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