Vitamin E – explaining the roles of tocopherols and tocotrienols

Vitamin E is a fat-soluble vitamin which has antioxidant properties. It is therefore considered important for tissues that have a high concentration of fat, preventing lipid peroxidation and thus supporting cell membranes and neurones.

Although vitamin E rich foods have shown positive benefits for health, particularly for cardiovascular and cognitive health; similar results have not been shown in research using α-tocopherol vitamin E supplements.  This article will look at vitamin E, explain its different forms and outline why, in spite of mixed research results in the past, vitamin E supplementation offers potential for future therapies.

Vitamin E describes a collection of 8 molecules; there are 4 tocopherols which are divided into 4 sub types alpha, beta, delta and gamma (α, β, δ and γ) and 4 tocotrienols (α, β, δ and γ). Tocopherols possess a saturated side chain whereas tocotrienols possess an unsaturated isoprenoid side chain, this will be explained later.

Tocopherols

Alpha-tocopherol predominates in the body due to specific mechanisms which favour its accumulation. For example, in the liver ‘α-tocopherol transfer protein’ preferentially incorporates α-tocopherol into plasma lipoproteins. The mechanisms are not yet fully understood (Stoker and Azzi, 2000), nevertheless, because of this, α-tocopherol has traditionally been considered the best form of vitamin E to supplement. Alpha-tocopherol has potent antioxidant capabilities and acts specifically (along with the other tocopherols and tocotrienols) as a fat-soluble antioxidant and is involved in reducing lipid peroxidation and supporting membrane stability.

The body will primarily use α-tocopherol and once it has exerted its effects as an antioxidant it is converted to a tocopheryl radical and therefore becomes pro-oxidative itself. The tocopheryl radical then needs to be regenerated back into α-tocopherol, by either vitamin C, glutathione or CoQ10, so that it can once again act as an antioxidant. If this regeneration does not occur, or if isolated α-tocopherol is present in high quantities, oxidative stress can be increased, this is most likely the reason for the negative research into vitamin E supplementation. Ouchi et al (2015) explain that the pro-oxidative effect of α-tocopherol is suppressed by the presence of the other tocopherols and tocotrienols. Therefore, it is essential that α-tocopherol is supplemented alongside the other forms of vitamin E and preferably in addition to other antioxidants such as vitamin C.

Gamma-tocopherol is the most abundant form of dietary vitamin E although it only possesses approximately 10% of the antioxidant activity of α-tocopherol and is also rapidly degraded. Along with β and δ tocopherol it complements the antioxidant actions of α-tocopherol. It has been shown to protect pancreatic β-cells against apoptosis induced by cytokine activation triggered by the presence of nitric oxide. In mice, a mixture of α and γ tocopherols reduced age-related transcriptional changes in the brain, therefore again supporting the use of a supplement which contains a full spectrum of vitamin E subtypes.

Tocotrienols

Until recently the tocotrienols have not received much attention as they are present in much lower concentrations than the tocopherols. However even though they are in low concentrations they have been shown to exert many positive actions in the body. The tocotrienols are distributed in tissue differently to tocopherols which suggests there are selective uptake mechanisms in various tissues.

The unsaturated side chain in tocotrienols allows for more efficient penetration into tissues with saturated fatty layers, particularly the brain and the liver and are better distributed in the lipid layers of cell membranes.

Added benefits of tocotrienols

Tocotrienols possess similar antioxidant capabilities to the tocopherols but have been shown to have many additional properties including (Ahsan et al, 2014):

Neuroprotection

In vivo studies by Sen et al (2002) demonstrated that at nano molar concentrations α-tocotrienol can protect against glutamate neuronal cell death and therefore have neuroprotective effects beyond its antioxidant properties. Osakada et al (2004) supported this and demonstrated in animal studies that, of the vitamin E analogues, α-tocotrienol had the most potent neuroprotection of cultured striated neurones. Other studies have also demonstrated that α-tocotrienol can protect against homocysteine induced apoptosis and therefore provide further neuroprotective properties.

Gumprict and Rockway (2014) identify a scientific case for the concomitant supplementation of omega 3 fatty acids along with tocotrienol containing vitamin E in children with autism. Many studies have identified consistently lower than normal levels of vitamin E as well as an increase in oxidative stress and neuro-inflammation in children with autism.

