Category Archives: Paleo Theory

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!

Available worldwide

Óscar Picazo Compiled a List of Scientific Articles on the Paleolithic Diet

Not Oscar Picazo

Not Oscar Picazo

Click the link below to see the articles, which are in English. Óscar’s introduction:

“Hace ya más de un año, compartí aquí la lista actualizada de estudios hasta la fecha, en relación a la paleodieta, dieta evolutiva, o como se le quiera llamar.El último año ha sido bastante activo en este sentido, con varios trabajos publicados, varios ensayos clínicos, y un meta-análisis.A continuación la lista actualizada. Si falta alguno, por favor indícamelo y lo incluyo.Y solo por recordarlo… mi opinión sobre el tema.”

Source: Paleodieta: Bibliografía actualizada | Óscar Picazo

Thanks, Oscar!

Paleo Diet Pioneer Melvin Konner’s Latest Thoughts on Healthy Eating

Back in 1985, Melvin Konner and S. Boyd Eaton got the ball rolling on the current Paleolithic diet movement. Thirty years later, what would Konner say is a healthy way to eat?

Recent data on these issues make me more comfortable today saying what not to eat. Our ancestors had no refined carbs, which are killing us. We’d be wise to limit salt and saturated fat, which our ancestors’ prey had little of, and fiber and omega-three fatty acids seem to be good. Most humans have to avoid dairy; many must avoid wheat. Find out if you’re one of them. Exercise. That’s about it.

I’ve seen good data saying salt restriction is both harmful an helpful. So flip a coin or talk to your personal physician. If I were looking at starting a drug for hypertension, I’d certainly cut back on salt first and see if that cured me.

Recent clinical studies show that saturated fat isn’t harmful to most of us.

Steve Parker, M.D.

No link to suicide

An Argument for Copious Carbohydrate Content In the Paleo Diet

Salivary amylase helps us digest starches like wheat

Salivary amylase helps us digest starches like wheat

A recent scientific paper proposes that carbohydrates—starches specifically—played a larger role in the ancestral human diet than previously thought. I’ll call this paper the Hardy study since she’s the first named author. The only author I recognize is Jennie Brand-Miller, of glycemic index fame.

A key part of the hypothesis is that our ancestors’ use of fire made starchy foods much more digestible. That’s not controversial. Wrangham thinks hominins have been using fire for cooking for over a million years. Humans, remember, arrived on the scene about 200,000 years ago.

I’m not saying I agree or disagree with the researchers. Read the paper and decide for yourself. I do feel somewhat vindicated in my inclusion of potatoes and other tubers in my version of the Paleolithic diet.

RTWT.

Steve Parker, M.D.

PS: The article references the Pleistocene Epoch. You’ll find various definitions of that, but the Pleistocene ranged from about 1.8 million to 11,000 years ago .