Vitamins, Minerals, and Nutrients

Micronutrients: Topic Overview

• Micronutrients include vitamins and minerals, essential for health but required in small amounts to maintain health and life.
• Vitamins are organic compounds, while minerals are inorganic.
• Vitamins are essential nutrients; the body cannot produce enough of them on its own; inadequate intake from diet leads to deficiency.
• Vitamins assist specific functions that promote growth, reproduction, and health; they do not provide calories.
• The RDA amount does not need to be memorized.

Vitamins: General Facts

• Vitamins are organic nutrients, meaning containing carbon-carbon (C-C) or carbon-hydrogen (C-H) bonds.
• Vitamins are individual units, unlike carbohydrates, proteins, and lipids, which are made of subunits linked together.
• Vitamins are not energy-yielding but assist enzymes that release energy from carbohydrates, fats, and protein.
• The amounts of vitamins that people ingest daily from foods are small, measured in mg or µg.
• To qualify as a vitamin, the body must be unable to synthesize the compound, and its absence from the diet for a defined period will produce deficiency symptoms.
• Vitamins are found naturally in fresh foods and can be added to processed foods via enrichment or fortification.
• Some vitamins in foods are inactive and known as precursors or provitamins, transformed into active forms once inside the body.
• Enrichment is adding vitamins to replace the loss during processing so that food meets a specified standard. E.g., wheat flour before enrichment contains 0.08 mg Vit B1, 0.06 mg Vit B2, 1.0 mg Vit B3 in 100g, and after enrichment, 0.81 mg Vit B1, 0.51 mg Vit B2, and 7.5 mg Vit B3 per 100g.
• Fortification is adding vitamins that were nonexistent or insignificant in a food. E.g., wheat flour contains 15 mg calcium per 100g and 252 mg calcium per 100g after being fortified with calcium.
• The bioavailability of a nutrient is the rate and extent to which it is absorbed & used by the body.
• Factors affecting bioavailability include efficiency of digestion, time of transit through the GI tract, previous nutrient intake, nutrition status, other foods consumed at the same time, the method of food preparation, and the source of the nutrient.
• Some vitamins in large amounts cause toxicity; fat-soluble vitamins A & D are not readily excreted and easily accumulate, causing toxicity.
• The Tolerable Upper Intake Level established by the Committee on Dietary Reference Intakes is the highest amount of a nutrient unlikely to cause harm for most healthy people when consumed daily.
• Vitamins were named alphabetically in order of discovery: A, B, C, D, E, & K.
• Vitamins are classified into two groups based on solubility. Fat-soluble vitamins: A, D, E, & K. Water-soluble: B vitamins (B1 thiamin, B2 riboflavin, B3 niacin, biotin, pantothenic acid, vitamin B6, folate, vitamin B12) & vitamin C.

Fat-Soluble Vitamins

• The comparison between fat-soluble and water-soluble vitamins are as follows.
• Fat-soluble vitamins occur together in the fats & oils of food, whereas water-soluble vitamins are found in the watery compartment.
• Fat-soluble vitamins enter the lymph and then the blood after absorption, and water-soluble vitamins move directly into the blood.
• Fat-soluble vitamins require protein carriers in the blood, and water-soluble vitamins travel freely.
• Fat-soluble vitamins are held in fatty tissues & the liver until needed, while water-soluble vitamins freely circulate in water-filled compartments of the body.
• Fat-soluble vitamins remain in fat storage sites and are not excreted, water-soluble vitamins are detected by and removed from Kidneys if there are small excesses.
• It is more likely to reach toxic levels with fat-soluble vitamins when consumed in access, but it is less likely (but still possible) to reach a toxic level with water-soluble vitamins.
• Fat-soluble vitamins are stored in the body and can last for a while to meet the body's needs, whereas water-soluble vitamins are retained for varying periods and eaten more regularly to address the body's needs.

Vitamin A

• Animal-derived foods provide preformed A/retinoids; Plant-derived foods provide provitamin A carotenoids.
• Three active forms are collectively known as retinoids: retinol, retinal, and retinoic acid.
• Retinyl esters from animal sources and B-Carotene from plant sources can be converted to Retinol in the body.
• Retinol has an important role in reproduction.
• Retinal has an important role in promoting vision.
• Retinoic acid has an important role in regulating growth.

