Assessment of Vitamin Nutritional Status

The same criteria used to define requirements can also be used to assess vitamin nutritional status.

Although vitamin deficiencies give rise to more-or-less clearly defined signs and symptoms, diagnosis is not always easy, so biochemical assessment is frequently needed to confirm a presumptive diagnosis. Furthermore, whereas experimental studies may involve feeding diets deficient in one nutrient, but otherwise complete, it is unlikely that under normal conditions an individual would have such a diet. Undernutrition is likely to lead to deficiency or depletion of several vitamins, with the signs of one deficiency predominating. Biochemical assessment will permit more specific diagnosis. There is an obvious advantage in being able to detect biochemical signs of early or marginal deficiency.

An individual who shows biochemical evidence of deficiency or inadequacy may be metabolically stable, and adequately adapted to his or her current intake, or may be in the early stages of developing clinically significant deficiency disease. In population studies, whereas the number of people with clear clinical deficiency signs gives some indication of the scale of the problem, detection of the larger number who show biochemical signs of deficiency gives a better indication of the number of people at risk of developing deficiency, and hence a more realistic estimate of the true scale of the problem.

Biochemical criteria of vitamin adequacy and methods for biochemical assessment of nutritional status can be divided into the following two distinct groups:

1. Determination of plasma, urine, or tissue concentrations of vitamins and their metabolites. These methods depend on comparison of an individual or group with the population reference range, which is normally taken as the 95% confidence interval: ± twice the standard deviation about the mean value. By definition, 5% of the normal healthy population will lie outside the 95% reference range.

Table 1.5 Reference Nutrient Intakes of Vitamins, U.K.,

1991

Vitamin A

Vitamin D

Vitamin B|

Vitamin B2 Niacin

Vitamin B6

Vit .1111111 b12

Folate

Vitamin C

Age

(l*g)

(mg)

(mg)

(mg)

(mg)

(l*g)

(l*g)

(mg)

0-3 m

350

8.5

0.2

0.4

3

0.2

0.3

50

25

4-6 m

350

8.5

0.2

0.4

3

0.2

0.3

50

25

7-9 m

350

7

0.2

0.4

4

0.3

0.4

50

25

10-12 m

350

7

0.3

0.4

5

0.4

0.4

50

25

1-3 y

400

7

0.5

0.6

8

0.7

0.5

70

30

4-6 y

500

0.7

0.8

1 1

0.9

0.8

100

30

7-1 Oy

500

0.7

1.0

12

1.0

1.0

150

30

Males

11-14 y

600

0.9

1.2

15

1.2

1.2

200

35

15-18 y

700

1.1

1.3

18

1.5

1.5

200

40

19-50 y

700

1.0

1.3

17

1.4

1.5

200

40

50+y

700

10

0.9

1.3

16

1.4

1.5

200

40

Females

11-14 y

600

0.7

1.1

12

1.0

1.2

200

35

15-18 y

600

0.8

1.1

14

1.2

1.5

200

40

19-50 y

600

0.8

1.1

13

1.2

1.5

200

40

50+ y

600

10

0.8

1.1

12

1.2

1.5

200

40

Pregnant

+ 100

10

+0.1

+0.3

+ 100

+ 10

Lactating

+350

10

+0.1

+0.5

+2

+0.5

+60

+30

Source: Department of Health, 1991.

Table 1.6 Population Reference Intakes of Vitamins, European Union, 1993

Vitamin A

Vitamin B|

Vitamin B2

Niacin

Vitamin B6

Folate

Vitamin B12

Vitamin C

Age

(l*g)

(mg)

(mg)

(mg)

(mg)

(l*g)

(l*g)

(mg)

6-12 m

350

0.3

0.4

5

0.4

50

0.5

20

1-3 y

400

0.5

0.8

9

0.7

100

0.7

25

4-6 y

400

0.7

1.0

1 1

0.9

130

0.9

25

7-10 y

500

0.8

1.2

13

1.1

150

1.0

30

Maies

11-14 y

600

1.0

1.4

15

1.3

180

1.3

35

15-17 y

700

1.2

1.6

18

1.5

200

1.4

40

18+y

700

1.1

1.6

18

1.5

200

1.4

45

Females

11-14 y

600

0.9

1.2

14

1.1

180

1.3

35

15-17 y

600

0.9

1.3

14

1.1

200

1.4

40

18+y

600

0.9

1.3

14

1.1

200

1.4

45

Pregnant

700

1.0

1.6

14

1.3

400

1.6

55

Lactating

950

1.1

1.7

16

1.4

350

1.9

70

Source: Scientific Committee for Food, 1993.

