Category Archives: Paleo Theory

Jane Brody Asks: Is the Paleo Diet Right for You?

Not your average cave-woman

Jane Brody at the New York Times wrote an article critical of the paleo diet. One of her objections is that average life spans in the pre-agricultural era were hardly longer than 40 years, so we have no idea what effect the paleo diet would have on longevity and prevention of late-onset “diseases of civilization.”

She writes:

Keep in mind that the life expectancy of people before the advent of agriculture 15,000 years ago rarely reached or exceeded 40, so their risk of developing the so-called diseases of civilization is unknown.

First of all, the widespread adoption of agriculture is thought to have occurred 10-12,000 years ago, not 15,000 years.

Secondly, even in 1900 average life span in the U.S. was only 47 years.

But read her entire article for yourself. She didn’t change my mind.

Steve Parker, M.D.

 

Paleo Theory: The sedentary (r)evolution: Have we lost our metabolic flexibility?

Gotcha!

If you can’t easily go over four hours without eating something, you’ve lost your metabolic flexibility. Or something.

European authors in F1000Research (?!) suggest we consider our hunter-gatherer roots for clues to prevention of diseases of modern civilization. Here’s the abstract to whet your appetite:

During the course of evolution, up until the agricultural revolution, environmental fluctuations forced the human species to develop a flexible metabolism in order to adapt its energy needs to various climate, seasonal and vegetation conditions. Metabolic flexibility safeguarded human survival independent of food availability. In modern times, humans switched their primal lifestyle towards a constant availability of energy-dense, yet often nutrient-deficient, foods, persistent psycho-emotional stressors and a lack of exercise. As a result, humans progressively gain metabolic disorders, such as the metabolic syndrome, type 2 diabetes, non-alcoholic fatty liver disease, certain types of cancer, cardiovascular disease and Alzheimer´s disease, wherever the sedentary lifestyle spreads in the world. For more than 2.5 million years, our capability to store fat for times of food shortage was an outstanding survival advantage. Nowadays, the same survival strategy in a completely altered surrounding is responsible for a constant accumulation of body fat. In this article, we argue that the metabolic disease epidemic is largely based on a deficit in metabolic flexibility. We hypothesize that the modern energetic inflexibility, typically displayed by symptoms of neuroglycopenia, can be reversed by re-cultivating suppressed metabolic programs, which became obsolete in an affluent environment, particularly the ability to easily switch to ketone body and fat oxidation. In a simplified model, the basic metabolic programs of humans’ primal hunter-gatherer lifestyle are opposed to the current sedentary lifestyle. Those metabolic programs, which are chronically neglected in modern surroundings, are identified and conclusions for the prevention of chronic metabolic diseases are drawn.

Source: The sedentary (r)evolution: Have we lost our metabolic flexibility?

Paleo and Mediterranean Diets Linked to Lower Risk of Death

The Journal of Nutrition in 2017 published a study that looked at baseline diet characteristics of over 21,000 folks, then over the next six years noted who died, and why. Guess how many died?

Here’s a clue. These U.S. study participants were at least 45 years old at the start of the study.

2,513 died. Seems high to me, so I bet the average age was close to 65.

Hank’s not worried about death

I can’t tell for sure from the report’s abstract, but it looks like the researchers were interested in the Mediterranean and caveman diets from the get-go. Study subjects who ate Paleo- or Mediterranean-style were significantly less likely to die over six years. They were less likely to die from any cause or from cancer or from cardiovascular disease.

Composition of the paleo diet is debatable (click for my 2012 definition).

Consider adopting some Mediterranean diet features, too.

Steve Parker, M.D.

Reference:

Paleolithic and Mediterranean Diet Pattern Scores Are Inversely Associated with All-Cause and Cause-Specific Mortality in Adults. First published February 8, 2017, doi: 10.3945/​jn.116.241919.

Abstract

Background: Poor diet quality is associated with a higher risk of many chronic diseases that are among the leading causes of death in the United States. It has been hypothesized that evolutionary discordance may account for some of the higher incidence and mortality from these diseases.

Objective: We investigated associations of 2 diet pattern scores, the Paleolithic and the Mediterranean, with all-cause and cause-specific mortality in the REGARDS (REasons for Geographic and Racial Differences in Stroke) study, a longitudinal cohort of black and white men and women ≥45 y of age.