Vitamin A: Animal-based food sources

• The main form of retinoid from food absorbed as retinol in the small intestine is retinyl esters.
• Good sources include beef liver, dairy products, fish liver oils, butter, eggs, and fish like tuna and sardines.
• Vitamin A can also be found in A-fortified milk and margarine.

Vitamin A: Plant-based food sources

• Foods derived from plants provide provitamin A carotenoids.
• Fewer than 10% of over 600 carotenoids exhibit vitamin A activity and can be converted to retinol.
• Beta-carotene, alpha-carotene, & beta-cryptoxanthin are three important provitamin A carotenoids absorbed as free carotenoids in the small intestine.
• Common dietary carotenoids are lycopene, lutein, and zeaxanthin, forming the yellow, red, and orange pigments in fruits & vegetables.
• Good sources include sweet potato, carrots, spinach, apricots, broccoli, cantaloupe, papaya, mango, and pumpkin.

Vitamin A: Bioavailability

• For preformed vitamin A, the efficiency of absorption is 70-90% as long as the meal contains some fat.
• 20-50% are absorbed for provitamin A carotenoids.
• Food processing affects absorption, e.g., < 5% absorbed from raw vegetables or non-heat-processed vegetable juices.
• Absorption also decreases with fiber intake.

Vitamin A: Functions

• Vitamin A is essential for proper cell development, helping to maintain epithelial tissues & skin health.
• It helps to promote vision through retinal activity.
• Supports reproduction & growth
• Carotenoids contribute antioxidant properties.
• Vitamin A maintains the normal structure & functions of epithelial cells that cover external & internal body surfaces.
• External body surface = skin; Internal body surface = mucous membranes, lining the mouth, stomach, intestine, lungs, urinary system, and reproductive system.
• Deficiency in vitamin A replaces other cells with mucous-secreting cells, causing epithelial cells to lose their protection from microorganisms & harmful substances like stomach acid.
• Vitamin A (retinal) forms part of the pigment in the retina (rhodopsin) to convert light energy into nerve impulses that caries visual information to the brain.
• Sufficient vitamin A allows for the detection of light (light-dark vision / prevents night blindness) as well as color vision.
• Retinol participates in sperm development in men.
• Retinol supports normal fetal development during pregnancy in women.
• Necessary for overall growth, including the epithelium and bone growth.
• Free radicals are molecules with unpaired electrons, which make them unstable, starts chain reactions and attacks cells, causing widespread damage.
• Antioxidants neutralize free radicals by donating one of their own electrons, ending the chain reaction.
• Antioxidants are stable in either form, preventing them from becoming free radicals themselves despite the loss of an electron.
• Beta-carotene & other carotenoids like lycopene, alpha-carotene, beta-cryptoxanthin & zeaxanthin have antioxidant properties.
• The adequate intake of antioxidants may be protective against diseases such as cardiovascular disease, cancer & age-related macular degeneration.

Vitamin A: Recommended Intake

• The Retinol Equivalents (µg RE/day) RDA for both adult men and women is 750.

Vitamin A: Deficiency

• Vitamin A is stored in the liver.
• If a person stops eating vitamin A-containing foods, deficiency symptoms would not appear until stores are depleted; 1-2 years in a healthy adult, much sooner in growing children.
• Vitamin A deficiency is a major nutrition problem in the developing world.
• More than 100 million children worldwide have some degree of deficiency.
• Groups at risk include premature infants, infants, young children, pregnant/lactating women in developing countries, alcoholics, individuals with liver disease/AIDS, and those with severe intestinal disease and fat malabsorption.

Vitamin A: Deficiency Symptoms

• One of the first detectable signs of vitamin A deficiency: Night Blindness
• The eye's retina does not receive enough retinal to regenerate the visual pigments (rhodopsin).
• Blindness (Xerophthalmia) occurs due to a lack of vitamin A in the cornea, not maintaining the structure & functions of corneal epithelial cells, which develops in stages.
• In the first stage, the cornea becomes dry & hard: xerosis.
• In the second stage, the cornea softens: keratomalacia
• Finally, degeneration & irreversible blindness: xerophthalmia.
• Keratinization happens when mucous-secreting epithelium cells are replaced by keratin-secreting cells.
• Keratin is a hard inflexible protein found in nails & hair, which means that mucus production and vision are affected (xerophthalmia).
• Changes to epithelial cells due to vitamin A deficiency cause susceptibility to infections.
• Mucosal barriers/defenses weakened: digestion & absorption affected.
• Other epithelial tissues weaken → more susceptible to infections, compromising immunity.
• Vitamin A deficiency can influence phagocytic activity and antibody response.
• In many developing countries, measles & other infectious diseases kill many children.
• Vitamin A supplementation protects against complications & reduces the risk of dying from these infections.