Table 1.7 Recommended Dietary Allowances (RDAs) and Acceptable Intakes for Vitamins, U.S./Canada, 1997-2001

Vitamin A

Vitamin D

Vitamin E

Vitamin K

Vitamin Bi

Vitamin B2

Niacin

Vitamin Bö

Folate

Vitamin B12

Vitamin C

Age

(l*g)

((¿g)

(mg)

(l*g)

(mg)

(mg)

(mg)

(mg)

((¿g)

(l*g)

(mg)

0-6 m

400

5

4

2.0

0.2

0.3

2

0.1

65

0.4

40

7-12 m

500

5

5

2.5

0.3

0.4

4

0.3

80

0.5

50

1-3 y

300

5

6

30

0.5

0.5

6

0.5

150

0.9

15

4-8 y

400

5

7

55

0.5

0.6

8

0.6

200

1.2

25

Males

9-13 y

600

5

11

60

0.9

0.9

12

1.0

300

1.8

45

14-18 y

900

5

15

75

1.2

1.3

16

1.3

400

2.4

75

19-30 y

900

5

15

120

1.2

1.3

16

1.3

400

2.4

90

31-50 y

900

5

15

120

1.2

1.3

16

1.3

400

2.4

90

51-70 y

900

10

15

120

1.2

1.3

16

1.7

400

2.4

90

>70 y

900

15

15

120

1.2

1.3

16

1.7

400

2.4

90

Females

9-13 y

600

5

11

60

0.9

0.9

12

1.0

300

1.8

45

14-18 y

700

5

15

75

1.0

1.0

14

1.2

400

2.4

65

19-30 y

700

5

15

90

1.1

1.1

14

1.3

400

2.4

75

31-50 y

700

5

15

90

1.1

1.1

14

1.3

400

2.4

75

51-70 y

700

10

15

90

1.1

1.1

14

1.5

400

2.4

75

>70 y

700

15

15

90

1.1

1.1

14

1.5

400

2.4

75

Pregnant

770

5

15

90

1.4

1.4

18

1.9

600

2.6

85

Lactating

900

5

16

90

1.4

1.6

17

2.0

500

2.8

120

Figures for infants under 12 months are Adequate Intakes, based on the observed mean intake of infants fed principally on breast milk; for nutrients

other than vitamin K, figures are RDA, based on estimated average requirement +2 SD; figures for vitamin K are Adequate Intakes, based on observed

average intakes.

Source: Institute of Medicine, 1997, 1998, 2000, 2001.

Table 1.8 Recommended Nutrient Intakes for Vitamins, FAO/WHO, 2001

Vitamin A

Vitamin D

Vitamin K

Vitamin Bi

Vitamin B2

Niacin

Vitamin Bö

Folate

Vitamin B12

Vitamin C

Panto

Biotin

Age

(l*g)

(l*g)

(l*g)

(mg)

(mg)

(mg)

(mg)

(l*g)

(l*g)

(mg)

(mg)

(l*g)

0-6 m

375

5

5

0.2

0.3

2

0.1

80

0.4

25

1.7

5

7-12 m

400

5

10

0.3

0.4

4

0.3

80

0.5

30

1.8

6

1-3 y

400

5

15

0.5

0.5

6

0.5

160

0.9

30

2.0

8

4-6 y

450

5

20

0.6

0.6

8

0.6

200

1.2

30

3.0

12

7-9 y

500

5

25

0.9

0.9

12

1.0

300

1.8

35

4.0

20

Males

10-18 y

600

5

35-55

1.2

1.3

16

1.3

400

2.4

40

5.0

30

19-50 y

600

5

65

1.2

1.3

16

1.3

400

2.4

45

5.0

30

50-65 y

600

10

65

1.2

1.3

16

1.7

400

2.4

45

5.0

30

>65 y

600

15

65

1.2

1.3

16

1.7

400

2.4

45

5.0

30

Females

10-18 y

600

5

35-55

1.1

1.0

16

1.2

400

2.4

40

5.0

25

19-50 y

600

5

55

1.1

1.1

14

1.3

400

2.4

45

5.0

30

50-65 y

600

10

55

1.1

1.1

14

1.5

400

2.4

45

5.0

30

>65 y

600

15

55

1.1

1.1

14

1.5

400

2.4

45

5.0

30

Pregnant

800

5

55

1.4

1.4

18

1.9

600

2.6

55

6.0

30

Lactating

850

5

55

1.5

1.6

17

2.0

500

2.8

70

7.0

35

Source: FAO/WHO, 2001.

2. Metabolic loading tests and the determination of enzyme saturation with cofactor measure the ability of an individual to meet his or her idiosyncratic requirements from a given intake, and, therefore, give a nearly absolute indication of nutritional status, without the need to refer to population reference ranges. A number of factors other than vitamin intake or adequacy can affect responses to metabolic loading tests. This is a particular problem with the tryptophan load test for vitamin B6 nutritional status (Section 9.5.4); a number of drugs can have metabolic effects that resemble those seen in vitamin deficiency or depletion, whether or not they cause functional deficiency.

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    How to assess for improved nutrition status with multivitamins?
    5 years ago

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