9: Vitamins Flashcards
What are vitamins and what do they do?
- Vitamins are organic micronutrients
- They facilitate body processes
how many vitamins do our bodies require?
The body requires 13 vitamins to survive and thrive
Are vitamins classified as either water- or fat-soluble vitamins?
They are classified as either water- or fat-soluble vitamins according to their behaviour in water
what are water-soluble vitamins?
hydrophilic and dissolve readily in water
what are fat-soluble vitamins?
hydrophobic and require a lipoprotein transporter to move around the watery environments of the body
what is the consumption frequency of water-soluble vitamins?
required more frequently from diet (everyday)
Ex: Vitamin B, C
what happens to excess water-soluble vitamins?
Excess water-soluble vitamins are excreted in urine (by kidney) and less likely to be toxic
what happens to excess fat-soluble vitamins?
excess fat-soluble vitamins are stored in adipose tissue, where they can build-up and lead to toxicity
what is the consumption frequency of fat-soluble vitamins?
Required less frequently from the diet (every few days)
Ex: Vitamin A, D, E, K
what are coenzymes?
Coenzymes are non-protein factors required for enzyme function
T/F: Our daily vitamin needs depend on our age and life stage
True,
younger individuals often have lower RDA/AI for various vitamins, while pregnancy and lactation typically increase needs
what happens when coenzymes bind to enzymes?
they activate the enzymes and allow them to function
what are the B vitamins?
a group of eight vitamins that act as coenzymes for energy metabolism
T/F: The B vitamins provide energy
False,
the B vitamins do not provide energy, they support the enzymatic activity that promotes energy metabolism
T/F: Many foods naturally contain B vitamins
True,
plants and animals naturally contain B vitamins and they are also fortified into foods (grains/cereals)
what is Vitamin B1?
Thiamine
What is the function of Vitamin B1: Thiamine?
- required by all body tissues
- plays a role in muscular contraction, nerve conduction and the synthesis of ATP
Vitamin B1: Thiamine is part of what coenzyme?
Thiamine is part of coenzyme thiamine pyrophosphate (TPP).
- TPP is required for citric acid cycle of cellular respiration and is important for carbohydrate metabolism
What are the food sources with Vitamin B1: Thiamine?
- abundant in many foods
- nuts, seeds, eggs, milk, poultry, fortified cereals
What are the effects of Vitamin B1: Thiamine deficiency?
- brain is particularly susceptible to thiamine deficiency ==> can promote neuronal death
Vitamin B1: Thiamine deficiency can be associated to what in the developed world?
- typically associated with alcoholism ==> poor diet and decreased nutrient intake
- compromises the absorption and storage of thiamine
Alcohol-related cases of severe Vitamin B1: Thiamine deficiency can lead to what disease?
- Wernicke’s syndrome – a potentially life-threatening disease that compromises central and peripheral nervous systems ==> can progress to Korsakoff syndrome, more severe and permanent neurological symptoms
Vitamin B1: Thiamine Deficiency:
What are the symptoms of Wernicke’s syndrome?
short-term memory loss, confusion, disorientation and changes in eye movements
In the developing world, associated with malnutrition vitamin B1: Thiamine deficiency can lead to what condition?
Beriberi - wet or dry
- can be life-threatening
- can lead to Wernicke’s or Korsakoff syndrome
Vitamin B1: Thiamine Deficiency:
What are the effects of wet beriberi?
negatively impacts the cardiovascular system and can lead to heart failure
Vitamin B1: Thiamine Deficiency: What are the effects of dry beriberi?
negatively impacts the nervous and muscular systems, potentially leading to muscle paralysis
Can Vitamin B1 Thiamine become toxic?
Thiamine is well tolerated and excess amounts can be secreted by the kidneys. Dietary toxicity is rare and there is no upper limit
What is Vitamin B2?
Riboflavin
what does vitamin B2 Riboflavin do?
Riboflavin helps form two important coenzymes: flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD)
Vitamin B2 Riboflavin:
What does flavin adenine dinucleotide (FAD) do?
FAD picks up electrons during the citric acid cycle to become FADH2. It then transports these electrons to the electron transport chain where they are necessary for ATP production
Vitamin B2 Riboflavin: What do the 2 coenzymes FMN and FAD do?
- conversion of the amino acid tryptophan to niacin
- further involved in maintaining appropriate levels of homocysteine, a risk factor for cardiovascular disease (CVD)
What are food sources of Vitamin B2 Riboflavin?