Methods: Participants completed questionnaires, including a Block food-frequency questionnaire (FFQ), at baseline and were contacted every 6 mo to determine their health status. Of the analytic cohort (n = 21,423), a total of 2513 participants died during a median follow-up of 6.25 y. We created diet scores from FFQ responses and assessed their associations with mortality using multivariable Cox proportional hazards regression models adjusting for major risk factors.

Results: For those in the highest relative to the lowest quintiles of the Paleolithic and Mediterranean diet scores, the multivariable adjusted HRs for all-cause mortality were, respectively, 0.77 (95% CI: 0.67, 0.89; P-trend < 0.01) and 0.63 (95% CI: 0.54, 0.73; P-trend < 0.01). The corresponding HRs for all-cancer mortality were 0.72 (95% CI: 0.55, 0.95; P-trend = 0.03) and 0.64 (95% CI: 0.48, 0.84; P-trend = 0.01), and for all-cardiovascular disease mortality they were 0.78 (95% CI: 0.61, 1.00; P-trend = 0.06) and HR: 0.68 (95% CI: 0.53, 0.88; P-trend = 0.01).

Conclusions: Findings from this biracial prospective study suggest that diets closer to Paleolithic or Mediterranean diet patterns may be inversely associated with all-cause and cause-specific mortality.

 

Who Said the Paleo Diet Cures Dementia?

Christopher E. Pitt, a general practitioner in Australia, wrote an article in 2016 questioning the safety of the paleo diet and veracity of some of its more prominent advocates. Dr. Pitt reviewed most of the available scientific studies and concluded:

Overall, conclusions about the effectiveness of the Palaeolithic diet should be considered cautiously. Positive findings should be tempered by the lack of power of these studies, which were limited by their small numbers, heterogeneity and short duration. Nevertheless, there appears to be enough evidence to warrant further consideration of the Palaeolithic diet as a potential dietary option in the management of metabolic diseases. Larger independent trials with consistent methodology and longer duration are required to confirm the initial promise in these early studies. Claims that the Palaeolithic diet could treat or prevent conditions such as autism, dementia and mental illness are not supported by clinical research.

The Palaeolithic diet is currently over-hyped and under-researched. While the claims made by its celebrity proponents are not supported by current evidence, the Palaeolithic diet may be of benefit in the management of various metabolic derangements. Further research is warranted to test these early findings. GPs should caution patients on the Palaeolithic diet about adequate calcium intake, especially those at higher risk of osteoporosis.

I’ve read most of the clinical studies cited by Dr. Pitt and reviewed them here, except I don’t recall the Bligh study. [Bligh HF, Godsland IF, Frost G, et al. Plant-rich mixed meals based on Palaeolithic diet principles have a dramatic impact on incretin, peptide YY and satiety response, but show little effect on glucose and insulin homeostasis: An acute-effects randomised study. Br J Nutr 2015;113:574–84.]

I’m not going to address Dr. Pitt’s article point by point. I merely bring it to your attention for your consideration. I will say I think Dr. Pitt is being too deferential to entrenched and sclerotic “authoritative” panels (e.g., Australian dietary guidelines). I was the same until 2009. Regarding calcium, you’ll find my assessment via the search box above and to the right.

I certainly agree with Dr. Pitt that the paleo diet is no panacea, and that further research is warranted.

Steve Parker, M.D.

Paleolithic Dieters: You May Have an Iodine Deficiency

A pinch of salt may cut the bitterness in a cup of coffee

An article in the European Journal of Clinical Nutrition suggests that paleolithic-type diets may be deficient in iodine. See my comment after the link below.

Abstract

BACKGROUND/OBJECTIVES:

Different diets are used for weight loss. A Paleolithic-type diet (PD) has beneficial metabolic effects, but two of the largest iodine sources, table salt and dairy products, are excluded. The objectives of this study were to compare 24-h urinary iodine concentration (24-UIC) in subjects on PD with 24-UIC in subjects on a diet according to the Nordic Nutrition Recommendations (NNR) and to study if PD results in a higher risk of developing iodine deficiency (ID), than NNR diet.

SUBJECTS/METHODS:

A 2-year prospective randomized trial in a tertiary referral center where healthy postmenopausal overweight or obese women were randomized to either PD (n=35) or NNR diet (n=35). Dietary iodine intake, 24-UIC, 24-h urinary iodine excretion (24-UIE), free thyroxin (FT4), free triiodothyronine (FT3) and thyrotropin (TSH) were measured at baseline, 6 and 24 months. Completeness of urine sampling was monitored by para-aminobenzoic acid and salt intake by urinary sodium.