Vitamin A: Toxicity

• Toxicity is possible when a person takes large amounts of preformed vitamin A/retinoids from animal sources, fortified foods, or supplements, which results in Hypervitaminosis A.
• Acute toxicity causes changes in vision, consciousness, headache, nausea, and vomiting.
• Chronic toxicity causes bone pain, liver damage/ liver abnormalities, vision problems, fatigue, and malaise.
• Children are most vulnerable because they need less and are more sensitive to overdoses.
• Serious toxic effects Bone defects contribute to fractures & osteoporosis, and birth defects can occur during early pregnancy due to the teratogen effect.
• The US Upper Intake Level (Adults): 3000 µg per day.
• Toxicity is not possible through overconsumption of natural beta-carotene; it is not converted efficiently enough to cause toxicity.
• Overconsumption of beta-carotene stored in fat under the skin turns the skin yellow but is harmless.
• High levels of beta-carotene intake from supplements may cause harmful prooxidant adverse effects.

Vitamin D

• Obtained primarily from animal-derived food sources in D3 form (cholecalciferol).
• Plant-based sources provide vitamin D2 (ergocalciferol).
• Good animal-based sources include liver, beef, veal, eggs, dairy products (milk, cheese), butter, some fish like salmon, tuna, and sardines, and vitamin D-fortified milk & margarine.
• Plant-based sources include mushrooms, cereals, & especially vitamin D-fortified cereals.
• One microgram (1µg) is equal to 40 International Units(IU) of vitamin D.
• About 80% of vitamin D from food is typically absorbed.
• Adequate dietary fat ensures absorption, but sunlight exposure makes dietary sources unnecessary, meaning vitamin D can be a non-essential nutrient.

Vitamin D: Activation and Functions

• Vitmain D synthesis requires exposure to UV rays.
• Vitamin D is actually a hormone!
• Vitamin D has three important functions: promoting normal cell differentiation, proliferation & growth, modulating neuromuscular & immune functions, reducing inflammation and ensuring calcium homeostasis.
• Vitamin D increases the absorption of calcium into the small intestine to maintain adequate serum calcium & phosphorous levels.
• Promotes strong bones through preventing the release of calcium into the serum from the bones as well allowing for normal bone mineralization through the deposition of calcium salt crystals.

Vitamin D: Recommended Intake

• The recommended allowance (RDA) of vitamin D = 2.5 µg (100 IU) for adults.
• The recommended allowance (RDA) of 15µg of Vitamin D to 70-year-olds in the US.
• Melanin pigment in dark skin provides natural protection against UV rays absorption, which is why people with darker skins need greater sun exposure to make the same amount of Vitamin D.

Vitamin D: Deficiency

• People with limited sun exposure
• People with darker skin
• Breastfed infants
• Older adults
• People with obesity
• Individuals with certain medical conditions such as chronic kidney or liver diseases, fat malabsorption disorders are at risk of vitamin D deficiency
• Children and Adolescents - A bone disease called rickets, the failure of bones to properly mineralize; bones weaken (soft bones) & bow under pressure; causing growth retardation & skeletal abnormalities.
• Dark-skinned adults living in northern regions are particularly vulnerable to deficiency
• Adults - Osteomalacia is the softening of the bones causing progressive bone demineralization as serum calcium levels cannot be maintained, and can lead to osteoporosis ("porous bone").
• Elderly - The skin, liver & kidney functions lose capacity to make and activate Vitamin D with advancing age, they typically consume little to no milk & other dairy products, they spend much time indoors.

Vitamin D: Toxicity

• Of all vitamins, vitamin D is most likely to cause toxic effects when consumed in excess → Hypervitaminosis D.
• The nonspecific symptoms are nausea, vomiting, poor appetite, constipation, weakness, & weight loss.
• calcification of soft tissues (blood vessels, kidneys, heart), mental status changes (confusion), and heart rhythm abnormalities are serious effects from toxicity.
• Toxicity is mainly observed from the use of supplements.
• Toxicity from excessive sun exposure is not possible because the body regulates the amount synthesized & activated, and prolonged sun exposure destroys vitamin D precursor.

