Fat, CHO, Fibre, Water and Micronutrient Requirements during Adulthood Flashcards Preview

Nutrition Through Life > Fat, CHO, Fibre, Water and Micronutrient Requirements during Adulthood > Flashcards

Flashcards in Fat, CHO, Fibre, Water and Micronutrient Requirements during Adulthood Deck (120)
Loading flashcards...
1
Q

Linoleic acid and a-linolenic acid compete for the same __________.

A

Desaturase enzymes

2
Q

When is the ratio of linoleic:a-linolenic important?

A

When diet is very low in AA (arachidonic acid), EPA, DHA

3
Q

How does the AI for N-6 FAs (linoleic) change at 50 years old for males and females?

A

Males: drops from 17 g/day to 14 g/day

Females: drops from 12 g/day to 11 g/day

4
Q

How is the AI determined for linoleic and a-linolenic acid?

A

based on highest median intakes in US populations where no evidence of deficiency

5
Q

What is linoleic acid metabolized in our body?

A

readily used for energy

6
Q

What is the AI for N-3 (a-linolenic) FAs during adulthood for males vs females?

A

Males: 1.6 g/day

Females: 1.1 g/day

7
Q

An overnight fasted male produces ~ how much glucose /day? What sources does he get the glucose from?

A

210-270 g/day

50% from glycogenolysis & 50% from gluconeogenesis

8
Q

In subjects fully adapted to starvation, ketoacids make up what % of the brain’s energy requirements? Therefore how much glucose is required?

A

80%

22-28 g/day

9
Q

What is the EAR for COH based on? What two things does this assume?

A

amount that would provide brain with adequate supply of glucose without additional glucose production from protein or TG and without increase ketones greater than the amount observed after overnight fast

  1. energy sufficient in diet with AMDR of CHO 45-65%
  2. glucose is not limiting to the brain
10
Q

Which one of our organs is ONLY dependent on CHO?

A

Brain

11
Q

What is the recommended amount of dietary CHO to decrease the risk of chronic disease?

A

Unknown

12
Q

In urbanized societies, what are 4 long term consequences that may be associated with a low CHO diet (which includes increased ketoacids)?

A
  1. Bone mineral loss
  2. High blood [cholesterol]
  3. Increased risk of kidney stones
  4. Urinary tract deposits
13
Q

What is dietary fiber?

A

Non-digestible CHO and lignin intrinsic /intact in plants

14
Q

What is functional fiber?

A

Isolated, non-digestible CHO shown to have beneficial physiological effects in humans

15
Q

Total fiber =

A

dietary fiber + functional fiber

16
Q

There is a strong indirect correlation between _________ and risk of CHD. There is a weak/nonexistent correlation between __________ and risk of CHD.

A

cereal fiber,

fruits and vegetable fiber

17
Q

How much fiber is recommended for heart health?

A

14 g dietary fiber/1000 kcal - particularly from cereals

18
Q

What are 4 benefits of eating fiber?

A
  1. Ameliorate constipation and diverticular disease
  2. Fuel for colonic cells
  3. Decrease blood [glucose] and [lipids]
  4. Source of nutrient rich low-energy foods satiety & decreases risk of obesity
19
Q
  1. What is the Dietary Fiber AI for men and women? When does it switch?
A
  1. Men: 38 g/d until 50 years old, then 30 g/day

2. Women: 25 g/day until 50 years old, then 21 g/day

20
Q

How is the AI determined for dietary fiber?

A

Based on strong data on relationship between dietary fiber intake and CHD risk

21
Q

Why can the EAR for total fiber not be determined?

A

Because the benefits of increased fiber intake are continuous across range of intakes

22
Q

Which type of fibers cause the greatest reduction in CHD?

A

Cereal fiber and some functional fibers (psyllium & pectin)

23
Q
  1. Certain kinds of fiber bind _______ and ________ absorption which decreases risk of CHD.
A
  1. Cholesterol

2. prevent

24
Q
  1. Beverages and food make up what % of water consumed by humans each day?
A

Beverages (80%) food (20%)

25
Q

_______, not ______, dictates daily fluid intake

A

Behavior / thirst

26
Q

What 2 things trigger thirst?

