Tag Archives: plant-based diet

Book Review: The Blue Zones

Here’s my review of  The Blue Zones: Lessons for Living Longer From the People Who’ve Lived the Longest, a 2008 book by Dan Buettner.  I give the book four stars on Amazon.com’s five-star system (“I like it”). 

♦   ♦   ♦

The lifestyle principles advocated in The Blue Zones would indeed help the average person in the developed world live a longer and healthier life.  The book is a much-needed antidote to rampant longevity quackery.  Dan Buettner’s idea behind the book was “discovering the world’s best practices in health and longevity and putting them to work in our lives.”  He succeeds. 

Mr. Buettner assembled a multidisciplinary team of advisors and researchers to help him with a very difficult subject.  Do people living to 100, scattered over several continents, share any characteristics?  Do those commonalities lead to health and longevity? 

They studied four longevity hot spots (Blue Zones):

  • Okinawa islands (Japan)
  • Barbagia region of Sardinia (an island off the Italian mainland)
  • Loma Linda, California (a large cluster of Seventh Day Adventists)
  • and the Nicoya Peninsula (Costa Rica). 

Research focused on people who lived to be 100. 

Until recently, two of the Blue Zones—the Nicoyan Peninsula and Sardinia—were quite isolated, with relatively little influence from the outside world. 

Mr. Buettner et al identify nine key traits that are associated with longevity and health in these cultures.  Of course, association is not causation, which Mr. Buettner readily admits.  He draws more conclusions from the data than would many (most?) longevity scientists.  Scientists can wait for more data, but the rest of us have to decide and act based on what we know today.  Here are the “Power Nine”:

  1. regular low-intensity physical activity
  2. hari hachi bu (eat until only 80% full—from Okinawa)
  3. eat more plants and less meat than typical Western cultures
  4. judicious alcohol, favoring dark red wine
  5. have a clear purpose for being alive (a reason to get up in the morning, that makes a difference)
  6. keep stress under control
  7. participate in a spiritual community
  8. make family a priority
  9. be part of a tribe (social support system) that “shares Blue Zone values”

Of these, I would say the available research best supports numbers 1, 4, 7, 8, and the social support system.

I doubt that hari hachi bu (eat until you’re only 80% full) will work for us in the U.S.  It’s never been tested rigorously.  The idea is to avoid obesity.  

The author believes that average lifespan could be increased by a decade via compliance with the Power Nine.  And these would be good, relatively healthy years.  Not an extra 10 years living in a nursing home.

Appropriately and early on, Mr. Buettner addresses the issue of genetics by mentioning a single study of Danish twins that convinces him longevity is only 25% deterimined by genetic heritage.  Environment and lifestyle choices determine the other 75%.  I believe he underestimates the effect of genetics. 

Over half the population of the Nicoya Peninsula Blue Zone are of Chorotega Indian descent, not from Spanish Conquistadores.  Would a Danish twin study have much tosay about Chorotega Indians’ longevity?  We don’t know, but I’m skeptical.  Also, the Sardinians and Okinawans would seem to have centuries of a degree of inbreeding, too, according to Buettner’s own documentation. 
 
Do the Adventists tend to marry and breed with each other (like Mormons), thereby concentrating longevity genes?  You won’t find the question addressed in the book.

Because I think genetics plays a larger role in longevity than 25%, I’d estimate that the healthy lifestyle choices in this book might prolong life by six or seven years instead of 10.  But I’m splitting hairs.  I don’t have any better evidence than Mr. Buettner, just a hunch plus years of experience treating diseased and dying patients.

These four Blue Zones do share a mostly plant-based diet of natural foods with minimal processing.  Two of the populations—the Okinawans and Costa Ricans—didn’t seem to have any choice.  Heavy meat consumption just wasn’t an option available to them.  Rather than promoting a low-meat plant-based diet, it might be more accurate to conclude that “you don’t have to eat a lot of meat, chicken, or fish to live a long healthy life.”

In other words, it may not matter how much meat you eat as long as you eat the healthy optimal level of fruits, vegetables, and whole grains.  It’s a critical difference not addressed in this book except among the Adventists.

Even if you could live an extra two years as a vegan, I’m sure many people would choose to eat meat anyway.  By the way, this book conflates vegan, lacto-vegetarian, lacto-ovo vegetarian, near-vegetarian, and vegetarian into one: vegetarian.  It’s a common problem when considering the health aspects of vegetarianism.  They are not necessarily the same.   

By the same token, plenty of my patients have told me they don’t like any kind of exercise and they won’t do it, even if it would give them an extra two years of life.  What many don’t realize is that from a functional standpoint, regular exercise makes their bodies perform as if they were ten years younger.  There’s a huge difference between the age of 80 and 70 in terms of functional abilities.

Why read the book now that you have the Power Nine?  To convince you to change your unhealthy ways, and indispensible instruction on how to do so.

Steve Parker, M.D.

Disclosure:  The publisher’s representative did not pay me for this review, nor ask for a favorable review.  They offered me a review copy and three give-aways, and I accepted.  I figure the cost of the books to the publisher was $16 USD total.  I gave away the books through my Advanced Mediterranean Diet Blog.  Cost of shipping the books to the winners came out of my pocket.

