What is vitamin E?
Vitamin E is a fat-soluble antioxidant, a yellowy, oily substance with eight isomers. It can be divided into the tocopherol/tocopherol subtype and the tocotrienol/tocotrienol subtype (which has an unsaturated side chain).
Each type is further divided into alpha -, beta -, gamma – or Îī- forms, which are defined by the number and position of methyl groups on the naphthol ring, and each varies in terms of stereoisomerization, esterification, and biological activity.
Vitamin E binds primarily to the hydrophobic interior of cell membranes and protects them from damaging oxidation by providing electrons to lipid peroxidation products to clear free radicals, with alpha-tocopherol being the most abundant form in the human body.
In addition, vitamin E is also known as tocopherol, because it was first found to be related to the reproductive ability of animals, if the lack of easy to cause infertility and abortion, but decades of research shows that the benefits of vitamin E do not end there.
What are the empirical benefits of vitamin E?
1. Beneficial primary menstrual pain
Menstrual pain is one of the most common gynecological disorders, affecting more than half of menstruating women. Most teenagers experience period pain in the first few years after menarche.
Primary menstrual pain refers to pelvic pain that occurs at the beginning of menstruation without obvious pathological changes. It is a common cause of absenteeism from work and hospital visits, and seriously affects both personal and financial aspects of life.
Severe period pain is estimated to cost 600 million hours of lost work time and $2 billion in lost productivity each year.
A meta-analysis of the literature (eight randomized controlled trials involving 1002 healthy women with primary dysmenorrhea) indicated that oral vitamin E significantly reduced the mean intensity of primary menstrual cramps in the first and second months compared with placebo.
Conclusions: Oral vitamin E may provide positive help for primary menstrual cramps, but due to the small sample size, more studies are needed to confirm it.
2. Beneficial for male infertility
Infertility affects millions of people of reproductive age worldwide (about 48 million couples and 186 million people), inflicting distress on families and communities, with male factors accounting for about half.
Male infertility can be caused by a variety of factors, including genetics, age, medications, surgical history, exposure to environmental pollutants, genetic abnormalities, and systemic diseases, all of which can affect reproductive ability.
A meta-analysis of the literature (eight randomized controlled trials involving 459 men with infertility) indicated that oral vitamin E significantly increased total sperm count and decreased semen volume (the decrease in semen volume may be the result of different periods of abstinence before and after the trial).
Subgroup analysis showed that the improvement in sperm forward motility was most significant after 6 months of vitamin E treatment.
Conclusion: Oral vitamin E can improve sperm quality and may have a positive effect on male infertility. However, due to the small sample size, it needs to be further verified by larger, rigorously designed and long-term follow-up studies.
3. Beneficial for nonalcoholic fatty liver disease
Nonalcoholic fatty liver disease is an exclusions diagnosis characterized by the absence of a history of alcohol use and other chronic liver causes such as: viral hepatitis, hemochromatosis, Wilson’s disease, autoimmune hepatitis, drug-induced hepatitis, and hepatitis with chronic endocrine or genetic causes.
Disease progression may range from benign nonalcoholic fatty liver disease to progressive nonalcoholic steatohepatitis with or without fibrosis, cirrhosis, and hepatocellular carcinoma.
NAFLD is the most common cause of chronic liver disease, affecting 15 to 30 percent of the general population, but is more prevalent (about 50 to 90 percent) in people with diabetes, metabolic syndrome, and severe obesity.
A meta-analysis of the literature (15 randomized controlled trials with a total of 1317 patients with NAFLD) indicated that vitamin E (either alone or in combination) had an advantage in improving biochemical outcomes (ALT, AST) in adults and children. It also contributed to additional histological improvements (fibrosis and NAFLD activity scores) in adults and metabolic improvements in the pediatric population.
Conclusions: Vitamin E may have a positive effect on nonalcoholic fatty liver disease, but due to the heterogeneity and small sample size of the studies included, more studies are needed to confirm it.
4. Cancer prevention
According to the World Health Organization, an average of 18.1 million people worldwide are diagnosed with cancer every year, which has become one of the major public health problems threatening human health worldwide.
Despite major advances in the treatment of malignant tumors, the tumors themselves and their treatment, especially surgery and cytotoxic therapy, make cancer patients susceptible to serious infections, prolong hospital stays and increase the medical burden.
A meta-analysis of the literature (12 randomized controlled trials with 167,025 participants) indicated that vitamin E supplementation had no effect on overall mortality, cancer incidence, or cancer mortality, and that the only positive effect was a reduction in prostate cancer incidence.
Conclusions: Vitamin E supplementation may help reduce the incidence of prostate cancer in high-risk individuals, but has no significant effect on other types of cancer.
5. Beneficial to blood lipid regulation
Hyperlipidemia is a genetic and environmental related multifactorial disease, mainly manifested by plasma dyslipidemia. It includes increases in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), and triglycerides (TG), as well as decreases in high-density lipoprotein cholesterol (HDL-C).
Hyperlipidemia has been shown to significantly increase the risk of atherosclerosis, stroke, myocardial infarction, and other cardiovascular and cerebrovascular diseases, and is 2 times more likely to develop cardiovascular and cerebrovascular disease than people with normal blood lipids.
