Tag Archives: longevity

Antioxidants prevent health-promoting effects of physical exercise

“Antioxidants prevent health-promoting effects of physical exercise in humans”

This is the title of a ground-breaking paper by a highly respected group of scientists (Ristow et al. 2009).   It is already received more than 320 citations in other peer-reviewed journals. That is phenomenal for any paper, let alone a paper that is just 4 or 5 years old.  Still, when someone posted the paper on a professional board as a topic of interest today, some readers tried to shoot it down as either sounding like “crap” or being old news of little interest.  The fact of the matter is it is a big-news high-impact paper that has led to a lot of interesting additional research.    All nine team members:

  • Michael Ristow
  • Kim Zarsea
  • Andreas Oberbach
  • Nora Kloting
  • Marc Birringer
  • Michael Kiehntopf
  • Michael Stumvoll
  • C. Ronald Kahne
  • Matthias Bluher

Deserve recognition and respect for the work they have done.  And generous license fees for replicas of their lab coats and various, sundry other merchandise such as that enjoyed by Dr. Who.  Dr. Who is frankly the envy of us all.

As with many papers, articles and books, the title does not tell the entire story.  If it did there would have been no need for hundreds of other researchers to continue working in this area.  While

Antioxidants prevent health-promoting effects of physical exercise in humans

Fighting about Anti-oxidants?
A Flatt posed in front of CrossFit Seven ladies Toilet. Don’t fight over antioxidants. Its going to end badly.

is a title that sounds like antioxidants should be consigned to the wastebasket the paper has a more interesting message.  Their purpose was to evaluate:

“the possibility that ROS are required for the insulin-sensitizing capabilities of physical exercise in healthy humans and that commonly used antioxidants, such as vitamin C and vitamin E, may abrogate the health-promoting effects of both physical exercise and oxidative stress in humans.”

ROS means Reactive Oxidizing Species.  ROS are what anti-oxidants are supposed to protect against.

The study found that giving healthy young men 1000mg or Vitamin C and 400IU of Vitamin E interfered with a beneficial effect of exercise.  That effect was increasing insulin sensitivity.  This is very important for diabetics.  Diabetics are encouraged to exercise in order to increase their insulin sensitivity.  If a diabetic takes vitamin C and/or vitamin E he or she may not benefit as much from exercise.  This doesn’t mean that anti-oxidants are bad.  Its that ROS and anti-oxidants are in a much more complicated relationship than we thought.  And that we should be careful with what we do to ourselves in the name of protecting our health.

ROS apparently play important signaling roles. In some contexts we need them. It is possible that taking high doses of anti-oxidants can interfere with the important function of ROS.

Ristow M, Zarse K, Oberbach A, Klöting N, Birringer M, Kiehntopf M, Stumvoll M, Kahn CR, & Blüher M (2009). Antioxidants prevent health-promoting effects of physical exercise in humans. Proceedings of the National Academy of Sciences of the United States of America, 106 (21), 8665-70 PMID: 19433800


Ristow M (2012). Interview with Michael Ristow. Aging, 4 (1) PMID: 22317964


CrossFit Calorie Restriction Diet and Longevity.

Crossfit calorie restriction . . . Maureen Dowd, the famous political columnist, predicts a dystopian future, with few survivors . . .

“The year is 2084, in the capital of the land formerly called North America . . . The Navy-Air Force game goes on, somehow, and there are annual CrossFit games on the Mall, led by flesh-eating Dark Seeker Paul Ryan, now 114 years old. CrossFit is still fighting the Department of Agriculture’s food pyramid, even though there’s no Department of Agriculture and no food.”

CrossFit HQ is currently advocating a fairly high protein diet.  But at the same time they recommend 30% of calories come from protein, 40% from carbohydrates and 30% from fat.  If you search for CrossFit calorie nutrition on the CrossFit website you will see that they also suggest that people look into calorie restriction to prolong life and preserve health.

Calorie restriction diet

A calorie restriction diet is a term used to describe a diet that is low in calories, but sufficient in nutrients.  The calorie restriction diet that is associated with life extension research is more tightly defined.   Laboratory animals (usually rats) are often kept on an ad libitum diet.  This means that food is available and the animal may eat whenever it feels like it.   A lab animal on a calorie restricted diet receives a percentage of what an average rat eats ad libitum.   For example, an animal may be fed 60% or 80% of an ad libitum diet.

Longevity and a Calorie Restriction Diet

Research using a number of different species shows that calorie restriction seems to prolong life.  Nematodes are remarkable in this respect.   Why animals on calorie restriction diets live longer is still uncertain.   Scientists continue to investigate the reasons.   Many believe that life extension is a reproductive strategy.  If times are bad a nematode (or other organism) may shift into low gear and  conserve resources in the hope that things will get better in the future.  If things get better the animal would then shift back into normal gear and get on with the business of reproduction.

