Monday, March 27, 2017

BROAD Study Whole Foods Plant-Based Diet Results Vs. Paleolithic Diet Study Results

Wright et al just published "The BROAD study: A randomised controlled trial using a whole food plant-based diet in the community for obesity, ischaemic heart disease or diabetes," in Nutrition & Diabetes [(2017) 7, e256; doi:10.1038/nutd.2017.3].  In this article I am going to highlight some of their data and compare their results to those obtained by Jonsson et al. in a study of a paleolithic diet intervention. 

The BROAD study randomized 65 people ages 35-70 to either a control group (n=32) or a whole foods plant-based (WFPB) diet with supplemental vitamin B12 group (n=33).  This WFPB diet was starch-based and the B12 supplement was methycolbalamin, not the common cyanocobalamin:
"This dietary approach included whole grains, legumes, vegetables and fruits. Participants were advised to eat until satiation. We placed no restriction on total energy intake. Participants were asked to not count calories. We provided a ‘traffic-light’ diet chart to participants outlining which foods to consume, limit or avoid (Supplementary Table S1). We encouraged starches such as potatoes, sweet potato, bread, cereals and pasta to satisfy the appetite. Participants were asked to avoid refined oils (e.g. olive or coconut oil) and animal products (meat, fish, eggs and dairy products). We discouraged high-fat plant foods such as nuts and avocados, and highly processed foods. We encouraged participants to minimise sugar, salt and caffeinated beverages. We provided 50μg daily vitamin B12 (methylcobalamin) supplements. The intervention group attended 2-h evening sessions twice-weekly for 12 weeks. We ran sessions at a local polytechnic, incorporating a chef-guided cooking tutorial and presentation by doctors, with a discussion. Programme outline provided (Supplementary Table S2). Special events included screening the documentary 'Forks Over Knives' and an accompanying film endorsing the WFPB diet; discussion sessions; restaurant meals; quiz night; potlucks; and graduation ceremony. Both intervention and control group participants received $40 petrol vouchers to cover travel costs and received a birthday card along with a voucher redeemable for a native plant."  
The control group received only "standard medical care" which is not described in detail in the report, but there is no mention of the 'standard' group receiving any dietary guidance at all.  It seems likely that the intervention group received much more interaction with health care providers and had strong social support to adhere to the WFPB diet.

The results were impressive to some WFPB diet advocates, but not so much in my view.

Mean BMI reduction was 4.4 at 6 months, but only 4.2 at 12 months; this means that over the second 6 months, some people regained weight lost in the first 6 months. In the authors' words "From 6 to 12 months intervention BMI increased non-significantly by 0.4."

Mean weight reduction at 6 months was 12.1 kg, and at 12 months was 11.5 kg.  Again, people lost weight during the first six months, then some regained.  More importantly to me, no data is given on the nature of the weight loss.  What proportion was fat or lean?  No data provided.

Cholesterol reduction followed a similar pattern.  "Within the intervention group mean reduction in total cholesterol was statistically significant at all time periods, although there was a smaller effect size with time: at month 3 it was 0.95 mmoll−1; at month 6 it was 0.71 mmoll−1; and at month 12 it was 0.55..."

In the BROAD study, the mean baseline body weight and BMI of subjects eating the WFPB diet were, respectively, 94.8 kg and 34.5, and these declined to 82.9 kg and 30.2 at 6 months.  For comparison, in the Jonsson et al. study using a paleolithic diet intervention in 13 subjects with T2 diabetes, the mean baseline body weight and BMI of subjects eating the paleolithic diet were, respectively, 87 kg and 30, and these declined to 82 kg and 28.  Thus the subjects eating the WFPB diet had a mean weight loss of 12.1 kg over 6 months, while the subjects eating the paleolithic diet had a mean weight loss of 5 kg over 6 months.  It is worth noting however the the subjects in the BROAD study started 7 kg heavier than those in the paleolithic diet study; generally, the rate of initial weight loss is greater the higher the initial starting weight.  Also, weight loss essentially stopped after 6 months in the BROAD study, and we don't know what happened after 6 months in the Jonsson et al. study.  Achieving a healthy body weight is a long-term proposition and this study doesn't inspire confidence that the WFPB diet is particularly successful long-term, since those eating the WFPB diet did not lose weight between 6 and 12 months and were still on average in the obese category at the 12 month mark.

