Tocopherols and tocotrienols: what is known about their health effects
What it found
In people, the antioxidant roles of alpha- and gamma-tocopherol are confirmed, while links to metabolic disorders are still being studied.
Many other proposed benefits come from animal and lab work.
What they found
Studies in people
Antioxidant roles in people
The antioxidant functions of alpha- and gamma-tocopherol have been confirmed in humans. Alpha-tocopherol neutralises free radicals and protects cell membranes from oxidative damage.
Blood levels and mortality
A large study following people for more than 30 years found that men with higher blood levels of alpha-tocopherol had lower overall mortality and lower mortality from cardiovascular disease, heart disease, stroke, cancer and respiratory disease.
Clinical trial results
Many clinical trials did not confirm a protective role for alpha-tocopherol in preventing disease in people who already had adequate nutritional status.
Animal and lab studies
Metabolites and inflammation
In lab tests, alpha-tocopherol metabolites such as alpha-13'-COOH inhibited the enzymes COX-1, COX-2 and 5-LO, which are involved in inflammation. In a mouse model of peritonitis, alpha-13'-COOH suppressed acute inflammation.
Cancer cells and tumours
In human liver cancer cells, alpha- and delta-tocopherol metabolites stopped cell growth. In a mouse model of colon cancer, metabolites from delta-tocopherol and delta-tocotrienol inhibited COX-2 and 5-LO and induced cell death.
Obesity and body weight
In lab tests, tocotrienols reduced fat droplet accumulation in liver and fat cells, with gamma-tocotrienol showing the strongest effect. In obese animals, tocotrienols reduced body weight, especially fat mass.
Other findings
Forms and sources
Vitamin E is a group of eight compounds: four tocopherols and four tocotrienols. The main natural sources are the oily parts of nuts and oil seeds, with alpha- and gamma-tocopherol most common in the diet.
Absorption and retention
The body absorbs 20% to 80% of the tocopherols and tocotrienols eaten. A liver protein called alpha-TTP preferentially keeps alpha-tocopherol in blood and tissues, while other forms are broken down and excreted.
What the authors conclude
“Some of the functions, for instance the antioxidant functions of α- and γ-tocopherols, have been confirmed in humans, while others, such as the relationship with metabolic disorders, are still under investigation.”
Also in their conclusions
- They say that gamma- and delta-tocopherol, as well as alpha- and gamma-tocotrienol, are bioactive compounds with documented health benefits beyond normal nutrition.
- They call for large-scale clinical trials to verify the biological role of gamma-tocopherol, tocotrienols and their metabolites.
- They advise that the exact mechanisms of action still require further research.
How it was done
The authors wanted to update knowledge on how tocopherols and tocotrienols are absorbed, distributed and broken down in humans, and on what their biological effects are.
They reviewed published human trials, cohort studies, systematic reviews and meta-analyses, plus animal and lab studies, on tocopherols, tocotrienols and their metabolites and health. The search covered cardiovascular disease, cancer and obesity.
What it can’t tell you
- Many of the findings on inflammation, cancer and obesity come from animal or lab studies, so they cannot show what happens in people.
- The studies following people over time can show links between vitamin E levels and health outcomes, but they cannot prove cause and effect.
- The review notes that the exact mechanisms of action for many effects are still under investigation.
Who paid
- Conflicts
- The authors declare no conflict of interest.
- Authors work at
- Warsaw University of Life Sciences (SGGW-WULS), Poland
The paper
- Title
- Tocopherols and Tocotrienols-Bioactive Dietary Compounds; What Is Certain, What Is Doubt?
- Type
- ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
- Evidence
- Studies in people · animals · lab
- Summarised from
- Full text
- Cite
- Szewczyk K, Chojnacka A, Górnicka M (2021). Tocopherols and Tocotrienols-Bioactive Dietary Compounds; What Is Certain, What Is Doubt?. International journal of molecular sciences. doi:10.3390/ijms22126222Free full textPubMed 34207571DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error