JUST  GOT  TO  SHARE  THIS  WITH  YOU,  FROM  THE  BLOCK-BUSTER  BOOK  "THE  BRAIN'S  WAY  OF  HEALING"  by  Norman  Doidge, M.D.

IT'S  A  BOOK  YOU  NEED  TO  READ,  EVERYONE  NEEDS  TO  READ  -  Keith Hunt

Deferring Dementia

The question inevitably arises: If walking can turn back Parkinsons symptoms, and can delay the onset of Huntington's, both degenerative diseases, might it have a role to play in the commonest degenerative disease of the brain—Alzheimer's disease?

The question is especially important because there are no effective —medications for Alzheimer's. Yet Alzheimer's and Parkinson's have smilarities. Dr. Mark P. Mattson, chief of the National Neurosciences Laboratory at the National Institute on Aging, National Institutes of Health, has shown that many of the cellular processes that cause problems in Parkinson's also occur in Alzheimer's but in different brain areas. In Parkinson's, the substantia nigra begins to malfunction first. In Alzheimer's, degenerative changes begin in the hippocampus (which turns short-term memories into long), which starts to shrink, so that its victims lose short-term memory. In Alzheimer's disease, the brain literally loses its plasticity, and its ability to make connections between neurons, many of which die.

In 2013 that pressing question about walking and Alzheimer's was answered. Walking was a key contributor to a very simple program that reduced the risk of dementia by a staggering 60 percent. If any drug could do that, it would be the most popular, talked-about treatment in medicine.

The breakthrough study was done by Dr. Peter Elwood and a team from the Cochrane Institute of Primary Care and Public Health, Cardiff University, United Kingdom, and released in December 2013. For thirty years, these researchers followed 2,235 men living in Caerphilly, Wales, aged 45 to 59, and observed the impact of five activities on their health and on whether they developed dementia or cognitive decline, heart disease, cancer, or early death. The Cardiff study was meticulous, examining the men every five years for the thirty years, and if they showed signs of cognitive decline or dementia, they were sent for detailed clinical assessments of high quality. It overcame study design problems from eleven previous studies (discussed in the endnotes).   

Results, showed that if the men did four or five of the following behaviors, their risk for cognitive (mental) decline and dementia (including Alzheimer's) fell by 60 percent:

Exercise (defined as vigorous exercise, or walking at least two miles a day, or biking ten miles a day). Exercise was the most powerful contributor to decreased risk of both general cognitive decline and dementia.

I  HAVE  GIVEN  YOU  ON  THIS  WEBSITE  AND  MY  BLOG,  THE  DR.  MERCOLA'S  BEST  WAY  TO  EXERCISE:  VIGOROUS  EXERCISE [LIKE  FLAT  OUT  GYM  BIKE  RIDING  AS  FAST  AS  POSSIBLE  FOR  30  SECONDS;  OR  AS  I  DO,  AS  FAST  AS  YOU  CAN  ONE  LAP  OF  THE  SWIMMING  POOL]  FOLLOWED  BY  60-90  REST,  THEN  REPEAT  THIS  A  NUMBER  OF  TIMES.  ALSO  DOING  WEIGHT-LIFTING  TWO  OR  THREE  TIMES  A  WEEK.  THEN  THERE  IS  THE  "CHARLES  ATLAS"  EXERCISES  FROM  HIS  HEALTH  AND  STRENGTH  COURSE  -  STILL  OBTAINABLE  -  Keith Hunt

Healthy diet (as measured by eating at least three to four servings of fruits and vegetables a day).*

Normal weight (as measured by having a body mass index between 18 and 25).

* We know much more about diet and the brain since that study was initiated thirty years ago. 

Low alcohol intake (alcohol is often a neurotoxin).

No smoking (also a case of avoiding a toxin).

All five factors promote the general cellular health of neurons and glia. All factors require that a person live closer to the ways our hunter-gatherer ancestors lived and thus use the body as it evolved to be used. All these behaviors are basically subtractive: don't do things we didn't evolve to do, such as sit all day, and travel sitting in cars; don't eat processed food, inhale smoke, or drink too much.

One of the reasons this work hasn't received more attention is that the scientific community has been so focused upon "curing" Alzheimer's by coming up with a drug for it, or thinking of it in terms of genetics. Of course, if "it is all in your genes," most people assume there is nothing they can do about it, except pray for "genetic breakthroughs." But as the Alzheimer's researcher and neurologist Tiffany Chow points out, "Only a very small percentage of people in the world carry an indelible familial pattern of inheritance of Alzheimer's." In addition, there are many known environmental causes of Alzheimer's and other forms of dementia: head injuries and exposure to certain toxins, like the pesticide DDT, increase the risk, while a high education level decreases the risk. As Chow puts it, environmental factors "interact with ... genetic makeup to eventually allow or deny dementia a foothold." People who have genetic risk factors commonly associated with Alzheimer's don't necessarily get it,* and even having multiple copies of the genetic materials associated with risk "is not sufficient to produce Alzheimer's Disease." So while having a first-degree relative with Alzheimer's increases one's genetic risk, that increased risk doesn't mean that protective techniques, like exercise, won't help. On the contrary, it probably makes them especially relevant for self-protection.

As for those without dementia, it is now crystal clear that physical exercise helps preserve brain functioning. Another breakthrough study, in 2011, shed important light on the cognitive effects of exercise. J. Eric

* The most commonly cited genetic risk factors are certain variations of the Apolipoprotein E gene on chromosome 19.

Ahlskog, of the department of neurology at the Mayo Clinic, and his team reviewed all 1,603 studies to date of exercise and cognitive impairment with a focus on dementia. Ahlskog did what is called a meta-analysis, examining all studies of high quality and selecting out the best, including randomized, controlled trials. The twenty-nine randomized, controlled studies that were selected documented that exercise—mostly aerobic— was helpful in improving cognitive functioning in adults without dementia, in terms of memory, attention, processing speed, and ability to form and act on plans. Typical doses in most studies are 2.5 hours of aerobic exercise a week. A recent randomized, controlled trial by the Mayo group shows that those (without dementia) who did aerobic exercise for a year showed significant hippocampal enlargement, compared with sedentary adults. These changes last, too. Another study showed that adults who walked had hippocampal enlargement nine years after they began their exercise program. Ahlskog also found that even those with dementia made some modest improvements with exercise.

Will incorporating these behaviors defer dementia indefinitely? 

We don't yet know. Right now, 15 percent of people over seventy have some dementia, and that number radically increases by age eighty-five. 

But it isn't inevitable in a long life: some people live to very advanced years without Alzheimer's. 

Only now that people are living longer are we able to study people over ninety—the "oldest old"—in significant numbers. These "nonagenarians" are the fastest-growing age group in North America: they number 2 million in the United States now and will number 10 million at midcentury. Though dementia increases with age, the University of California at Irvine's excellent "Ninety Plus" study of sixteen hundred nonagenarians has found that the majority do not have dementia. 

Studying that group as they age will tell us what characterizes the remarkable brains that don't radically degenerate even after a century of activity.

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