A
  1. Decreased body water (sensed by low blood volume)

2. Increased [Na] (primarily sensed by cells of the brain)

27
Q

How is thirst not well correlated with fluid needs?

A

You only get feeling of thirst ONCE you had significant fluid losses or a change in Na status

28
Q

What is the primary indicator of water status? How is it assessed?

A

Hydration status which is assessed by plasma or serum osmolarity

29
Q

What 3 things have a substantial influences on water needs?

A
  1. PA
  2. Environment
  3. Diet
30
Q

How do dietary factors influence water requirements?

A

metabolizing dietary proteins and organic compounds + varying intakes of electrolytes create an osmotic load which must be accommodated by adequate total water consumption

31
Q

Is there a general daily total water requirement?

A

no

32
Q

What is a side effect of dehydration?

A

unable to dissipate heat

33
Q

When you are dehydrated and unable to release heat as sweat, in what two ways does this affect your body?

A
  1. increases body core temperature

2. increase strain on cardiovascular system

34
Q

What is the AI for water for males and females: sedentary vs. active?

A

Sedentary:
Males: 3.7 L/d ~ 16 cups
Females: 2.7 L/d ~ 12 cups

Active:
Males: > 3.7 L/d
Females: > 2.7 L/d

35
Q

What condition can someone obtain if they drink waaaay too much water?

A

hypoatremia (rare) condition that occurs when the level of sodium in your blood is abnormally low

36
Q

What is acute water toxicity?

A

When fluid consumption is > kidney’s max excretion rate (0.7-1.0 L/h)

37
Q

What is the RDA for calcium for men and women?

A

1000 mg (25 mmil)/day

38
Q

What 3 things are correlated with inadequate Ca intake?

A
  1. increase risk of osteoporosis
  2. hypertension
  3. colon cancer
39
Q

Phosphorus is found in what form in the body?

A

PO4

40
Q

___% of adult body P is in ____.

A

85%, bone

41
Q

What 3 molecules can phosphorus be found in in the human body?

A
  1. phospholipids
  2. nucleotides
  3. nucleic acids
42
Q

How does P work with pH?

A

it buffers excess acids/bases to maintain normal pH

43
Q

P is required for _______, the activation of many catalytic proteins.

A

phosphorylation

44
Q

What is the absorption efficiency of P?

A

60-65%

45
Q

What % of body magnesium is found in bone?

A

50-60%

46
Q

___ (fraction) of skeletal Mg is exchangeable as reservoir for maintaining normal extracellular [Mg].

A

1/3

47
Q

Mg is popular in the body as a…

A

coenzyme

48
Q

What increases the EAR of magnesium as people age?

A

renal function declines, elderly eat more fibre

49
Q

What fraction of our body iron is found in hemoglobin? What % is found in myoglobin?

A

2/3

15%

50
Q

What 4 factors are used in determining iron requirements?

A
  1. basal iron losses (feces, urine, sweat, skin cells)
  2. menstrual losses
  3. fetal requirements in pregnancy
  4. Growth: expansion of blood volume, and/or increase tissue and storage iron
51
Q

What is the EAR for Iron based on?

A

need to maintain minimal functioning Fe store

52
Q

How is Fe absorption regulated in our body?

A

The more serum ferritin we have, the less Fe will be absorbed – there is max 15 ug/L of ferritin in serum - we don’t need more and this means stores are full

53
Q

What is the bioavailability of iron in children > 1 years old, adolescents, & non-pregnant adults on a mixed diet?

A

18%

54
Q

What is the upper limit of iron?

A

18% absorption

55
Q

What is the EAR based on in men and women?

A

Men: basal Fe losses
Women: basal iron losses and menstrual losses

56
Q

What are the electrolytes?

A

P, K, Na,

57
Q

What 4 things is adequate K intake important for?

A
  1. lowering blood pressure
  2. blunting the adverse blood-pressure effects of salt intake
  3. Reduces the risk of kidney stones
  4. Potentially reducing bone loss
58
Q

What is the primary route of loss of sodium in sedentary adults via physically active adults?

A
Sedentary = urine via kidney regulation 
Active = sweat
59
Q

Which amino acids is sulphur present in?

A
  1. methionine
  2. cystine
  3. cysteine
60
Q

Sulfur is an essential component of what essential compound?

A

glutathione

61
Q

What are sources of sulfur in our diet?

A

S containing a.a.s from protein digestion

62
Q

What is the recommended intake of sulfur?

A

None because intake typically exceeds needs & recommendation for sulfur aa intake covers the need for inorganic sulfate

63
Q

Why is there no need to set sulphate RDA in a North American diet?

A

adequate to excess protein

64
Q

What does Thiamin function as in our body?

A

coenzyme on metabolism of CHO and branched chain AAs

65
Q

What is the thiamin requirement based on?

A

Thiamin needed to achieve and maintain RBC transketolase activity without excessive thiamin excretion

66
Q

In what 3 ways can thiamin status be assessed?

A
  1. erythrocyte transkelotase activity
  2. [Thiamin] & its phosphorylated esters in blood
  3. Urinary thiamin excretion under basal conditions or after thiamin loading
67
Q

Do biochemical changes of thiamin deficiency occur in our body before of after the appearance of physical signs?

A

before

68
Q

What is the down biochemical function of thiamin?

A

Thiamin pyrophosphate (TPP) in CHO metabolism

69
Q

By what % do the thiamin requirement for women and men differ?

A

10%

70
Q

What is the function of riboflavin?

A

coenzyme in numerous oxidation-reduction reactions

71
Q

What are the requirements of riboflavin based on?

A
  1. erythrocyte glutathione reductase activity coefficient
  2. RBC [riboflavin]
  3. Urinary riboflavin excretion
72
Q

What 3 things is the EAR for riboflavin based on?

A
  1. studies of occurrence of signs of clinical deficiency
  2. biochemical values
  3. urinary excretion in relation to dietary intake
73
Q

What is the function of niacin?

A

cosubstrate or coenzyme for H ion transfer (dehydrogenases)

74
Q

What is the primary criteria for RDA of niacin ?

A

urinary excretion of niacin metabolites

75
Q

What is niacin requirements expressed as?

A

niacin equivalents

76
Q

Which amino acid can be converted to niacin?

A

tryptophan - wide variation in efficiency of conversion of tryptophan to niacin

77
Q

Vitamin B6 is a coenzyme in the metabolism of what 3 things?

A

a.a.’s
glycogen
sphingoid bases

78
Q

What is the primary criterion used to estimate RDA of vitamin B6?

A

maintenance of adequate blood 5’-pyridoxal phosphate levels

79
Q

What is the RDA of vitamin B6 for men and women?

A

1.3 mg/day for both

80
Q

What is the function of folate?

A

coenzyme in single-carbon transfers in the metabolism of nucleic and amino acid

81
Q

What are the 2 primary indicators for RDA estimates of folate?

A
  1. Erythrocyte folate

2. Blood [homocysteine] and [folate]

82
Q

What is RDA for folate based off of?

A

dietary folate equivalents

83
Q

Because food folate is only 50% bioavailable, how do we get all we need?

A

dietary folate equivalents

84
Q

1 ug of dietary folate equivalents =

  1. ___ ug of food folate
  2. ___ ug folic acid (fortified food/supplement)
  3. ___ ug supplement taken on empty stomach
A
  1. 1.0
  2. 0.6
  3. 0.5
85
Q

What is the folate RDA?

A

400 ug/d of DFEs (dietary folate equivalents)

86
Q

What are the two main functions of vitamin B12?

A

coenzyme for methyl transfer rxn:

1. homocysteine –> methionine L-methylmalonyl-coenzyme A (CoA) –> succinyl-CoA

87
Q

What is the RDA of Vitamin B12 based on?

A
  1. maintenance of hematological (disease) status

2. normal blood vitamin B12 values

88
Q

What is the RDA for men and women for Vit. B12?

A

2.4 ug/day

89
Q

what is the function of biotin?

A

coenzyme in bicarbonate-dependent carboxylation rxns

90
Q

What is used to set the AI for biotin?

A

estimates of intake

91
Q

What is the AI for biotin for men and women?

A

30 ug/day

92
Q

What 3 things is choline a precursor of?

A
  1. acetylcholine
  2. phospholipids
  3. the methyl donor betaine
93
Q

What is the primary criterion used to estimate the AI of choline?

