Vitamin E — Health Benefits, Deficiency Symptoms, Side Effects

by Arpi Gasparyan | Last updated on April 01, 2024

Medically reviewed by Victoria Mazmanyan

Introduction

Vitamin E is a fat-soluble, plant-derived vitamin with strong antioxidant activities. It comprises tocopherols (alpha-, beta-, gamma-, and delta-tocopherol) and tocotrienols (alpha-, beta-, gamma-, and delta-tocotrienol) (1).

Alpha-tocopherol (α-tocopherol) is the primary form of vitamin E in the blood and tissues. It is the only form of vitamin E with dietary requirements to prevent deficiency (1, 2).

Absorption & Metabolism

Vitamin E is absorbed in the distal or farther parts of the small intestines, along with dietary fats and other fat-soluble vitamins. All forms of vitamin E undergo digestion by pancreatic and intestinal enzymes, get incorporated into chylomicrons, and are transported to the liver and other tissues. Under normal conditions, alpha-tocopherol is transported mainly via chylomicrons, VLDL (very low-density lipoprotein), and HDL (high-density lipoprotein) cholesterols, whereas under fasting conditions, it is transported via LDL (low-density lipoprotein) cholesterol (3).

Vitamin E absorption rates typically range from 20% to 80%, which are thought to be lower than those of other fat-soluble vitamins like vitamin A (3).

The liver secretes only alpha-tocopherol into the bloodstream via a protein called α-TTP (alpha-tocopherol transfer protein) but metabolizes and excretes other forms of vitamin E (2).

Factors Affecting the Bioavailability of Vitamin E

Consuming vitamin E with foods containing retinoic acid, plant sterols, eicosapentaenoic acid, and dietary fiber and regularly consuming alcohol decreases the vitamin’s absorption rates. Different types of the vitamin also have varying bioavailability (3).

Some of the factors affecting vitamin E’s bioavailability are listed below:

Gender, age
Genetic factors
Lifestyle factors, such as smoking, chronic alcohol consumption, and obesity
Levels of vitamin E intake and foods interfering with its absorption
Disorders causing disturbed absorption of fats
Interaction with medicines (3).

Physiological Functions of Vitamin E

The primary role of vitamin E is its antioxidant activity, protecting cells and tissues against harmful free radicals.

Vitamin E is also required for the normal functioning of the nervous and immune systems, stabilization of biological membranes, cell interactions, formation of red blood cells, widening of blood vessels, and regulation of some enzymes. Vitamin E may also play a role in gene expression (4, 5).

Recommended Intakes

The 2020–2025 Dietary Guidelines for Americans calculated the recommended daily value (RDV) for vitamin E considering only its one type, alpha-tocopherol.

The RDVs are shown in the table below, considering the age; there are no differences in the values between genders (6).

2-3	4-8	9-13	14-18	19 -30	31-50, 51+
6 mg	7 mg	11 mg	15 mg	15 mg	15 mg

The RDV is the same during pregnancy but increases to 19mg daily during lactation (2).

Food Sources

Vitamin E is mainly found in vegetables (such as green leafy vegetables), plant oils, nuts, seeds, and fruits. Cereals may also be fortified with alpha-tocopherol. In American diets, most vitamin E is gamma-tocopherol from soy products, canola, corn (maize), and plant oils (2).

Food	Per one serving
Sunflower seeds, dry	16.2 mg per 1 cup (46g)
Almonds	7.26 mg per 1 oz
Wheat germ oil	6.7 mg per 1 tsp
Sunflower oil	5.59 mg per 1 tbsp
Safflower oil	4.64 mg per 1 tbsp
Hazelnuts	4.25 mg per 1 oz
Grape seed oil	3.92 mg per 1 tbsp
Spinach, cooked	3.74 mg per 1 cup (180g)
Peanut butter	2.91 mg per 2 tbsp
Babassu oil	2.6 mg per 1 tbsp
Peanuts	2.36 mg in 1 oz
Palm oil	2.16 mg per 1 tbsp
Olive oil	1.94 mg per 1 tbsp
Red bell pepper	1.88 mg per 1 medium pepper (120g)
Soybean oil	1.1 mg per 1 tbsp

You can visit our “Foods high in vitamin E” page to find more foods based on 100g servings.

Vitamin E & Human Health

Heart Disease

Several sources mention vitamin E could help prevent or delay coronary heart disease. In vitro studies showed that the vitamin blocks LDL or bad cholesterol oxidation, a risk factor for atherosclerosis. Moreover, vitamin E might help prevent blood clotting, a risk factor for heart attack and thromboembolism.