As I will discuss below, adherence to the WFPB diet deteriorated significantly over the 12 months of follow-up.  I will also add that when first adopting a WFPB diet many people do not understand how much whole plant food one must eat to achieve a normal caloric intake.  In my experience, most people new to a WFPB diet take portions similar to what they are used to eating of foods having a higher energy density.  After some time with the diet, people get the idea and get really hungry, and find that they are able to eat large amounts of starches.  This might account for a stalling of weight loss as participants became more familiar with the WFPB diet.  

In the BROAD intervention group the mean total cholesterol decreased from 5.4 mmoll−1 (208 mg/dL) at baseline to 4.5 (174) at 3 months, then rose to 4.7 (182) at 6 months, and to 5.0 (193) at 12 months.  For comparison, in the Jonsson et al.  paleolithic diet study the mean cholesterol in that trial started at 4.4 mmol (170 mg/dL) and consistently dropped to 4.3 (166 mg/dL) at 6 months during which time the subjects consumed a mean of 340 g (~0.62 lb.) meat, meat products, and fish and 71 g eggs (about 1.5 eggs) every day and had a mean daily intake of 577 mg cholesterol.

The apparent paradox here is that the subjects eating the meat- and cholesterol-rich paleolithic diet and having a slightly slower rate of weight loss had a more consistent trend to lower total cholesterol levels, and achieved lower total cholesterol levels at 6 months, than subjects eating the WFPB diet in the BROAD project.

According to the BROAD report, HDL decreased slightly (baseline 1.3, 3 months 1.1, 6 months 1.2) in subjects on the WFPB diet, despite total cholesterol reduction being rather modest and short-lived.  In contrast, in the paleolithic diet study by Jonsson et al. HDL remained stable over 6 months despite a consistent reduction in total cholesterol.

According to the BROAD report the cholesterol reduction at 6 months was not significantly different from the control group :  "Comparing standard care plus dietary programme (intervention) to standard care (control) at month 6, our analysis showed a nonsignificant reduction in total cholesterol at 0.45."

How did this happen?  The control group was taking cholesterol-lowering medications.  In fact, "Control group medications increased from 74 to 80 over 6 months, an 8% increase, and intervention group medication usage decreased from 94 to 74 at 6 months, and to 67 over 12 months: a 29% decrease..."  So, a positive interpretation is that the WFPB diet produced cholesterol reductions similar to pharmaceutical treatments.

In the BROAD study, triglycerides increased in subjects eating the WFPB diet, starting at 1.6 at baseline, up to 1.8 at 3 months and 1.9 at 6 months.  In the Jonsson et al. paleolithic diet study, triglycerides declined from 1.5 at baseline to 1.3 at 3 months and 1.2 at 6 months. Comparing these two studies, the paleolithic diet appears more effective than a starch-based WFPB diet at reducing triglycerides.

The authors of the BROAD study describe the intervention participants as "highly adherent with the dietary changes, although this decreased with time."  They report that "Multiple intervention participants stated 'not being hungry' was important in enabling adherence."

Nevertheless, despite reporting 'not being hungry' and getting intensive education and social support, adherence to the WFPB diet declined significantly over time:  "Dietary indiscretions (diet) over 3 days were used as adherence measure...In the intervention group, indiscretions increased significantly from 1  at 3 months to 3 (±1) at 6 months, and then increased significantly to 5 (±1) at 1 year."  Assuming 3 meals daily, 5 'indiscretions' over 3 days suggests an 'indiscretion' at more than half of meals by 12 months.

I am curious to know whether these 'indiscretions' consisted more of refined plant foods, higher fat plant foods, or animal products but the authors of the BROAD report give no data in this report.  In contrast Jonsson et al. listed in their Table 5 the mean intakes of beans, cereals, rice, milk products, bakery products by their subjects when assigned to the paleolithic diet intervention.  It appears that the subjects assigned to the paleolithic diet intervention were able to reduce intakes of these items to negligible levels for 6 months. 

In the BROAD study, HbA1c (mmolmol-1) declined in the WFPB intervention group from 42 (6%) to 39 (5.7%) at 6 months and to 37 (5.5%) at 12 months.  Thus, over 6 months the decline (using HbA1c%) was 5%.  In comparison, Jonsson et al. reported a decline of HbA1c from 6.6% to 5.6% over 6 months, or 15% in subjects consuming a paleolithic diet.  Comparing these two studies alone, the paleolithic diet appears to have been far more effective in reducing HbA1c levels.

