From: "Steve Harris" <sbharris@ix.RETICULATEDOBJECTcom.com>
Newsgroups: sci.med,sci.life-extension,sci.med.nutrition
Subject: Re: Multivitamin Scares. (was Re: How about supplemental calcium??)
Date: Sun, 11 May 2003 12:28:14 -0700
Message-ID: <b9m8el$1e0$1@slb0.atl.mindspring.net>

"Tom Kobzina" <tkobzina@msn.com> wrote in message
news:2cc7ec87.0305110215.4423a26e@posting.google.com...
> > So there you are. Take your multivitamin, so long as it has only beta
> > carotene for the A and no retinyl palmitate.
>
> Not so fast:
>
> 1) Variability in conversion of beta-carotene to vitamin A in men as
> measured by using a double-tracer study design.
>
> Hickenbottom SJ, Follett JR, Lin Y, Dueker SR, Burri BJ, Neidlinger TR,
> Clifford AJ.
>
> Department of Nutrition, University of California, Davis, CA 95616, USA.


COMMENT

I'm aware of those studies and more. They are irrelevant to
Western countries where retinyl palmitate is a very widely
used fortification to processed foods, from cereals to
breads to skim milk (look in your fridge). Find me some
vitamin A deficiency studies from the modern First World---
pretty difficult where retinyl palmitate is even harder to
avoid than vitamin D. Third worlders aren't reading this
unless they have computers, and if they do then they are in
a socioeconomic class then it doesn't apply to them either.

The best studies of beta carotene as vitamin A source are
from nutritional studies in the malnourished of Africa,
where beta carotene studies have been extensively done to
see if beta carotene rich foods (widely available from
vegetable sources) can be used as a primary vitamin A source
in low fat low calorie diets. Answer is probably not.
Although the kids do get enough vitamin A to prevent the
worst eye effects (corneal ulcerations), most people in the
field have concluded that in very low fat low calorie diets,
you can't do it with beta-carotene or plant-based diets
alone. That doesn't mean it won't work for fat-eating fat
Westerners, even if they are vegetarians. And that goes
double for fat Westerners eating the pre-formed vitamin A
fortified highly-processed Western diet, again even if they
avoid meat and eggs and milk.  You have to work
extraordinarily hard to avoid retinyl palpitate in the
West-- you have to basically go to the supermarket but only
buy vegan produce, on which you graze lightly like a poor
African, and nothing else. So whether you should take
pre-formed vitamin A in pills in this culture is pretty
silly, unless you're that kind of a person, and a child to
boot.

Studies in rodents of beta carotene are rarely worth
quoting, since their handling of it differs so much from
that of humans. You might not be able to restore Vit A
status in rodents with a single beta carotene dose, but the
only reason this question was even asked was rodents
fantastic ability to split beta-carotene compared with
humans. I suppose this study suggests that if EVEN rodents
can't do it on a single megadose of beta carotene, humans
certainly can't. But nobody ever thought humans could.
Retinyl palmitate is the only real choice for very widely
spaced vitamin A replacement programs in malnourished
people.

SBH


      J Trop Pediatr 2003 Feb;49(1):42-7


Vitamin A status and nutritional intake of carotenoids of
preschool children in Ijaye Orile community in Nigeria.

Oso OO, Abiodun PO, Omotade OO, Oyewole D.

University College Hospital, Department of Paediatrics,
Ibadan, Nigeria. muyiwaoso@hotmail.com

This study was carried out to determine the vitamin A status
and nutritional intake of carotenoids of 213 children
between the ages of 6 months and 6 years in a rural
community in Nigeria. There were 109 males and 104 females.
A total of 57 (26.8 per cent) children were deficient in
serum retinol levels (< 10 microg/dl) while 102 (47.9 per
cent) had low levels (10-19 microg/dl). The highest
prevalence of serum retinol deficiency was in the 6-12
months age group, most of whom were breastfeeding and there
was poor correlation between duration of breastfeeding and
serum retinol levels. The prevalence of night-blindness was
1.5 per cent; however, none of the children had
xerophthalmia. Chronically malnourished children had lower
mean serum retinol levels than well nourished children.
There was a high consumption of carotenoid-containing food,
but despite this there was a high prevalence of vitamin A
deficiency. We therefore suggest that measures to combat
vitamin A deficiency should include vitamin A
supplementation on a short-term basis. On a long-term basis
parents should be educated on the importance of the
consumption of locally available sources of provitamin A and
pre-formed vitamin A rich foods, and the avoidance of
overcooking. Parents should also be encouraged to grow more
beta-carotene containing foods.

PMID: 12630720 [PubMed - indexed for MEDLINE]

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        2: J Nutr 2002 Dec;132(12):3693-9 Related Articles,
Links


  A randomized, 4-month mango and fat supplementation trial
improved vitamin A status among young Gambian children.

  Drammeh BS, Marquis GS, Funkhouser E, Bates C, Eto I,
Stephensen CB.

  Department of Epidemiology and International Health,
University of Alabama at Birmingham, USA.

