Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

nutrition thru life > Fat/Carb/Micronutrient/Fibre requirements (adults) > Flashcards

Fat/Carb/Micronutrient/Fibre requirements (adults) Flashcards

(118 cards)

Start Studying
1
Q

Why is the AI for linoleic and linolenic acid higher for males?

A

Readily oxidized for energy; males have higher metabolic rates and require more energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

True/False: linoleic acid is elongated to produce DHA

A

False. linolenic can be converted to DHA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How can the body adapt during carbohydrate depletion to support the brain?

A

ketoacid oxidation - alternate fuel for brain, glucose needs are reduced significantly
Glycogenlysis and gluconeogenesis also contribute to glucose supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why is the ratio of linolenic and linoleic acid so important?

A

They compete for the same desaturase enzyme required for elongation. If there is too much linoleic acid, then the products of linolenic acid will not be made.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How can supplementation with DHA or EPA help with a deficiency in linolenic acid?

A

linolenic acid is converted by the body to produce DHA and EPA; if those fatty acids are already in good supply, then the omega 3s will be spared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

True/False: DHA and EPA are essential in the diet.

A

False. The essential fatty acids are linoleic and linolenic.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What essential fatty acid can be converted to arachidonic acid?

A

Linoleic acid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

True/False: there are RDAs established for the essential fatty acids

A

False; only AI (median in populations without deficiency)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

A diet high in omega 6 and low in omega 3 would lead to high levels of ____ acid, and low levels of ___ and ____ .

A

arachidonic; EPA; DHA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Differentiate dietary and functional fibre

A

Dietary: fibre found naturally in food (nondigestible carbohydrates - cellulose, lignins, etc)
Functional: isolated fibre (psyllium), can be used as supplement or fortification, but may lack the other health benefits of dietary fibre

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What organ in the body is DEPENDENT on glucose?

A

brain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How is the recommended fibre intake calculated?

A

14g per 1000kcal intake

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is total fibre?

A

Sum of dietary and functional

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the risks of long term low carb diets?

A

Can lead to kidney stones, urinary tract deposits, high blood cholesterol, loss of bone mineralization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How might fibre lower CHD risk?

A

certain types bind to bile acids, removing them and lowering cholesterol levels.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Fibres from what source in particular have been associated with lowered risk of coronary heart disease?

A

Cereals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the benefits associated with fibre consumption?

A
  1. prevent constipation/diverticulosis
  2. fuel for colon cells
  3. lower blood glucose and lipids
  4. usually in nutrient rich low energy foods, contribute to satiety
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

True/False: the body will send thirst signals to indicate fluid needs, which is a good indicator for intake.

A

False. Thirst signifies that water levels have already dropped significantly (or Na levels have increased significantly) - body is already under stress!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does water intake mostly depend on?

A

Behaviour (not thirst)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How is hydration status assessed?

A

plasma/serum osmolality

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

True/False: water intake refers to the amounts of water and beverages consumed.

A

False. It also includes the water present in food items. (20%)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Why is water impacted by dietary factors?

A

Water is needed for digestion/metabolism

Metabolism and dietary electrolytes create OSMOTIC LOAD

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Define osmolality and osmolarity, and explain which is preferred for measuring hydration status.

A

Osmolality: mols solute/kg SOLVENT
osmolarity: mols solute /L SOLUTION
osmolality is preferred since the intake of fluid would increase the weight of the solution, making it difficult to determine osmolarity.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why can we not set an EAR or RDA for water?