According to Table 2 of the BROAD report, both systolic and diastolic blood pressure were virtually unchanged over 6 months of WFPB diet (baseline 133/81, 6 months 132/82). In comparison, Jonsson et al. reported a baseline mean BP of 150/83 and a decline to 145/82 at 6 months in their paleolithic diet intervention.

The BROAD report does not include data on C-reactive protein (CRP), a measure of systemic inflammation.  I would have liked to see this, given that systemic inflammation is a risk factor for cardiovascular disease.  Jonsson et al. reported a decrease in CRP from 2.4 at baseline to 1.8 at 6 months for their subjects consuming a paleolithic diet.  It would be interesting to know if the WFPB diet matched or surpassed this.

Of particular interest in comparing these studies is the difference in amount of educational time devoted to helping the subjects adopt the intervention diets.  As already quoted above, in the BROAD study subjects received quite a bit of education, documentaries, support groups, restaurant meals, potlucks, etc..  In comparison, in the paleolithic diet intervention study of Jonsson et al. the instruction was quite limited, as described in their report:

  "All eligible subjects were informed of the intention to compare two healthy diets in the treatment of type 2 diabetes and that it was unknown if any of them would be superior to the other. At study start all eligible subjects were randomized to start with either a Diabetes diet in accordance with current guidelines [17] or a Paleolithic diet. Randomization was performed by UCB, GP and AH by opening opaque, sealed envelopes (prepared by TJ) containing a note of the initial diet with equal proportions of envelopes for both diets. After randomization, there was no blinding of dietary assignment to study participants, nor to those administering the interventions or assessing the outcomes. Immediately after randomization, all subjects received oral and written information individually (by UCB, GP or AH) in the morning about their respective initial diet. After three months all subjects switched diets and received new oral and written information individually (by UCB, GP or AH) about the diet of the following three months. Written information with dietary advice and food recipes were similarly formulated for both diets. For increased conformity, the dietary advice and data collection procedure were discussed by all authors except YG at several meetings prior to start of study. Advice about regular physical activity was given equally to all subjects.
"The information on the Diabetes diet stated that it should aim at evenly distributed meals with increased intake of vegetables, root vegetables, dietary fiber, whole-grain bread and other whole-grain cereal products, fruits and berries, and decreased intake of total fat with more unsaturated fat. The majority of dietary energy should come from carbohydrates from foods naturally rich in carbohydrate and dietary fiber. The concepts of glycemic index and varied meals through meal planning by the Plate Model were explained [18]. Salt intake was recommended to be kept below 6 g per day.
"The information on the Paleolithic diet stated that it should be based on lean meat, fish, fruit, leafy and cruciferous vegetables, root vegetables, eggs and nuts, while excluding dairy products, cereal grains, beans, refined fats, sugar, candy, soft drinks, beer and extra addition of salt. The following items were recommended in limited amounts for the Paleolithic diet: eggs (≤2 per day), nuts (preferentially walnuts), dried fruit, potatoes (≤1 medium-sized per day), rapeseed or olive oil (≤1 tablespoon per day), wine (≤1 glass per day). The intake of other foods was not restricted and no advice was given with regard to proportions of food categories (e.g. animal versus plant foods). The evolutionary rationale for a Paleolithic diet and potential benefits were explained [19]."
In both the BROAD study and the Jonsson et al. study subjects were allowed to consume some foods in unlimited quantities (WFPB: whole grains, legumes, vegetables, fruits; Paleolithic diet: lean meat, fish, fruit, leafy and cruciferous vegetables, root vegetables).  In both studies subjects lost body weight without intentional energy restriction.  However, in the Jonsson et al. the outcomes were achieved without giving the subjects support groups, cooking classes, potlucks and so on.  In the BROAD study the greatest beneficial changes occurred in the first three months, during which the subjects received the intensive intervention with twice weekly meetings, cooking classes, potlucks, documentary viewings, and so on.  After 3 months adherence declined and some markers started to reverse.  This might suggest that people can adhere to a low-fat, starch-based WFPB diet only when intensively coached and supported; while it seems the subjects assigned to the paleolithic diet in the study by Jonsson et al. were able to adopt and adhere to a paleolithic diet without similarly intensive intervention and yet achieve progressive improvements in metabolic function.

