Chapter 8 - Vitamins Flashcards
Water Soluble Vitamins
What is the RDA of B1 - Thiamine
1.2 mg for men
1.1 mg for women
Functions of Thiamine
- Plays a role in muscle contraction, nerve conduction, and the synthesis of ATP
- Contributes to thiamine pyrophosphate (TPP), a coenzyme required for cellular reactions and the citric acid cycle
Sources of thiamine
nuts, seeds, eggs, milk, poultry and fortified cereal
Thiamine Deficiency
- The brain is particularly susceptible and can lead to neuronal death
- Alcoholism can lead to thiamine deficiency and in severe cases cause wernickes syndrome - associated with short-term memory loss, confusion, disorientation, and changes in eye movement. If not treated can lead to ferment damage also known as korsakoffs syndrome
- Wet Beriberi which negatively impacts the cardiovascular system and can lead to heart failure
- Dry Beriberi which impacts the nervous and muscular systems
Thiamine toxicity
N/a no upper limit, thiamine is well tolerated by the kidneys
What is the RDA of B2 - Riboflavin
1.3 mg for men
1.1 mg for women
Riboflavin function
- Help form flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD) which picks up electrons during the citric acid cycle
- converts tryptophan to niacin
- maintains levels of homocysteine (risk factor for CVD)
Sources of riboflavin
Egg yolk, oregano meat, fortified cereal, oats, milk, salmon, tuna, soybeans, and almonds
Riboflavin deficiency
- ariboflavinosis: skin disorders, swelling in the mouth and throat, dry and cracked lips, red eyes, and hair loss
- thyroid hormon deficiency and lack of meat may cause this
Riboflavin toxicity
N/a no upper limit
What is the RDA and UL of B3 - Niacin
16mg for men
14 mg for women
UL: 35mg
Niacin functions
- forms the coenzyme nicotinamide adenine dinucleotide (NAD) which is a key electron transporter in cellular respiration
- NAD is required by over 400 enzymes so niacin is involved in many different reactions in the body
Sources of Niacin
animal products such as chicken, beef, fish and plant products such as nuts, legumes, and grains
Niacin deficiency
- Pellagra: dermatitis, diarrhea and dementia and can also lead to death
Niacin toxicity
_ usually seems in people taking high levels for management of blood lipids and CVD
- Niacin flush: flushing or reddening of the skin accompanied by burning or itching
- Can also lead to nausea and vomiting
Niacin special uses
Has been prescribed by doctors for improving blood lipids associated with CVD - reduced triglycerides, VLDL and LDL
What is the AI of B5 - Pantothenic acid
5mg
Pantothenic acid functions
helps form coenzyme A - required for citric acid cycle
Sources of pantothenic acid
fortified cereals, beef, chicken, grains and vegetables but is widely found
Pantothenic deficiency
Rare
- if present is often associated with malnutrition
- May lead to numbness in hands and feet, headache, tiredness, disturbed sleep, and GI issues
Pantothenic toxicity
megadoses have been associated with diarrhea and digestive tract distress but there is no upper limit and toxicity is rare
what is the RDA and UL of B6
RDA 1.3 mg
UL 100 mg
B6 functions
- involved in more than 100 enzymatic reactions including the metabolism of carbohydrates, lipids, and amino acids
- help to form neurotransmitters such as serotonin and norepinephrine which supports cognitive functions
-helps lower homocysteine levels by converting it to cysteine
Sources of B6
chickpeas, beef liver, tuna, salmon, chicken, fortified cereals and grains, potatoes, bananas, squash, rice
B6 deficiency
rare alone but can be found in combination with other B vitamin deficiencies
- Can lead to microcytic anemia - red blood cells are small and do not properly transport oxygen
- symptoms include fatigue, lethargy, dry and cracked lips and a swollen tongue
- people with kidney issues, alcohol dependency and autoimmune disorders are at higher risk for deficiency
B6 toxicity
- Not common from food but can be seen from prolonged supplementation of > 1000mg per day can lead to loss of control over body movements
B6 special uses
implicated in improving cognitive function and reducing cancer risk
AI for B7 - Biotin
30mcg
Biotin functions
generic name for 5 vitamins
- involved in metabolism of carbohydrates, lipids, and proteins
- Involved in cell signalling and DNA structure and function
Special uses for biotin
can help with compromised hair, nail and skin health
Sources of biotin
beef liver, chicken, tuna, pork sunflower seeds, sweet potatoes, almonds, spinach, broccoli
Biotin deficiency
- biontinidase caused by genetic condition
- Chronic alcohol abuse can lead to deficiency : hair loss, red eyes, and rashes around eyes, nose and mouth
- In serious cases can lead to seizures, depression and decreased muscle tone and strength
RDA and UL of vitamin B9 folate
RDA 400mcg
UL 1000 mcg
folate functions
- coenzyme in the synthesis of DNA and RNA
- involved in the metabolism of amino acids
- involved in the conversion of homocysteine to methionine
sources of folate
beef live, spinach, legumes, asparagus, Brussel sprouts, avocados, fortified cereals and grains
folate deficiency
rare in non-pregnant individuals
- can causes neural tube deficits in the fetuses on pregnant women - can lead to miscarriage or neural complications such as spina bifida and anencephaly
megaloblast anemia - red blood cells are immature, large, misshapen, and unable to properly perform (due to inability to synthesize DNA during RBC production) leads to tiredness, weakness, and heart irregularities