A

Needs are too variable for the population, and even for a person from day to day, depending on physical activity, environment, diet, etc.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Why do males have a higher water AI?
More water needed for metabolism
26
Dehydration can impair ____ ____, which can cause strain on the cardiovascular system.
heat dissipation (results in higher core temp)
27
How could water toxicity occur?
Consuming vast amounts of water that exceeds the kidney filtration rate.
28
How might low potassium be associated with bone demineralization?
Lack of available mineral buffers to neutralize acid in body -> body will draw minerals from bone
29
What is the difference between the potassium found in salt substitutes and the natural potassium in food? Why would natural potassium be more beneficial?
Salt substitute: KCl Natural: K citrate K citrate can be converted to bicarbonate and act as a buffer in the body, while KCl does not have buffering capacity.
30
What are the main minerals in bone?
Ca, P, some Mg
31
What macromineral is needed in the highest quantity?
Ca
32
How is the EAR of P determined?
Looking at response of serum P with greater intake (the lower range in the population); rate of increase declines sharply once adequacy is reached
33
Most of the body's iron is contained in ____.
RBCs
34
85% of the body's phosphorus stores are in ____. Where is the remainder found?
bone; phospholipids, nucleotides, nucleic acids act as buffer
35
How is the Ca RDA determined?
Through calcium balance studies | based on amount needed for small increases in bone mineral content
36
What serves as a reservoir for minerals?
bone
37
In addition to being a constituent in body molecules/structures, what other roles does phosphorus serve?
Temporary energy storage/transfer (ATP, Creatine-P) Buffer Activate/deactivate proteins through phosphorylation
38
Magnesium is an important _____ for many ____ systems.
cofactor; enzyme
39
Why would elderly people suffer more Mg losses?
recommended high fibre diets (fibre binds to Mg) | decreased renal function
40
True/False: iron is an important part of many enzymes for oxidative metabolism (and other critical functions)
True.
41
Most of iron is contained in the proteins ____ and ____.
Hemoglobin; myoglobin
42
How is the RDA for magnesium determined?
Balance studies (maintenance of body Mg)
43
True/False: Iron RDA is determined through balance studies.
False. Determined through factorial analysis.
44
What is the Iron EAR based on?
Enough iron for functional concentration, but with minimal stores (as ferritin)
45
What does the body do if serum ferritin reaches 15ug/L?
Absorption will decrease
46
What are the factors considered for the Fe RDA? (4)
- Basal losses (sweat/skin/urine/feces) - menstruation - Fetal requirements - Growth
47
True/False: elderly women need less iron.
True; no more menstrual losses.
48
True/False: All sources of iron are equal.
False. Heme has much higher bioavailability; nonheme iron may be bound to or interact with other components (such as Ca) and is limited by solubility
49
True/False: Heme iron is found in meat, while nonheme is found in plants.
False: Heme is found only in meat, but nonheme is present in all foods.
50
True/False: the RDA and EAR amounts are equal to the amount of iron needed in our body
False; assume only 18% bioavailability of consumed iron (need to adjust numbers for more consumption)
51
What is the primary loss of sodium? What controls this?
Urine; controlled by adjusting the reabsorption rate by kidneys
52
How is potassium beneficial for blood pressure?
- Lowers blood pressure | - Blunts the adverse effects of Na on blood pressure
53
True/False: athletes require more salt intake.
True. Sweat will lead to sodium loss.
54
What are the sources of sulfur?
Amino acids
55
What is the intake requirement for sulfur?
None established.
56
True/False: Sulfur intake is a concern for North Americans.
False. North Americans get sufficient protein in the diet and so sulfur is usually not a concern (usually excess)
57
Thiamine is an important ____ in metabolism of ____ and ____.
coenzyme (Thiamine Pyrophosphate); branched AA; carbs
58
Sulfur is an important component of what essential antioxidant?
Glutathione
59
Which B vitamin is important coenzyme for redox reactions?
Riboflavin
60
What enzyme in RBCs is thiamine required for, and what does this enzyme do?
Transketolase; part of pentose phosphate pathway for anabolic reactions
61
What is the definition of adequate thiamine?
Adequate RBC transketolase activity, without excessive urinary excretion
62
Why are requirements generally higher for men than women?
bigger size, higher energy requirements
63
What could cause a thiamine deficiency?
Poor diet | Heavy alcohol use
64
How might riboflavin deficiency affect other nutrient statuses?
Compromises GI tract, affects metabolism of other nutrients such as Fe
65
The requirement of ____ is based on RBC glutathione reductase activity. What else is it based on?
Riboflavin | Also based on concentrations in RBCs, and urinary excretion
66
How is non-severe thiamin deficiency detected?
Thiamine loading (if body level is inadequate, no rise in excretion)
67
The EAR for riboflavin is determined through what types of studies?
deficiency; balance
68
What is the primary criteria for niacin RDA?
urinary excretion of niacin metabolites
69
What amino acid can be converted (in small amounts) to vitamin B3?
Tryptophan
70
What is the key role of vitamin B3?
Niacin is cosubstrate/coenzyme for DEHYDROGENASES (H transfer enzymes)
71
True/False: Niacin requirement is adjusted for bioavailability.
False. Expressed as Niacin equivalents (take into account the amount synthesized by body)
72
Why is the CV (variability) for requirements so much higher in Niacin?
Some conversion of Tryptophan will also provide niacin, but rate of conversion varies widely depending on diet, individuals, etc.
73