A meta-analysis of the literature (10 randomized controlled trials with a total of 613 participants) indicated that vitamin E supplementation did not affect total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels in patients with diabetes.
In addition, subgroup analysis showed that vitamin E supplementation reduced total cholesterol (TC) and increased high density lipoprotein cholesterol (HDL-C) levels only in subjects who continued for 12 weeks.
Conclusion: Vitamin E supplementation may have positive effects on blood lipid regulation in diabetic patients, but it needs further verification due to the heterogeneity and bias of the samples included.
6. Reduce inflammation index: C-reactive protein
C-reactive protein, an acute phase protein of the pentacyclic protein family, is synthesized by liver cells and is one of the most well-known biomarkers of systemic inflammation, an indicator of a variety of pathological processes including infection, tissue damage and chronic inflammatory diseases.
Its elevated levels are considered to be independent and strong predictors of cardiovascular disease and atherosclerotic thrombotic events.
A meta-analysis of 12 randomized controlled trials with 495 participants indicated that vitamin E supplementation (in the form of alpha-tocopherol or gamma-tocopherol) reduced serum C-reactive protein levels.
In addition, subgroup analyses showed that serum CRP levels decreased more significantly after vitamin E supplementation in participants with baseline CRP water greater than 3mg /l compared to participants with baseline CRP levels of 3mg /l.
Conclusions: Vitamin E may have a positive effect on the reduction of C-reactive protein, but due to small sample size and heterogeneity, more studies are needed for further verification.
7. Aid in weight loss
Obesity is a chronic disease that can lead to a variety of conditions such as: diabetes, coronary heart disease, and osteoarthritis. Several factors can contribute to obesity, including: energy intake exceeding energy requirements, low physical activity, being sedentary, and genetics.
Globally, obesity rates are rising for all ages and genders regardless of geography, race, or socioeconomic status, and more than 50% of the population will be overweight by 2030, including about 11% of Americans who will be severely obese.
A meta-analysis of the literature, consisting of 24 randomized controlled trials with 1,267 participants, found that vitamin E supplementation (interventions ranging from 1 to 24 months and daily doses ranging from 67 to 900 mg) had no significant effects on body weight, body mass index, or waist circumference.
Conclusions: Vitamin E supplementation did not provide significant benefits for weight loss.
8. Reduce the risk of senile cataract
A cataract is an opaque object visible in the lens that causes visual loss when it is on the axis of vision.
Senile cataracts, on the other hand, are those that do not develop until the age of 50 and are not associated with known congenital, metabolic disorders, drug-induced turbidity, trauma, chemical or radiation factors.
The main mechanisms that trigger senile cataract may be related to the following factors: protein breakdown and aggregation, destruction of fiber cell membranes, glutathione deficiency, oxidative damage, calcium elevation, and abnormal migration of lens epithelial cells.
A meta-analysis of the literature (27 studies with 245,531 participants) indicated that dietary vitamin E intake, dietary and supplemental vitamin E intake, and higher serum tocopherol levels may be significantly associated with a reduced risk of age-related cataract.
Dose-response analysis showed that dietary vitamin E intake was associated with cataract riskreduction starting at levels above 7 mg per day.
Conclusions: Dietary vitamin E intake is inversely associated with cataract risk, especially nuclear cataract, but randomized controlled trials are needed to determine whether additional supplementation is helpful.
9. Beneficial for myocardial infarction
A myocardial infarction is a heart attack in which the buildup of plaque in the lining of the arteries reduces blood flow to the heart and causes a lack of oxygen that damages the heart muscle.
The British Heart Association estimates that the annual incidence of an acute heart attack among people aged 30 to 69 is 0.6 per cent in men and 0.1 per cent in women
Symptoms at onset include: chest pain (from the left arm to the neck), shortness of breath, sweating, nausea, vomiting, abnormal heart beat, anxiety, fatigue, weakness, stress, depression… And so on.
A Meta-analysis of the literature (16 randomized controlled trials) showed that vitamin E supplementation alone reduced the risk of myocardial infarction by 18% (especially at daily doses greater than 400 IU), but not when combined with other antioxidants.
The underlying mechanism is related to the anticoagulant, antiplatelet, antioxidant and anti-inflammatory activities of vitamin E.
Conclusions: Vitamin E supplementation alone may help reduce the incidence of fatal myocardial infarction, but more research is needed due to possible experimental bias.
10. Beneficial blood sugar control
Type 2 diabetes is the most common chronic disease in adults, with a global prevalence of 8.3 percent, or 330 million people, and the number of people affected is increasing year by year.
Long-term poor blood sugar control is more likely to lead to small and large vascular diseases, such as cardiovascular events, kidney failure, blindness, peripheral neuropathy are associated with.
A meta-analysis of the literature (14 randomized controlled trials with 714 participants) found that, on average, there is currently insufficient evidence to support that vitamin E supplementation improves HBA1c, fasting glucose, and fasting insulin in patients with type 2 diabetes.
In the subgroup analysis, additional supplementation was found to have statistically significant improvements in HBA1c and FBG in subjects with low blood vitamin E concentrations and poor glycemic control.