Anti-Inflammatory

Tocotrienols can act on many aspects of the inflammatory cascade, they have been shown to:

  • Suppress inflammatory markers (IL-1, IL-6, TNFα and NO) and down-regulate the transcription factor NF-kB.
  • Suppress Cyclooxygenase 2 (COX2) expression

Anti-cancer

The antioxidant and anti-inflammatory properties of tocotrienols help to prevent cell and DNA damage and therefore can protect against cancer, however they have also been shown to:

  • Induce apoptosis in prostate and breast cancer cells
  • Inhibit angiogenesis (growth of blood vessels within a tumour)
  • Inhibit cell cycle proliferation through cell cycle arrest, therefore inhibiting multiplication of cancer cells

Cardiovascular Support

Again, the anti-inflammatory and anti-oxidant (particularly as they are fat soluble antioxidants and can inhibit lipid peroxidation) properties of tocotrienols can provide support and protection for the cardiovascular system and studies have also demonstrated that they:

  • Suppress HMG CoA reductase (enzyme involved in production of cholesterol) and therefore reduce cholesterol levels (Quereshi et al, 1991)
  • Inhibit expression of cell adhesion molecules, therefore reducing the risk of thrombosis
  • Reduce the production of apolipoprotein B, platelet derived factor-4 and thromboxane B2 (all risk factors for cardiovascular disease)
  • Protect polyunsaturated fatty acids in tissues and cell membranes and red blood cells from haemolysis by oxidative agents

Anti-Diabetic Activity

In vivo studies have demonstrated multiple effects on diabetic animal models, including:

  • Oral administration decreased HbA1c, plasma glucose, plasma lipids, albuminuria, proteinuria, all of these are raised in diabetic patients
  • Improved insulin sensitivity
  • Prevented diabetic neuropathy
  • Counteracted inflammatory and oxidative markers in streptozotocin-induced diabetes

Immune-stimulating

Tocotrienols also may support healthy immune function as they:

  • Induce antibody production
  • Supress TNFα (immune marker often raised in auto-immune conditions)

Bone Support

Vitamin E supplements but particularly γ-tocotrienol have benefits to the maintenance of bone metabolism. It was shown that vitamin E supplements, containing γ-tocotrienol, reversed nicotine-induced bone loss and stimulated bone formation. In vivo studies have also demonstrated that tocotrienols can reverse bone loss caused by oxidative stress (free-radical induced) or excess glucocorticoids.

The antioxidant capabilities have also demonstrated a protective effect on the kidneys, liver and digestive system.

It therefore can be seen that isolated α-tocopherol may not be useful and potentially even harmful in excess but when vitamin E is supplemented in conjunction with all eight active molecules it can be used very effectively.

Vitamin E rich foods

It is obviously important to obtain vitamin E from the diet especially as many people are not reaching the optimum intake. Vitamin E rich food will contain the full spectrum of tocopherols and tocotrienols. You can increase vitamin E intake by eating:

  • A handful of almonds, eg alongside a piece of fruit to reduce the glycaemic load of the fruit
  • Half an avocado (contains 2mg of vitamin E)
  • Green vegetables such as swiss chard, spinach, kale and broccoli
  • Raw seeds including sunflower and pumpkin, add a handful to a salad.
  • Olives

Try a vitamin E rich smoothie by blending:

  • 1 handful of kale
  • Half an avocado
  • 1 tbsp of almonds
  • 1 tbsp of mixed seeds (include chia seeds for additional omega 3 fatty acids)
  • 1 cup of frozen cherries, raspberries or blue berries
  • Coconut water (enough to reach max line)

 

If you have any questions regarding the topics that have been raised, or any other health matters please do contact me (Amanda) by phone or email at any time.

amanda@cytoplan.co.uk, 01684 310099

Amanda Williams and the Cytoplan Editorial Team: Helen Drake, Clare Daley.


Relevant Cytoplan Products

Mixed tocopherols and tocotrienols – Containing the full spectrum of vitamin E as it occurs in nature; alpha, beta, delta, gamma tocopherol and alpha, beta, delta, gamma tocotrienol.

Food State Vitamin E – Food State Vitamin E capsules made from pea protein and vegetable oil. It therefore comes complete with all the four tocopherols and tocotrienols that make it a natural food complex.

Vitamin C Extra – A highly bioeffective and gentle Food State supplement of both vitamins C and E.

Wholefood Cherry C – Cherry-C capsules are rich in vitamin C and carotenoids, with the cherry-like fruits being one of the richest-known natural sources of vitamin C.

Liposomal glutathione – An antioxidant formula designed to help protect cells from free radicals.


Related Cytoplan blogs

Glutathione – the master antioxidant

Nutrient support for cardiovascular health

 


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