg absorption
• Mg is excreted in urine, faeces and to a lesser extent, during intensive exercise & sweating.
• Mg homeostasis is regulated primarily by the kidneys.
• 99% of our body’s Magnesium resides inside our cells. Therefore, serum Mg levels do not accurately reflect Mg status❗️

Question 16

Magnesium Supplementation

Answer 16

Supplementation / Salt Baths:
• When using Magnesium supplements, Mg Glycinate, Citrate and Malate are favoured over Mg Oxide due to its low bioavailability.
• Different formulations may have different applications; e.g. Mg Citrate can be more effective for constipation.
• Epsom Salt Baths (Mg Sulphate) are an effective way of administering Mg (with a therapeutic dose of 500g-1kg per bath)
• Toxicity is generally not a concern but excessive intakes from supplements can lead to diarrhoea, as only so much can be absorbed at once.
• Caution using high dose Mg for someone with hypotension❗️

Question 17

Magnesium

Answer 17

Mg Deficiency is rare, but insufficiency is extremely common:
• Common causes of Mg insufficiency include poor nutrition (high in processed foods, low in dark green vegetables, legumes, nuts and seeds), chronic stress (increases Mg excretion), alcoholism and other malabsorption conditions.

Symptoms of Insufficiency:
• Fatigue and insomnia
• Anxiety, depression, irritability, panic attacks
• Muscle cramps / spasms / twitches
• Headaches (e.g. tension-type and migraines)
• Palpitations

Question 18

Zinc

Answer 18

• Zn is a cofactor in over 200 hundred metalloenzymes involved in catalytic, structural and regulatory functions; such as:
- Superoxide Dismutase (SOD) - antioxidant.
- Alcohol Dehydrogenase - breakdown of
alcohol (↑ alcohol intake = ↑ zinc demand).
- Carboxypeptidase - digestion of proteins.
- Other enzymes involved in Haem synthesis, folate absorption and DNA/RNA synthesis.

• Zinc is the most abundant intracellular trace element (the body contains 2g of Zn).

Question 19

Zin: Food Sources

Answer 19

• The highest food source of Zinc is oysters. With seeds, nuts, whole grains, meat and other shellfish also containing good amounts.
• Vegetables vary in Zn content depending on the soil quality❗️

Nuts & seeds: e.g. sesame, brazil, pecans, Grains: e.g. rye flour, oats, amaranth, wheat, Legumes: e.g. adzuki, chickpeas (garbanzo), Shellfish: e.g. oysters, crabs, lobster, clams, Meat: e.g. calf’s liver, beef, lamb

Question 20

Zinc: Functions

Answer 20

Question 21

Zinc

Answer 21

Absorption:
• Zn absorption ranges from 20-40% depending on the bioavailability of the food source.
• Protein generally enhances absorption but phytates in plants form a complex with Zn and inhibit absorption.
- Phytates are highest in wholegrains, legumes, nuts and seeds (phytate levels can be
reduced by soaking, sprouting and fermenting).
• Excess Ca, Cu and non-haem Fe may also inhibit Zn absorption (e.g. simultaneous intake of milk or cheese can decrease Zn absorption).
• Note: Zn supplementation antagonises Cu absorption

Question 22

Zinc

Answer 22

Deficiency:
• Deficiency is fairly common and can be caused by malabsorption, a diet high in phytates or low intake of Zn-rich foods (no body reserve of Zn, therefore continued dietary intake needed❗️).
• Groups at an increased risk: older adults, alcoholics, pregnant women and athletes.

Signs and Symptoms of Deficiency:
• Poor sense of taste and smell.
• Recurrent infections, delayed wound healing.
• Skin disorders (e.g. acne) , dandruff, white spots on finger nails.
• Infertility (male and female) and low libido.
• Signs of weak digestion (e.g. bloating, fatigue).

Question 23

Zinc: Supplementation

Answer 23

• When using Zn supplements, the best absorbed form appears to be Zn picolinate but Zn citrate, Zn acetate and Zn glycinate are also well-absorbed.
• Typical supplemental dosage is between 15-25mg/day and it’s advised to take with food as taken on an empty stomach can cause stomach upset.