The authors of the BROAD study attributed the weight loss in subjects eating the WFPB diet to a reduction in energy density of the diet. 
"This randomised controlled trial compared a 12-week WFPB dietary programme to normal care alone. The intervention led to significant and sustained BMI and weight reduction at all measurement points compared with the control group. To the best of our knowledge, there are no randomised controlled trials that have achieved a greater average weight loss over a 6- or 12-month period, without mandating regular exercise or restricting total caloric intake.9, 10, 41 The key difference between this trial and other approaches to weight loss was that participants were informed to eat the WFPB diet ad libitum and to focus efforts on diet, rather than increasing exercise. The mechanism for this is likely the reduction in the energy density of the food consumed (lower fat, higher water and fibre).42"
Unfortunately it appears that this reduction of energy density was efficacious for only a limited time.  In contrast, Jonsson et al. offer several lines of explanation for the effectiveness of the paleolithic diet intervention; in their words:
"No advice was given to restrict food intake. Therefore, the lower reported energy intake during the Paleolithic diet despite no difference in weight of reported food intake agrees with the notion that such a diet is satiating and facilitates a reduced caloric intake [4,27]. Accordingly, energy density was lower in the Paleolithic diet and also correlated with alterations of both weight and waist circumference. The higher amount of fruit and vegetables during the Paleolithic period may have promoted weight loss due to its high content of water, which is thought to be satiating [28]. Interestingly, the Paleolithic diet appeared to be satiating despite a lower content of fiber in this study. The slightly higher relative protein intake, as percentage of total calorie intake, may also have added to a satiating effect [29,30]. Alternative explanations on satiation, such as dietary effects on leptin resistance, could also be considered [31]."
"A reduced energy intake would evidently be a major explanation for the beneficial effects of the Paleolithic diet on weight and waist circumference. Meta-analyses and large trials with various lifestyle interventions indicate that reduced caloric intake is more important for long-term weight loss than other known dietary factors, including macronutrient composition [32-40]. In studies shorter than 6 months, such as this one, differences in GI and/or GL may also have played a role for weight change. A Cochrane review found that overweight or obese people lost slightly more weight during 5–12 weeks of low GI diets [41], and short-term carbohydrate restriction possibly results in greater weight loss than low-fat diets [29]. However, dietary GI and dietary GL did not correlate with alterations of weight, waist circumference or metabolic variables in our study. It should also be noted that, in the present study, reported mean absolute carbohydrate intake in the Paleolithic diet (g per day) was only slightly below the 130 g per day recommended by the American Diabetes Association, and clearly above 50 g per day, which has been proposed as the level below which a diet should be termed a low carbohydrate diet [42]."
 All in all, the BROAD study results were not as exceptional as advocates of whole foods plant-based diets might like them to be.  Although the initial weight loss was large, it was not sustained for more than 6 months, and adherence deteriorated substantially after 3 months despite intensive initial intervention.  It also appears that the WFPB diet did not have uniquely favorable effects on total cholesterol. It appeared less effective than a paleolithic diet for reducing HbA1c and blood pressure, and actually increased triglycerides despite being composed of unrefined starches, whereas a paleolithic diet intervention decreased triglycerides.  I feel disappointed that the BROAD study authors either did not measure or did not report CRP levels, so we don't know if it performs as well as or better than a paleolithic diet intervention in this respect. 

 

20 comments:

FXScouse said...
This comment has been removed by the author.
FXScouse said...

It is difficult to get excited about either study.
First, all subjects were either significantly overweight or obese. It is known that overweight people are affected differently by nutrients because of the consequent damage to their metabolic and endocrine systems:
"Diets low in SFA and cholesterol are less effective in improving the lipid profile in obese individuals and in patients with metabolic syndrome. In contrast, lean persons are more responsive to reductions in dietary SFA and cholesterol. Multiple mechanisms likely contribute to the altered plasma lipid responses to dietary changes in individuals with excess adiposity. The greater rate of hepatic cholesterol synthesis in obese individuals suppresses the expression of hepatic LDL receptors (LDLR), thereby reducing hepatic LDL uptake. Insulin resistance develops as a result of adipose-tissue induced inflammation, causing significant changes in enzymes necessary for normal lipid metabolism. In addition, the LDLR-mediated uptake in obesity is attenuated by alterations in neuroendocrine regulation of hormonal secretions (e.g. growth hormone, thyroid hormone, and cortisol) as well as the unique gut microbiota, the latter of which appears to affect lipid absorption."
http://advances.nutrition.org/content/2/3/261.full

Further, many of the subjects had diabetes and/or other morbidities which would also confound results. Additionally, it appears that most of the subject were also on multiple prescription medications.

