|
Vitamin E has many biological functions; the antioxidant function being the most important and/or best known.[20] Other functions include enzymatic activities, gene expression and neurological function(s). It's also been suggested that the most important function of vitamin E is in cell signaling (and, that it may not have a significant role in antioxidant metabolism).[21][22]
- As an antioxidant, vitamin E acts as a peroxyl radical scavenger, preventing the propagation of free radicals in tissues, by reacting with them to form a tocopheryl radical which will then be oxidized by a hydrogen donor (such as Vitamin C) and thus return to i
CAD and VITAMIN E
Types: Alpha, beta, gamma and delta
Sources:
Fruits
Vegetables
Eggs
Butter, margarine, vegetable oils
Eggs
Sources
Important source is in commercial breakfast cereal and tomato sauce.[17]
A 100 g serving of certain fortified breakfast cereals may contain 24 mg (or more) vitamin E.[17]
Vitamin E content per 100 g of source include:[18][19]
------------------------------------
Sources of gamma E
Nuts: Walnuts, pecans and legume peanuts. Nuts also provide omega-3 fatty acids, magnesium,
fiber and other nutrients.
Oils: Corn, soybean, sesame, olive and sunflower oils. All are rich sources of gamma tocopherol.
Commercially available seed oils may contain excess trans-fatty acids and omega-6 fatty acids
leading to various types of degenerative disorders.
-------------------------
American Journal of Clinical Nutrition 2002;76:582-587. 8/2002
Ruth D. Smith, Colette N. M. Kelly, Barbara A. Fielding, David Hauton, K. D. Renuka R. Silva, Margaretha C. Nydahl, George
J. Miller and Christine M. Williams (2003). Long-term monounsaturated fatty acid diets reduce platelet aggregation in healthy young
subjects. British Journal of Nutrition, 90 , pp 597-606
VITAMIN E, HEART DISEASE, AND OLIVE OIL
Atherosclerosis is the process of plaque formation, thickening and blocking of the arteries that can lead to heart attacks
and stroke. LDL cholesterol, the "bad" cholesterol is thought to be partially responsible for these changes when it oxidizes
in the artery wall. It has been hoped that anti-oxidants in the diet would be found to decrease atherosclerosis. Studies show
that people who eat antioxidant rich foods such as vegetable oils, fruits, vegetables, grains, and nuts have a lower chance
of getting heart disease and cancer. It was assumed that taking Vitamin E supplements would do the same but oddly enough newer
studies show that this is not true.
In the American Journal of Clinical Nutrition, Iannuzzi and colleagues of Cardarelli Hospital in Naples found that women
who consumed more vitamin E were less likely to get early signs of cardiovascular disease. They looked at ultrasound evidence
of thickening in the carotid arteries, a marker for vascular disease throughout the body. Study participants were women from
Southern Italy. They got most of their vitamin E from legumes, vegetables and olive oil.
1.6mg, or 2.3 IU (International Units) of Vitamin E, a natural antioxidant, is present in one tablespoon of olive oil.
One tablespoon of olive oil would provide 8% of the recommended daily allotment for vitamin E.
Doctor Uannuzzi found that additional Vitamin E only helped those women whose levels started out low. Women with an adequate
intake could not lower their risk of atherosclerosis by adding vitamin E to the diet. Other anti-oxidants such as Vitamin
A and C did not seem to affect carotid thickening.
More recently 10,000 patients at high risk for heart attack or stroke were followed for 4.5 years in the the Heart Outcomes
Prevention Evaluation (HOPE) Study. People who received 265 mg (400) IU of vitamin E daily did not experience significantly
fewer cardiovascular events or hospitalizations for heart failure or chest pain when compared to those who received placebo.
Supplements of Vitamin E alone do not appear to be effective in reducing heart disease. However, Vitamin E which is consumed
within an anti-oxidant rich diet is correlated with decreased atherosclerosis. It seems that whole foods, rather than derived
supplements, are responsible for the health benefits of the Mediterranean diet (Dr. John Deane 12/03/03). Olive oil is one
of these Vitamin E-containing, antioxidant whole foods.