Toxicity:
• Long-term intakes in excess may lead to Cu deficiency 🚩 (and for this reason supplement manufacturers often include 1-2mg Cu).

Question 24

Phosphorus

Answer 24

• Phosphorus (P) is the body’s second most abundant mineral❗️
• About 85% of P is found combined with Ca in hydroxyapatite crystals of bones & teeth.
• In nature P is rarely free; it’s almost always bound to oxygen as ‘phosphate’ (PO43-).
• Phosphate is an essential constituent of all plant and animal tissues and thus is widely distributed in all foods:
- seeds, nuts, beans, legumes.
- meat, poultry, fish, dairy
- Soft drinks (not a recommended source)!

Question 25

Phosphorus: Functions

Question 26

Phosphorus

Answer 26

Phosphorus Toxicity:
• Phosphorus intake from natural foods will never lead to toxicity.
• However, phosphorus as a preservative (inorganic phosphorus) as used in carbonated soft drinks, processed food, fast food, enhanced meats) can lead to hyperphosphataemia (high P in the blood) as well as hyperactivity in children- This could result in decreased Ca absorption, as P can form a complex with Ca in chyme.
• Polyphosphates from food additives can also interfere with Zn, Cu and Fe absorption.

Question 27

Potassium

Answer 27

• Potassium (K) is the principal cation inside body cells and along with Sodium Chloride, it is a key electrolyte in the body.
• Food Sources widely distributed but highest in plant sources.

Food Sources:

• Vegetables: raw spinach, baked potato with skin
• Fruit: avocado, banana, kiwi, melon, papaya
• Grains: quinoa, rye flour, buckwheat, oats
• Nuts & seeds: pistachio, sunflower, pumpkin
• Seafood: clams, crab, red snapper, salmon
• Meat & dairy: calf’s liver, pork, cheddar (98mg)

Question 28

Potassium: Functions

Question 29

Potassium

Answer 29

Deficiency:
• Potassium levels are very tightly regulated by homeostatic mechanisms in the kidneys.
• Deficiency (hypokalaemia) usually results from excessive losses.

Question 30

Potassium

Answer 30

Potassium Toxicity:

• Potassium toxicity does not occur from overeating K-rich foods. However, it can result from excessive potassium salts, supplements or certain diseases (e.g. kidney failure). Due to the risk with supplements, always try to increase K using foods.

• Acute potassium toxicity from supplements can lead to cardiac arrest.
• Chronic potassium toxicity can lead to cardiac irregularities, paralysis of extremities, mental confusion, tingling, weakness,
kidney failure and adrenal insufficiency.

Question 31

Sodium and Chloride

Answer 31

• Sodium (Na+) is the main extracellular cation in the body.
• In nature it is only found as a compound due to its high reactivity.
• It is most commonly bound to the anion Chloride (Cl-) forming Sodium Chloride (NaCl), otherwise known as salt.
• Common table salt is 40% Sodium and 60% Chloride by weight.

• Plasma sodium is tightly controlled in the body, and its principle role is regulating extracellular fluid volume.
• When Na levels fall, Renin is secreted by the kidneys, eventually stimulating the formation of angiotensin II in the lungs and the release of aldosterone from the adrenal cortex.
• Aldosterone increases sodium (and subsequently water) reabsorption in the kidneys (increasing BP).
• Raised plasma sodium stimulates the release of antidiuretic hormone which stimulates renal
reabsorption of water (increasing BP).

Question 32

Salt:

Answer 32

Question 33

NaCl: Food Sources:

Answer 33

• Sodium and chloride are sufficiently present in most natural foods.
• However, approx. 70% of the sodium intake in the typical western diet comes from processed food or is added during food preparation.

Question 34

Sodium and Chloride: Functions

Answer 34

Question 35

Sodium and Chloride

Answer 35

Deficiency:
• Like Potassium, Sodium levels are very tightly regulated by the kidneys and, therefore, deficiency is difficult to induce.
• When it does occur, it is usually a result of a medical condition.

Question 36

Sodium and Chloride

Answer 36

Hypertension (High Blood Pressure):
• Eliminating table salt is a crucial intervention in hypertension due to its toxicity. In cases of hypertension, opt for healthy salt alternatives.
• Excessive table salt intake can also contribute to coronary artery disease, strokes, gastric cancer, osteoporosis and asthma.