RESULTS:

At baseline, median 24-UIC (71.0 μg/l) and 24-UIE (134.0 μg/d) were similar in the PD and NNR groups. After 6 months, 24-UIC had decreased to 36.0 μg/l (P=0.001) and 24-UIE to 77.0 μg/d (P=0.001) in the PD group; in the NNR group, levels were unaltered. FT4, TSH and FT3 were similar in both groups, except for FT3 at 6 months being lower in PD than in NNR group.

CONCLUSIONS:

A PD results in a higher risk of developing ID, than a diet according to the NNR. Therefore, we suggest iodine supplementation should be considered when on a PD.

(European Journal of Clinical Nutrition advance online publication, 13 September 2017; doi:10.1038/ejcn.2017.134.PMID: 28901333 DOI: 10.1038/ejcn.2017.134)

Source: A Paleolithic-type diet results in iodine deficiency: a 2-year randomized trial in postmenopausal obese women. – PubMed – NCBI

Parker here. I thought I knew a little about the Paleolithic diet, so was surprised to read above that table salt is excluded. It’s not excluded from the Paleobetic Diet. Most table salt purchased in the U.S. iodine-fortified. The introduction of iodized salt in the U.S. in 1924 raised IQ in iodine-deficient regions by 15 points!

Dietitian Amy Kubal Answers, “Are Potatoes Paleo?”

Rosemary Chicken (garnished with pico de gallo) and Rosemary Potatoes

Rosemary Chicken (garnished with pico de gallo) and Rosemary Potatoes

“The whole “to spud or not to spud” issue is seriously ‘no small potatoes’ in the Paleosphere. It’s highly debated as to whether or not white potatoes are ‘safe’ or ‘allowed’, and if they are okay, the questions really start rolling in – Can I eat the skin? I should only eat the red ones, right? How should I prepare them? Do I need to only eat them cold? If I do eat them, does it mean I’m not ‘doing Paleo’? It’s exhausting and absolutely amazing how such an innocent looking food can create so much controversy. Seriously, people are VERY opinionated on the issue, and I’m sure my opinions will not go unopposed. Well, haters be damned, you’re going to get them anyway.”

RTWT.

Source: “Ask Amy The RD”: Are Those Spuds For You?? The “Paleoness” of Potatoes

paleo diet, Steve Parker MD

Sweet potatoes ready to pop in the oven

What Are Our Ancestral Sleep Patterns?

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He got up before sunrise

Here are some answers in the summary of an article in Current Biology:

How did humans sleep before the modern era? Because the tools to measure sleep under natural conditions were developed long after the invention of the electric devices suspected of delaying and reducing sleep, we investigated sleep in three preindustrial societies. We find that all three show similar sleep organization, suggesting that they express core human sleep patterns, most likely characteristic of pre-modern era Homo sapiens. Sleep periods, the times from onset to offset, averaged 6.9–8.5 hr, with sleep durations of 5.7–7.1 hr, amounts near the low end of those industrial societies. There was a difference of nearly 1 hr between summer and winter sleep. Daily variation in sleep duration was strongly linked to time of onset, rather than offset. None of these groups began sleep near sunset, onset occurring, on average, 3.3 hr after sunset. Awakening was usually before sunrise. The sleep period consistently occurred during the nighttime period of falling environmental temperature, was not interrupted by extended periods of waking, and terminated, with vasoconstriction, near the nadir of daily ambient temperature. The daily cycle of tem- perature change, largely eliminated from modern sleep environments, may be a potent natural regulator of sleep. Light exposure was maximal in the morning and greatly decreased at noon, indicating that all three groups seek shade at midday and that light activation of the suprachiasmatic nucleus is maximal in the morning. Napping occurred on <7% of days in winter and <22% of days in summer. Mimicking aspects of the natural environment might be effective in treating certain modern sleep disorders.

RTWT.

Paleolithic and Mediterranean Diet Patterns Reduce Markers of Inflammation

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Many chronic medical conditions are though to be caused by chronic inflammation in our bodies. Sample conditions include high blood pressure, coronary artery disease (heart attacks), metabolic syndrome, type 2 diabetes, autoimmune diseases, and perhaps some cancers.

