Vitamin A // Retinol
Surveys undertaken in several countries suggest that intake patterns vary considerably across Europe and the U.S. The number of people at risk of vitamin A deficiency depends on the intake of total vitamin A, which is defined as preformed (retinol) plus provitamin A (e.g. beta-carotene, beta cryptoxanthin).
The survey data show that a high intake of provitamin A is possible under special conditions (as shown for vegans and vegetarians), but that the intake of preformed vitamin A (retinol) is often critically low and does not meet the recommendations.
According to the latest German consumption study (25) 15% men and 10% women are below the recommended reference value for vitamin A.(retinol). In addition, the study shows that the vitamin A precursor beta-carotene, contributes significantly to the overall vitamin A intake.
In The Netherlands, male average intake exceeded Dutch recommendations of 1,000 micrograms Retinol Activity Equivalents/day in adults, while for women average intake was 5% below the EU recommended 800 micrograms/day (26).
In the U.K., 50% of men and 49% of women did not meet current U.K. national recommendations for vitamin A (27).
Likewise in Ireland, daily average intakes for men and women were considerably below national recommendations (28).
In Austria, average male intakes were between 105% and 125% of the recommended dietary allowance(RDA) for all age groups. Female intakes ranged from 125% to 160% of the RDA in women aged above 56 years (29).
Groups at risk of inadequate vitamin A supply are mainly pregnant and lactating women, newborns, children with frequent infections, the elderly and people who avoid animal-derived foods.
A lack of vitamin A can occur as either a primary or secondary deficiency. A primary vitamin A deficiency occurs among children and adults who do not consume an adequate amount of yellow and green vegetables, fruits and liver. Early weaning can also increase the risk of a deficiency. Secondary vitamin A deficiency is associated with chronic inability to absorb lipids (malabsorption), low fat diets, and chronic exposure to oxidants such as cigarette smoke.
Authored by Dr Peter Engel in 2010, reviewed by Dr. Adrian Wyss on 31.08.2017