Question 37

Iron

Answer 37

• Iron is the most abundant element on earth❗️
• It plays a crucial role in the biosynthesis of chlorophyll and production of haemoglobin.
• It exists in several oxidation states, however, the only two forms present in the human body are: Ferrous (Fe2+) and Ferric (Fe3+) iron. The ferrous state is needed for absorption❗️
• The bone marrow uses large quantities of iron to produce erythrocytes.
• We have between 3-4g of iron in our bodies distributed throughout blood, bone marrow, muscles, and enzymes.

Question 38

Iron: Food Sources

Answer 38

• There are two dietary forms of iron:

• Non-haem iron (plant and animal foods) – ferric form of iron.
• Haem iron (animals: meats, poultry, fish) – ferrous form of iron.

Sources:

• Grains: quinoa, amaranth, rye, oats
• Legumes: soybeans, lentils, chickpeas, kidney
• Vegetables: spinach, swiss chard, rocket
• Nuts & Seeds: pumpkin, sesame, cashew, flax
• Meat & Fish: clams, calf’s liver, oysters, prawns, sardines, salmon

Question 39

Iron: Functions

Answer 39

Question 40

Iron:

Answer 40

Storage:
• Iron that is not used for haemoglobin production is stored in the protein ferritin, which is constantly made and broken down.
• When iron stores are high, the liver converts ferritin into another storage protein – hemosiderin, which releases iron more slowly.
• The lifespan of an erythrocyte is 3-4 months, at which stage the spleen and liver dismantle erythrocytes and salvage the iron. This is recycled to make more erythrocytes.
• The body loses some iron daily via the GI tract and when bleeding occurs (only tiny amounts are lost in urine, sweat and shed skin)

Question 41

Iron

Answer 41

Absorption & Excretion:
• Humans cannot excrete Iron and, therefore, iron levels in the body are regulated by the amount absorbed in the intestine.
i.e. Higher levels in tissues→down-regulation of gut absorption.

Proteins help the body to absorb iron from food:
• Mucosal Ferritin receives iron from food and stores it in the small intestinal mucosal cells.
• Mucosal Transferrin transfers the iron to Blood Transferrin which transports the iron to the rest of the body.
• If the body does not need iron, it is carried out when the intestinal cells are shed and excreted in the faeces (happens every 3 days).

• Iron absorption depends on various factors like GI tract health, the presence of supportive/inhibiting nutrients (e.g. vitamin C / phytates), and the food source (haem v. non-haem).
• Haem-iron has a higher absorption rate (15%-35%) than non-haem iron (2%-20%).
• Non-haem iron absorption is more sensitive to body iron stores:
• In states of iron deficiency, non-haem iron absorption increases. In iron overload, non-haem absorption decreases.
• Note: Iron from supplements is less well absorbed than from food, so doses are typically high: Ferrous sulphate/gluconate/succinate.

Question 42

Iron:

Question 43

Optimising Non-Haem Iron Intake:

Answer 43

• Eliminate junk food (nutrient depleted, highly processed foods).
• Build meals around Fe-rich foods: e.g. Dark green vegetables, beans, whole grains.
• Eat high vitamin C vegetables & fruit with meals (peppers, cruciferous, kiwis, oranges, lemon) to promote Fe absorption.
• Avoid drinking black tea and dairy at meal times.
• Eat foods that contain yeast (e.g. bread), are sprouted (e.g. bean sprouts), and fermented (e.g. tempeh) to reduce inhibitors like phytates.