For these reasons, I doubt that either study provides definitive guidance for people of normal weight seeking a diet that would promote healthy longevity.

FXScouse said...

Also, did paleolithic diets really include daily oil consumption as the Jonsson et al experimental diet did?

Don Matesz said...

Regarding oil, it is possible that stone age people did use some oils extracted from soft seeds like sunflower or soft nuts like brazil, pecan, etc. After grinding soft oil seeds with stones, just letting the mash rest the oil will separate. I recall reading references in ethnographic literature to native Americans using sunflower oil, but I don't have direct reference (haven't recalled the text source yet). However, I have found this from the National Sunflower Association:

"Sunflower was used in many ways throughout the various American Indian tribes. Seed was ground or pounded into flour for cakes, mush or bread. Some tribes mixed the meal with other vegetables such as beans, squash, and corn. The seed was also cracked and eaten for a snack. There are references of squeezing the oil from the seed and using the oil in making bread."

https://www.sunflowernsa.com/all-about/history/

Don Matesz said...

According to the National Institutes of Health:

"More than one-third (35.7 percent) of adults are considered to be obese. More than 1 in 20 (6.3 percent) have extreme obesity. Almost 3 in 4 men (74 percent) are considered to be overweight or obese. The prevalence of obesity is similar for both men and women (about 36 percent)."

https://www.niddk.nih.gov/health-information/health-statistics/Pages/overweight-obesity-statistics.aspx

And according to the CDC:

"From 1980 to 2014, the crude incidence of diagnosed diabetes among adults aged 18-79 years more than doubled from 3.3 to 6.9 per 1,000 population, and the age-adjusted incidence nearly doubled from 3.5 to 6.6 per 1000 population. From 1990 to 2008, age-adjusted incidence increased sharply; the rates more than doubled from 3.8 to 8.5 per 1,000. From 2008 to 2014, age-adjusted incidence significantly declined from 8.5 to 6.6 per 1,000."

https://www.cdc.gov/diabetes/statistics/incidence/fig2.htm

Thus, normal weight individuals are a minority population in the U.S.A. and diabetes is a widespread problem. Hence studies of the effects of diet on overweight, obese, and diabetic individuals seem extremely relevant.

In both of these studies dietary intervention reduced the use of medications, allowing some individuals to cease taking either diabetes or lipid control medications. I find it difficult to consider medications a confounding factor when the interventions helped eliminated medications.

Lean people are presumably already at a lower risk of morbidity or mortality from disease. Consequently I am not sure why they would want to alter their lipids or metabolic conditions. Is there such a thing as "superhealth" and does it impact life span? Do people who have lower lipids live longer on average than people who have higher lipids yet in the "normal" range?

Its my impression that healthy longevity is about avoiding cardiovascular, metabolic and neurological diseases that would either cut life short or make it miserable toward the end. Research that shows us how best to reverse these diseases with diet would then seem quite relevant to those who are "lean" but want to avoid these diseases. The way to study this is to look at people who show premature aging, i.e. those who have the age-related diseases (heart disease, diabetes, sarcopenia, etc.) at younger ages. Mostly those are people who are overweight or obese. Hence I find it highly plausible that studies of the effect of diet on people who have these diseases will yield valuable information about how to prevent those diseases from occurring in the first place.

A basic principle is: the cure is to remove the cause. All of these studies aim to identify the cause(s) of obesity, overweight, cardiovascular disease, etc. We look to find out what works best to reverse the disorder. Should we remove fat (total fat, or only certain types?), sugar, protein, calories, animal products, grains, beans....that's the question. Just as removal of tobacco smoke allows the smoker's lungs to heal, removal of the substances incompatible with health will allow the endocrine or metabolic systems to "heal," or, better, return to the ground state of least disturbance i.e. homeostasis. From that, "lean" people can glean what creates the problem from the beginning.

Gillian said...

So I am fairly new to your blog, Dan--but with all the research you have done and in light of the recent B12, fish, etc. articles, how would you eat for health (ethics, as important as they are, aside)? Complete vegan? Middle? Lacto-ovo vegentarian? Etc.? I gather not paleolithic....