Vitamin E

• First identified as a component of vegetable oil necessary for reproduction in rats
• Called tocopherol = to bring forth offspring
• Two forms exist, Tocopherols - α, β, γ, δ and Tocotrienols - α, β, γ, δ.
• All differ in chemical & physical properties.
• a-tocopherol is the only one with vitamin E activity in the human body.

Vitamin E: Food Sources, Bioavailability and Functions

• Vitamin E is widespread in plant & animal foods.
• Oils from plants (vegetable oils), canola, olive, sunflower, safflower & products made from them (salad dressings, mayonnaise, margarine) are the richest sources..
• Also in nuts & seeds (products like peanut butter), whole-grain cereals (esp the bran & germ parts, thus products like wheat germ & wheat bran), legumes, some fruits & green leafy vegetables.
• Liver, egg yolk, fatty meats can also provide the vitamin.
• The extent of absorption of vitamin E is unclear, ranging from 20 – 80% and depends on the simultaneous digestion & absorption of dietary facts.
• Absorption is hindered by dietary fiber (> 3% pectin or >20% wheat bran).
• Vitamin E is easily destroyed and oxidized by heat processing, so go for fresh and lightly processed foods.
• Vitamin E acts as an antioxidant and maintains membrane integrity; it prevents the oxidation of unsaturated fats in the phospholipid bilayer, which is especially important for red blood cells.
• Vitamin E has complementary roles with other antioxidants with vitamin C, carotenoids & selenium and may protect against cardiovascular disease, cancer & age-related macular degeneration.

Vitamin E: Recommended Intake, Deficiency and Excesses

• The recommended allowance (RDA) in United States(US) for both men and women is 15 mg (22.5 IU).
• The upper limit (UL) (adults) is 1000 mg (1500 IU).
• No RDA of Vitamin E for Singapore population.
• Deficiency is rare in healthy adults.
• Premature infants and people with fat malabsorption are susceptible to deficiency.
• Deficiency symptoms include Neuromuscular dysfunction involving the spinal cord, retina of the eye, loss of muscle coordination, reflexes, impaired speech and vision.
• A serious consequence of deficiency is Erythrocyte hemolysis is in which red blood cells break open & spill their contents due to oxidation of PUFA in their membranes.
• Vitamin E deficiency has been observed in premature infants (before the transfer of vitamin E from mother to baby which occurs in the last weeks of pregnancy).
• Vitamin E seems to be one of the least toxic of the vitamins. Reports of its toxicity are rare.
• Excessive amounts can inhibit the role of vitamin K in the blood clotting mechanism causing increased tendency for bleeding/hemorrhage.

Vitamin K

• The name comes from Danish word; Vitamin K (K for koagulation, Danish for coagulation or blood clotting).
• Occurs in two forms: vitamin K1 (phylloquinone) from plants and vitamin K2 (menaquinones) from bacterial synthesis.
• Richest plant sources are spinach, some salad greens, broccoli, watercress, kale.
• Others are oils & margarine (especially soybean, olive & products made from these) and smaller amounts in cereals, fruits, dairy products, and meat. Exposure to light & heat destroys vitamin K.
• Absorption is enhanced by the presence of dietary lipids.
• Vitamin K2(menaquinones) from bacterial synthesis is produced especially in the colon and not sufficient to meet the needs of children/adults.
• The primary function is to activate proteins that form clots and stops for bleeding. Inactive prothrombin turns into Thrombin, creating fibrinogen that forms fibrin strands
• Secondary Bone mineralization is also enhanced; Vitamin K participates in the synthesis of bone proteins (Osteocalcin). Without vitamin K, osteocalcin cannot bind to the minerals to form strong bones, resulting in low bone density.
• The recommended intake for adults (19 - > 70 years) is 120 ug/day for men, and 90 ug/day for women in The US.
• No RDA for Vitamin K for Singapore.
• Deficiency is not common in adults, but can be fatal when deficiency occurs, causing hemorrhage. Some drugs disrupt vitamin K's synthesis & action, antibiotics, and Anticoagulant drugs.
• It's more Likely in newborn infants due to their sterile Gl tract. Also, Vitamin K-producing bacteria take weeks to establish themselves, causing Plasma prothrombin concentrations to be low. So they are Usually given vitamin K injection to prevent hemorrhagic disease in the newborn
• Toxicity is not common, and UL is not established. However, with Certain High doses can reduce effectiveness of anticoagulant drugs used to prevent blood clotting. So People taking Warfarin should reduce intake of vitamin K-rich foods and keep their intakes consistent from day to day.