Question 44

Iron: Deficiency

Answer 44

Vulnerable stages of life:
• Women of reproductive age (menstrual blood loss).
• Pregnancy (↑ blood volume; blood loss in labour).
• Times of rapid growth (e.g. teenagers)

Iron deficiency anaemia (different from iron deficiency) is a severe depletion of iron resulting in a low haemoglobin concentration.
• Symptoms: Fatigue on exertion, weakness,
headaches, apathy, breathlessness, poor resistance to cold temperatures.
• Signs: Pallor, nail spooning, hair loss, tachycardia

Question 45

Iron: Toxicity 🚩

Answer 45

• Iron toxicity is a risk for millions of people because there is no physiological mechanism for iron excretion❗️
• Non-haem Fe absorption is down-regulated when Fe levels in the body are high, but Haem iron is absorbed much more efficiently, and the body has less control over how much it absorbs.
• This can lead to Iron overload which can be harmful, because:
- Free iron is a pro-oxidant and can cause oxidative damage (associated with atherosclerosis, cancer, Alzheimer’s etc.)
- Iron is a bacterial growth factor and can cause increased
infection rates (hence only 1% of iron in the body is unbound).
- Excess iron can accumulate in organs (e.g. the brain and liver).

Contributors to Iron overload can be:
• Haemochromatosis (a common genetic disorder affecting 1 in 250 individuals that enhances iron absorption).
• Indiscriminate use of iron supplements.
• High-dose vitamin C supplementation.
• Excessive red meat (haem-iron) consumption, which has been linked to greater iron stores and a higher risk of:
- Some cancers (e.g. colon, prostate).
- Diabetes mellitus and Heart disease

Question 46

Iron:

Question 47

Selenium

Answer 47

• A non-metallic trace element found in the body mainly as part of the antioxidant enzyme ‘glutathione peroxidase’.
• Glutathione peroxidase reduces free radicals into water and other harmless molecules.
• Selenium is found in food as an organic compound bound to the amino acids cysteine and methionine.
• Its main function is exerted in the cytosol and in mitochondria (as opposed to vitamin E, which acts in cell membranes).
• The active site of glutathione peroxidase can be occupied by mercury if in abundance, e.g. from mercury fillings and large fish.

Question 48

Selenium: Food Sources

Answer 48

• Grains: whole wheat (Durum), rye, corn
• Nuts & seeds: Brazil nuts❗️, sunflower
• Seafood: yellowfin tuna, swordfish, clams, oysters
• Vegetables: garlic, mushrooms
• Meat & Organs: calf’s liver, pork, turkey, chicken

Question 49

Selenium: Functions

Question 50

Selenium

Answer 50

Absorption:
Selenium
Selenomethionine
• Selenium is absorbed mostly in the duodenum (55-85% absorption rate).
• Absorption is more efficient under conditions of deficiency.
• Selenium from plant sources (selenomethionine) is more bioavailable (>80%) than selenium
from animal sources or supplements❗️
• Selenium homeostasis is managed primarily by the kidneys.
• Increased intake very often results in increased excretion in urine.

Question 51

Selenium: Deficiency

Answer 51

• Se deficiency is rare, but insufficiency may be widespread.
• Se levels decrease in response to inflammation.
• An elevated T4 and lowered T3 serum level is a functional marker of Se deficiency (due to depressed iodothyronine deiodinase activity).
• ‘Keshan disease’: an endemic cardiomyopathy that affected children in China where the soil
in certain areas was known to be deficient in Se.

• Deficiency signs: cardiomyopathy, muscle pain, weakness, elevated liver enzymes, growth retardation, infertility.

Question 52

Selenium: Toxicity 🚩

Answer 52

Toxicity:
• Se is among the most toxic of the essential minerals❗️ (and the margin between beneficial and harmful intakes is narrow).
• The TUL for adults is 300μg/day but the dose to cause toxicity is about 850-900 μg/day (combined intake food/supplements).
• Efficient methylation is important for detoxification of Selenium.

Toxicity symptoms include:
• Brittle hair and nails (or loss of nails).
• Skin lesions, dermatitis, secondary infections.
• Depression, neurological abnormalities.
• Garlic odour (from expiration of dimethylselenide).

Question 53

Copper

Answer 53

• As a component of several enzymes known as *cuproenzymes. Cu is an essential mineral for human health.
• Cu is absorbed mostly in the small intestine, and to a lesser degree, the stomach (enhanced by stomach acid). It is excreted in bile.
• Cu is found in both plant and animal foods (dairy is a poor source).