Don Matesz said...

Gilian,

I am writing a new book to answer this question with thorough explanation. I eat primarily what humans can (and sometimes do) eat raw and could find provided by Nature even if they did not control breeding or feeding of any plants or animals, which includes:

Fruits and berries
Vegetables (roots, tubers, bulbs, stems, leaves, flowers, gums, etc.)
Nuts from trees (almonds, pecans, etc.)
Soft oil seeds (sunflower, hemp, pumpkin, etc.)
Meat, organs, etc. from fish, birds, mammals etc.
Honey and saps and syrups from trees (maple, birch, etc.)

I would call this a paleolithic style of eating, but without the ideology/dogma that it must always be primarily meat-based, high fat or low carbohydrate. Humans are by Nature omnivorous frugivores, and my diet currently provides ~50% or more of energy from fruits, nuts, and oil seeds (which are considerably more nutrient-dense and easily digested than grains or legumes). Currently my intake is ~80-90% plant-based by weight, although it is about ~75% plant-based by energy. And this ratio may change in accord with season or if I change my habitat (e.g. move to a more northern, colder habitat).

I aim to eat these in a proportion guided by what external Nature provides (in season and bioregion) and my appetite and satisfaction (internal Nature) seeks: what looks, smells, and tastes good to me (that's what the senses are for); and eat any item only to the extent that I enjoy it, never beyond the point that I find it enjoyable.

I eat more limited amounts of eggs and oils from nuts, seeds, or oil-rich fruits, as pre-agricultural humans could eat these only in limited amounts.

Everything else I consider more or less man-made or edible only when transformed by artifice (including whole grains and legumes, dairy, refined foods, etc.) and hence more or less suspect; to be consumed only occasionally, with caution or not at all.




bookgirl said...

May I ask how your current Paleo diet is different from the paleo diet you followed a couple of years ago? Less animal products?

Gillian said...

Dan, thank you so much for your response and time! I deeply respect your journey and research, and thus the balanced perspective. I greatly appreciate it. Thank you

FXScouse said...

Don Thank you for your thoughtful responses to my comments.

However, I still have reservations. There is as far as I know no evidence that paleolithic peoples consumed vegetable oil. Or any reason to think that paleolithic people would discard the extra calories and nutrients in whole foods to manufacture oil. That would seem to me to be only a sensible or even a feasible strategy where an agricultural surplus exists. However, there may have been natural seasonal surpluses so it is not impossible (just somewhat unlikely IMHO).

Native Americans may have manufactured oil, as you point out, but these were most likely peoples that practised some kind of agriculture ie they were living a neolithic rather than a paleolithic lifestyle. Further, most paleo gurus seem to advise against vegetable oils like rapeseed (canola) oil as used in the Jonsson trial. Therefore calling their diet, which included daily oil consumptio, a paleolithic diet still strikes me as rather odd. Anyway, didn't the Twinkie diet case underscore the point that a diet that brings about benefits in the short term should not be assumed to automatically deliver long term health benefits?

Finally,you asked "Do people who have lower lipids live longer on average than people who have higher lipids yet in the "normal" range?" I suppose the answer depends on what you call "normal". If we are talking about US or other Western average cholesterol levels, isn't the answer "yes"? in the US, optimal LDL cholesterol is defined as less than 100 mg/dl and total cholesterol lower than 200 mg/dl. The reasons are explained reasonably fully in the NCEP ATPIII report. The Framingham Study of course illustrated this
"Under age 50 years these data suggest that having a very low cholesterol level improves longevity. After age 50 years the association of mortality with cholesterol values is confounded by people whose cholesterol levels are falling--perhaps due to diseases predisposing to death."
http://jamanetwork.com/journals/jama/article-abstract/365739

Don Matesz said...

bookgirl,

Yes, less meat, and complete elimination of the compromise but often justified as "primal" dairy products (I used butter and cream a lot as fat and calorie sources back then). Also, at this point in time I don't use any palm oil or coconut products, whereas previously I used large amounts of coconut milk, coconut cream, and coconut oil, all of which are high in saturated fats and likely contributed to my having elevated cholesterol. On the other hand, I am eating larger amounts of non-tropical fruits and nuts.


Don Matesz said...

Gillian,

Thank you.

Don Matesz said...

FXScouse,

The !Kung have so many mongongo nuts available to them that they provide 50% or more of their calories at some times of the year, yet the people can't eat all of them. These are not cultivated.