In what types of reactions are dehydrogenases particularly important?
Synthesis (FA, steroids) | Redox
74
What B vitamins have the same requirements for healthy men and nonpregnant women?
B6, B9, B12
75
Pyridoxine is a coenzyme for metabolism of...?
AA, glycogen, sphingoid bases
76
Folate is a coenzyme for catalyzing ____ transfer in metabolism of ___ and ____.
single carbon; AA, nucleic acids
77
High ___ levels could indicate folate deficiency
homocysteine
78
True/False: Natural folate is the best source in terms of bioavailability.
False. Supplements have higher bioavailability.
79
What is the criteria for folate requirements?
RBC folate levels Blood levels of homocysteine Blood levels of folate
80
The CV of what nutrient is particularly high, and why?
Niacin; due varying Tryptophan to niacin conversion rates among individuals
81
Which vitamin is necessary coenzyme for methyl transfer reactions?
B12
82
what is the folate recommendation?
400ug/day (men and women)
83
What are DFEs? List them for the various sources.
Dietary Folate Equivalents: 1ug for food 0.6 for food/supplement/fortified 0.5 for supplement alone
84
List 2 key conversion reactions that require vitamin B12
CoA -> succinyl coA | homocysteine -> methionine
85
What B vitamins do not have an RDA? What do they have instead?
B5 (pantothenic acid) B7 (biotin) AI
86
High alanine aminotransferase levels signal ____ damage caused by _____ deficiency.
liver; choline
87
True/False: the body cannot synthesize choline and we must consume it.
False: we can synthesize some (but it is insufficient for most life stages).
88
A choline deficiency can lead to NAFLD. What is this and how does this occur?
Non alcoholic fatty liver disease Phospholipids (such as phosphotidylcholine) are required to assemble lipoproteins. Without sufficient choline to synthesize phospholipids, cholesterol and fat are deposited in the liver and cannot be exported.
89
Choline and its derivatives can lower blood concentrations of ____ and _____.
cholesterol; homocysteine
90
Biotin functions as a coenzyme in _____ reactions
Bicarbonate dependent carboxylation
91
pantothenic acid is part of ____ and _____; it is important for metabolism of _____.
coenzyme A, phosphopantetheine | Fatty acids
92
Why do RDAs not exist for choline?
insufficient number of studies
93
Choline is a precursor for:
acetylcholine, phospholipids, betaine
94
True/False: B5 is widely distributed in foods and deficiencies are rare.
True.
95
True/False: Aging will naturally decrease vitamin C absorption.
False. No change in absorption/metabolism with age, unless poor diet and chronic disease.
96
For optimal vit C levels, the levels of ____ should be maximized, while ____ should be minimized.
neutrophils | urinary excretion
97
What are the main functions of vitamin C in the body? (2)
Antioxidant | Cofactor for synthesis of collagen, carnitine, neurotransmitters
98
How are the different dietary sources of vitamin/provitamin A compared?
Retinol Activity Equivalents
99
Vitamin A adequacy is based on the amount needed to ____.
maintain a healthy vitamin A store in body (in case of periods of stress or low intake)
100
What are the ways vitamin A can be supplied in the diet?
As preformed vitamin A (animal sourced) | As carotenoid provitamin A (dark fruit/veg, oil)
101
``` What are the RAEs for vitamin A (preformed) beta carotene alpha carotene beta cryptoxanthin ```
1ug, 12ug, 24ug, 24 ug
102
What is vitamin A important for? (6)
``` (VIGGER) Vision Reproduction Embryo development Growth Gene expression Immune function ```
103
A vitamin D deficiency could cause deficiencies in the minerals ___ and ___. Why?
Ca, P | Vitamin D increases intestinal absorption of Ca and P
104
What forms does vitamin D occur in food?
Ergocalciferol (D2) | Cholecalciferol (D3)
105
How does vitamin D affect cell growth?
decreases proliferation, increases differentiation
106
True/False: vitamin D is found naturally in a variety of foods.
False. Found naturally in very few foods (supplemented in milk).
107
How might vitamin D be regulatory and prevent cancer growth?
antiproliferative effects, prevent uncontrolled cell growth
108
What is the vitamin E requirement based on?
sufficient levels to protect against PEROXIDE induced lysis of RBCs in in-vitro studies
109
Vitamin E prevents lipid _____.
peroxidation propagation/oxidation
110
How are the antioxidant functions of vitamin C and E different?
Vitamin C is water soluble (target water soluble free radicals) while vitamin E is fat soluble and prevents lipid oxidation
111
True/False: Synthetic vitamin E is more effective than natural sources.
False; only certain stereoisomers of a certain configuration of vitamin E are useful Mixtures of synthetic alpha tocopherol are only 50% effective
112
Your main source of vitamin E is from supplements. You read the label and see that you are consuming the appropriate amount for the RDA. Is there any problems with this scenario?
The RDA is for 2R a-tocopherol only; by consuming supplements (an all-rac mix) you are also consuming 2S and so only getting 50% of what the bottle says.
113
True/False: the ineffectiveness of some types of vitamin E is due to limited absorption
False; they are absorbed but have LOW AFFINITY for hepatic alpha-tocopherol transfer protein, and so are not effectively distributed
114
What forms of vitamin E exist?
Tocopherols and tocotrienols (alpha, beta, gamma, and delta forms) - each has 8 stereoisomer forms
115
What is the natural form of vitamin E in food?
All R (RRR) alpha tocopherol
116
What forms of vitamin E are effective?
R isomers of alpha tocopherol
117
Vitamin K is a coenzyme for synthesis of ____, which are important for what purposes?
proteins | blood clotting, bone metabolism
118
What are the dietary and endogenous forms of vitamin K?
in diet: phylloquinone | Endogenous: Menaquinones (from gut microbiota)

nutrition thru life (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions