Chapter 070. Nutritional Requirements and Dietary Assessment (Part 2) pps

Chapter 070. Nutritional Requirements
and Dietary Assessment
(Part 2)

Water
For adults, 1.0–1.5 mL water per kcal of energy expenditure is sufficient
under usual conditions to allow for normal variations in physical activity,
sweating, and solute load of the diet. Water losses include 50–100 mL/d in the
feces, 500–1000 mL/d by evaporation or exhalation, and, depending on the renal
solute load, ≥1000 mL/d in the urine. If external losses increase, intakes must
increase accordingly to avoid underhydration. Fever increases water losses by
approximately 200 mL/d per °C; diarrheal losses vary but may be as great as 5 L/d
with severe diarrhea. Heavy sweating and vomiting also increase water losses.
When renal function is normal and solute intakes are adequate, the kidneys can
adjust to increased water intake by excreting up to 18 L/d of excess water (Chap.
334). However, obligatory urine outputs can compromise hydration status when
there is inadequate intake or when losses increase in disease or kidney damage.
Infants have high requirements for water because of their large ratio of
surface area to volume, the limited capacity of the immature kidney to handle high
renal solute loads, and their inability to communicate their thirst. During
pregnancy, 30 mL/d additional water is needed. During lactation, milk production
increases water requirements by approximately 1000 mL/d, or 1 mL for each mL
of milk produced. Special attention must be paid to the water needs of the elderly,
who have reduced total body water and blunted thirst sensation, and may be taking
diuretics.
Other Nutrients
See Chap. 71 for a detailed description of vitamins and trace minerals.
Dietary Reference Intakes and Recommended Dietary Allowances
Fortunately, human life and well-being can be maintained within a fairly
wide range for most nutrients. However, the capacity for adaptation is not
infinite—too much of a nutrient, as well as too little, may have adverse effects on

health. Therefore, quantitative benchmark recommendations on nutrient intakes
have been developed to guide clinical practice. These estimates are collectively
referred to as the dietary reference intakes (DRIs). The DRIs supplant but include
the recommended dietary allowances (RDAs), the single reference values used in
the United States since 1989. DRIs include the estimated average requirement
(EAR) of a nutrient, as well as three other reference values used for dietary
planning for individuals: the RDA, or, if it cannot be established, the adequate
intake (AI), and the tolerable upper level (UL). The current DRIs for vitamins and
elements are provided in Tables 70-1 and 70-2, respectively.
Table 70-1 Dietary Reference Intakes: Recommended Intakes for
Individuals—Vitamins
Vitamin,
µg/d ife-
Stage
Grou
p
a

b,c

d

hiami
ne,
mg/d

ibofla
vin,
mg/d
iacin

,
mg/
d
e

itami
n B
6
,
mg/d

olat
e,
µg/d
f

itami
n
B
12
,
µg/d

P
antoth
enic
Acid,
mg/d
iotin
,

µg/d

holin
e,
mg/d
g

nfants


1
0–6
mo
00 0 .0 .2 .3 .1 5 .4 .7 25
7–12
mo
00 0 .5 .3 .4 .3 0 .5
1
.8 50
hildre
n

1–3 y

00 5 0 .5 .5 .5 50 .9
2
00
4–8 y

00 5 5 .6 .6 .6 00 .2

3
2 50
ales

4
9–13
y
00 5 1 0 .9 .9 2 .0 00 .8 0 75
14–
18
y
00 5 5 5 .2 .3 6 .3 00 .4
5
5 50
19–
30
y
00 0 5 20 .2 .3 6 .3 00 .4
5
0 50
31–
50
y
00 0 5 20 .2 .3 6 .3 00 .4
5
0 50
51–
70
y
00 0 0 5 20 .2 .3 6 .7 00 .4

h

5
0 50
>70 y

00 0 5 5 20 .2 .3 6 .7 00 .4
h

5
0 50
emale
s

9–13
y
00 5 1 0 .9 .9 2 .0 00 .8
4
0 75
14–
18
y
00 5 5 5 .0 .0 4 .2 00
i
.4
5
5 00
19–
30
y

00 5 5 0 .1 .1 4 .3 00
i
.4
5
0 25
31–
50
y
00 5 5 0 .1 .1 4 .3 00
i
.4
5
0 25
51–
70
y
00 5 0 5 0 .1 .1 4 .5 00 .4
h

5
0 25
>70 y

00 5 5 5 0 .1 .1 4 .5 00 .4
h

5
0 25
regna
ncy

≤18 y

50 0 5 5 .4 .4 8 .6 00
j
.6
6
0 50
19–
30
y
70 5 5 0 .4 .4 8 .9 00
j
.6
6
0 50
31–
50
70 5 5 0 .4 .4 8 .9 00
j
.6
6
0 50
y
actati
on

≤18 y

200

15

9 5 .4 .6 7 .0 00 .8
7
5 50
19–
30
y
300

20

9 0 .4 .6 7 .0 00 .8
7
5 50
31–
50
y
300

20

9 0 .4 .6 7 .0 00 .8
7
5 50