Taking the association further: could we prevent or alleviate these conditions by reducing inflammation? If so, diet is one way to do it.

Here’s an abstract from a scientific article I found:

Background: Chronic inflammation and oxidative balance are associated with poor diet quality and risk of cancer and other chronic diseases. A diet–inflammation/oxidative balance association may relate to evolutionary discordance.

“Objective: We investigated associations between 2 diet pattern scores, the Paleolithic and the Mediterranean, and circulating concentrations of 2 related biomarkers, high-sensitivity C-reactive protein (hsCRP), an acute inflammatory protein, and F2-isoprostane, a reliable marker of in vivo lipid peroxidation.

Methods: In a pooled cross-sectional study of 30- to 74-y-old men and women in an elective outpatient colonoscopy population (n = 646), we created diet scores from responses on Willett food-frequency questionnaires and measured plasma hsCRP and F2-isoprostane concentrations by ELISA and gas chromatography–mass spectrometry, respectively. Both diet scores were calculated and categorized into quintiles, and their associations with biomarker concentrations were estimated with the use of general linear models to calculate and compare adjusted geometric means, and via unconditional ordinal logistic regression.

Results: There were statistically significant trends for decreasing geometric mean plasma hsCRP and F2-isoprostane concentrations with increasing quintiles of the Paleolithic and Mediterranean diet scores. The multivariable-adjusted ORs comparing those in the highest with those in the lowest quintiles of the Paleolithic and Mediterranean diet scores were 0.61 (95% CI: 0.36, 1.05; P-trend = 0.06) and 0.71 (95% CI: 0.42, 1.20; P-trend = 0.01), respectively, for a higher hsCRP concentration, and 0.51 (95% CI: 0.27, 0.95; P-trend 0.01) and 0.39 (95% CI: 0.21, 0.73; P-trend = 0.01), respectively, for a higher F2-isoprostane concentration.

Conclusion: These findings suggest that diets that are more Paleolithic- or Mediterranean-like may be associated with lower levels of systemic inflammation and oxidative stress in humans.”

Source: Paleolithic and Mediterranean Diet Pattern Scores Are Inversely Associated with Biomarkers of Inflammation and Oxidative Balance in Adults

Impact of meat and Lower Palaeolithic food processing techniques on chewing in humans 

Gotcha!

Gotcha!

Catherine Zink and Daniel Lieberman have a research paper you science nerds might be interested in. A teaser:

“Yet Homo erectus differs from earlier hominins in having relatively smaller teeth, reduced chewing muscles, weaker maximum bite force capabilities, and a relatively smaller gut. This paradoxical combination of increased energy demands along with decreased masticatory and digestive capacities is hypothesized to have been made possible by adding meat to the diet, by mechanically processing food using stone tools, or by cooking. Cooking, however, was apparently uncommon until 500,000 years ago.

Source: Impact of meat and Lower Palaeolithic food processing techniques on chewing in humans : Nature : Nature Publishing Group

Grant Schofield Defends the Paleo Diet for Diabetes

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Schofield is a Professor of Public Health at Auckland University of Technology and Director of the Human Potential Centre. Prof. Sofianos Andrikopoulos authored an anti-paleo diet editorial in the Medical Journal of Australia.

Schofield penned a rebuttal at Sciblogs. A sample:

“The paleo diet – the idea that we should be guided in human nutrition/public health nutrition by evolutionary history is steeped with controversy. Health experts and authorities are seemingly going well out of their way to make sure people are warned off such ways of eating.

Proponents are often mystified by this, because the idea of using human evolutionary history to understand human function is common in human biology. In fact its a guiding principle. As well, in the midst of a chronic disease epidemic, including diabetes and obesity which are potentially improved by this approach, you’d think approaches which are based on whole food eating, and appeal to at least some of the population would be welcomed.

I find it curious that other approaches such as vegetarianism, which are often based not around science, but religion and other beliefs are welcome in public health nutrition advice. Yet the paleo approach is not.

Yes, people who are follow this way of eating are restricted to eating much less processed food and often lower carbohydrate diets. Neither of these approaches are known to be anything but beneficial for human health, especially in the context of diabetes.”

Source: Sciblogs | Anti-paleo diet attacks miss the point Read the whole thing.

Steve Parker, M.D.

No degludec up in here!

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