Did you know that vitamin E isn’t just a single performer but rather a complex group of 8 analogs? These 8 compounds include 4 tocopherols and 4 tocotrienols. Interestingly, the predominant form in the body is alpha-tocopherol, making up more than 90%. So, when we talk about vitamin E, we mostly focus on alpha-tocopherol, the key player that guides our daily vitamin E requirements.
Our bodies get alpha-tocopherol from 2 main sources. There’s the naturally sourced version, found in seed oils and various foods, and then there’s the synthesized kind of alpha-tocopherol. Both forms are commonly found in commercially available vitamin E and fortified products.
Enhanced bioavailability and health benefits of natural vitamin E
Exploring the nuances of vitamin E reveals a striking distinction between its natural and synthetic forms. Natural Vitamin E , scientifically known as D-alpha-tocopherol or RRR-alpha-tocopherol, consists of a single isomer, and is the one found in nature and in certain foods. On the other side, synthetic vitamin E, labeled as DL-Alpha-Tocopherol, is a blend of 8 different isomers, only 1 of which is identical to the natural form.
Research indicates that this difference is crucial in how our bodies absorb and utilize these 2 variants. Natural vitamin E is known to be more bioavailable compared to its synthetic equivalent. Moreover, it stays longer in human tissues, whereas the synthetic version is expelled more swiftly. Higher levels of D-Alpha-Tocopherol than DL-Alpha-Tocopherol in various tissues, including plasma, red blood cells, and muscles, corroborate this [1].
The root of this difference lies in their molecular structures, which allows our body’s absorption mechanisms to recognize and utilize them more effectively. Furthermore, the liver shows a notable preference for natural vitamin E, selecting it first for release into the bloodstream. This selective behavior by the liver ensures that natural vitamin E is preferentially incorporated into lipoproteins. As a result, natural vitamin E is more likely to accumulate in body tissues.
Absorption, dosage, and industrial considerations of vitamin E
Vitamin E is a fat-soluble nutrient, meaning it requires dietary fat for proper absorption. Its absorption occurs in the small intestine via mechanisms similar to dietary lipid uptake. It relies on emulsification by bile salts and pancreatic secretions, enabling the incorporation of vitamin E into mixed micelles, structures that facilitate the absorption of fat-soluble compounds in the intestine. From there, vitamin E is packaged into chylomicrons, lipoproteins that serve as transport vehicles, carrying vitamin E and other lipids through the lymphatic system and into the bloodstream.
The liver plays a key role in deciding which forms are retained and used. A specific protein called α-TTP selectively recognizes the natural form, D-alpha-tocopherol, and ensures it is distributed to body tissues. Other forms, such as synthetic isomers, are more quickly broken down and excreted, meaning their retention is less.
In terms of vitamin E dosage for adults, the Panel on Dietetic Products, Nutrition and Allergies (NDA) set the vitamin E daily requirement at 13 mg/day for men and 11 mg/day for women [2]. Regarding the tolerable upper intake level (UL) for α-tocopherol from all dietary sources, according to the 2024 EFSA Scientific Opinion, the limit is set at 300 mg/day [3]. This vitamin E upper limit value is maintained from earlier evaluations, as no new evidence was found to alter the dose–response relationship for adverse effects.
From an industrial perspective, compliance with such regulatory benchmarks is essential in product development. Manufacturers must consider both the bioavailability and stability of the vitamin E forms they use, particularly when selecting between free tocopherol and esterified derivatives such as tocopheryl acetate or succinate.
The power of natural vitamin E for optimal health and wellness
The US Food and Drug Administration (FDA) established that, for food-labeling purposes, natural vitamin E is about twice as bioavailable as synthetic vitamin E. This means that taking equal doses of both types results in the accumulation in the body of twice as much natural vitamin E as the synthetic form.
But the benefits of natural vitamin E are not limited to bioavailability alone. It’s a powerful biological antioxidant that protects cells from oxidative stress caused by free radicals, reducing the risk of chronic diseases, including heart disease, cancer, and neurodegenerative disorders. It’s also an ally of our immune system and promotes skin health by protecting against UV radiation and improving skin barrier function. Moreover, it contributes to eye health by reducing the risk of age-related macular degeneration and cataracts. Its anti-inflammatory effects protect against chronic inflammation, a root cause of many health conditions.
Read more about Examples of natural and synthetic antioxidants
Nutrabiol® E: the best alternative to synthetic vitamin E
BTSA, as a leading European manufacturer specializing in natural antioxidants and vitamin E, proudly presents Nutrabiol® E as the premier alternative to synthetic vitamin E. Our product is derived from top-quality D-Alpha-Tocopherol sourced from non-GMO vegetable oils, ensuring both purity and efficacy. It can be used to enrich food products and to fortify nutritional supplements, and it is available in ester form as well, for products that require greater stability.
Sources
- Ferslew KE, Acuff RV, Daigneault EA, Woolley TW, Stanton PE Jr. Pharmacokinetics and bioavailability of the RRR and all racemic stereoisomers of alpha-tocopherol in humans after single oral administration. J Clin Pharmacol. 1993 Jan;33(1):84-8. doi: 10.1002/j.1552-4604.1993.tb03909.x.
- EFSA NDA Panel (EFSA Panel on Dietetic Products, Nutrition and Allergies). Scientific Opinion on Dietary Reference Values for vitamin E as alpha-L-tocopherol. EFSA Journal 2015; 13(7):4149, 72 pp. doi:10.2903/j.efsa.2015.4149.
- EFSA NDA Panel (EFSA Panel on Nutrition, Novel Foods and Food Allergens), Turck D, Bohn T, Castenmiller J, de Henauw S, Hirsch-Ernst K-I, Knutsen HK, Maciuk A, Mangelsdorf I, McArdle HJ, Pentieva K, Siani A, Thies F, Tsabouri S, Vinceti M, Traber MG, Vrolijk M, Bercovici CM, de Sesmaisons Lecarré A, Fabiani L, … Naska A. Scientific opinion on the tolerable upper intake level for vitamin E. EFSA Journal, 2024;22(8), e8953. doi:10.2903/j.efsa.2024.8953