Water-Soluble Vitamins

• Include the B vitamins (Thiamin (B1), Riboflavin (B2), Niacin (B3), Pantothenic Acid (B5), Pyridoxine (B6), Biotin (B7), Folate (B9), Cobalamin (B12) and Vitamin C which form a B-complex
• B vitamins energy production, brain function, and maintains healthy cells.
• B vitamins function as key parts of coenzymes, which assist biochemical reactions performed by enzymes.
• B vitamins like NAD+ from B3 and FAD from B2 help break down carbohydrates, fats, and proteins into energy and Coenzymes derived from B vitamins during energy metabolism
• B vitamins B9 (folate) and B12 (cobalamin) are vital for DNA synthesis, red blood cell production and cell division.
• Without B vitamins, key enzymatic reactions in the body slow down or stop which, affect energy levels.

Thiamin (Vitamins B1)

• Functions include assisting in energy metabolism of all cells via coenzyme TPP (thiamin pyrophosphate)
• Thiamin occupies a special site on the nerve membranes to support neuromuscular processes
• Richest food source is pork, followed by wholegrains, meat, and fish
• Other good sources includeFortified/ enriched cereals and bread, milk, soymilk, and sunflower seeds
• Absorption increases when intakes are low and primarily takes place in the jejunum
• Inactivated by thiaminase found in raw fish and polyphenols like tannic & caffeic acids in coffee, and tea
• Easily destroyed by heat.

Singapore RDA mg/day

18-30 years

Men

1. 18

30-60 yrs

Women

1. 16
2. 84
3. 86

Thiamin(Vitamins B1) Deficiency and Toxicity:

• Deficiency can happen to people who fail to eat enough nutritious food to meet energy needs and alcoholics are at risk
• Prolonged deficiency results in beriberi: dry beriberi - damage to the nervous system, leading to muscle weakness in the arms and legs,and wet beriberi – damage to the cardiovascular system which cause the heart to retainsalt and water, resulting in edema,work harder and kidney to dilate blood vessels which cause the heart to work harder and kidney to retain salt and water, resulting in edema
• No adverse effects have been reported with excesses of thiamin, No UL has been determined

Riboflavin (Vitamins B2):

• Flavus means "yellow" in Latin,Becomes fluorescent when it comes into contact with UV light
• Acts as a part of two important coenzymes:Flavin mononucleotide (FMN) and Flavin adenine dinucleotide (FAD) and Participates in many energy-yielding metabolic pathways, acting as electron/hydrogen donors & acceptors in many oxidation-reduction reactions

DIETARY SOURCES

• Richest source: Milk & milk products (cheese & yoghurt) Other good sources:
• Beef liver, steak
• Clams, oysters
• Whole/enriched grains
• Fortified cereals
• Eggs

BIOAVAILABILITY

• About 95% of riboflavin from foods is absorbed, Easily destroyed by ultraviolet light and radiation,Stable to heatRecommended Dietary Allowance (RDA)

Singapore RDA mg/day:

• Men: 18-30 years: 1.77mg,30-60yrs:1.74mg
• Women: 18-30 years: 1.26mg,30-60yrs: 1.29mg

DEFICIENCY

• Most often occurs along with other nutrient deficiencies, Prolonged deficiency results in the disease ariboflavinosis

• Symptoms:Inflammation of the membranes of the mouth, skin, eyes, Gl tract, sore throat, cracks & redness on the outside of lips & at corners of mouth, painful, smooth, purplish-red tongue, inflammation
  

TOXICITY

• No adverse effects have been reported with excesses of riboflavin, No UL has been determined

Niacin (Vitamins B3):

• The name niacin describes two chemical structures: nicotinic acid & nicotinamide/niacinamide, Part of two coenzymes: Nicotinamide adenine dinucleotide (NAD) and Nicotinamide adenine dinucleotide phosphate (NADP)
• Functions in energy-transfer reactions especially in the metabolism of glucose, fat & alcohol,mainly in oxidation-reduction reactions is general are excellent sources of.