Food Sources:

• Seeds & Nuts: sesame, cashews, sunflower
• Grains & Legumes: quinoa, oats, chickpeas
• Vegetables and fungi: shiitake, avocado, garlic
• Organ meat: calf’s liver
• Shellfish: oysters, lobster, crab, prawns

Question 54

Copper: Functions

Answer 54

Question 55

Copper: Deficiency

Answer 55

• Copper deficiency is rare because many foods contain good amounts of Cu and we need very little (Adults: 1.3mg-1.6mg/day).
• However, deficiency may be induced by:
- Long-term high Zinc supplementation (>50mg/day) depresses Cu absorption and restricts utilisation of Cu).
- Infants fed cow’s milk (dairy is a very poor source of copper).

• The most frequent signs and symptoms of deficiency are:

• Anaemia (due to Cu role in iron metabolism).
• Bone fractures (due to Cu role in collagen structure).
• Impaired growth and reduced skin pigmentation.
• Recurrent infections

Question 56

Copper: Toxicity 🚩

Answer 56

Cu Toxicity and Overload:
• Acute toxicity is typically only seen from contaminated drinking water (e.g. copper pipes) or genetic disorders (Wilson’s disease).
- Symptoms of acute Cu toxicity include: vomiting, diarrhoea, liver / kidney damage, haemolytic anaemia, coma and death.
- Investigate water supply, supplementation or high-Cu food intake.

• Copper Overload is more common, especially in women as oestrogen can cause Cu retention.

• Symptoms of Cu overload include: emotional instability, ADHD, intolerance to OCP, low immunity (Zn deficiency), skin sensitivity to cheap metal, allergies, acne and more.
• In Cu overload, explore Zinc deficiency and gut function.

Question 57

Iodine

Answer 57

• Iodine (I) is a component of thyroid hormones which regulate the metabolic rate of all cells in the body.
• Iodine from food is efficiently absorbed and converted in the GI tract to Iodide ions (close to 100% of dietary iodine is absorbed).
• Iodine levels in soil vary widely globally but are relatively low.
• The Ocean is Earth’s main source of iodine.

Food sources include:
• Sea vegetables (excellent source); ocean fish and shellfish such as cod and scallops;
Iodine is also in eggs & dairy foods (due to the fortification of animal feed) with small amounts in plants depending on the soil.

Question 58

Iodine: Functions

Answer 58

Question 59

Iodine: Deficiency

Answer 59

• In the early 20th century iodine deficiency (ID) was common in the UK / IRE and many other countries around the globe- The ‘iodisation’ of table salt began to be implemented in many countries to reverse ID (ID was addressed by the use of iodine- fortified cattle feed and an increase in milk consumption).
• ID leads to decline in thyroid hormone production and if prolonged, it can lead to ‘hypothyroidism’ with symptoms like: fatigue, weight gain and depression. Prolonged
ID can lead to a goitre (enlarged thyroid).
* Note: hypothyroidism can occur without ID; e.g. Hashimoto’s Thyroiditis (auto-immune).
• Severe ID during pregnancy causes extreme and irreversible mental and physical retardation (a daily intake of 150mcg is recommended by the World Health Organisation).
• Children with even mild iodine deficiency have goitres and perform poorly at school; with treatment mental performance improves

Question 60

Iodine

Question 61

Manganese

Answer 61

• Manganese (Mn) is both a constituent and activator of enzymes involved in both metabolic and antioxidant functions.
• Intestinal absorption is low at 1%-5%. It is stored mostly in bone (>40%) and very metabolically active organs; e.g. liver, kidneys, pancreas and brain.

Key Food Sources:

• Grains: wheat germ, rye (6mg), oats, amaranth
• Nuts & seeds: hazelnuts, pine nuts, walnuts
• Spices: cloves, saffron, ginger, black pepper
• Shellfish: blue mussels, other shellfish (≤1mg)

Question 62

Manganese: Functions

Question 63

Manganese

Answer 63

Deficiency:
• Not observed in humans on a whole foods diet but ‘insufficiency’ can lead to loss of hair colour,
skin rashes, tendon and bone abnormalities.

Toxicity:
• Not documented from dietary sources but observed in workers exposed to high manganese dust in air (welders and smelters).