Egg yolks, organ meats, fortified breakfast cereals, oats, milk, salmon, tuna, soybeans, dairy products, and almonds are all high in riboflavin
T/F: Vitamin B2 Riboflavin is sensitive to light
True, typically packaged in opaque containers to preserve their riboflavin content
Vitamin B2 Riboflavin:
What is Riboflavin deficiency called and what are the symptoms?
Ariboflavinosis (rare - more common in vegetarians since riboflavin is in animal products)
Symptoms: skin disorders, swelling in mouth, throat, dry and cracked lips, red eyes and hair loss
Is Vitamin B2 Riboflavin Toxicity common?
Rare because body does not absorb more than a certain level and the kidneys excrete excess amounts
- Excess intake from food or supplements have not been observed to promote toxicity
- no upper limit
What is Vitamin B3?
Niacin
What is the function of Vitamin B3 Niacin?
forms the coenzyme nicotinamide adenine dinucleotide (NAD) ==> AD is a key electron transporter in cellular respiration, picking up electrons to become NADH+H+
Vitamin B3 Niacin: Why is NAD so important?
- NAD is critical to many metabolic reactions since more than 400 enzymes require it to function properly
- critical to the metabolism of carbohydrates, lipids and proteins
- NAD involved in reduction/oxidation reactions
What are food sources of Vitamin B3 Niacin?
- Animal products (chicken, beef, fish) are high in niacin - Plant products (nuts, legumes, grains) high in niacin, but half the niacin content of animal products
What are the special uses of Vitamin B3 Niacin?
- High doses of niacin (>2000 mg) have been shown to reduce triglycerides, lipid transporters VLDL and LDL and increase HDL
- no clear link established with niacin megadoses and decreased risk of heart attacks, strokes, mortality
Vitamin B3 Niacin deficiency can cause what? and what are the symptoms?
Causes Pellagra
- 4Ds of pellagra: dermatitis, diarrhea, dementia, death
Can Vitamin B3: Niacin Toxicity occur?
- rare from food
- Doses of 30 mg or more can cause niacin flush
- Medically prescribed doses of more than 1,000 mg/day can lead to nausea and vomiting, low blood pressure, fatigue, insulin resistance
Vitamin B3 Niacin:
What is Niacin Flush?
flushing, or reddening, of the skin accompanied by burning and itching sensations
What is the function of Vitamin B5 Pantothenic Acid?
Pantothenic acid helps form coenzyme A ==> essential for energy metabolism
What is Vitamin B5?
Pantothenic Acid
Vitamin B5 Pantothenic Acid: What is the function of Coenzyme A?
Coenzyme A is required for lipid, carbohydrate and certain amino acid metabolites to enter the citric acid cycle as acetyl CoA ==> essential for energy metabolism
What are food sources of Vitamin B5 Pantothenic Acid?
Pantothen is Greek for everywhere
- available in a wide variety of both animal and plant products, fortified cereals, beef, chicken, grains, vegetables
Is Vitamin B5 Pantothenic Acid Deficiency common?
Due to its abundance in a variety of foods, pantothenic acid deficiency is rare
What are symptoms of Vitamin B5 Pantothenic Acid Deficiency?
numbness in the hands and feet, headache, tiredness, disturbed sleep and gastrointestinal issues
What is Vitamin B6 the generic name of?
Vitamin B6 is the generic name for six different vitamers
Vitamin B6:
What are Vitamers?
- different forms of the same vitamin that have a common function
Vitamin B6:
What are the functions of Vitamers?
- act as coenzymes in the catalyzation of more than 100 enzymatic reactions, including metabolism of carbs, lipids and amino acids
- help form neurotransmitters (serotonin, norepinephrine)
Vitamin B6 helps lower what?
vitamin B6 helps lower homocysteine levels by converting it to cysteine
- Elevated levels of homocysteine are a risk factor for CVD
Vitamin B6, B9 and B12 are involved in what?
Vitamin B6, B9 and B12 are involved in regulating homocysteine levels
What are the special uses of Vitamin B6?
- improving cognitive function
- reducing CVD risk, premenstrual syndrome (PMS), vomiting and nausea in pregnancy
==> however, no firm link has been established
What are food sources of Vitamin B6?
Plant: CHICKPEAS,
Animal: beef liver, tuna, salmon, chicken
Food: fortified cereals, grains, potatoes, bananas, squash, rice
Supplement: Pyridoxine