I don't see any reason why some seed sources, such as the sunflower, could not be so abundant in some regions that the people would have more than they needed. I also do not see a reason to assume they would take the oil and discard the rest. They could use the oils for certain purposes and still eat the remainder. Traditional people extract fats from animals to use for soap and candles and grease, but this doesn't mean that they discard the rest of the carcasses unused. However, I certainly agree that this behavior is more likely for neolithic people.

So, is it "wrong" to include any vegetable oils in a modern diet based on paleolithic principles? Leading authorities say no.

One of the authors of the Jonsson trial is Staffan Lindeberg, author of Food and Western Disease (ftp://nozdr.ru/biblio/kolxo3/B/Lindeberg%20S.%20Food%20and%20western%20disease..%20Health%20and%20nutrition%20from%20an%20evolutionary%20perspective%20(Wiley,%202010)(ISBN%201405197714)(O)(370s)_B_.pdf).

Lindeberg is certainly one of the world's leading experts on ancestral diets from a medical perspective. He considers that although vegetable oils may not have been used by paleolithic people, the key factors are whether the oil comes from an oil source that is neither cereal or legume, and whether the oil would contribute to optimal fatty acid intake.

Similarly, Loren Cordain,the leading proponent of paleolithic dieting, admits that it is unlikely that paleolithic people ate plant-derived oils, but writes:

"So if this is the case, then why should you not eliminate all vegetable oils from your diet? Simply stated, there are at least six oils (flaxseed, walnut, olive, macadamian, coconut, and avocado) that can promote health and facilitate getting the correct balance of good fats in your diet. Because hunter-gatherers ate the entire carcass of wild animals (tongue, eyes, brains, marrow, liver, gonads, intestines, kidneys, etc.) and relished fatty plant foods (nuts and seeds), they did not have to worry about the correct balance of fatty acids in their diet. It came out correctly in the wash. For most of us, the thought of eating organs is not only repulsive, but is also not practical as we simply do not have access to wild game. Consequently, by eating grass produced or free ranging meats, fish, and seafood along with healthful oils, nuts, and seeds, you can get the correct balance of fatty acids in your diet."

http://thepaleodiet.com/vegetable-oil-fatty-acid-composition/

So these experts consider that eating some plant oils helps us to replicate the fatty acid ratio that hunter-gatherers would have obtained from eating wild game. In the linked article, Cordain explains that when he first published The Paleo Diet he did recommend canola oil because of its high n-3 and low n-6 ratios and this is why some earlier trials of paleolithic diets included canola oil. However he later changed his mind due to some emergent research suggesting some adverse effects from canola oil consumption.

The point is that because the foods most people have available are not nutritionally identical to those eaten by prehistoric people, it may be necessary to include plant oils to augment the monounsaturated and n-3 and reduce the n-6 ratios of the diet to make it more nutritionally similar to ancient diets.

Don Matesz said...

The two studies I discussed in this blog indicate that the paleolithic style diet was more effective for controlling cholesterol than the oil-free WFPB diet. If you think that the paleolithic diet worked only because it was energy deficient like the Twinkies diet, then what happened with the WFPB diet? It too was energy deficient, at least initially, yet it did not perform as well as the paleolithic style diet.

It is well known that insulin elevations stimulate hepatic cholesterol synthesis. I hypothesize that this made the difference between these two studies regarding cholesterol outcomes. The WFPB diet was much higher in carbohydrate hence may have required more frequent rises in insulin levels.

Studies show very low cholesterol levels in contemporary hunter-gatherers, generally under 150 mg/dL, despite the fact that they consume large amounts of meat and cholesterol. (See Lindeberg) The findings of the Jonsson study point in the direction that eating a diet based on paleolithic principles may produce this lower level of cholesterol provided there is attention to the ratio of fatty acids, which may make use of oil seeds or derived oils desirable in modern contexts.

Don Matesz said...

Also, the Frassetto trial showed a paleolithic style diet reduces cholesterol levels without weight loss: https://www.nature.com/ejcn/journal/v63/n8/full/ejcn20094a.html

Thus this is not the Twinkie diet effect due only to caloric restriction and weight loss.

Don Matesz said...

