The recommended intakes are given in retinal activity equivalents RAE and

range between 0.3 mg and 0.6 mg for children and are 0.7 mg and 0.9 mg, respectively, for females and males (1000 ]ag RAE ^ 3000 IU) (see also p. 136). During pregnancy and lactation the requirements are higher since plasma values in neonates are always lower than in the mother, and vitamin A use increases significantly during pregnancy. For this reason, supplementation of 0.7 mg/d is recommended during pregnancy and 0.6 mg during lactation. Official recommendations state that liver should not be eaten during pregnancy. Depending on the feed, liver may contain up to 2500 IU vitamin A/g. With average portions of 100 g and a 45% absorption rate, such consumption could result in an uptake of more than 100 000 IU in extreme cases.

However, no teratogenic effects of eating liver have been proven with certainty. The warnings are based mostly on findings from pharmacological use of retinoic acid for therapy of severe acne. There are reports of miscarriages and malformations. Since retinoic acid cannot be metabolized to its reduced forms (retinal, retinol), it is questionable whether these results apply to vitamin A from foods. Nevertheless, to be on the safe side, women wanting to get pregnant, as well as during the first trimester, should abstain from eating liver. Outside of pregnancy, toxic effects of high doses of vitamin A from foods are not relevant. Reports of hypervitamino-sis A are rare, and it occurs mostly in children after intake of medications. The UL is 3000 ug/d for adults.

Vitamin A deficiency is of much greater significance. Even though in the industrial nations, intakes tend to be above the recommendations, depletion of the liver pool may occur through disease or insufficient intakes in case of predominantly plant-based nutrition. Worldwide, vitamin A deficiency has enormous impact: the FAO assumes approximately 14 million children under five to be vitamin A deficient, up to 500 000 a year go blind, and 60% of those die within a few months thereafter. In the U.S., vitamin A deficiency is the main cause of blindness in people over 65.

Xerophthalmia (C) is a typical symptom of advanced deficiency, causing the cornea to become opaque and necrotic. Without treatment this leads to blindness. Early stages are characterized by impaired dark adaptation, commonly known as night blindness, caused by vitamin A deficiency. There may also be changes in skin and mucous membranes, causing increased susceptibility to infections, especially of the respiratory tract (see p. 142).

- A. Occurrence and Daily Requirement -

The daily requirement of 0.9 mg vitamin A (retinol) is contained in:

100g liver pate 5-10gl iver 150g caviar 100 g eel 200g tuna

2-3kg fish

100g liver pate 5-10gl iver 150g caviar 100 g eel 200g tuna

2-3kg fish

Fish Nutrition Chart

3 l whole milk

1.5 l sheep's milk

3 l whole milk

1.5 l sheep's milk

150g butter 200g margarine 350 g Dutch Gouda 300g Swiss cheese 300g mozzarella 220g brie 8 eggs

100g liquid egg yolk

- B. Recommended Intakes (DRI/AI*, 2000) and UL

Life Stage and

Age

Vitamin A

UL

Gender Group

(M RAE/d)

(IU)

(M RAE/d)

Infants

0 - 6 mo

400*

1200

600

7 - 12 mo

500*

1500

600

Children

1- 3 y

300

900

600

4 - 8 y

400

1200

900

9 - 13 y

600

1800

1700

Males

14 - 18 y

900

2700

2800

> 19 y

900

2700

3000

Females

14 - 18 y

700

2100

2800

> 19 y

700

2100

3000

Pregnancy

14 - 18 y

750

2250

2800

19 - 50 y

770

2310

3000

Lactation

14 - 18 y

1200

3600

2800

19 - 50 y

1300

3900

3000

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