………………………………………………………………………………………………………………
SOURCES
American Journal of Clinical Nutrition 2002;76:582-587. 8/2002
Ruth D. Smith, Colette N. M. Kelly, Barbara A. Fielding, David Hauton, K. D. Renuka R. Silva, Margaretha C. Nydahl, George
J. Miller and Christine M. Williams (2003). Long-term monounsaturated fatty acid diets reduce platelet aggregation in healthy young
subjects. British Journal of Nutrition, 90 , pp 597-606
-------------------------
Studies suggest that vitamin E may play an important role in prevention of CAD.
Other studies of vitamin E and coronary artery disease prevention have generated conflicting outcomes
"The daily administration of 400 IU vitamin E for an average of 4.5 years
to middle-aged and elderly people with diabetes and CV disease and/or additional coronary risk factor(s) has no effect on
CV outcomes or nephropathy."2
".... dietary vitamin E supplementation is associated with reduced risk of atherosclerosis. Evidence indicates that vitamin
E, in addition to inhibition of oxidative modification of LDL, may inhibit atherogenesis through several other mechanisms
at the molecular and cellular levels, which also include its nonantioxidant functions."3
" My conclusion from the evidence summarized above and other reports in the medical literature, developed by other physicxians
other than the Shutes, is that there is no doubt that vitamin E has great value in cotrolling peripheral vascular disease,
which often occurs together with heart disease and with diabetes, and also in preventing and treating blood clots (thromboembolism
and thrommbophlebitis). In addition, I believe that are sound arguments that support the claim made by the Shutes about the
value of vitamin E for preventing and controlling coronary heart disease and other diseases."4
(The Shutes: They are threenCanadian physicians, Dr James Schute and his sons, Evan and Wilfred who used vitamin E in the
treatment of diseases in 1933.)
--
Sixteen cohorts of the Seven Countries Study in whom flavonoid
intake at baseline around 1960 was estimated after
25 years of follow-up.
Average intake of antioxidant flavonoids was inversely associated with mortality
from coronary heart disease. It did not seem to be an important
determinant of cancer mortality.8
==========================================================================================
Jiang Q, Christen S, Shigenaga MK, Ames BN. gamma-tocopherol, the major form of vitamin E in the US diet, deserves more attention.
Abstract
"gamma-tocopherol is the major form of vitamin E in many plant seeds and in the US diet, but has drawn little attention
compared with alpha-tocopherol, the predominant form of vitamin E in tissues and the primary form in supplements. However,
recent studies indicate that gamma-tocopherol may be important to human health and that it possesses unique features that
distinguish it from alpha-tocopherol. gamma-Tocopherol appears to be a more effective trap for lipophilic electrophiles than
is alpha-tocopherol. gamma-Tocopherol is well absorbed and accumulates to a significant degree in some human tissues; it is
metabolized, however, largely to 2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxychroman (gamma-CEHC), which is mainly excreted
in the urine. gamma-CEHC, but not the corresponding metabolite derived from alpha-tocopherol,
has natriuretic activity that may be of physiologic importance. Both gamma-tocopherol and gamma-CEHC, but not alpha-tocopherol,
inhibit cyclooxygenase activity and, thus, possess antiinflammatory properties. Some human and animal studies indicate that
plasma concentrations of gamma-tocopherol are inversely associated with the incidence of cardiovascular disease and prostate
cancer. These distinguishing features of gamma-tocopherol and its metabolite suggest that gamma-tocopherol
may contribute significantly to human health in ways not recognized previously. This possibility should be further evaluated,
especially considering that high doses of alpha-tocopherol deplete plasma and tissue gamma-tocopherol, in contrast with supplementation
with gamma-tocopherol, which increases both. We review current information on the bioavailability, metabolism, chemistry,
and nonantioxidant activities of gamma-tocopherol and epidemiologic data concerning the relation between gamma-tocopherol
and cardiovascular disease and cancer.