DIETARY SOURCES:

• Protein containing foods

• Meat, poultry, fish, legumes, whole/enriched grains
  

• Nuts, legumes, eggs and fortified cereals
  

• Niacin can also be made from tryptophan
  

Body can make niacin from the amino acid tryptophan: 1m and Niacin requires 60 mg of tryptophan

BIOAVAILABILITY:

• Niacin is less vulnerable to losses during food preparation & storage than other water-soluble vitamins and Very stable to heat, little is lost with reasonable cooking time, Chemical treatment with alkaline such as lime water Ca(OH)2 can improve availability

RECOMMENDED DIETARY ALLOWANCE (RDA) 1NE = 1mg niacin or 60mg Tryptophan

Singapore RDA mg NE/day:

• Men: 18-30 years: 19.5, 30-60 yrs: 19.1
• Women: 18-30 years: 13.9,30-60 yrs: 14.2 . DEFICIENCY:
• In populations whose diets lack sufficient protein & niacin and Prolonged deficiency results in the disease pellagra Symptoms:
• '4 Ds' : Diarrhea, Dermatitis, Dementia, Death

TOXICITY:

• Naturally occurring niacin from food causes no harm

• UL for male & female, *19yrs old: 35mg*
  

• Large doses (3-4x RDA) of nicotinic acid – dilate the capillaries and causes a tingling sensation that can be painful → "niacin flush"

• Excessive nicotinamide does not cause skin flushing and has fewer adverse effects than nicotinic acid, and these effects typically begin with much higher doses: nausea, vomiting, and signs of liver toxicity
  

Pantothenic Acid (Vitamin B5):

• Part of coenzyme A, which forms acetyl CoA, an important compound in energy metabolism pathways of CHO, lipids & protein

• Present in all foods
  

• Good sources: beef, poultry, wholegrains, potatoes, tomatoes, broccoli
  

BIOAVAILABILITY:

• Easily destroyed by the freezing, canning and refining processes

• Primarily in the jejunum
  

RECOMMENDED INTAKE:

• RDA not established: Adequate intake (Al) is 5 mg/day for adults

DEFICIENCY:.

• Deficiency is rare (except for persons suffering form severe malnutrition) Symptoms: numbness and burning of the hands and feet, headache,fatigue, irritability, restlessness, disturbed slee;p

TOXICITY:

• None reported
• No UL has been determined

Pyridoxine (Vitamin B6):

• Occurs in 3 forms: Pyridoxal, Pyridoxine and Pyridoxamine
• All 3 forms can be converted to the coenzyme PLP (pyridoxal phosphate)
• Coenzyme PLP is active in amino acid metabolism:
  the synthesis of non-essential amino acids from essential amino acids
• The synthesis of non-essential amino acids from essential amino acids
• The synthesis of neurotransmitter serotonin from tryptophan
• The synthesis of heme (part of hemoglobin), urea, nucleic acids (DNA & RNA)

Dietary sources:

• Animal foods (meat, fish, poultry) and organ meat are best sources

• Potatoes, legumes, whole grains, fortified cereals, soy products, prune juice, tomato juice
  

BIOAVAILABILITY:

• Easily destroyed by heat: More readily absorbed from animal foods than plant
• Primarily in the jejunum*

Recommended Dietary Allowance (RDA):

US RDA mg/day: Adults (19-50 yrs): 1.3

• Singapore RDA mg/day: Not established

DEFICIENCY:

• Synthesis of key neurotransmitters diminish, abnormal compounds from tryptophan metabolism accumulate in the brain
• Early symptoms: depression & confusion,Late symptoms: abnormal brain wave patterns & convulsions
• Alcohol contributes to the destruction & loss of Vitamin B6, alcohol metabolism creates a byproduct, acetyldehyde which dislodges PLP coenzyme from its enzyme
• Medication such INH drug: this drug acts as a vitamin B6 antagonist and Incan induce a deficiency

TOXICITY

• Very rare through diet
• Intake of 1–6 g oral pyridoxine per day for 12–40 months can cause severe and progressive sensory neuropathy characterized by ataxia (loss of control of bodily movements)
• and Other effects of excessive vitamin B6 intakes include painful, disfiguring dermatological lesions- photosensitivity; and gastrointestinal symptoms, such as nausea and heartburn