3 Comments

Filed under Book Reviews, Vegetarian Diet

Are Vegetarian Diets Any Good For Diabetes?

Plant-based diets may offer special benefits to people with diabetes, according to a recent review article by U.S. researchers who reviewed the pertinent English language literature published since 1966.  They found 116 potentially relevant articles, 10 of which were directly related to diabetes management and glucose control.

The authors failed to define “vegetarian” early on.  Some vegetarians eat eggs, some eat cheese, some drink milk.  I assume vegans eat no animal products whatsoever.  On the last page of the review the authors write that a vegetarian “does not eat meat, fish, or poultry” although it’s not clear if that applies throughout the review.  There are many references to “low-fat vegetarian” diets, with little or no mention of moderate- or high-fat vegetarian diets.

The authors often refer to vegetarian diets as “plant-based.”  No doubt, they are.  But even the healthy Mediterranean diet is considered plant-based, while clearly not vegetarian.

It’s also unclear whether they focused on type 1 or type 2 diabetes.  My sense is, probably type 2.

Here are the major points: 

  1. Are vegetarians less likely to develop diabetes?  Observational studies have found a lower prevalence of diabetes among vegetarians compared to non-vegetarians, especially among Seventh Day Adventists.  In other studies, meat consumption is linked to higher risk of diabetes among women. 
  2. Do vegetarian diets help control diabetes?  Several small studies showed that low-fat near-vegetarian and vegan diets improved glucose control and insulin sensitivity and reduced diabetes medication use, compared with a traditional diabetes diet – which is typically low-fat and high-carb.  I’m not sure, but I assume that the intervention diets were not heavy in refined, processed carbohydrates, but instead consisted of natural whole plant foods.  “Weight loss accounts for much although not all, of the effect of plant-based diets on glycemic control,” they write.
  3. Heart disease is quite common in older diabetics.  Do vegetarian diets offer any cardiac benefits?  They cite Dr. Ornish’s Lifestyle Heart Trial of a low-fat vegetarian diet and intensive lifestyle intervention: smoking cessation, stress management (meditation?), mild exercise, and group meetings.  Dr. Ornish’s program reduced LDL cholesterol by 37%, reversed heart artery blockages in 82% of participants, and found 60% lower risk of cardiac events compared to the control group. Dr. Ornish’s Multisite Lifestyle Cardiac Intervention Program also documented impressive cardiac results at 12 weeks, but had no control group.  Dr. Caldwell Esselstyne is also mentioned in this context.
  4. Vegetarian diets are linked to lower blood pressure, which may help prolong life and prevent heart attacks and strokes.
  5. Antioxidant-rich foods like fruits and vegetables—common in the Mediterranean diet and vegetarian diets—may lower cardiovascular disease risk. 
  6. People with diabetes are at risk for impaired kidney funtion.  In women with impaired baseline kidney funtion, high animal protein intake is associated with continued kidney deterioration. 
  7. A small study showed dramatic improvement in type 2 diabetics with painful neuropathy over 25 days on a low-fat vegan diet and a daily 30-minute walk.  Many participants were able to reduce diabetes drug dosages.
  8. Do any diabetes advocacy associations endorse vegetarian diets for people with diabetes?  The American Dietetic Association deems that vegetarian and vegan diets, if well-planned, are nutritionally adequate. I don’t know the position of the American Diabetes Association.  Vegetarians need planning to get adequate vitamin D, B12, and calcium.
  9. “Low-fat vegetarian and vegan diets do not require individuals to limit energy or carbohydrate intake….”  If true (and these guys should know), that might broaden the diet’s appeal.
  10. I saw no mention of decreased overall mortality in vegetarians.

My Comments

Have you heard of the Physicians Committee for Responsible Medicine?  Their president is Neal Barnard, the lead author of the study at hand.  He has a new book on reversal of diabetes with a low-fat vegetarian diet.

The authors cite a journal article (reference #16) in support of plant-based diets, but the article doesn’t mention a vegetarian or vegan diet—it’s high-carb, high-fiber diet.  I didn’t review all 92 of their references to see if any others were misleading.

“Plant-based diets” must be a euphemism for vegetarian diets.  Too many people shut down when you talk to them about vegetarian diets.

I won’t rule out the possibility that vegetarian/vegan diets may be helpful in management of diabetes.  Such diets are, of course, 180 degrees different from the very low-carb diets I’ve reviewed favorably in these pages!  Both models, ideally, move away from the over-processed, concentrated carbohydrates so prevalent in Western culture.  Perhaps that’s the unifying healthy theme, if there is one. 

Or different sub-types of diabetes respond better to particular diets.

I heartily agree with the authors that larger clinical trials of vegetarian diets in diabetics are needed.  I’d love to see a long-term randomized controlled trial comparing a very low-carb diet diet with a low-fat vegetarian diet.  That’s the best way to settle which is better for diabetics: vegetarian or low-carb.

It’ll never be done.

Has a vegetarian diet helped control your diabetes?

Steve Parker, M.D.

Reference:  Barnard, Neal, et al.  Vegetarian and vegan diets in type 2 diabetes managementNutrition Reviews, 67(2009): 255-263.   doi: 10.1111/j.1753-4887.2009.00198.x

19 Comments

Filed under coronary heart disease, Diabetes Complications, Vegetarian Diet