Experts Emphasize That Beta-Carotene is Indispensable as a Safe Source of Vitamin ABy Communipower Wolfgang Zoell, PRNE
Tuesday, November 30, 2010
JENA, Germany, December 1, 2010 - The intake of preformed vitamin A from animal products is not
sufficient in parts of the population in Europe, the U.S. and Asia. The
vitamin A precursor beta-carotene therefore has an important function in
providing for an adequate supply of total vitamin A, international carotenoid
experts state in a recently published consensus answer. An appropriate intake
of beta-carotene from diet, fortified foods and/or dietary supplements could
safely compensate for the lack of vitamin A. However, based on recent data
from national nutrition surveys, the dietary intake of beta-carotene from
food sources is insufficient in a substantial part of the population.
Moreover, many people may suffer from a reduced ability to produce sufficient
amounts of vitamin A from beta-carotene due to genetic variations.
Consequently, experts are calling for guarantees that recommended intakes of
beta-carotene are met or, if the current recommended dietary amounts for
vitamin A are not met, that beta-carotene intake should be increased. This
would ensure that at least 95% of the population consume an adequate amount
of total vitamin A.
Leading experts in the fields of medical and nutritional
science from Europe, the U.S and Asia met at a Consensus Conference to
elucidate the current knowledge with respect to physiological function,
supply situation, and intake recommendations of beta-carotene. The experts
reached an agreement formulated in a consensus answer published recently in
The Journal of Nutrition.
Vitamin A and beta-carotene intake often critically low
Vitamin A is essential for normal growth and development,
immune system, vision and other functions in the human body. In situations
such as pregnancy and lactation, vitamin A plays a particularly important
role in the healthy development of the child, and an increase in vitamin A
(retinol) intake has been recommended under these conditions. However,
surveys undertaken in several countries suggest that vitamin A intake
patterns vary considerably across Europe, the U.S. and Asia. National survey
data show that the intake of preformed vitamin A (retinol) - as such only
present in animal products (especially liver) - is often critically low and
does not meet the recommendations. Groups especially at risk of inadequate
vitamin A supply are pregnant and lactating women, newborns, children with
frequent infections, young women, the elderly and people who avoid
National Consumption Surveys indicate that beta-carotene - as
a vitamin A precursor - contributes significantly to balance inadequate
vitamin A supply in large parts of the population. However, European, U.S.
and Asian studies show that a substantial part of the population does not
reach the recommendation for beta-carotene necessary to compensate the low
vitamin A intake from sources containing preformed vitamin A in the regular
Recent evidence has shown that suboptimal levels of vitamin A
and beta-carotene, even well above those causing clinical deficiency
syndromes, can be risk factors for chronic diseases.
Vitamin A deficiency through beta-carotene-dependent gene
The bioavailability of beta-carotene is influenced by numerous
factors. In addition to food-related factors, such as food matrix, food
processing, dosage, fat in the meal, and dietary fibers, the bioavailability
of beta-carotene depends on consumer-related factors including vitamin A
status, gut integrity and genetic variations.
Recent research on female subjects has shown that almost 50%
of the population have a genetic variation which reduces their ability to
produce sufficient amounts of vitamin A from beta-carotene. Studies indicate
that younger women carrying the genetic variation are at particular risk as
they tend to eat not enough vitamin A-rich foods relying heavily on the
beta-carotene form of the nutrient.
Experts call for increase of beta-carotene intake
It is apparent from a variety of studies that beta-carotene is
essential in striving for the recommended vitamin A intake. In cases of a
poor vitamin A status due to low intake of preformed vitamin A, the current
recommendations for beta-carotene in the range of 2-4 mg per day still might
not sufficiently correct the individual vitamin A status.
In their consensus answer the experts conclude that ignoring
inter-individual differences in the ability to convert beta-carotene to
vitamin A and assuming that intakes of preformed retinol do not change, it
should be ensured that the current recommended intakes of beta-carotene are
attained. At the same time, people with an inadequate intake of preformed
vitamin A should increase consumption to 7 mg per day, based on a realistic
and now in the scientific community generally accepted conversion efficiency
of 1:12 (12 milligrams of beta-carotene are necessary to form one milligram
of vitamin A). This should ensure that at least 95% of the population meet
the recommended intakes of total vitamin A.
Individuals with reduced conversion efficiencies due to a
genetic variability in beta-carotene metabolism might need to increase their
daily intakes even further. This is currently being investigated.
No functional difference between natural and synthetic
According to the experts, there is no difference in function
between naturally occurring and chemically synthesized beta-carotene, whereas
there is a difference in bioavailability from different food sources. In
humans, the predominant molecular type is 'all-trans beta-carotene', used for
most dietary supplements and fortified foods; it is absorbed preferentially
compared to other forms.
As the general population is not obtaining sufficient
beta-carotene from fruit and vegetables, foods fortified or colored with
beta-carotene and dietary supplements can be important contributors to the
daily supply of vitamin A.
Tilman Grune, Georg Lietz, Andreu Palou, A. Catherine Ross,
Wilhelm Stahl, Guangweng Tang, David Thurnham, Shin-an Yin, and Hans K.
Biesalski. [beta]-Carotene Is an Important Vitamin A Source for Humans. J
Nutr 140:2268S-2285S, 2010 doi: 10.3945/jn.109.119024 (Hohenheim Consensus
Conference July 2009)
Georg Lietz, School of Agriculture, Food and Rural Development
(AFRD), University of Newcastle, Newcastle upon Tyne, UK:
"In the U.K., 50% of men and 49% of women do not meet current
national recommendations for preformed vitamin A when other provitamin A
sources are not taken into consideration. Thus, people with reduced ability
to convert provitamin A sources to active vitamin A could be susceptible to
wide-ranging health risks. This is especially important since recent research
indicates that approximately 40% of all Europeans possess a gene variant that
restricts the amount of beta-carotene their bodies can utilize and convert
into vitamin A. If the gene-related restrictions on the utilization of
beta-carotene would be taken into account, then the daily recommendation
might need to be significantly higher, or alternatively, these individuals
might have to increase their preformed vitamin A intake from animal sources
David Thurnham, Northern Ireland Centre for Diet and Health,
University of Ulster, Coleraine, UK:
"Based on numerous studies it is evident that parts of the
U.K. population do not meet the recommendation for vitamin A with dietary
sources for preformed vitamin A (e.g., liver). To fill the gap between the
low intakes from sources containing preformed vitamin A, adequate amounts of
beta-carotene must be supplied. Foods fortified or colored with beta-carotene
and dietary supplements are important contributors to the daily supply of
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Contact: CommuniPoweR, Wolfgang Zöll, Mrs. Lisa Loewenthal, Berner Str. 111, D-60437 Frankfurt/Main, tel: +49-69-950-905-60, fax: +49-69-950-905-63, info at communipower.de .
Tags: Communipower Wolfgang Zoell, December 1, Germany, Jena