Biotin(Vitamin B7)

• In food, biotin is bound to protein or to the amino acid lysine
• Function as a part of a coenzyme in energy metabolism, mainly carrying activated CO2 for carboxylation reactions in Fatty acid synthesis, Gluconeogenesis,Metabolism of certain fatty acids & amino acids

DIETARY SOURCES:

* Widespread in foods: Good sources are Liver, kidney, yeast, egg yolks, soy beans, fish, whole grains, synthesizes B vitamins by intestinal bacteria, Al biotin absorbed

• May not contribute much to the biotin absorbed- by intestinal bacteria

BIOAVAILABILITY:

• Dietary biotin is thought to be nearly completely absorbed, Certain processing techniques (e.g. canning) can reduce the biotin content of foods, Avidin, a glycoprotein in raw eggs white, binds biotin and prevents absorption.

  Cooking denatures avidin & improves bioavailability, ,biotin transported primarily in jejunum, synthesized by colonic bacteria is absorbed in the colon

RECOMMENDED INTAKE:

• Biotin is needed in very small amounts
• RDA not established and Adequate intake is 30 µg/day for adults

DEFICIENCY:

• Deficiency is rare, Induced by feeding raw egg whites (> 2 dozens daily for several months)

Symptoms: thinning hair with progression to loss of all hair on the body; scaly, red rash around body openings (eyes, nose, mouth) TOXICITY:

• None reported, No UL has been determined

Folate (Vitamin B9)

• Part of the coenzyme THF (tetrahydrofolate), which transfers one-carbon compounds during metabolism and Converts vitamin B12 to one of its coenzyme forms,. Required in amino acid metabolism, Helps synthesize DNA required for all rapidly growing cells
• Relationships with diseases: Defending against heart disease ,Folate breaks down homocysteine, and High levels of homocysteine seem to enhance blood clot formation & arterial wall deterioration
• Adequate folate taken in the early weeks of pregnancy ensures normal brain & spinal cord development from the neural tube Dietary sources Dark green leafy vegetables and Spinach, liver, asparagus, and brussel sprouts are the foods with the highest folate levels. Legumes, kidney beans, mushrooms. avocado, citrus fruit and their juices. bioavaliability -the bioavailability of folate ~ 50% from food. the bioavailability is 100% taken from supplements on empty stomach
• Alcohol consumption affects folate absorptions*
• Folate travels in the same Enterohepatic circulation *

recommended dietary allowance DFE=dietary folate lug DFE = 1 ug food of folate' Adults (19-50 yrs) : 400,600 pregnancy,500 lactation

deficiency -Impaired cell division & synthesis critical in growing tissues

• magaloblastic/macrocytic GI: diarrhea, loss of appetite & weight loss, sore tongue Also headaches, heart palpitations, irritability,forgetfulness & behavioral disorders

Toxicity - naturally does not make harm to your health in food form but, high intake of folate from supplements may mask vitamin B 12 deficiency as damage UL(adult): 1000ug per day

Cobalamin- B12:

Functions: B12 together with folate, participates in the Conversion of the amino acid methionine to homocysteine and synthesis of DNA & RNA B12 activates the folate coenzyme and maintains myelin sheaths that protect nerve fibres & maintain their normal growth.

Dietary Sources:

• found exclusively in foods derived from animals and plants (fortified products) bioavailability Ingested cabalamin is a polypeptide which release the hydrogen chloride and pectin' The absorption of cobalamin must occur in the the small instestine so it can bnd with the inner molecule

Recommended dietary allowance (RDA): Adults(19-50 yrs) 2.4, 2.6 preagnancy, 2.8 lactation

Deficiency caused by inadequate absorption vs inadequate dietary intake

• Lack of HCL and inner factor* -Absence of part or all of the stomach or ileum -Bacterial Overgrowth in small intestine Also helps people's secretion of hydrochloric acids in the stomach. Since B12 is required to convert folate,defeciency will develop The anemia can be treated with either folate or B12 but at the same time... Vitamin B12 is essential for electrical signals to travel If the condition is wrongly recognised than paraylisis can happen and correct treatment should come. Toxicity Does not report and no UL

Vitamin C:

Also known as ascorbic acid or ascorbate, it is a vitamin that forms collagen for wounds to heal and act as antioxidants

Functions for vitamin c

• Collagen formation structure of connective tissues, Wounds heal as collagen glues the separated tissue together
• Acts as antioxidants. Protecting our tissues from oxidative stress
• Aids in iron absorption- absorption of non time iron also known for it's treatment of common cold.