Calorie restriction produces some interesting physiological and behavioral changes. In animals, calorie restriction

  • Increases activity levels (possibly because food seeking behavior increases)
  • Improves blood lipid profile
  • Results in fewer tumors
  • Improves memory and cognitive function (Ha!  I know exactly where to find that sunflower seed I hid last week!)

Short-term Calorie Restriction.

Short term calorie restriction produces a lot of the same effects.  This might be good.  Calorie restriction for life is probably unappealing to most.   Short term or intermittent calorie restriction also up-regulate certain biochemical pathways.  Or down-regulate others.  So far, it looks like short term calorie restriction does a number of interesting things:

  • Decreases inflammatory response (may help with healing and reduce coronary artery disease)
  • Increasing apoptosis (cell death) in tumors (Mukherjee et al. 2004)
  • Slowing growth of blood vessels (which slows tumor growth)
  • Lowering production of growth hormones (which would also slow tumor growth).

These things would extend life.  People who practice intermittent fasting tend to have lower risk of coronary artery disease and diabetes (Horne et al. 2008).  Maybe restricting calories sometimes might be a good idea.  Before surgery, for example.  People who fast before surgery seem to have fewer complications.

Calorie Restriction Diet and Longevity

Would calorie restriction extend life in humans?  That question has not been answered.  The idea that a person could permanently follow the kind of restrictive diet needed to to induce life-prolonging effects without sacrificing quality of life seems unlikely.  It also seems unlikely that, as CrossFit HQ maintains, a person could follow this type of diet and still have all the energy they need to live a healthy active life.    Once of the things observed in animals is that they appear to be “more energetic” than control animals on normal diets. However, it is possible that the “youthful  vigor” exhibited by animals on highly restrictive diets is not youthful vigor, but agitation, anxiety and restlessness.  These are the kinds of behaviors we expect in starving people.  Calorie restriction may be an adaptive change to stress.

Calorie restriction can have some undesirable side effects

  • Reduced Growth Hormone levels
  • Ovarian atrophy
  • Reduced Thyroid hormone levels
  • Loss of Muscle mass
  • Loss of Bone Mass

And some other probably unwanted effects as well:

  • Increased Aggression
  • Hoarding behavior
  • Voracious eating patterns
  • Throwing feces at researchers
  • Throwing whatever else you can get your little paws on at researchers

An important thing to keep in mind is that there is a difference between following an ad libitum diet when you are locked alone in a small cage with nothing but a pile of kibble and living a free life.    Animals in the wild live through good times and bad.  Having 20 – 40% less calories than you would eat if you were stuck in your room with a big bag of chips is a far cry from leading an active life.  Restricting calories in an otherwise free-living wild animal who works for a living may have very different effects.  Don’t be in a huge hurry to do this to your self.

A probably well-meaning lunatic  talked about putting his infant daughter on a calorie restriction diet so she would live a very long, healthy life.  (I must be a nut magnet.)  To all who are considering doing this to their children remember those news stories about kids found starving in locked closets.  The kids did not do well in there.   If you are considering doing it to yourself, understand that the point to reach is not starvation.  Calorie restriction may result in beneficial changes in physiology by causing mild stress.  That might mean just enough stress to increase activity levels, and alter physiology to produce some health benefits.  Huge food stress may not give the same results.  Huge stress in general has little going for it.


Robertson LT, & Mitchell JR (2013). Benefits of short-term dietary restriction in mammals. Experimental gerontology, 48 (10), 1043-8 PMID: 23376627

Mukherjee P, Abate LE, & Seyfried TN (2004). Antiangiogenic and proapoptotic effects of dietary restriction on experimental mouse and human brain tumors. Clinical cancer research : an official journal of the American Association for Cancer Research, 10 (16), 5622-9 PMID: 15328205

Telomeres and aging and exercise

Telomeres and Aging

Teleomeres are little caps on the ends of DNA that protect DNA from damage during cell division.  They get a little shorter with each cell division.  Telomeres are shorter in older people than in younger people. Telomere length has been reported to be longer in older endurance athletes than in older couch potatoes  Telomeres are thought to be important in aging.  You can find the abstract and access the full text through: http://www.pubmed.gov/.   This is hopefully good news for older endurance athletes and an encouragement to others to get moving.   (It is also possible that people with more resistant telomeres are the ones able to continue intense exercise into middle age and that the exercise did not change the nature of the telomeres.)  But interesting . . . Take a look at table 1.  There are a number of other variables aside from telomere length that you’d think would have been statistically significant but weren’t.  More research?

Congratulations to authors Larocca, Seals and Pierce.  And thank you for publishing this, Mechanisms of Ageing and Development (journal).