However, the results on vitamin E and heart disease risks are controversial. For example, a study of nearly 90,000 nurses found a 30% to 40% lower risk of heart disease in those taking vitamin E supplements, and another study of over 5,000 people found that vitamin E might decrease coronary heart disease risks. In contrast, the HOPE study followed almost 10,000 patients at high risk of heart attack or stroke (people with diagnosed heart disease or diabetes) for over 4 years and found that those taking 400 IU/day (268 mg) of vitamin E had the same health outcomes as those taking a placebo. After 3 more years, the HOPE-TOO follow-up study found that the participants taking vitamin E were 13% more likely to experience heart failure and even be hospitalized in some cases (2).

A clinical trial of almost 40,000 healthy women over 45 showed that supplementing with vitamin E might decrease heart attacks and cardiovascular death rates. Whereas another study on almost 15,000 healthy men over 50 found negative associations between vitamin E intake and the risk of hemorrhagic stroke (2).

Cancer

Even though vitamin E is an antioxidant, it is less likely to be associated with a decreased cancer risk.

The HOPE-TOO Trial and Women’s Health Study found no associations between vitamin E intake and cancer risk. Additionally, a study of over 29,000 men found no links between vitamin E consumption and the risk of prostate cancer. (2).

Several studies suggest that daily supplementation with vitamin E might significantly decrease the risk of advanced prostate cancer in ever-smokers. In contrast, according to the SELECT trial, daily supplementation with vitamin E might increase the risk of prostate cancer development (2).

The first largest Mendelian randomization (MR) analysis was applied to data comprising almost 298,000 cancer cases and over 304,000 controls of European ancestry. The MR analysis did not find evidence supporting a causal effect of vitamin E on the risk of cancer development, stating that supplementation with vitamin E may not benefit cancer prevention (7).

Eye Disorders

Age-related macular degeneration (AMD) and cataracts are the leading causes of eye disorders in older people. The results regarding vitamin E intake and decreased risk of eye disorders are also controversial: several studies demonstrated positive associations between vitamin intake and eye disorders, whereas others showed no associations at all.

The AREDS clinical trial found that participants at greater risk of developing advanced AMD supplementing with vitamin E (D-Alpha Tocopheryl Acetate), beta-carotene, vitamin C, zinc, and copper reduced the risk of disease progression by 25%. Further, the AREDS2 study confirmed the previous results.

Several observational studies noted that vitamin E intake may beneficially affect cataract formation, leading to clearer lenses and slower disease progression. However, the AREDS and AREDS2 trials found no significant associations between vitamin E intake and cataract development or progression (2).

Cognitive Decline

Researchers hypothesize that vitamin E might somewhat protect against neurodegenerative diseases due to its antioxidant, neuroprotective, and anti-inflammatory properties. Moreover, low vitamin E levels were found in people with Alzheimer’s disease (8).

A clinical trial in 341 people with Alzheimer’s disease with moderate severity showed delayed functional and cognitive decline; however, the participants tended to fall more. Another study also found that adequate vitamin E intake was negatively associated with the risk of cognitive decline (2).

A prospective cohort study of the elderly noticed a beneficial effect of vitamin E supplementation on cognitive decline, whereas several clinical trials found no significant benefits in supplementing (2).

Skin Diseases

Vitamin E is known to benefit the skin; however, reports to confirm this link have been inconsistent. According to a meta-analysis, people with vitiligo, psoriasis, atopic dermatitis, and acne had lower serum vitamin E levels (10).

Vitamin E intake in people with acne showed fewer inflammatory and non-inflammatory lesions after several weeks. Studies on people with atopic dermatitis demonstrated an inverse association between serum vitamin E and immunoglobulin E levels, a significant factor linked to atopic dermatitis. A study also mentioned symptom improvements in conditions like facial erythema and lichenification (skin becomes thick and leathery after scratching) (11).

Fatty Liver

Fatty liver or MASLD (metabolic dysfunction-associated steatotic liver disease) is the most common chronic liver disease, which at some point may lead to liver cirrhosis. Vitamin E is being studied for its potential protective role in the disease.

According to a cross-sectional study using the NHANES data, vitamin E intake, whether dietary, supplemental, or both, showed a protective effect against MASLD, particularly in people with normal blood lipid levels (12).

Period Pain

Vitamin E blocks the release of arachidonic acid and its conversion to prostaglandin, associated with relieved period pain or dysmenorrhea.