In the Frasseto trial, LDL dropped from 116 mg to 88 mg; total chol dropped from 181 mg to 154 mg/dL. HOMA dropped 72%. The diet:

"Meat, fish, poultry, eggs, fruits, vegetables, tree nuts, canola oil, mayonnaise and honey were included in the Ramp and Paleo phases of the diet. We excluded dairy products, legumes, cereals, grains, potatoes and products containing potassium chloride (some foods, such as mayonnaise, carrot juice and domestic meat were not consumed by hunter-gatherers, but contain the general nutritional characteristics of preagricultural foods)."

So again, the point is to replicate the general nutritional characteristics of a paleolithic diet using the types of foods that were edible to paleolithic people, including oil seeds, although we may use different technology and make carrot juice or extract some oils, thus consuming the nutrients in different forms.

Don Matesz said...

bookgirl,

I should also mention that I have restricted egg intake. When I did paleo previously, I ate something like a dozen eggs weekly. Now I understand that would not have been possible in paleolithic times, and limit myself to no more than 3 eggs a week.

FXScouse said...

Thanks, Don, for explaining these points. Very interesting.

I must confess that, despite that explanation of the reasoning behind this, I still find it hard to accept that a diet that includes vegetable oil and mayonnaise can be called "paleolithic". Or that such diets must necessarily exclude cereals, grains and tubers since we know that people in the paleolithic did actually eat these foods eg.
http://www.pnas.org/content/110/14/5380.long
https://www.sciencedaily.com/releases/2009/12/091217141312.htm

In fact the whole paleolithic diet premise seems dubious to me. That is, that humans are best adapted to foods that they ate during the paleolithic period and therefore that eating these foods will promote good health. That seems like a pretty big non sequitur. I am no expert on evolution but isn't it more about what benefits a species' survival and reproduction rather than selecting for healthy longevity in individual members of a species? Also, there must have been many different diets eaten during the Paleolithic varying according to the available food resources in a particular location in any given era and season. Yet most modern paleolithic diets seem to be quite high in animal foods .... which isn't necessarily reflective of all diets actually eaten in the paleolithic era. Grubs, insects, lizards etc also seem to be notably lacking in modern paleo diets.

Yes, the Jonsson diet delivered better results than the BROAD trial. This is what one would have expected in obese, diabetic subjects. See my previous reference to the article on the effects of adiposity. I think the literature is fairly clear that dietary fat and cholesterol have different effects in lean and obese people eg
https://www.ncbi.nlm.nih.gov/pubmed/16256004
My concern is that such diets eaten long term, especially post weight loss, may be hazardous. Observational studies indicate that low carb diets tend to be associated with higher mortality. As do a number of mouse trials,

That said, I firmly believe that modern "paleolithic" diets are bound to be an improvement on the standard Western diet in so far as they eliminate trans fats, refined carbs and processed foods generally. Especially if they incorporate modern nutritional knowledge about the importance of SFA/PUFA/MUFA ratios, including omega 6/3 ratios. Ditto for no-oil plant based whole food diets even though they require B12, DHA/EPA and other supplements for long term health if they exclude animal foods totally.

My point about the Twinkiw diet was not that weight loss alone explains all the benefits of these diets ("paleolithic" and no-oil WFPB diets). While very important, it doesn't. It was simply to make the point that we should not assume that diets which deliver significant benefits in short term trials, will necessarily prove the diets which promote long term good health. Most people would accept that eating a Twinkie based diet would have long term adverse health consequences. But the same principle (short term benefits are no guarantee of long term benefits) must surely also apply to the Jonsson and BROAD diets? Both would, I suspect, be healthier long term choices than the standard Western diet but would either be the optimal diet? My doubts remain.

Debbie said...

Wow. I haven't read your blog in awhile. When did you go back to paleo and why? You were so keen on the macrobiotic diet. BTW, what do you think of Dr. Robert Morse?

bookgirl said...

Don,

This is about something else, but I know you once posted research about Inuit's high osteoporosis and their diet, but could this not have been because they have low calcium intakes? I read an ncbi article about that.

Also, I think rancidity of oils and cholesterol has a huge effect on cholesterol levels in humans. For example, I had been eating canned sardines a couple of times these past few months thinking it was healthy, but when I researched it came across studies that showcased canning fish results in oxidized cholesterol and fat. The nasty smell of sardines is the rancidity of oils. So this led me to believe that rancidity of cholesterol and oils probably plays quite a huge part in why people have heightened cholesterol as paleolithic people ate pretty much only fresh food.

Thanks again for your blog.