Dietery Resources almost in all all fruits and citrus BIOAVAILABILITY: absoprtion in small intestine Absorption becomes less efficient with high intake Ingestion of large amounts of iron together. Also a heat sensitive vitamin and is easily oxygenized

RECOMMENDED DIETARY ALLOWANCE (RDA) For Men : 105 For Women: 85

Defiency is when acute vitamin c leads to scurvy. Other deficiency is leads fatugue and inflammatuon As the condition becomes worse gums begin to bleed Inadequate synthesis can lead to hemorrhaging in the muscles in general.

TOXXICITY

Symptoms: Nausea, abdominal cramps & diarrhea, headache, fatigue, insomnia, flushes, rashes, and Upper limit For adults = 2000mg/day

Minerals - Overview

• Minerals are micronutrients and are organized into Macro Minerals and Micro Minerals
• Major and Macro minerals: These minerals are required and the body may need more than it per day to meet and do its regular functions. They should be required in an amount of 100 mg per day and should range from minerals like , sodium or potassium as other examples.
• Minor Minerals: These are the minerals which are essential for various physiological processes as and in amounts < 100 g per day. These minerals can lead to iron , zinc, iodine selenium, chromium,copper and fluoride -Cation - An ion that has a positive charge -Anion - An ion that has a negative charge.
• Sodium [Na+]- maintains normal fluid balance (regulating amount of sodium with different compartments) also assist with nevere implulse transmission and acid base balance. limit: sodium is to < salt< 5g(<1 teaspoon of salt]
• Toxicity: the kidneys are functionary . if water is not regulated it results In hypernatremia that is an increased concentration of sodium,

Sodium: Deficiency and Food Sources:

• Usually happens from vomitting or sweating. Muscle cramp and appetite loss, must add sodium to diet and replace water loss
• Diets lack in NAT but the body will adapt by reducing sodium losses in urine and also sweat

Chloride:

• This a a main aion bound in extra cellular and is very assocaited with NA functions
• With K+ to maintain and electrolyte balance component of the gastric HCi

#Recommended intake

Adults: 19-50 years ➖ 2300ml 51-70 years : 2000ml 73> years : 1800ml

UL Adult : 3600

Toxicity : the only known cause of high blood chloride is dehydration due to water deficiency and may even cause vvominting 800 ml.

Diet Deficiency: are diets do not lack so it may occor with chronic heavy sweating, chromnic dirarrhea and vomitting

Functions - together with Na+, K+ & other electrolytes Helps regulates fluid and electrolytes balance and its component potassium: maintains cell integrity and helps regulates bp and help with heartbeat. maintaing cell integrity

Potassium: Food, Recommendations, and Deficiency

• food are often fresh meats fruits vegetables Singapore : mg/day

al mg /day Male: 3400 Pregnancy: 2900 Women: 2600 Lactating 2000

Toxicity : Kidney effectively remove potassium The cause includes high doses of potassiums supplements Or over functioning kidneys

May Lead to muscular weakness or vomitting Deficiency : is cause by excessive losses and drugs intake leading to cardiac function and glucose intolerant Low intake of potassium can lead to the risk in kidneys and is a reason for increased blood pressure

Calcium(CA)

• is abundant in the body, The 99% is stored in our teeth and bones
• Functions in blood clotting, regulation of muscle contraction, and helps the integrity of bones
• It is known helps strengthen teeth*

Calcium and bones is when bone deposit is higher than skeletal modelling and peak bone mass for the calcium.

bioavailability - the adults absorbs 25% of calcium

• Enhance with: Physioloscal Need
• Stomach Acidity
• Vitamin. D

decrease with bioavailability

• -lack if stomach acids*
• -vitamin D deficiency
• -and dietary fibers
• -high intakes would supplement and decreased to aborspotion -may cause :hypercalcemia where

Explore the role of micronutrients, including the key differences between vitamins and minerals, their classification, and dietary importance. Understand the physiological processes and strategies for improving nutrient absorption. This resource covers essential nutritional concepts.