BPK 110 Modules 9 & 10

Vitamin Overview

• Vitamins are organic micronutrients

  • They facilitate body processes

• They are either fat-soluble or water-soluble

• Body requires 13 vitamins to survive and thrive - provides 0 kcal of energy

Vitamins Can Function as Coenzymes

• Coenzymes are non-proteins factors required for enzyme function. When coenzyme bind to enzymes, they can activate the enzymes and allow them to function. Vitamins facilitate many enzyme-dependent body reactions

The B Vitamins

• A group of eight vitamins that act as coenzymes for energy metabolism

  • Many have other roles as well ( don’t provide energy, support enzymatic activity that promotes energy metabolism)

• Plants and animals naturally contain B vitamins and they are also fortified into foods, such as grains and cereals

Vitamin B1: Thiamine

• RDA: 1.2 mg (M); 1.1mg (F)

• Plays a role in muscular contraction, nerve conduction and is required for ATP synthesis

• Also part of the coenzyme thiamine pyrophosphate (TPP)

  • Required for citric acid cycle

• No known toxicity

Thiamine Sources

• Abundant in many foods like nuts, seeds, eggs, milk, poultry and fortified cereals

Thiamine Deficiency

• Rare in Canada

• The brain is particularly susceptible to thiamine deficiency, can lead to neuronal death in areas with higher thiamine requirement

• In developed world, typically associated with alcoholism and malnutrition

  • Can lead to Wernicke/Korsakoff Syndrome

  • Can lead to BeriBeri

Wernicke/ Korsakoff Syndrome

• Short-term memory loss, confusion, disorientation and changes in eye movements

• Korsakoff syndrome has more severe and permanent neurological symptoms

Wet BerBeri

• Negatively impacts the cardiovascular system and can lead to heart failure

Dry BeriBeri

• Negatively impacts the nervous and muscular systems, potentially leading to muscle paralysis

Vitamin B2: Riboflavin

• RDA: 1.3mg (M); 1.1mg (F)

• Form two important coenzymes: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)

  • FAD = electron transporter required for electron transport chain

• Also involved in:

  • Conversion of the amino acid tryptophan to niacin

  • Maintaining appropriate levels of homocysteine, a risk factor for CVD

Sources of Riboflavin

• Egg yolks, organ meats, fortified breakfast cereals, oats, milk, salmon, tuna, soybeans and almonds are all high in riboflavin

• Dairy products high in riboflavin + bacteria in large intestine promote riboflavin availability

Riboflavin Deficiency

• Rare

  • More common in vegetables

  • Hormonal abnormalities may promote it

• Can lead to ariboflavinosis

Ariboflavinosis

• Skin disorders, swelling in the mouth and throat, dry and cracked lips, red eyes and hair loss

Vitamin B3: Niacin

• RDA: 16mg (M), 14mg (F); UL: 35 mg

• Forms the coenzyme nicotinamide adenine dinucelotide (NAD)

  • NAD = electron transporter required for electron transport chain, pics up electron to become NADH + H+

• NAD is required by more than 400 enzymes

  • Involved in more reactions than any other vitamins

Sources of Niacin

• Animal products such as chicken, beef and fish are high in niacin

• Plant products such as nuts, legumes and grains are also high in niacin, but about half the niacin content of animal products by mass

Niacin Deficiency

• Causes pellagra

  • 4Ds of pellagra: dermatitis, diarrhea, dementia, death

• Pellagra plagued the Southern US in the early 1900s before its cause was known

  • Southern diet was high in corn, wheat and rice

    • low in niacin

Niacin Special Uses

• High doses (>2000 mg) have been shown to reduce triglycerides, VLDL, LDL and increase HDL

• However, no clear link has been established with niacin megadoses and decreased risk of heart attacks, strokes, mortality

