man with a confused and surprised expression, prevent dementia

Vitamin E and selenium do not appear to help prevent dementia. Many people may be disappointed in these results from a clinical trial of these popular supplements. But is there reason to remain hopeful that what we eat and how we exercise can affect cognitive function?

Could Antioxidants Help Prevent Dementia?

Over the last several decades neurologists have considered oxidative stress as an important risk factor for neurodegenerative disorders like Alzheimer’s disease. That’s why they hoped antioxidant supplements might protect older people from cognitive decline and prevent dementia.

Unfortunately, a new study in JAMA Neurology shows no benefit from either vitamin E or selenium or the combination. The study ran from 2009 to 2015 and included 3,786 older men. They were randomly assigned to get vitamin E, selenium, a placebo or a combination of the two antioxidants. The men took tests of their cognitive ability at a few times during the study.

Results, Please:

An equal proportion of men in each group developed dementia. The authors concluded that the supplements were no better than placebo.

Kryscio et al, JAMA Neurology, March 20, 2017 

Is There Anything We Can Do To Prevent Dementia?

There are data to suggest that a Mediterranean diet does make a difference when it comes to cognitive decline and dementia. So, even though specific dietary supplements like vitamin E and/or selenium don’t seem beneficial by themselves, food with these nutrients is good for the brain. So is exercise.

We have always wondered why modern medicine insists on a reductionist way to study complex biological systems. Instead of trying to isolate one or two ingredients we suspect that a multifactorial process will be far better in the long run. That means LOTS of fruits and vegetables, fish and perhaps a glass of red wine now and again.

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  1. Cindy M. B.
    Seattle, WA

    Any article that says, ” X doesn’t prevent heart disease!” or ” Y doesn’t help Alzheimer’s!” always irritates me, because it indicates: “X and Y are no good.” This can be very misleading, because X and Y might very well do OTHER things which the study did not assess and — more importantly — which the study results do not acknowledge.
    This is exactly like those car commercials which focus on legroom or some other aspect of cars, and then crow that theirs is the best. Well, fine! But they don’t mention the other, more important, stuff which their car may NOT be best in! It’s not really lying, but it does leave a deceptive “takeaway.”

  2. Scott
    Chicago USA

    I am taking Carlton’s Fish Oil 1600 mg Omega 3’s with EPA and DHA. I understand, and correct if I am wrong, helps keep arteries more pliable and helps then with better blood flow.

    Consumer Reports more than 5 years ago said only Hupericin A helps with memory loss. Is this correct?

  3. chuck

    Neither your article nor the link to the study say what FORM of vitamin E and selenium was used. Since most medical “studies” are predisposed to being dismissive of nutritional supplements, they probably used the cheapest ones they could find, which no doubt means SYNTHETIC vitamin E, and sodium selenite, a relatively useless form of selenium. And who paid for this “study”? Probably a drug company.

  4. Sally

    What form of Vitamin E was used in the Neurology study? Unfortunately the abstract does not specify this critical detail and I can’t afford a Neurology subscription to read the full text. Too many studies of Vitamin E in the last decade have used only alpha tocepherol, which can actually be counter-therapeutic in doses over 100 mg, since the alpha form outcompetes with the more effective gamma form. Also, a complete E complex should include tocotrienols, which are usually not included in studies. See Joshua Trutt, MD, at for an excellent overview of the issues here.

  5. Virginia

    I think the photo accompanying this article is in poor taste.

  6. Mary

    Is Selenium good for muscle cramps in legs.? Have heard that it is a good suppliment for the muscles if you can barely walk? Please answer.

  7. Maria

    Dont be silly, both sides of my extensive Italian family ate EXCLUSIVELY a Mediterranean diet, and there are multiple incidences of Dementia and Alzheimer.

    I believe it is a genetic disorder and not much can be done to stop it.
    TOO BAD, SO SAD !!!!

  8. Jane H

    Prescription drug Minocycline 50mg daily will probably prevent alzheimers onset by reducing inflammation. It only works as a preventative and will not treat existing disease. This is a great drug that is under used.
    Doctors are using it more but usually as an antibiotic and not as anti inflammatory. It also will prevent(!) traumatic head injury damage when used immediately. It also prevents(!) osteoarthritis of the fingers. Do not use it as a last resort, it won’t work. See British Journal of Pharmacology as reference

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