SUBJ: Value and use of antioxidant supplements

SUBtitle: Reader comment and discussion

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SHORT NOTES:

Reader asks whether taking antioxidant vitamins are safe and proven to benefit\

Vitamin C is safe and proven at 500mg twice a day

Vitamin E is dangerous as a supplement at high doses

Most antioxidants are obtained with a healthy diet. Only C requires a supplement.

LONG NOTES:

I like your article about health, longevity and nutrition. I know that you take many antioxidants by pill, but when I read Pubmed, I also read that most Antioxidants Don’t Extend Lifespan In the past two decades, many large studies found that antioxidants do not slow down aging and don’t reduce mortality (R,R,R)[set 1]. One large meta-analysis consisting of 230,000 people even found that some antioxidants are associated with an increased risk of dying (R): vitamin A, vitamin E and beta-carotene intake was associated with slightly increased mortality.  Of course, many arguments can be brought up to counter these findings: in many studies the wrong form of antioxidants are given, or too low doses, or too late.

Still, both animal and human studies have painted a disappointing picture about the role of antioxidants in longevity. Animals have been given all kinds of antioxidant cocktails, but they didn’t live longer. At least according to well-conducted studies; there are many low-quality studies that sometimes do show that antioxidants slow down aging. But often, when these studies are reproduced by other research groups no longevity effects are seen.

 

I think there is a real danger of Antioxidants. Many studies have shown that antioxidants can even be dangerous, for example by increasing the risk of cancer or helping cancer to spread (metastasize) (R,R,R,R,R)[set 2].  This makes sense: cancer cells are metabolically very active, so they produce huge amounts of free radicals as a side effect of their metabolism. This means that especially cancer cells benefit from antioxidants that neutralize free radicals.

So it is not always advisable for cancer patients to take antioxidants.

Other studies show that antioxidants can undo the beneficial effects of exercise (R). Taking antioxidants to “recuperate” faster from exercise is also not always a good idea.

 

I appreciate your answer about my research because I like your newsletter that full of good information.

Best Regards, Bruno Lacroix MD

 

ROC’S RESPONSE

Dear Dr. Lacroix,

Thank you for a wonderfully documented letter.  At the Linus Pauling meetings, biannually, a top antioxidant research professor speaks frequently, explaining how the press loves to report stories of how bad vitamin C is, then a month later how good it is, and back and forth…a great way to get readers’ attention.  He then speaks of the articles published since his last presentation to explain the flaws in the media interpretation or the study conclusions.

 

Let me discuss vitamin C first.  Despite my publications and discussion with vitamin C researchers, they continue to do studies taking vitamin C supplements once a day. My publications point out that only raises vitamin C serum levels for 12 hours, so there is no protection half the day.  The researchers respond that there is low compliance by volunteers even to take one pill a day, and few would take it twice a day.  So appropriate studies have never been done with humans.

As I look at your references set 1, I find flaws in each one.  For instance, ref 1 and 2 states multivitamins do not prolong life or reduce heart disease.  I was taken to lunch by the executives of Centrum because I criticize their multivitamins.  Not enough vitamin C, too much iron, too much selenium, etc.  I agree a multivitamin is not good for health – though perhaps if you eat a typical horrible Western diet, it might help a little.

Ref 3 is great, “All randomized trials involving adults comparing beta carotene, vitamin A, vitamin C (ascorbic acid), vitamin E, and selenium either singly or combined vs placebo or vs no intervention were included in our analysis.  Conclusions: Treatment with beta carotene, vitamin A, and vitamin E may increase mortality. The potential roles of vitamin C and selenium on mortality need further study.”  It is well known that taking too much VA and VE is hazardous.  I think that selenium is also dangerous for people eating a healthy diet.

Looking at set 2 of your references, I again find that they focus on vitamin E and beta-carotene, where again too much vitamin E in known to promote cancer.  In contrast, intravenous vitamin C is being used now in many clinical trials to treat cancer patients because high dose vitamin C kills cancer cells.  That is the basis of my Triumph supplement, designed to reduce the risk of bladder cancer (R).  In my March 9 newsletter I remind people to take 500mg vitamin C twice a day to reduce stroke damage.  I have reported this before, but it bears repeating. Serum Vitamin C Concentration Was Inversely Associated With Subsequent 20-Year Incidence of Stroke in a Japanese Rural Community.

As for effect on animal longevity,  “In our review of literature on vitamin C supplementation and its effect on lifespan in different model organisms we found that some studies suggest an increase in lifespan, other studies failed to observe any beneficial effect of vitamin C on longevity and some studies even reported a decrease in lifespan following vitamin C supplementation.” (R) Of the 14 studies included in our analysis, three were carried out in worms, four in flies and seven in rodents. The discrepancies between the studies may be related to species-specific differences, the concentration of vitamin C administered, the duration of supplementation and whether vitamin C was used alone or as part of a combined antioxidant diet.

I am reminded often about confirmation bias.  We all take notice of information that supports our beliefs, and discount data which disagrees with our opinions.  That is why I am more reliant on biochemical mechanisms which document healthy effects.  There is a valid mechanism by which high vitamin C levels reduce the development of plaque in the arteries.  Vitamin E is need also, but only enough to load the LDL particles to transfer free radicals from the LDL to vitamin C in the serum.  There oxidized vitamin C is enzymatically regenerated.

So I continue to advocate for 500 mg vitamin C twice a day, and caution with most other vitamins.  My wife found an article recently of a study claiming 40% of supplement contain none of the ingredient on the label, and 70% do not contain the amounts on the label.  Eating a Mediterranean diet, getting exercise, avoiding stress, and following the other 69 steps on my essay how to live a long life is working well for me, as a youngster who is 75.

Thanks again for prompting this information/discussion.

-Roc