• Also, high doses can lead to niacin toxicity

  • Niacin Flush

Niacin Flush

• Doses of 30 mg or more

• Flushing, itching, burning of skin

• May also lead to low blood pressure, fatigue, insulin resistance

• Consuming niacin in its nicotimade form instead of it nicotinic acid form can reduce symptoms of toxicity

Vitamin B5: Pantothenic Acid

• AI: 5 mg

• Helps form coenzyme A

  • Required for acetyl CoA

    • Essential for energy metabolism

• Deficiency, toxicity = rare

Sources of Pantothenic Acid

• Pantothen = everywhere

  • Found in a wide variety of food

• Fortified cereals, beef, chicken. grains and vegetables

Vitamin B6: Pyridoxine

• RDA: 1.3 mg; UI: 100 mg

• Generic name for six vitamers

• Act as coenzymes in more than 100 reactions

  • Ex: Energy metabolism

• Also help form the neurotransmitters serotonin and norepinephrine, which support cognitive functions

• Also helps lower homocysteine levels by converting it to cysteine

• Elevated levels of homocysteine are a risk factor for CVD

Vitamin B6 Sources

• Found in many animal and plant foods

• Chickpeas are the best source, while beef, tuna, salmon and chicken are good food sources. Supplements works too

Vitamin B6 Special Uses

• Supplementation has been used for:

  • Improving cognitive function

  • Reducing CVD risk, not CVD incidence

  • Reducing PMS symptoms

  • Reducing vomiting and nausea in pregnancy

    • However no firm link has been established for any of these

Vitamin B6 Defiency

• Rare, typically in combination with other B vitamin deficiencies

• In pronounced cases can lead to microcytic anemia

Microcytic anemia

• A condition which RBC are small and don’t properly transport oxygen

• Can promote fatigue, lethargy, dry and cracked lops and a swollen tongue

Vitamin B6 Toxicity

• Rare; typically due to over supplementation (>1000 mg/d)

  • Can promote loss of control over body movements

  • High supplements doses should be taken only under the advice of a medical doctor & closely monitored

Vitamin B6: Biotin

• AI: 30 mcg

• Generic name for five vitamers that function as coenzymes

  • Involved in energy metabolism, cell-signalling, DNA structure/function

• Special uses:

  • Biotin is sold to improve hair, nail, skin health

    • However, clear benefit has not been scientifically established

Vitamin B7 Sources

• Abundant in many foods. One serving of beef liver afford 100% of RDA

• Chicken, tuna & pork are good sources while sunflower seeds, sweet potatoes, almonds, & broccoli are also high in biotin

Biotin Deficiency

• Rare

• May occur with a genetic disorder called biotinidiase defiency

Biotinidase defiency

• A rare genetic condition that negatively affects biotin availability & can lead to deficiency

  • Hair loss, red eyes, rashes

  • Can progress to seizures, depression, muscle disorders

Biotin Toxicity

• Rare

• But over-supplementation can compromise laboratory results

• Ne lead to symptoms or upper limit

Vitamin B9: Folate/Folic Acid

• Folate = basic form (food), Folic Acid = acid form (supplements)

• Coenzyme in DNA/RNA synthesis, amino acids metabolism

• Also involved in conversion of homocysteine to methionine

• The fortification of grain with folic acid has led to a reduction in the incidence of neural tube effects

Vitamin B9 Sources

• Beef liver is the most concentrated source of folate, with one serving providing more than half of the RDA

• Spinach, legumes, asparagus, Brussels sprouts & avocados are also high in folate

Folate Deficiency (Birth)

• Deficiency during pregnancy can lead to neural tube effects

  • Can cause birth defects such as spina bifida and anencephaly

Spina bifida

• Leads to physical problem, such as leg weakness, scoliosis, and bladder and bowel issues, as well as neurological problems in which planning, organizing & attention are compromised

Anencephaly

• When a child is born missing parts of the brain. Results in infant death in few hours

Folate Deficiency (RBC)

