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Experts Emphasize That Beta-Carotene is Indispensable as a Safe Source of Vitamin A

December 1, 2010

JENA, Germany, December 1, 2010 /PRNewswire/ — The intake of preformed
vitamin A from animal products is not sufficient in parts of the population
in the U.S., Europe 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 the
U.S., Europe 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 animal-derived foods.

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 diet.

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 variants

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 recommendations

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 beta-carotene

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.

Source

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)

Quotes

A. Catharine Ross, Department of Nutritional Sciences, Pennsylvania State
University, University Park
, USA:

“A recent U.S. report found large parts of the population to have
insufficient intakes of vitamin A. A large quantity of vitamin A is consumed
in the form of its precursor beta-carotene. However, the current
beta-carotene intake does not fill the gap of low vitamin A intakes from
diet. To bridge the gap, increased amounts of beta-carotene and vitamin A
must be supplied by regular diet and fortified food or dietary supplements if
needed.”

Guang-Wen Tang, USDA Human Nutrition Research Center on Aging, Friedman
School of Nutrition Science and Policy, Tufts University, Boston, USA:

“Recent research indicates that many people possess a gene variant that
restricts the amount of beta-carotene their bodies can utilize, for example
convert into vitamin A. If the gene-related restrictions on the utilization
of beta-carotene are taken into account, then the current daily intake
recommendations need to be increased to reach adequate vitamin A supply.”

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SOURCE CommuniPoweR Wolfgang Zoell


Source: newswire