Conclusions: Vitamin E supplementation may be beneficial for those with poor glycemic control and vitamin E deficiency
11. Beneficial Dementia (especially Alzheimer’s disease)
Memory and cognitive function decline slowly with age, and this process is usually very slow, unless you have a sudden stroke, or some kind of injury to the brain, otherwise it is not possible to suddenly develop dementia.
Generally, forgetfulness caused by aging is a very different situation from dementia. Forgetfulness is occasionally forgetting things, but it will be remembered later, while dementia is the frequency of forgetting will increase, even when reminded by others, it will not remember, and even begin to deny that it has happened.
At present, about 60% of the cases of dementia are Alzheimer’s disease, which is a disease in which brain nerve cells gradually die, and even lose cognitive and behavioral abilities in the advanced stage, requiring people to take care of their daily life.
A double-blind controlled study of 613 people with mild-to-moderate Alzheimer’s disease over an average period of 2.3 years found that vitamin E helped slow the progression of clinical symptoms (such as eating, bathing, shopping and eating) by about 19 percent compared to taking the drug Memantine (acetylcholinesterase inhibitor) and a placebo. Equivalent to 6.2 months).
Conclusion: For Alzheimer’s disease, vitamin E may help patients maintain a longer period of independent life and reduce the likelihood of being cared for, but due to the small sample size, more studies are needed to further verify.
12. Beneficial for seasonal allergic rhinitis
Seasonal allergic rhinitis, also known as hay fever, is a complex condition characterized by runny nose, nasal congestion, sneezing, and nasopharyngeal itchiness. It is an inflammatory condition of the upper respiratory tract that occurs when sensitizers are exposed to airborne allergens (usually tree, grass, and weed pollen). It affects 30 to 40 percent of adults and children, and is on the rise.
To date, treatment for allergic rhinitis has included avoidance of allergens, medication, and immunotherapy. For SAR, however, avoiding allergens completely may not be advisable, as it may require limiting time spent outdoors.
Therefore, medications, including selective antihistamines, corticosteroids, decongestants, bronchodilators, intranasal mast cell stabilizers, and leukotriene receptor antagonists, are more likely to relieve symptoms than avoiding allergens.
A double-blind controlled study of 112 hay fever patients receiving conventional treatment found that vitamin E(800 mg daily) further reduced nasal symptoms (e.g., sneezing, nasal congestion, runny nose, itching) during the hay fever season compared to placebo.
The mechanism behind this is thought to be associated with vitamin E’s ability to suppress inflammation and the production of the allergic antibody IgE (immunoglobulin E).
Conclusion: Vitamin E may have positive effects on seasonal allergic rhinitis, but due to the small sample size, more studies are needed for further verification.
So what are the main points to pay attention to when taking vitamin E?
Oral vitamin E is generally considered safe when taken in proper doses. Most people experience no side effects when taking the recommended dose of 15 mg (22.5 IU) per day.
Note, however, that possible side effects that have been reported with high doses of vitamin E include: nausea, diarrhea, stomach cramps, fatigue, weakness, headache, sarcosinuria, blurred vision, rash, constipation, bruising, and bleeding.
Safety precautions (9 points of use contraindications)
1. Stop taking vitamin E supplements two to four weeks before scheduled surgery, including dental surgery, to reduce the risk of bleeding during and after surgery.
2. Patients with retinitis pigmentosa, an inherited vision degenerative disorder, should avoid taking high doses of vitamin E supplements (more than 400 IU daily may accelerate the loss of retinal function).
3. Do not take high doses of vitamin E if you have any of the following symptoms (e.g. bleeding disorder, vitamin K deficiency, diabetes, history of previous heart attack or stroke, head and neck cancer, prostate cancer, liver disease), or consult your doctor before use, as unauthorized use may worsen symptoms, cause bleeding, or pose unknown risks.
4. Do not take vitamin E in combination with anticoagulants and antiplatelet drugs, which may increase the risk of bleeding, such as: aspirin (Aspirin), clopidogrel (Clopidogrel), diclofenac (diclofenac), ibuprofen (ibuprofen), naproxen (Naproxen), dalteparin (Dalheparin), enoxaparin (Enoxaparin), warfarin (warfarin).
5. Do not use in combination with drugs that are metabolized by cytochrome P450 3A4 enzymes. Vitamin E may increase the rate at which the liver breaks down certain drugs, reducing their effectiveness. Related drug names: lovastatin (lovastatin), ketoconazole (ketoconazole), itraconazole (itraconazole), fexofenadine (fexofenadine), triazolam (triazolam).
6. Do not combine with immunosuppressant Cyclosporine, vitamin E may increase the amount of cyclosporine absorbed by the body, increasing the possibility of side effects.
7. High doses of vitamin E may interfere with the effectiveness of chemotherapy drugs.
8. Do not use it in combination with health products with anti-clotting effects, such as fish oil, garlic, curcumin or ginkgo biloba, which may increase the risk of bleeding.
9. Consult your doctor about the medication or condition you are using before using any supplement to prevent adverse events or unexpected interactions.