• Can lead to megaloblastic anemia

  • RBC are immature, large, misshapen and unable to properly carry oxygen

    • Symptoms include tiredness, weakness and heart irregularities

    • Inability to properly synthesize DNA during RBC production

• Has also been studied for its potential link with autism, but firm link has not been established

Folate toxicity

• Rare

  • But may promote nausea, bloating, decreased appetite and difficulty sleeping

  • Can also mask a vitamin B12 deficiency, since it can prevent megaloblastic anemia

Vitamin B12: Cobalamin

• RDA: 2.4 mcg

• Required for DNA synthesis, red blood cell formation, brain function

• Also acts as coenzymes for conversion of homocysteine to methionine

• Has also been studied for reduction in dementia risk - evidence is currently lacking to support supplementation

Vitamin B12 Absorption

• Factors that negatively affect the stomach (ex: Atrophic gastritis) can compromise the release of intrinsic factor, negatively affecting B12 absorption

  • More common in older adults

  • Relies on stomach secretions

Atrophic gastritis

• An immune disorder that results in the breakdown of the stomach’s lining, restricts intrinsic factor secretion & significantly increases the risk for B12 deficiency.

B12 Sources

• Found only in animal products

  • With exception of nutrition yeast

• Supplementation is recommended for vegans, vegetarians

Vitamin B12 Deficiency and Toxicity

• Deficiency can lead to megaloblastic anemia

  • Can also promote balance issues, depression, poor memory, confusions

• Toxicity = rare

  • However, can interact with certain medications

Vitamin C: Ascorbic Acid

• RDA: 90mg (M), 75mg (F); UL: 2000 mg

• Critical for collagen formation

• Also involved in protein metabolism, iron absorption

• Without it, collagen fibres do not properly cross-link and organize themselves. This can negatively affect collagen-dependent structures as well as wound healing

Vitamin C is an Antioxidant

• Substances that helps reduce the activity of free radicals → reactive molecules that have an unpaired electron. Stops oxidation by donating their extra electrons to free radicals, neutralizing them so they cannot cause damage

Vitamin C Special Uses

• Immune System Effects

  • Vitamin C supports the proper function of the immune system

    • May lower risk of developing colds if taken before they occur

      • Especially in certain athletes

• Chronic disease prevention

  • Has been studied for potential to reduce cancer, CVD risk

    • However, supplementation has not been shown to reduce risk

Vitamin C Sources

• Synthesized by most animals except humans. Consume this from food or supplements.

• Abundant in fruits or vegetables. Half a cup of raw red peppers or ¾ of a cup of orange. Abundant in citrus foods, broccoli, Brussels sprouts and cauliflower

Vitamin C Deficiency and Toxicity

• Deficiency = rare

  • Can lead to scurvy

• Toxicity = rare

  • >2000 mg/d can promote gastrointestinal symptoms

Scurvy

• Characterized by bleeding gums, fatigue, poor collagen formation

An Indigenous Lens: The Cure for Scurvy

• The Scottish doctor, James Lind is often credited with discovering the cure for scurvy

  • Citrus fruits

• However, ~ 100 years earlier, Canadian Iroquois cured Jacques Cartier’s crew of scurvy

  • Served them a concoction of boiled winter leaves and bark of annedda tree

    • Later found that this concoction was high in Vitamin C and the amino acids arginine

      • all critical for collagen synthesis, scurvy prevention

• The story does not end well for the Iroquois chief, Donnacona, who helped saved Jacques Cartier’s crew

  • He and members of his tribes were kidnapped and taken to France to brag about the riches found in the “discovered” area of Canada

    • They died without ever returning to Canada

Vitamin A

• RDA: 900 mcg (M), 700 mcg (F); UL: 3000 mcg

• Has several vitamers = retinoids

  • Provitamin A is found in plats and its vitamers are collectively known as carotenoids

    • Must be converted into retinols

  • Preformed vitamin A is found in its almost-active forms: retinol and retinal ester; found in animal products