A

prevention of liver damage as assessed by serum alanine aminotransferase levels

94
Q

In what two ways can choline be found in the diet?

A
  1. free choline

2. bound as esters (phosphocholine, glycerophosphocholine, shingomyelin, phosphatidylcholine)

95
Q

What is another name for phosphatidylcholine?

A

lecithin - can lower blood cholesterol

96
Q

Which enzyme works to remove cholesterol from tissues?

A

Lecithin-cholesterol acyltransferase

97
Q

Choline is also used to lower the concentration of what in the blood?

A

homocysteine

98
Q

What is choline requirement influenced by?

A
  1. methionine & folate availability

2. gender, pregnancy, lactation, stage of development

99
Q

What is the AI for choline for men and women? Elderly?

A

Men: 550 mg/d
Women: 425 mg/d
Elderly: no adjustment, although transport across BBB may decrease

100
Q

within what molecules can pantothenic acid be found in the human body?

A

component of coenzyme A & phosphopantetheine

101
Q

For what two reasons might someone become deficient in pantothenic acid even though it is so widely available?

A
  1. semi-synthetic diet

2. antagonist to the vitamin

102
Q

What is the primary criterion to estimate AI of pantothenic acid?

A

intake adequate to replace urinary excretion

103
Q

What is the usual intake of pantothenic acid? Therefore what do you think the AI is for adults due to the fact that there is no evidence of inadequacy?

A

4/7 mg/day

AI = 5 mg/day

104
Q

What is the AI for men / women?

A

5 mg/day

105
Q

What is vitamin C?

A

a water soluble antioxidant

106
Q

Vitamin C is a cofactor for enzymes involved in biosynthesis of what 3 molecules?

A

collage, carnotite, neurotransmitters

107
Q

The RDA for vitamin C is based off of what?

A
  1. maintain near-maximal neutrophil concentration

2. minimal urinary excretion of ascorbate

108
Q

What is the vitamin C RDA for men / women? What is the median intake in men and women compared to the RDA?

A

Men: 90 mg/day
Actual intake: 102mg/d

Women: 75 mg/day
Actual intake: 72 mg/day

109
Q

For what 4 reasons is the RDA for vitamin C lower for women than it is for men ?

A
  1. smaller lean body mass
  2. less total body water
  3. smaller body size
  4. maintain higher plasma [ascorbate] than men at a given intake
110
Q

Is there a difference in vitamin C metabolism or absorption with age?

A

no

111
Q

What would a low blood [Vit. C] be due to in elderly?

A

poor dietary intake / chronic disease

112
Q

What 6 things is vitamin A important for?

A
  1. normal vision
  2. gene expression
  3. reproduction
  4. embryonic development
  5. growth
  6. immune function
113
Q

What is the EAR of vitamin A based on? What does this assure?

A

Amount of dietary vitamin A required to maintain a given body-pool size in well-nourished subjects. This assures vitamin A reserves to cover increased needs during periods of stress and low vitamin A intakes

114
Q

What is used to set vitamin A requirements?

A

retinol activity equivalents

115
Q

In what two sources can vitamin A be found?

A
  1. preformed vitamin A can be found in animal derived foods

2. Provitamin A carotenoids can be found in darkly coloured fruits and vegetables, oily fruits & red palm oil

116
Q

What are the 3 different types of dietary provitamin A carotenoids?

A
  1. beta-carotene = 12 ug
  2. alpha-carotene = 24 ug
  3. beta-cryptocantin = 24 ug
117
Q

What is the EAR/RDA for men/women for vitamin A?

A

Men:
EAR = 625 ug RAE/d
RDA = 900 ug RAE/d

Women:
EAR = 500 ug RAE/d
RDA = 700 ug RAE/d

118
Q

What does vitamin D increase the absorptive efficiency of in the small intestine?

A

Ca, P which helps maintain blood [Ca] and [P]

119
Q

What are the two major physiologically relevant forms of Vitamin D?

A

D2 = ergocalciferol ; yeast and plant sterols

D3 = cholecalciferol ; from 7-dehydrocholesterol

120
Q

Is vitamin D is found naturally is a lot of foods?

A

nah