Vitamin
E
Vitamin
E was identified in 1922 as an essential nutrient in the diet.
Vitamin E is one of the more potent biological antioxidants that
protect cell membranes and other fat-containing parts of the body
against damage from free radicals, peroxides and various pollutants.*
Vitamin E became known as the “anti-sterility vitamin” because it
was found to be necessary in normal reproduction.* Tocopherol, which means “to bear offspring” in Greek, was
the name given to the isolate of wheat germ oil that contains vitamin E.
Vitamin E
interacts extensively with other antioxidants, especially vitamin C and
selenium.*1 These nutrients
enhance each others’ effects. Vitamin E also improves the use of
vitamin A, and may be
necessary in the conversion of vitamin B12 to its most active form.*2
The recommended Dietary Allowance (RDA) for vitamin E is 30 IU
per day. Nature’s Life
offers a wide variety of forms and potencies, depending on your
individual needs.
Beneficial
Effects
Vitamin E
functions primarily as an antioxidant in protecting against damage to
all cell membranes in the body.* It is actually incorporated into the lipid (fatty) protein of
the cell membrane, where it acts to protect against the body’s natural
free-radical metabolites, heavy metals such as lead and mercury, toxic
chemicals and radiation.* Human
studies also suggest that vitamin E may help inhibit the formation of
abnormal cells.*3,4
Heart
Health
Vitamin
E’s protection against the oxidation of low-density lipoprotein (LDL
or “bad” cholesterol) has been shown in recent studies to help
maintain a healthy heart.* Two
large studies show that both men and women who supplement with at least
100 IU of vitamin E per day, for at least two years, have a 37-41%
better chance of maintaining a healthy heart.*5,6
Even more impressive are the results from a double blind study of
2,002 people taking 400 to 800 IU of vitamain E daily. The results
indicated a 77% improvement in heart health.*7
Researchers in the above studies concluded that supplementation
of vitamin E at higher levels than those achievable by diet alone may be
needed to reduce oxidation of LDL cholesterol.*
Several
large-population studies have demonstrated that vitamin E levels in the
blood may be a better indicator of heart health than levels of total
cholesterol. In one study,
high blood cholesterol was predictive of poor heart health 29% of the
time, high blood pressure was predictive 25% of the time and low levels
of vitamin E was predictive almost 70% of the time.*8
Although amounts as low as 30 IU (the RDA) are effective at
offering some protection, supplements greater than 400 IU a day are
required to produce clinically significant effects.*9
Blood
Sugar
Those
with elevated blood sugar levels appear to have an increased requirement
for vitamin E for a number of reasons, probably because oxidative stress
is a major factor in raising blood sugar levels.*10
Vitamin E improves insulin action and exerts a number of
beneficial effects that may aid in maintaining healthy blood sugar
levels.*10,11,12
A Finnish
study of 7,526 healthy people published in 1999 found a protective
effect of vitamin E in maintaining healthy blood sugar levels.*11
Another study found that 800 IU of vitamin E per day diminished
platelet aggregation (helping to maintain a healthy cardiovascular
system) for those with elevated levels of
blood sugar.*12 Further, several studies have shown that supplementing with
high amounts (1,350 IU per day) of vitamin E improves glucose tolerance
and sensitivity to insulin thus helping to normalize blood sugar
levels.*10
Immune
System
Vitamin
E is also critically important for immune function.*
It protects the immune system from damage during times of
oxidative stress and in the presence of abnormal cells.*
In a study of healthy elderly subjects, supplementation of 800 IU
of vitamin E for 30 days improved immune responsiveness, especially
cell-mediated immunity, which otherwise tends to decline in function as
we age.*13
Natural
vs. Synthetic Vitamin E
The names
of all forms of vitamin E begin with either “d” (the natural form)
or “dl” (the synthetic form), referring to differences in chemical
structure. The natural form
is more absorbable (“bioavailable”) so less is required to be taken
as a supplement than the synthetic form.
All vitamin E supplements from Nature’s
Life are the natural “d” form, which has been shown in recent
studies on human subjects to have 50% or greater potency.14,15
Vitamin E potency is indicated by International Units (IU) which
measure the biological value of vitamin E.