  Supplementation with carotene-rich fruits may be an
effective and sustainable approach to prevent vitamin A
deficiency. To test the effectiveness of mango
supplementation, 176 Gambian children, aged 2 to 7 y, were
randomly assigned to one of four treatments: 75 g of dried
mango containing approximately 150 micro g retinol activity
equivalents with (MF) or without (M) 5 g of fat, 5 d/wk for
4 mo or 60,000 micro g of vitamin A (A) or placebo (P)
capsule at baseline. After 4 mo, plasma beta-carotene was
greater in both the M (P < 0.05) and MF (P = 0.07) groups
compared with the P group. After controlling for baseline
plasma retinol, elevated acute phase proteins and age,
plasma retinol concentrations in the A and MF, but not M,
groups were higher than in the P group at the end of the
study (P < 0.01). Increases in retinol concentrations,
however, were small in both groups. These results support
the use of dietary supplementation with dried mangoes and a
source of fat as one of several concurrent strategies that
can be used to help maintain vitamin A status of children in
developing countries where there is a severe seasonal
shortage of carotenoid-rich foods.

  Publication Types:
    a.. Clinical Trial
    b.. Randomized Controlled Trial

  PMID: 12468609 [PubMed - indexed for MEDLINE]

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        3: J Nutr 2002 Sep;132(9 Suppl):2947S-2953S Related
Articles, Links


  Assessment and control of vitamin A deficiency disorders.

  Ramakrishnan U, Darnton-Hill I.

  Department of International Health, Rollins School of
Public Health, Emory University, Atlanta, GA 30322, USA.
uramakr@sph.emory.edu

  The XX International Vitamin A Consultative Group (IVACG)
meeting in Hanoi, Vietnam, in February 2001 celebrated 25 y
of progress in prevention and control of vitamin A
deficiency disorders (VADD). Programmatic themes included
the following: 1) intervention innovations, 2) integration
of vitamin A interventions, 3) the increased risk to health
of women who are deficient, 4) measurement of progress and
impact and 5) programmatic sustainability. The history of
IVACG was remembered and the growth of the group from a
meeting of 30 to 40 persons in 1975 to nearly 600 delegates
from 63 countries was described. Successful adaptation to
new challenges and scientific advances, in moving science to
practice, was noted. Guidelines for indicators and
interventions were reviewed. A set of revised
recommendations were made, including the following
indicators for assessment (and, for some, outcome
evaluation) of VADD: 1) under-five mortality rate >50 as a
surrogate indicator to trigger action, 2) maternal night
blindness >5%, 3) rapid dark adaptation worse than -1.11 log
cd/m(2) and 4) serum retinol <0.7 micro mol/L (>15%) in
young children (<6 y). Key recommendations for specific
interventions were to double the existing dose of
prophylactic vitamin A supplementation to 50,000
international units (IU) at the three Expanded Programme on
Immunization contacts for young infants (<6 mo) and to two
doses of 200,000 IU each for women within 6 wk after
delivery; to support fortification as a valid and necessary
strategy to combat VADD; and to recognize that food-based
approaches should include promoting breast-feeding and
consuming animal products, because promoting plant-based
foods alone will not eliminate VADD in young children due to
the low bioefficacy of dietary beta-carotene. This meeting
clearly set the agenda for the twenty-first century and
called for successful implementation of integrated
approaches that will eliminate VADD.

  PMID: 12221275 [PubMed - indexed for MEDLINE]

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        4: J Nutr 2002 Sep;132(9 Suppl):2920S-2926S Related
Articles, Links


  Consequences of revised estimates of carotenoid
bioefficacy for dietary control of vitamin A deficiency in
developing countries.

  West CE, Eilander A, van Lieshout M.

  Division of Human Nutrition and Epidemiology, Wageningen
University, Wageningen, The Netherlands.
clive.west@staff.nutepi.wau.nl

  According to existing recommendations of the Food and
Agriculture Organization (FAO)/World Health Organization
(WHO), the amount of provitamin A in a mixed diet having the
same vitamin A activity as 1 microg of retinol is 6 microg
of beta-carotene or 12 microg of other provitamin A
carotenoids. The efficiency of this conversion is referred
to as bioefficacy. Recently, using data from healthy people
in developed countries and based on a two-step process, the
U.S. Institute of Medicine (IOM) derived new conversion
factors. The first step established the bioefficacy of
beta-carotene in oil at 2 microg having the same vitamin A
activity as 1 microg of retinol; the second step established
the bioavailability of beta-carotene in foods relative to
that of beta-carotene in oil at 1:6. Thus, 2 microg of
beta-carotene in oil or 12 microg of beta-carotene in mixed
foods has the same vitamin A activity as 1 microg of
retinol. Based on existing FAO food balance sheets and the
FAO/WHO conversion rates, all populations should be able to
meet their vitamin A requirements from existing dietary
sources. However, using the new IOM conversion rates,
populations in developing countries could not achieve
adequacy. Additionally, field studies suggest that, instead
of 12 microg, 21 microg of beta-carotene has the same
vitamin A activity as 1 microg of retinol, which implies
that effective vitamin A intake is even lower. Therefore,
controlling vitamin A deficiency in developing countries
requires not only vitamin A supplementation but also
food-based approaches, including food fortification, and
possibly the introduction of new strains of plants with
enhanced vitamin A activity.

  PMID: 12221270 [PubMed - indexed for MEDLINE]