Week 7: Micronutrients

macronutrient = large amounts are required

micronutrient = small amounts are required (trace amounts, less than gram quantities) —> vitamins and minerals, non of these are used as energy

role of vitamins in the diet:

vitamins = essential organic molecules, cannot be synthesized by the body therefore must be ingested

13 vitamins

Fat soluble = ADEK

Key roles:

antioxidants = ACE —> inflammation during exercise, ingestion of antioxidants gets rid of free radicals and harmful molecules.

energy release: thiamine, riboflavin, niacin, biotin, B6 and pantothenic acid.

Otheir functions:

1. Blood cells = E

2. Skin: A, C, B6, niacin, riboflavin, patothenic acid

3. eyes: A

4. Teeth: ADC

5. Hormone function: A, B6, Pantothenic acid

6. Neuromuscular function:

water soluble vitamins:

• B vitamins, Biotin, Vitamin C

they are passed out through urine, meaning they must be consumed more often, vitamins that are bound to water can be lost during exercise due to sweat.

Vitamin B:

• B1, B2, B3, B5, B6: coenzymes that facilitate pyruvate to acetyle-co-a, essential for enzyme production

• B5, B6, B7, B9, B12: processes related to red blood cell production and help transport gasses

What is a Co-Enzyme:

• enzyme is inactive without a co-enzyme, chemical compounds can not bing to enzymes

Vitamin Niacin (B3): involved in formation of NAD, which is important in citric acid cycle and in beta oxidation

Do athletes need more vitamin B?

• highly trained athletes have a higher rate of fat oxidation during exercise, and are able to release more energy that the average

increased vitamin B may result in:

1. altered absorption

2. increased tissue turnover, metabolism

3. biomechanical adaptations

4. related to red blood cells

Deficiencies in vitamins:

B1: can cause Beriberi —> difficulty walking, loss of sensation of hands and feet, loss of muscle functions and mental confusion

B9 and B12: altered shape and function of red blood cells, inhibiting them to go through small capillary wholes —> Megaloblastic anemia

B6: skin conditions like dermatitis, dry skin

Pellagra: when not enough niacin (B3) is consumed

Relation of B vitamins and exercise performance:

• a study showed that restriction in intake of vitamin B1, B2 and B6, caused decrease in VO2 max (12%), Decrease in peak and mean power (9-7%) as well as decrease in PO and OBLA (lactate threshold and blood lactate accumulation)

Vitamin C (ascorbic acid)

• water soluble, excreted if consumed in excess, daily consumption required, destroyed by heat and bright light

• antioxidant, facilitate iron absorption and immune function

too much: GI distress, kidney oxalate stone formation

too little: scurvy poor health

Vitamin A:

• obtain from plant (beta carotene) and animal sources (retinol)

• digested and transported in chylomicrons with fats

Aids in: skin, vision

commonly deficient in third world countries

Too much vitamin a can be very toxic:

• sickness and impacts vision

accumulates in the liver therefore it is stored in the liver with fats as chylomicrons

Vitamin D: calcitriol

• We can make it in our skin from cholesterol from sunshine — > calciferol activated in the kidney and the liver

healthy bones, kidneys and intestines

Deficiency: rickets

toxicity: bone demineralisation

>50nmmol/L of vitamin D

well balanced diet is essential for athletes, whole food based submentation, vitamin D status is probably more improtant for those who work in the northen hemisphere.

Fat soluble vitamins: ADEK

Vitamin E (tocopherol)= potent antioxidant (ACE), related with a reduced risk of cardiovascular disease

Vitamin K = coagulation of blood.

• too much - bleeding and bruising

Micronutrients = Minerals:

1. classification of minerals: essential inorganic molecules (chemistry, inorganic molecules do not contain carbon)

2. reduced prevalence of disease risk when injested

macrominerals > 100 mg daily

• calcium, magnesium, sodium and potassium

microminerals < 100 mg daily

• iron and zinc

• trace minerals, typically required in less than 1mg a day

recommended daily intake for sodium is around 1.5 grams (dietry shifts, it is hard to avoid salt)

iron: legumes, meet, broccoli

• different requirements for males and females, females must ingest more

• involved in the formation of haemoglobin in RBCS and myoglobin in muscle

energy production:

• cytochromes in the mitochondria

immunity:

• healthy immune system

heme, ferrous: fish, meats (better absorbed)

non heme, ferric: vegetables (Poorly absorbed 5% of the iron in a vegetable is absorbed, vitamin C and calcium helps with absorption)

if ferritin is high in the blood, ferritin is used in the bone marrow to produce red blood cells, plasma ferritin would get too low if there wasn’t a feedback loop to release hepcidin and close ferritin release.

• • poor bone marrow health and impacts blood synthesis

iron in athletes:

increased demand for iron as they sweat it out more, deficiency in iron is the most common micronutrient deficiency

consuming less calories may lead to having less iron in the body

• consuming iron in greater recommended daily levels will not elicit further benefits

zinc:

• less pronounced between females and males, males need to consume 3 mg more.

zinc is a cofactor for energy metabolism

• deprivation of zinc; bones show the biggest reaction, if zinc is being lost in the bone

• protein rich food contain highest amounts of zinc, oysters are a good source, nuts and legumes for vegetarians

prolonged exercise and result in loss of zinc as it is water soluble, athletes competing in high body mass requiring zinc may struggle to gain weight.

sodium and table salt: if you multiply salt by 2.5 results in sodium levels

• sodium and potassium are essential for transmembrane activity.

too much sodium can lead to hypernatremia, dehydration.

• electrical impulse transmission (extracellular)

sodium loss is high in sweat 500-1800mg/L

• need to be attentive if athletes consume diuretics.

Potassium:

• bananas

• intracellular fluid

magnesium is a cofactor for synthesis of fat oxidation, promotes calcium absorption and neurotransmission.

Calcium = essential for bone health and

• good vitamin D

• muscle contraction —> heart beating, body prioritises using calcium for muscle contraction rather than for bones

athletes who lose calcium in sweat —> can be risky for those who are lactose intolerant, high physical activity ( impact travelling through their bones may increase risk of stress fractures)

provided athletes are ingesting enough minerals and vitamins,

excess and too much will not lead to better performance and can result in toxicity.