Many studies have indicated a link between excessive Vitamin E supplement use in diet/nutrition and a higher incidence of brain cancer and prostate cancer. Some studies have shown cancer preventive benefits for other cancers. The jury is still out on the risk/benefit of using plant-derived Vitamin E supplements by cancer patients, however excessive use of Vitamin E may not add much value.
Vitamin E are fat-soluble compounds found in many food sources such as corn oil, peanuts, vegetable oils, fruits and vegetables that we consume in our diets. Vitamin E is also taken as a supplement either individually or part of multi-vitamin supplementation for its health benefits of being an antioxidant and protecting cells from damage caused by reactive free radicals.
Use of Vitamin E & Brain Cancer
A study based in different neuro oncology and neurosurgery departments across United States hospitals analyzed structured interview data from 470 patients which was conducted following diagnosis of brain cancer glioblastoma multiforme (GBM). The results of the study indicated that a significantly large number of these patients (77%) reported randomly using some form of complementary therapy such as vitamins or natural supplements. Surprisingly, Vitamin E users had a higher mortality as compared to those that did not use Vitamin E (Mulphur BH et al, Neurooncol Pract., 2015).
In another study by Umea University, Sweden and Cancer Registry of Norway, the researchers used a different approach in determining risk factors for brain cancer, glioblastoma. They took serum samples up to 22 years prior to glioblastoma/brain cancer diagnosis and compared the metabolite concentrations of serum samples of those that developed the cancer from those that did not. They found significantly higher serum concentration of Vitamin E isoform alpha-tocopherol and gamma-tocopherol in cases that developed glioblastoma/brain cancer (Bjorkblom B et al, Oncotarget, 2016).
The above confounding association is also supported by another finished follow-up of a very large Selenium and Vitamin E Cancer Prevention Trial (SELECT) that showed a higher prostate cancer incidence in subjects who took Vitamin E supplementation (Klein EA et al, JAMA, 2011). Despite the above clinical data showing association of excessive Vitamin E levels and brain cancers, there are multiple studies that also support cancer preventive benefits of Vitamin E supplementation in many other cancers including lung, breast and others. Hence the jury is still out on the risk/benefit aspects of Vitamin E use for cancer patients and could be context dependent on the specific cancer type and the unique molecular characteristics of the cancer.
One reason why the excessive Vitamin E antioxidant supplementation can be harmful is because it could disrupt the fine balance of maintaining the right level of oxidative stress in our cellular environment. Too much oxidative stress can cause cell death and degeneration but too little of oxidative stress can also interfere with the inherent antioxidant capacity that in turn leads to other consequential changes. One such change is a decrease in a key tumor suppressor gene called P53, that is considered the guardian of the genome, thus increasing the probability of developing cancer (Sayin VI et al, Sci Transl Med., 2014). Hence, excessive use of Vitamin E supplements in cancer diet/nutrition (such as brain cancer) may be too much of a good thing!
Cancer patients often have to deal with different chemotherapy side effects which affect their quality of life and look out for alternative therapies for cancer. Taking the right nutrition and supplements based on scientific considerations (avoiding guesswork and random selection) is the best natural remedy for cancer and treatment related side-effects.