Did You Know Just That Many Cancers Are Linked To A Vitamin Deficiency?
Believe
it or not, there are many different kinds of Vitamin E,
and they all have different potencies and different costs.
Most commonly, you will see dl-alpha tocopherol, the l in
the dl meaning it is the synthetic, or cheaper form. Cheaper
does not always mean better though, as the synthetic form
has one of the least bioactivity of them all, so taking
this form will do virtually nothing for you.
The Different Forms of Vitamin E
The Different Forms of Vitamin E
By: Dr. George Obikoya
Vitamin
E is a fat-soluble antioxidant vitamin that helps to neutralize
potentially damaging free radicals in our body. It exists
in eight different forms, alpha-tocopherol being the most
active form of vitamin E in humans and a powerful biological
antioxidant. The natural, and preferred form to take is
d (not dl) alpha tocopherol.
Each
form has its own biological activity, the measure of potency
or functional use in the body. The tocopherol and tocotrienol
subfamilies are each composed of alpha, beta, gamma and
delta vitamins having unique biological effects.
Vitamin E is thought to help in some skin conditions, male
infertility, heart disease prevention, Alzheimer's disease,
type 1 diabetes, circulatory problems, arthritis, premenstrual
symptoms, and aging. It is also used as an antioxidant and
to enhance immune system functioning in the elderly.
The
tocopherols are a closely related group of biologically
active compounds that vary only in number and position of
methyl groups in the molecule; however, these structural
differences influence the biological activity of the various
molecules. (In other words, each type of vitamin e is similar,
but work in slightly different ways).
The
active tocopherols are named in order of their potency.
Thus alpha-tocopherol is the most active. Some metabolites
of alpha-tocopherol, for example, alpha-tocopherolquinone,
and alphatocopheronolactone have activity in some mammals
such as rats and rabbits although not in humans and these
metabolites do not support all the functions attributed
to vitamin E. In other words, stick with the tocopherols.
The
vitamin E group also is necessary for normal mammal (including
human) growth; without these tocopherols, our fertility
is compromised and we may have children that develop abnormalities
of the central nervous system, muscles, and organs, especially
the liver.
Most
of the stored vitamin E is found in body fat, although large
amounts also occur in the uterus of females and the testis
of males. The various forms of vitamin E are stored in tissues
in different amounts; alpha-tocopherol is stored in higher
concentrations than the other forms.
Many
people don’t know that there are several different forms
of vitamin E. Why is this important to know? The different
forms of vitamin E are truly disctinct and have different
levels of effectiveness. Each form functions differently
in the body and only one form truly represents natural vitamin
E - the d-alpha-tocopoheryl form.
There
are several distinct forms of vitamin E in dietary supplements
vying for your attention. While tocotrienols, the form of
vitamin E that features an unsaturated side chain, is becoming
more popular, tocopherols (mainly alpha-tocopherol) still
remain the most widely used and researched form. Tocopherol
supplements usually feature either alpha-tocopherol, alpha-tocopheryl
acetate or alpha-tocopheryl succinate, the latter two thought
to confer enhanced stability.
You
can get Vitamin E in synthetic form as dl-alpha tocopheryl.
This is the cheapest and least effective form of vitamin
E. The chemically produced dl-alpha-tocopher(y)l acetate
or succinate, identified by the letter "l" after
"d", was originally used as the industry standard
for research. This was because it showed higher blood levels
than the natural forms, alpha, beta, gamma and delta tocopherols,
spelled with an "o" instead of a "y"
to identify them as natural forms. Alpha-tocopherol can
be derived from natural sources or can be synthetically
produced. Natural-source alpha-tocopherol is a single stereoisomer
and is also designated by the prefix "RRR." The
synthetic form is a mixture of eight stereoisomers identified
by the prefix "dl-" or "all-rac."
Natural-source
d-alpha-tocopherol (as opposed to dl) has been shown to
have a higher biopotency than the dl-rac form. The currently
accepted ratio is 1.36:1 (d:dl). A recent proposal has been
made to the National Academy of Sciences to change this
biopotency factor to 2:1 based on the results of more recent
research studies. But some researchers challenge this idea
believing it is based on incomplete conclusions extrapolated
from the studies.1
The
fact that Vitamin E works at the mitochondrial rather than
cellular level, and does not work at the blood level is
proof that synthetic Vitamin E is an ineffective form. Furthermore,
diabetics usually show high blood levels of Vitamin E because
their heavily sclerosed circulatory system does not permit
synthetic Vitamin E to reach the mitochondria level. Indeed,
only natural form vitamin E has been discovered in brain
tissue. Synthetic Vitamin E also causes side effects including
heart palpitations even at relatively low dosage.
Esterified
vitamin E is d-alpha tocopheryl. Originally alpha-tocopherol
was erroneously thought to be the only active factor of
the Vitamin E group: alpha, beta, delta, and gamma. We now
know better. Alpha, beta, gamma, delta tocopherol, can all
be esterified (converted) into a single acid ester.
However,
esterified vitamin E is very resistant to destruction by
oxidation even in the presence of minerals or at high temperatures
but this destroys its antioxidant properties, although not
its ability to prevent clot formation in our blood vessels.
Mixed Tocopherols or d-alpha tocopherol are recommended
for both vitamin E’s antioxidant and anti-thrombotic effects.
A
good multivitamin is the foundation of health and nutrition.
Take a look at our scientific reviews of many of the popular
brands for factors such as ingredients, areas of improvement,
quality level, and overall value. If you are looking for
a high quality liquid multivitamin, we suggest that you
take a look at the Multivitamin Product Comparisons.
References
1. Hoppe PP, Krennrich G. Bioavailability and potency of
natural-source and all-racemic a-tocopherol in the human:
a dispute. Euro J of Nutr 2000;39:183-93.
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