Natural
Forms
-
d-alpha-tocopherol
(pure, unesterified)
-
d-alpha-tocopheryl
acetate (esterified)
-
d-alpha-tocopheryl
succinate (esterified)
Synthetic Forms
Greater
bioavailability of natural Vitamin E means that it is absorbed faster
and more completely into the blood stream, and is retained longer.*
More recent evidence demonstrates that the ratio of natural
versus synthetic vitamin E bioavailability is 2:1 in the human liver and
4:1 across the human placenta.16,17,18
This finding is significant for pregnant women looking for the
optimal form of vitamin E in their prenatal supplementation, as in Nature’s
Life Prenatal Multiple formula.
Most prenatal vitamins use the less well absorbed synthetic
vitamin E.
Natural
Vitamin E, moreover, has many other functions and benefits in human
health, including inhibiting platelet aggregation, enhancing immune
function and stabilizing membranes.*3,10,12 It is not yet clear whether synthetic vitamin E performs
these functions as well as the natural form.
d-Alpha
vs. other Tocopherols
Another
important aspect of vitamin E involves its chemical structure.
Synthetic vitamin E is only prepared in the alpha form, as in dl-alpha-tocopherol.
Natural vitamin E can be found in alpha or in combination with
other tocopherols, including beta, gamma and delta.
The combination form is labeled “mixed” as in
“natural mixed tocopherols.”
The bulk of the research to date strongly suggests that the alpha
form, whether synthetic or natural, is instrumental in supporting heart
health.*19
Nearly
all research showing positive health effects from Vitamin E
supplementation have been done with the alpha tocopherol form.
A group of researchers compared the gamma tocopherol form, the
principal type found in the American diet, with alpha, the major type
used in supplements. The researchers found that gamma tocopherol is
necessary for the efficient antioxidant functioning of the alpha form.20
The researchers suggest that the current practice of
supplementing only alpha tocopherol should be reconsidered.
Considering
that this research is based only on a laboratory study, the issue of
alpha versus gamma requires much more research before it can be fully
understood. Until more is known, those that desire the gamma form can
opt for vitamin E supplements containing significant amounts of gamma,
beta and delta tocopherols, such as Nature’s
Life Mega E 400.
Food Sources
The
amount of vitamin E in the diet is largely dependent on the amount of
polyunsaturated fats in the diet. These
fats are found in vegetable oils, seeds, nuts, whole grains and fish.
These fats are susceptible to oxidative damage in the body, and
vitamin E is protective against this damage.*
Fortunately, these foods contain substantial amounts of vitamin E
themselves. Sunflower seeds, almonds, sweet potatoes, flax oil, spinach,
and other green vegetables also contain significant amounts of vitamin E
and all grains and legumes contain some.
The gamma form is the most common tocopherol found in foods. Much
vitamin E research shows that positive results require hundreds of units
of total tocopherols per day (about 400 IU on average) - an amount
impractical to obtain from food.*21
The
Safe Supplement
All forms of vitamin E have an excellent safety
record. A review of the
literature concerning the safety of oral intake of vitamin E indicated
that toxicity is extremely low and that even at doses as high as 3,200
IU/day, few side effects (and none serious) were reported.*22
Nature’s
Life Natural Source Vitamin E
Although originally extracted from wheat, most
natural vitamin E is now derived from soybeans. Nature’s Life
primarily uses unesterified d-alpha tocopherol, the finest natural
vitamin E available. Esterification
is a chemical process that stabilizes the vitamin E to allow for
different forms, such as Dry E. This process helps remove traces of the
original source (soy). The shelf life is longer for esterified products,
but some people prefer the more natural, unadulterated product.
Vitamin E
supplements from Nature’s Life,
with naturally-occurring mixed tocopherols, are available in 100
IU, 200 IU, 400
IU, 800 IU and 1,000 IU potencies. In addition, the following
specialty products are offered:
-
Super E Complex 200 IU: a
combination of vitamin E, Lecithin and Wheat Germ Oil for added
essential fatty acids to maintain a healthy cardiovascular system*
-
Mega E 400 IU Complex: 400
IU d-alpha with 67 mg of added
gamma, beta and delta tocopherols
-
Dry E 400 IU: Dry,
esterified and water-soluble for those sensitive to oil forms
-
Pure E 400 IU: 100%
natural Vitamin E with no soy oil or other filler.