    • The body must convert retinols into retinal and retinoic acid = active form of vitamin A

Vitamin A is Critical for Visual Pathway

1. Rhodopsin is a visual pigment found in the eye’s retina. It is composed of retinal bound to opsin

2. Rhodopsin is stimulated when certain visual stimuli are projected onto the retina

3. This causes retinal to change shape, and a nerve message to be sent to the brain about what was seen

4. Retinal and opsin then break apart

5. Some retinal is lost in the process, but this can be replenished with retinal from dietary vitamin A intake

6. Retinal and opsin come together again to continually repeat this process

Other Functions of Vitamin A

• Gene expression

  • i.e. Whether genes are turned on/off

• Immune Function

  • Contributes to formation of infection-fighting T-cells

• Carotenoid form (plants) functions as an antioxidant

Vitamin A Special Uses

• Promotes skin health by switching on the genes that cause immature skin cells to become mature and healthy

  • Many skin care products contain retinoids

    • Ex: Accutane

Accutane

• A retinoic acid product is used to treat acne

• Can have severe skin, gastrointestinal, nervous, and cardiovascular side effects and increase risk of birth defects if taken by pregnant women

How Carrots were used to hide the invention of radar

• Urban legend = vitamin A help us see better at night

• While vitamin A can help prevent night blindness, it does not improve night vision

• This rumour started with the British Air Force’s (WWII) propaganda campaign to convince people to eat more carrots to improve night vision

  • They were actually trying to hide the invention of a new form of radar, which helped their military find targets at night

Sources of Vitamin A

• Preformed vitamin A is found in animal products

• Provitamin A is found in plant products, and oranges

• Beef liver is especially high in vitamin A, affording more than seven times the RDA in a single serving

Vitamin A Deficiency

• Rare in North America, common in developing countries

  • Often linked with poverty, low diet variability

• Can lead to xeropthalmia

Xeropthalmia

• Abnormal dryness of the eye that affects the body’s ability to form tears

  • If untreated, can lead to breaks in cornea, even blindness

• Night blindness is an early sign of xeropthalmia

Vitamin A Toxicity

• Carotenoids may turn skin slightly orange, but otherwise have no toxicity symptoms

• Preformed vitamin A toxicity can have serious side effects

  • Elevated pressure around the brain, dizziness, nausea, headaches and can be fatal

    • Typically due to over-supplementation

    • Has also been evidenced in arctic explorers who consume polar bear liver

Vitamin D

• RDA: 15 mcg; UL: 100 mcg

• Generic name for a group of compounds including vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol)

• Their main role is maintaining calcium homeostasis

  • Increase calcium, phosphorus and magnesium absorption

• Also plays roles in cellular growth, immune function and the reduction of inflammation

• Has also been studied for its role in cancer prevention

  • Establishing adequate vitamin D from food may have a role in cancer prevention, but supplementation has not been established to lower risk

Sources of Vitamin D

• Fatty fish and fish oils

• Orange juice + milk products sometime fortified with vitamin D

• Sun light

Activation of Vitamin D

1. When UVB light hits the skin, it promotes the synthesis of vitamin D3 from its precursors

2. The liver modifies vitamin D3 into the form of vitamin D that circulates through the blood

3. In order for vitamin D to perform its functions, the kidneys must convert the circulating version into its active form

Vitamin D Deficiency

• Common, due to inadequate dietary consumption, limited sun exposure

  • Older adults, individuals with black skin, individuals with obesity, breastfed infants, people who have undergone gastric surgery are all at high risk

• In children, can promote rickets

• In adults, can lead to osteomalacia

  • softening of bones due to decrease in bone mineralization

  • Can progress to osteoporosis

Rickets

• Lack of bone mineral density that leads to soft bones

Osteoporosis

• Less hardened bone tissue, making them more likely to break

Vitamin D Toxicity

• Toxicity from food is rare, typically due to over-supplementation

  • Can promote anorexia, weight loss, increased urination, irregular heart rhythms

  • Can also increase blood calcium

    • Can harden blood vessels, eyes and negatively impact kidneys and heart

Vitamin E

• RDA: 15 mg; UL: 1000 mg

• Generic term for eight vitamers

  • Alpha tocopherol = main one from diet

• Vitamin E exerts its main functions through its antioxidant role

  • Help protect cells from the harmful effects of free radicals by donating electrons and neutralizing them

• Also involved in immune function, cell signalling

• Has also been studied for potential to decrease Cancer, CVD, Alzheimer’s risk

  • However, supplementation has not been shown to decrease risk

Vitamin E Sources

• Found primarily in the oily green of cereal grains. Richest sources are vegetable oils

• Fatty shellfish and fatty plants such as nuts, seeds, fortified cereals and nut butter are also good sources

Vitamin E Deficiency

• Rare; typically due to compromised fat absorption

  • Symptoms may include peripheral neuropathy, movement difficulties, muscle disorders and an impaired immune response

Vitamin E Toxicity

• Due to over-supplementation

  • Increases mortality rate

  • Has been linked to lung illnesses in those that vape

    • High levels of vitamin E were found in the blood of individuals with vaping-related lung issues such as difficulty breathing, chest pain, fatigue and vomiting

Vitamin K

• AI: 120 mcg(M), 90 mcg(F)

• Named for the Danish word for coagulation (blood clotting)

• Prothrombin synthesis is dependent on a vitamin K coenzyme

  • Prothrombin is needed for the pathway that leads to the formation of sticky fibrin fibres - which help red blood cells clump together

Vitamin K Deficiency and Toxicity

• Deficiency is rare

  • Except in newborns, those with compromised absorption, those who overuse antibiotics

    • Can lead to excessive bleeding, hemorrhaging

      • Newborns get a shot of vitamin K to prevent this

• Toxicity has not been observed

Vitamin K Sources

• Leafy-green vegetables. Attained from animal products such as liver, ham, and cheese and milk

Vitamin K and Warfarin

• Anticoagulant (blood thinner) that blocks the vitamin K-dependent coagulation pathway

  • Prescribed for those at high risk for heart attacks and strokes

• First came to the market as rat poison - rodents died from excessive bleeding and blood loss - in humans, prescribed at much lower doses

Vitamin-Infused Beverages

• Make vague promises based on vitamin provision

• Regulated as natural health products

  • Do not have to have nutrient facts box

• Typically contain water-soluble vitamins - those that are much less likely to be deficient in the diet

• Also, may have a lot of added sugar

Overview of Minerals

• Minerals are elements that form solid compounds and that are not bound to carbon

  • Inorganic

• Divided into:

  • Major minerals

    • Required in higher amounts from diet

  • Miner/trace minerals

    • Required in lower amounts from diet

Mineral Bioavailability

• Availability in food as well as its propensity to be absorbed and available for use within the body

• Minerals are found in both plants and animals

  • Mineral content of plants depends on the soil

  • Mineral content of animals depends on what they eat

    • Animal products, especially from larger animals, are a better source of minerals than plant products

Plants Contain Compounds That Can Negatively Affect Bioavailability

• Phytates

• Oxalates

• Tannins

• Glucosinolates

Phytates

• Impair iron, zinc absorption

  • Phytate effects can be reduced by:

    • Soaking certain foods overnight

      • Ex: Soaking beans

    • Fermenting foods

      • Ex: Making sourdough bread

Oxalates

• Impair Calcium, iron absorption

• Found in leafy vegetables, nuts and seeds

Tannins

• Impair iron absorption

• May have disease-reducing effects

  • Anti-cancer, antioxidant, antimicrobial, and anti-inflammatory

• Found in tea, coffee, red wine and legumes

Glucosinolates

• Impair iron absorption

• Found in cruciferous vegetables such as broccoli, Brussel sprouts and cabbage

Minerals can act as Cofactors

• Cofactors are inorganic metals that bind to enzymes, often activating them and thus improving the rate of reaction