- Autism spectrum disorder
Folate toxicity
generally well tolerated
- May include nausea, bloating, decreased appetite and difficulty sleeping
- Can mask b12 deficiency as it prevents megaloblastic anemia
what is the RDA of vitamin 12 cobalamin
2.4 mcg
Vitamine b12 functions
- required for DNA synthesis
- the formation of mature red blood cells
- brain function
- coenzyme for the conversion of homocysteine to methionine
- fat and protein metabolism
Special uses for B12
reduced the risk of dementia
Absorption of B12
hydrochloric acid in the stomach helps to release b12 from food
Intrinsic factor (IF) is also released in the stomach and is required for the absorption of b2 in the small intestine
Atrophic gastritis results in the breakdown of the stomach lining and a lack of IF
Sources of B12
shellfish, fish, beef liver, not typically found in plants
B12 deficiency
- Megaloblastic anemia: fatigue, lethargy, constipation, and loss of appetite
- can also lead to balance issues, depression, poor memory, and confusion
B12 toxicity
No UL
RDA and UL of Vitamin C - Ascorbic acid
- crucial in the formation of collagen
- metabolism of protein
- antioxidant
- can increase iron absorption
Describe antioxidants
Help reduce the activity of free radicals, reactive molecules that have an unpaired electron and can steal electrons from other molecules such as DNA and cell membranes. They work by donating an electron neutralizing the free radicals
Special uses for vitamin c
- Immune system
- chronic disease prevention: no evidence but believed to reduce cancer and CVD
Sources of vitamin C
citrus fruits (oranges, grapefruits, kiwis and lemons) tomatoes, strawberries, broccoli, Brussel sprouts, cauliflower, and fortified in cereals and grains
Vitamin C deficiency
- Rare
- Can lead to scurvy which causes fatigue and gum inflammation
- can also effect collagen formation, wound healing, and joint integrity
Vitamin C toxicity
rare
- mild symptoms, diarrhea, nausea, abdominal cramps
Fat soluble vitamins
RDA and UL of vitamin A
900 mcg for men
700 msg for women
UL 3000 mcg
What are the forms of vitamin A
- Provitamin A is found in plants and its vitamins are collectively known as carotenoids (not active)
- Performed vitamin A is found in its almost-active form retinol and retinal ester
- The active form is retinal and retinoic acid
Functions of vitamin A
- retinal binds to opsin to form rhodopsin, a visual pigment found in the retina
- Gene expression helping to turn certain genes on or off affecting whether DNA is transcribed into proteins
- Formation of T cells
- Antioxidant
Special uses of vitamin A
- Promotes healthy skin by switching on the genes that cause immature skin cells to become mature and healthy
- Overuse can cause skin irritation, burning, scaling and dermatitis
Vitamin A deficiency
-xerophthalmia: abnormal dryness of the eye that affects the bodies ability to produce tears –> can lead to breaks in the cornea
- Night blindness is an early sign of xerophthalmia
- most prevalent in pregnant women and children
Sources of vitamin A
found in animal products and many orange and leafy green plants. Beef liver, fish oils, milk and eggs, spinach, carrots, pumpkin, cantaloupes, red peppers
Vitamin A toxicity
- Skin turns orange
- If over consuming supplements may experience pressure around brain, dizziness, nausea, headaches and can be fatal
RDA and UL of Vitamin D
RDA: 15mcg
UL 100 mcg
Functions of vitamin D
- Vitamin D2 and D3 are critical for maintaining calcium homeostasis (increase calcium absorption in the digestive tract
- Bone health
- cellular growth
- immune function
- reduction of inflammation
Special uses for vitamin D
- potential role in cancer protection no evidence
Sources of vitamin D
fatty fish (salmon, tuna, mackerel) fish oils. orange juice, milk (if fortified)
- Sun increases vitamin D synthesis
Vitamin D deficiency
- Can lead to rickets in children, lack of bone mineral density that leads to soft bones (causes legs to bow outwards)
- Can lead to osteomalacia in adults, a softening of bones due to decreases in bone mineralization, also causes muscle weakness, difficulty walking, and pain in bones and joints
- Osteoporosis
- Risk factors: darker skin, lactose intolerance, vegetarianism
Vitamin D toxicity
Over-supplementation –> leads to anorexia, weight loss, increased urination and irregular heart rhythms
RDA and UL of Vitamin E
RDA 15 mg
UL 1000 mg
Functions of vitamin E
- antioxidant
- immune functioning
- cell signalling
- gene expression
Special uses for vitamin E
- potential decrease in risk for cancer and CVD
Sources of vitamin E
vegetable oils, fatty shellfish, fatty plants such as nuts, seeds, fortified cereals. and nut butter
Vitamin E deficiency
- Compromised fat absorption –> gastric bypass surgery, Crohn’s disease or cystic fibrosis
- Symptoms: peripheral neuropathy, movement difficulties, muscle disorders, and an impaired immune system
Vitamin E toxicity
- lung issues in those that vape
AI of vitamin K
120 mcg in men
90 mcg in women
Functions of vitamin K
- coagulation - blood clotting via the synthesis of the protein prothrombin which is then activated into thrombin. Thrombin converts fibrinogen to fibrin which helps blood clot together
Sources of vitamin K
ready green vegetables - spinach, broccoli, as well as oils and nuts. Can be found in animal products such as liver, ham, cheese and milk
Vitamin K deficiency
- newborns are at risk, and can causes issues in bone mineralization
Vitamin K toxicity
no UL