Interactions:
• High intakes of Fe, Ca, Mg may impair intestinal absorption of Mn but this is mostly associated with supplements.
• If Fe intake is low, iron deficiency may result from manganese supplementation (Mn competes with Fe for absorption).

Question 64

Chromium

Answer 64

• Chromium (Cr) is an essential trace mineral that potentiates the action of insulin.
• The predominant form in the body is trivalent chromium (Cr3+)
• Absorption of Cr from the intestinal tract is low (0.4-2.5%).
• Cr is widely distributed in the food supply but most foods contain very small amounts (<2mcg).

Key Food Sources:

• Vegetables: broccoli, green beans, potatoes
• Grains: barley, oats, whole wheat
• Meat and poultry: turkey, beef
• Herbs/spices: black pepper (2tsp), basil, garlic

Question 65

Chromium: Functions

Question 66

Chromium

Answer 66

Deficiency:
• Marginal Cr deficiency leads to poor blood sugar control and subsequent symptoms; e.g. anxiety, sugar cravings, fatigue.
• High carbohydrate intake and vigorous exercise ↑ Cr excretion.

Toxicity:
• Cr in foods and supplements is one of the least toxic minerals (No Tolerable Upper Limit (TUL) has been established).
• Adequate intake (AI) for adults spans from 30-44mcg/day but no adverse effects are seen in amounts up to 10mg/day.

Interactions:
• Fe overload (haemochromatosis) can impair Cr transport.

Question 67

Sulphur:

Answer 67

• Sulphur (S) is the third most abundant mineral (after calcium and phosphorus) in the human body (0.3% of total body mass).
• It has a characteristic smelly odour – “burning hair” (Keratin is particularly high in Sulphur).
• Sulphur is a key component in important molecules:
- Acetyl CoA - a key molecule for ATP production.
- Vitamins: Biotin, Thiamine – essential B-vitamins.
- Key antioxidants: Glutathione, Lipoic acid.
- Mineral transporters: Metallothionein (a metal-binding protein).
- Methylsulfonylmethane (MSM) – inhibits cartilage breakdown.
- S is in four amino acids: Methionine, Cystine, Cysteine, Taurine.

Question 68

Sulphur: Food Sources

Answer 68

• Amino acids are the main dietary source of Sulphur, but there are also many Sulphur-based compounds in food.

Rich food sources of Sulphur include:

• Alliums: e.g. garlic, onions, shallots, leeks, chives.
• Cruciferous (Brassicas): broccoli, cauliflower, cabbage, Brussel sprouts, turnips, kale, spring greens, radish.
• Legumes: especially soyabeans, black beans, kidney, split peas and white beans.
• Eggs and Dairy: parmesan, gorgonzola, cheddar.
• Protein foods: meat, poultry, fish and seafood.

Question 69

Sulphur: Functions

Answer 69

Question 70

Molybdenum

Answer 70

• Molybdenum (Mo) is an essential trace mineral that is a cofactor in various enzymes involved in detoxification; e.g.
– Sulphite oxidase: detoxification of Sulphite to Sulphate to prevent the dangerous accumulation of Sulphites in the body.
– Xanthine oxidase: formation of uric acid from purine breakdown.
– Aldehyde oxidase: the clearance of drugs containing aldehydes.

• Food Sources include:
– Legumes (the richest source), whole grains, nuts, green leafy vegetables, beef liver and milk.

• Deficiency - unknown in humans and average consumption falls within the recommended levels (Adults: 45mcg/day: TUL 2mg).

Question 71

Other Minerals:

Answer 71

• Boron (B) – a trace mineral not considered essential in humans but plays a role in mineral metabolism and bone development.
– The richest food sources are fruit, vegetables, nuts and legumes (meat, fish and dairy are poor sources).

• Silicon (Si) – not considered essential to humans but plays a role in bone mineralisation and the integrity of connective tissue.
– The richest food sources are whole grains, root vegetables, dried fruit and bananas (meat, fish and dairy have low values).

• Fluoride (F) – only a trace of F occurs in the human body, mainly in bones and teeth. In excess (i.e. from toothpaste, tap water), it is highly toxic, especially to the thyroid gland and tooth enamel.

Question 72

Drug-Mineral Interactions: