Lecture 26 - A snapshot of vitamins and minerals from a nutrition perspective

Question 1

Vitamins and minerals are considered

Answer 1

micronutrients

Question 2

Nutrient status

Answer 2

How do we know if we get enough vitamins and minerals from the foods we eat? - clinical examination (look for symptoms), anthropometry (energy balance/ growth), biochemical tests (blood is the most common but also urine and saliva), dietary assessment (measure what you eat with a diary, recall, history etc, convert food into nutrients (food composition database), compare with Nutrient Reference Values)

Individuals, groups or national samples - e.g. adult nutrition survey 2008/2009

Question 3

Characteristics of vitamins

Answer 3

“Vital to life” or “vital amines”
Essential, individual, organic molecules
Do not provide energy when broken down
If absent or low in the diet, symptoms of deficiency appear
Required in the diet in small amounts i.e. micro gram or milligram
Bioavailability = the amount absorbed and used

Question 4

Fat soluble vitamins

Answer 4

Vitamins A,D,E and K

Can be stored in the fat cells in the body

Question 5

Water soluble vitamins

Answer 5

Vitamin C 
B vitamins (B1-12, there is no 4, 8, 10, 11 however) 

water-soluble vitamins can’t be stored in the body. If water-soluble vitamins aren’t used or absorbed shortly after ingesting, they’re flushed out of the body.

Question 6

Roles of vitamins and minerals

Answer 6

Some enzymes need help to speed up a reaction and they get this help via coenzymes and cofactors

Coenzymes are organic carrier molecules e.g. NADH which acts as an electron carrier

Cofactors directly participate in the enzymes catalytic mechanism, they might stabilise the enzyme or substrate or help convert substrate from one form to another e.g. DNA polymerase (Mg2+ cofactor is directly involved)

Vitamins and minerals can’t be made from scratch and you need to get them from your diet to be healthy

Vitamins - organic cofactors and coenzymes
Minerals - inorganic (no carbon) cofactors

Question 7

Functions of vitamins and minerals

Answer 7

Act as coenzymes and cofactors

Huge variety of other roles too, for example …
Structural
Antioxidants
DNA/RNA

Question 8

Vitamin Bs play an important role as…

Answer 8

Coenzymes involved in energy metabolism

Question 9

Niacin deficiency

Answer 9

Niacin or Vitamin B3 = Nicotinic acid and Nicotinamide

Source in the diet - milk, liver, fish, meats, legumes and wheat

Function …
Nicotinamide adenine dinucleotide (NAD) and NADP
Over 200 enzymes depend on NAD and NADP to carry out oxidation and reduction reactions
Involved in synthesis and breakdown of carbohydrates, lipids and amino acids

Niacin deficiency is more likely to be caused by problems that affect absorption of niacin or tryptophan.

Niacin is a B vitamin that’s made and used by your body to turn food into energy. It helps keep your nervous system, digestive system and skin healthy.

Question 10

Pellagra

Answer 10

Pellagra is the result of cellular deficiency of niacin (vitamin B3)

Pellagra literally means rough skin

Pellagra is often defined by the 4 D’s - dermatitis, diarrhoea, dementia and death

Need to take a niacinamide supplement to heal

Question 11

Minerals

Answer 11

Essential, non-organic elements
Do not provide energy
If absent or low in the diet, symptoms of deficiency may appear
Required in the diet in small amounts I.e. micrograms or milligrams
Bioavailability = amount absorbed and used

Question 12

Roles of minerals

Answer 12

Cofactors - transfer of electrons in redox reactions

Structural role - hydroxyapatite crystal: Ca5(PO4)3(OH)

Key constituent of molecules

Nerve impulse and muscle contraction

Fluid and electrolyte balance

To summarise there are a range of roles that minerals can have

Question 13

Trace elements and minerals

Answer 13

Minerals are required by the body in larger amounts (over 100mg/day). Trace elements are required by the body in smaller amounts (below 100mg/day).

Question 14

Magnesium

Answer 14

Cofactor that is involved in more than 300 enzymes and is therefore involved in a myriad of cellular processes - chelates to ATP (kinases), enzymes requiring water therefore acts as a carrier, Lipid and CHO metabolism (glycolysis, glucose homeostasis, insulin action)

Also.. 
Stabilises proteins, nucleic acids, membranes 
Electrolyte 
Bone metabolism and remodelling 
Nerve impulse and muscle contraction

Question 15

Magnesium deficiency

Answer 15

Magnesium deficiency is an electrolyte disturbance in which there is a low level of magnesium in the body.

When you are deficient you are prone to skeletal muscle cramps as well as restless leg syndrome

Question 16

What are the two major groups of vitamins?

Answer 16

Fat soluble and water soluble

Question 17

If someone is deficient in niacin, what consequences would we expect to observe?

Answer 17

Pellagra for bad cases

Question 18

What groups of individuals are most at risk of niacin deficiency?

Answer 18

Risk factors include poverty, staple diet that is poor in niacin, eating disorders, human immunodeficiency virus (HIV), alcohol abuse, medication, chemotherapy etc

Question 19

How can we overcome niacin deficient in these susceptible groups?

Answer 19

Take a supplement in order to bring niacin levels back to normal

Question 20

Is there concrete evidence to confirm the effectiveness of magnesium supplementation?

Answer 20

No