Human Brain Size Shrinking For Last 10,000+ Years

An article at Scientific American offers some explanations, but nobody knows why with certainty. Maybe it’s simply related to the decline in average human body size that started about 10,000 years ago, the dawn of the Agricultural Revolution.

I’d credit the SciAm author but can’t figure out who it is. A quote:

The way we live may have affected brain size. For instance, domesticated animals have smaller brains than their wild counterparts probably because they do not require the extra brainpower that could help them evade predators or hunt for food. Similarly, humans have become more domesticated.

Discovery magazine looked at shrinking brains in 2010.

Steve Parker, M.D.

Segmented Sleep: Our Ancestral Pattern?

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Richard Wrangham estimates hominins tamed fire and started cooking with it 1.8 million years ago

I heard about segmented sleep a couple years ago. The idea is that you sleep for maybe three hours, then get up and putter around for two or three hours, then go back to sleep for another three or four hours.

The easy availability of light after sunset has changed our sleeping patterns only recently, on an evolutionary scale. Before we had electric lights, candles, oil and gas lamps, our only sources of artificial light after sundown were campfires and short-lived torches.

Karen Emslie has an article on segmented sleep at Aeon. A snippet:

Before electric lighting, night was associated with crime and fear – people stayed inside and went early to bed. The time of their first sleep varied with season and social class, but usually commenced a couple of hours after dusk and lasted for three or four hours until, in the middle of the night, people naturally woke up. Prior to electric lighting, wealthier households often had other forms of artificial light – for instance, gas lamps – and in turn went to bed later. Interestingly, Ekirch found less reference to segmented sleep in personal papers from such households.

For those who indulged, however, night-waking was used for activities such as reading, praying and writing, untangling dreams, talking to sleeping partners or making love. As Ekirch points out, after a hard day of labouring, people were often too tired for amorous activities at ‘first’ bedtime (which might strike a chord with many busy people today) but, when they woke in the night, our ancestors were refreshed and ready for action. After various nocturnal activities, people became drowsy again and slipped into their second sleep cycle (also for three or four hours) before rising to a new day. We too can imagine, for example, going to bed at 9pm on a winter night, waking at midnight, reading and chatting until around 2am, then sleeping again until 6am.

Think about this if you have insomnia that wakes you in the middle of the night and you can’t get back to sleep. It may not be a detrimental condition that requires medication or other intervention. Can you really win a fight with a million years of evolution?

RTWT.

Steve Parker, M.D.

QOTD: Walter Voegtlin on Intellectual Independence

If this book must be dedicated to someone, it should be to the occasional man, woman, or child who still can resist the specious authority of food merchants, their lavish advertisements and spectacular television commercials, and retain sufficient intellectual independence to think for themselves.

—Walter L. Voegtlin, M.D., F.A.C.P., in The Stone Age Diet (1975)

Anne Hathaway Abandons Vegan Diet for Low-Carb Paleo

I don’t generally follow lifestyles of the rich and famous, but if you do, here you go.

“Hathaway” always makes me think of the Beverly Hillbillies, which gives you an idea how old I am. The Beverly Hills movie is a good one, too. It’ll teach you how to do the “California howdy.”

My wife and I are going to Hathaway’s latest movie tonight: Interstellar. I hear it’s best in the IMAX format.

Steve

Listen to Low-Carb Diet Proponents Franziska Spritzler and Dr. Troy Stapleton

Who says low-carb paleo diets are mostly meat?

Who says low-carb paleo diets are mostly meat?

Jimmy Moore posted an interview with Dr. Troy Stapleton and Franziska Spritzler, R.D. These two wouldn’t consider themselves paleo diet gurus by any means. They advocate carbohydrate-restricted diets for management of blood sugars in diabetes, consistent with my approach in the Paleobetic Diet. Dr. Stapleton might argue I allow too many carbohydrates. By the way, he has type 1 diabetes; I’ve written about him before. Franziska is available for consultation either by phone, Skype, or in person.

Steve Parker, M.D.

David Spero, RN, Makes the Case for Tight Blood SugarControl

at Diabetes Self-Managment. David writes:

“Two famous studies showed that tight control of glucose did not cause a statistically significant reduction in heart attacks or early death. But roughly 20 years after the studies ended, tight control subjects are living longer and healthier than those who were in the comparison groups.”

Those two famous studies, however, did originally show evidence of better eye, nerve, and kidney function via good control.

Steve Parker, M.D.

Metformin: More Effective in Blacks Than Whites

Diabetes Self-Management has some of the details.

The implication is that the genetically determined physiology of black diabetics is different from whites. There could be other explanations, admittedly.

 

Here’s why I bring this to your attention. You don’t see me review many scientific articles involving mice, rats, pigs, or rabbits. In fact, I hardly ever read them. I take care of human patients. I suspect there are too many genetic differences between us and them that clinically pertinent studies are rare.

If you read my blogs carefully, you’ll also note I often hesitate to generalize clinical study results from one ethnic group to others. The different black/white responses to metformin validates my approach.

Type 2 diabetes in whites and blacks may not be the same disease, and it could be different in Asians, Australian aborigines, and North American Native Americans. For that matter, Ethiopian black diabetes may not be the South Africa black diabetes.

You may also be starting to understand why there’s so much confusion about which diabetic drugs are the best. We have 12 different classes of drugs now; what’s best for me may not be best for you.

Steve Parker, M.D.

PS: Type 1 diabetes, on the other hand, is probably more homogenous across ethnic and national boundaries.

Jimmy Moore Found a Paleo-Friendly Periodontist, Dr. Alvin Danenberg

Click to listen to the recent podcast interview. Dr. Danenberg favors a Mark Sisson-style “primal” paleo diet. Dr. Danenberg attributes most common periodontal and dental problems to our modern diets with their prominent acellular carbohydrates and associated gut microbiome changes.

To find other dentists and dental hygienists who support a paleo diet approach to dental issues, click on “Teeth” in the subject categories in the far right-hand column.

Steve Parker, M.D.

Jimmy Moore’s Interview of Paleo Diet Pioneer Ray Audette

Click to listen.

Ray Audette is the author of the classic Neanderthin book from 1995. He credited his Paleolithic-style diet with curing his type 2 diabetes and rheumatoid arthritis.

Chris Highcock published an interview with Ray in 2010. The Dallas Observer News published an article about him in 1995.

Steve Parker, M.D.

Yet Another Benefit of Exercise: Memory Preservation

The NYT’s Well blog has the details. The brain’s hippocampus is a critical center for memory. Alzheimers disease is associated with a gene called apo-E4. Carriers of that gene who exercise regularly have less shrinkage of the hippocampus than non-exercisers.

To PROVE that regular exercise prevents dementia-related shrinkage of the hippocampus, you’d have to force some folks to exercise and stop others who wanted to exercise. A couple years later, scan their brains and compare the two groups. That study may never be done.

Another way to preserve your memory could be to keep your fasting blood sugars closer to the lower end of the normal range, rather than the higher end. That strategy may prevent degeneration of your hippocampus and amygdala.

The Mediterranean diet also seems to prevent or forestall dementia.

Steve Parker, M.D.