Several studies suggested vitamin E supplementation might relieve period pain and reduce blood loss. Greater effects may be achieved by supplementing vitamin E with vitamin D and ginger (13, 14).

Vitamin E Deficiency

Risk Groups & Causes

In developed countries, vitamin E deficiency is rarely due to inadequate dietary intake, whereas in developing countries, it is the leading cause.

More common causes are listed below (15).

Premature underweight infants weighing less than 1500g or 3.3 pounds
Genetic mutations, such as in tocopherol transfer protein, abetalipoproteinemia, isolated vitamin E deficiency syndrome
People with pancreatic insufficiency of either cause, e.g., cystic fibrosis, chronic pancreatitis
People with Crohn’s disease, ulcerative colitis with backwash ileitis, celiac disease, and more
People with short-bowel syndrome
Chronic hepatobiliary disease in people with cholestasis causes decreased bile flow to the intestines and subsequent decreased micelle formation.

Symptoms

Vitamin E deficiency may lead to neuromuscular disorders and the destruction of red blood cells. Vitamin E deficiency appears when serum vitamin levels are below 0.5 mg/dL, and may cause no symptoms or manifest as subtle neurologic abnormalities.

Neuromuscular disorders primarily manifest as peripheral neuropathy (nerve damage causing pain, numbness, or tingling), myopathy (muscle weakness, stiffness, cramps, and muscle spasms), eye problems, and in rare cases, brown bowel syndrome (16, 17, 18).

Vitamin E deficiency may also shorten the lifespan of red blood cells and cause hemolytic anemia in premature infants (16).

The most severe symptoms of vitamin E deficiency are blindness, dementia, and heart arrhythmias (19).

Side Effects of Vitamin E

Vitamin E Toxicity

Vitamin E toxicity appears when serum vitamin levels are over 40 µg/mL. It may lead to increased all-cause mortality, heart failure, easy bruising or bleeding, changes in coagulation tests, impaired immune response, and general and gastrointestinal symptoms, such as nausea, indigestion, abdominal cramps, diarrhea, headache, fatigue, and muscle weakness. As previously mentioned, increased intake of vitamin E may be associated with an increased risk of prostate cancer (16, 20).

Vitamin E toxicity may increase the risk of sepsis in premature infants (16).

Maximum Daily Dose of Vitamin E

The table below demonstrates the tolerable upper intake levels of vitamin E (2).

1-3 years	4 - 8 years	9 - 13 years	14 - 18 years	18+ years
200 mg	300 mg	600 mg	800 mg	1000 mg

Vitamin E Interactions & Contraindications

Vitamin E may decrease the activity of vitamin K, a vitamin involved in the synthesis of several clotting factors, reducing the risk of blood clot formation (21).

Along with decreasing vitamin K’s activity, vitamin E might block platelet aggregation and increase the risk of bleeding in people taking anticoagulant or antiplatelet medications, such as warfarin (Coumadin).

People taking simvastatin (Zocor) and niacin, along with antioxidants such as vitamins E, selenium, and beta-carotene, may have increased HDL cholesterol serum levels.

Oncologists advise against taking antioxidant supplements during chemotherapy or radiotherapy due to the risk of reduced treatment effectiveness (2).

Vitamin E is contraindicated to people with previous allergic reactions to vitamin E supplementation or allergic reactions to any of the components in the formula.

Summary

Vitamin E is a fat-soluble, plant-derived vitamin with strong antioxidant activities. Alpha-tocopherol (α-tocopherol) is the primary form of vitamin E in the blood and tissues. It is the only form with dietary requirements to prevent vitamin E deficiency. It is absorbed in the distal parts of the small intestine, along with dietary fats.

The primary role of vitamin E is its antioxidant property, protecting cells and tissues against harmful free radicals.

Vitamin E is mainly found in vegetables and their oils, nuts, seeds, and fruits. Retinoic acid, plant sterols, eicosapentaenoic acid, dietary fiber, and alcohol may decrease vitamin E’s absorption rates.

The current evidence regarding vitamin E and its effects on heart health, cancer, eye disease, and cognitive decline is mainly controversial, ranging from beneficial health effects to increased disease risks.

In developed countries, vitamin E deficiency is rarely due to inadequate dietary intake, whereas in developing countries, it is the leading cause. Vitamin E deficiency may lead to neuromuscular disorders and the destruction of red blood cells.

Vitamin E may interact with vitamin K and anticoagulants, decreasing their activity.

References

Author name: Arpi Gasparyan

Education: General Medicine at YSMU

Last updated: April 01, 2024

Medically reviewed by Victoria Mazmanyan