References
-
National
Research Council, Vitamin E Function & Metabolism Recommended
Dietary Allowances,
1989;100.
-
Garrison Jr. R, Somer E.
Vitamin E Function, The Nutrition Desk Reference, 1995;84.
-
Knecht P, et al. Vitamin E
in cancer prevention.
Am J clin Nutr 1991;53(Suppl. 1):283S-286S.
-
Knecht P. Vitamin E and
cancer; epidemiology. In: Sauberlich HE, Machlin LJ, eds. Beyond
deficiency New
York; NY Academy of Sciences 1992: p.269.
-
Stampfer MJ, Hennekens CH,
Manson JE, Colditz GA, et al. Vitamin E consumption and the risk of coronary disease in
women. N Engl J Med
1993;328:1444-9.
-
Rimm EB, Stampfer MJ,
Ascherio A, Giovannucci E, et al. Vitamin E consumption and the risk of coronary heart disease
in men. N Engl J Med
1993;328:1450-6.
-
Stephens NG, Parsons A,
Scofield PM, et al. Randomised
controlled trial of vitamin E in patients with coronary disease:
Cambridge Heart Antioxidant Study (CHAOS). Lancet 1996;347:781-6.
-
Gey KF, et al. Inverse
correlation between plasma vitamin E and mortality from ischemic
heart disease in cross-cultural epidemiology. Am J Clin Nutr 1991;53:3263-3343.
-
Princen HMG, et al.
Supplementation with low doses of vitamin E protects LDL from
lipid peroxidation in men and women.
Arterioscler Thromb Vasc Biol 1995;15:325-333.
-
Paolisso G, et al.
Chronic intake of pharmacological doses of vitamin E might be
useful in the therapy of elderly patients with coronary heart
disease. Am J Clin Nutr
1995;61:848-852.
-
Knekt P, Reunanen A,
Marniemi J, et al. Low
vitamin E status is a potential risk factor for insulin-dependent
diabetes mellitus. J Intern Med 1999;245:99-102.
-
Collette C, Pares-Herbute N,
Monnier LH, Cartry E. Platelet
function in type I diabetes: effects of supplementation with large
doses of vitamin E. Am J Clin
Nutr 1988;47:256-61.
-
Meydani SN, Barklund MP, Liu
S, et al. Vitamin E
supplementation enhances cell-mediated immunity in healthy elderly
adults. Am J Clin Nutr 1990;52:557-63.
-
Acuff RV, Thedford SS,
Hidiroglou NH, et al. Relative
bioavailabity of RRR- and all-rac-alpha-tocopheryl
acetate in humans: studies using deuterated compounds. Am
J Clin Nutr 1994;60:397-402.
-
Cheng SC, Burton GW, Ingold
KU, Foster DO. Chiral
discrimination in the exchange of alpha-tocopherol stereoisomers
between plasma and red blood cells.
Lipids 1987;22:469-473.
-
Kiyose C, Muramatsu R, et
al. Biodiscrimination
of alpha-tocopherol stereoisomers in humans after oral
administration. Am J Clin Nutr 1997;65:785-9.
-
Acuff RV, Dunworth RG, et
al. Transport of
deuterium-labeled tocopherols during pregnancy. Am
J Clin Nutr 1998;67:459.
-
Gorden MJ, Campbell FM,
Dutta-Roy AK. Alpha-
tocopherol-binding protein in the cytosol of the human placenta. Biochem
Soc Trans 1996;24:2025.
-
Reaven PD, Witztum JL.
Comparison of supplementation of RRR-alpha-tocopherol and
racemic alpha-tocopherol in humans. Thrombosis
1993:13:601-8.
-
Christen S, Woodall AA,
Shigenaga MK, et al. Gamma-tocopherol
traps mutagenic electrophiles such as NO(X) and complements alpha-tocopherol:
physiological implications. Proc
Natl Acad Sci 1997;94:3217-22.
-
Horwitt M. Data supporting
supplementation of humans with vitamin E. J
of Nutr 1991;121:424-9.
-
Bendich A and Machlin LJ. Safety of oral intake of vitamin E. Am J Clin Nutr
1988;48:612-9.
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