------------------------------------------------------------------------------
References:
2. Eva Lonn. etal.
Effects of Vitamin E on Cardiovascular and Microvascular Outcomes in High-Risk Patients With Diabetes
Results of the HOPE Study and MICRO-HOPE Substudy Diabetes Care November 2002
vol. 25 no. 11 1919-1927
3. Meydani M. Vitamin E and atherosclerosis:
beyond prevention of LDL oxidation.
4, Linus Pauling. How to live longer and feel better. Page 159, 1086 edition.
6. Peluzio MC, Miguel E Jr, Drumond TC, Cesar GC, Santiago HC, Teixeira MM, Vieira EC, Arantes
RM, Alvarez-Leite JI.. Monocyte chemoattractant protein-1 involvement in the alpha-tocopherol-induced reduction of atherosclerotic
lesions in apolipoprotein E knockout mice.Br J Nutr. 2003 Jul;90(1):3-11.
7. Yusuf S, Dagenais G, Pogue J, Bosch J, Sleight
P.
Vitamin E supplementation and cardiovascular events in high-risk patients. The Heart
Outcomes Prevention Evaluation Study Investigators.
--------------------------------------------------------------------------------
Heart disease
Preliminary research has led to a widely held belief that vitamin E may help prevent or delay coronary heart disease, but larger controlled studies have not shown any benefit.[49] Many researchers advance the belief that oxidative modification of LDL-cholesterol (sometimes called "bad" cholesterol) promotes blockages in coronary arteries that may lead to atherosclerosis and heart attacks.[citation needed] Vitamin E may help prevent or delay coronary heart disease by limiting the oxidation of LDL-cholesterol. Vitamin E also may help prevent the formation of blood clots, which could lead to a heart attack. Observational
studies have associated lower rates of heart disease with higher vitamin E intake. A study of approximately 90,000 nurses
suggested that the incidence of heart disease was 30% to 40% lower among nurses with the highest intake of vitamin E from
diet and supplements. The range of intakes from both diet and supplements in this group was 21.6 to 1,000 IU (32 to 1,500
mg), with the median intake being 208 IU (139 mg). A 1994 review of 5,133 Finnish men and women aged 30 – 69 years suggested
that increased dietary intake of vitamin E was associated with decreased mortality (death) from heart disease.
Despite these promising observations, randomized clinical trials have consistently shown lack of benefit to the role of
vitamin E supplements in heart disease. The Heart Outcomes Prevention Evaluation (HOPE) Study followed almost 10,000 patients
for 4.5 years who were at high risk for heart attack or stroke. In this intervention study the subjects who received 265 mg
(400) IU of vitamin E daily did not experience significantly fewer cardiovascular events or hospitalizations for heart failure
or chest pain when compared to those who received a sugar pill. The researchers suggested that it is unlikely that the vitamin
E supplement provided any protection against cardiovascular disease in the HOPE study. This study is continuing, to determine
whether a longer duration of intervention with vitamin E supplements will provide any protection against cardiovascular disease.
Furthermore, meta analysis of several trials of antioxidants, including vitamin E, have not shown any benefit to vitamin
E supplementation for preventing coronary heart disease.[50] One study suggested that Vitamin E (as alpha-tocopherol only) supplementation may increase the risk for heart failure.[51] Supplementing alpha-tocopherol without gamma-tocopherol is known to lead to reduced serum gamma- and delta-tocopherol
concentrations.[52]
A large-scale 10-year study published in 2007 examined the rates of venous thromboembolism (VTE) and pulmonary embolism
in women taking 600 IU of vitamin E on alternate days. The study found a significant reduction in VTE especially in women
who had a history of thrombtic events or a genetic predispostion.[53]
http://en.wikipedia.org/wiki/Tocopherol
|