Calcium

• RDA: 1000 mg; UL: 2500 mg

• Most abundant mineral in the human body

  • Also abundant in nature

    • Ex: Limestone, chalk, pearls

• Key signalling mineral

  • Contributes to nerve signalling, key intracellular messenger

• Required for muscle and heart contraction, gland secretion

• 99% of body calcium in stored in bones and teeth

  • Promotes their structural integrity

Calcium Homeostasis

• Maintaining blood calcium is critically important

• When levels drop, parathyroid hormone (PTH) is released

• When levels are too high, calcitonin is release

  • Opposes actions of PTH

    • i.e. impairs osteoclast activity, promotes calcium excretion

PTH

1. Promotes calcium release from bones by activating bone breaking cells called osteoblasts

2. Decreases calcium excretion at the kidneys, so more is kept within the blood and less is lost in urine

3. Promotes the activation of Vitamin D at the kidneys, which promotes Ca+ absorption at small intestine

Sources of Calcium

• Dairy products, eggs, canned fish with bones, fortified alternatives + leafy green vegetables

Calcium Deficiency

• Negatively affects our ability to achieve peak bone mass

• Increases risk for osteoporosis

  • As low vitamin D, physical inactivity, smoking, alcohol consumption, female gender, age, family history

Peak Bone Mass

• Typically achieved within our 20s, after which it decreases over time

Osteoporosis

• A lack of bone mineralization and density and is the main cause of bone functions in older adults

• Caused by an imbalance in bone remodelling favouring the breakdown of bone by osteoclasts

Calcium Toxicity

• Minor increases are typically asymptomatic

• Chronically elevated levels can lead to abdominal/bone pain, mental confusion

  • Can progress to the calcification, hardening of tissues

    • Can lead to cardiac arrest

      • Rarely due to dietary excess, typically due to other chronic conditions

Phosphorus

• RDA: 700 mg; UL: 4000 mg

• Second most abundant mineral in body

• Found within hydroxyapatite - crystal that contains both calcium, phosphorus

  • This crystal mineralizes bones and teeth, hardening them and promoting strong structure

Phosphorus Sources

• Abundant in animal products such as salmon, cheese, milk, eggs, and beef

• Plant sources: boiled lentils, cashew, potatoes, kidney beans, rice and oatmeal

Phosphorus Deficiency and Toxicity

• Since abundant in foods, deficiency is rare

  • Can lead to osteoporosis, seizures, coma, anorexia, muscle weakness, anemia, and an increased risk of infection

• Toxicity is rare

  • May lead to calcification of tissues

Sodium

• AI: 1500 mg; UL: 2300 mg

• A key electrolyte

  • It is the primary cation of the extracellular space

  • In water, electrolytes become positively/ negatively charged ions

    • Their movement leads to the creation of an electrical current

Sodium Fluid Balance

• Also contributes to fluid balance

• Ex: If there is a lot of sodium on one side of a membrane compared to the other side, water will move towards there that sodium to even out this difference in concentration

Sources of Sodium

• 75% processed food

• 5% added at table

• Rest is Naturally found in food, added during food prep and supplements + tap water

Sodium Deficiency

• Deficiency = Hyponatremia

  • Typically caused by excessive vomiting, sweating, diarrhea

    • Symptoms include nausea, vomiting, irritability, fatigue, loss of appetite, confusion, muscle weakness and spasm

      • Can progress to loss of consciousness and coma

Sodium Toxicity

• Toxicity typically due to excessive loss of body water, which concentrates sodium

  • Symptoms include thirst, weakness, nausea and loss of appetite

    • Can progress to confusion, muscle twitching and brain hemorrhages