Modern Scientific Controversies Part 6

By Kip Hansen – Re-Blogged From

food_plates_smPrologue:  This is a follow-up to  a series of five essays that discussed ongoing scientific controversies, a specific type of which are often referred to in the science press and elsewhere as “Wars” – for instance, one essay covered the “Salt Wars1 and another the “Obesity War”.  The purpose of the series was to illuminate the similarities and differences involved in these ongoing controversies, with the final part (Part 5) showing the commonalities with the Climate Wars.    This essay illuminates two important new, potentially paradigm-shifting papers in the field of Human Nutrition and new findings in the Salt Wars that turn that entire field on its head.

Warning:  This is not a short essay.  Dig in when you have time to read a longer piece. 


Human Nutrition — the field of human physiology and health that concerns itself with the question:

What is the ideal diet for free-living human beings for optimum health and maximum longevity? 

Human nutrition and its continued onslaught of sensational news stories about the “latest research findings” — each one touting the benefits or harms of some item of the human diet, or the life-enhancing, lifetime-expanding benefits (or life-shortening harm) of a particular type of diet — has caused more damage to the reputation of Science as an enterprise than any other topic.  The continual series of whipsawing stories from the field has turned human nutrition into a public joke.2  

“Coffee: a poisonous carcinogen” last month, and now a “Coffee found good for your heart”.  “Butter is a killer, eat margarine for long life” last year, “Margarine causes heart attacks, avoid at all costs” this year.  “Alcohol is bad for you”, “Red wine is good for heart health”.3

For several years now, there has been a constant drumbeat of demand to reduce the amount of fats of all kinds from recommended diets — health insurers4,  medical associations, and the governmental health agencies in the West all urge reduced fat diets, with some fats being particularly targeted.  The stated reasons are many:  heart disease, obesity, trans-fat phobia, “artery clogging fats”, etc.   US FDA and Australian Health ministry both have issued recommended balanced diets in the last several years that included reduced fats.


So, what’s not to like about that? ……….  Science — unbiased carefully crafted and executed research — says differently, challenging three sacred cows of dietary science.


The PURE Study

The PURE Study  (NIH link) has been making big news since last week, having issued two new papers laying out their results accompanied by presentations at the ongoing meeting of the European Society of Cardiology.  McMaster University issued a Press Release on the 29th of August, covered by ScienceDaily here.

“Research with more than 135,000 people across five continents has shown that a diet which includes a moderate intake of fat and fruits and vegetables, and avoidance of high carbohydrates, is associated with lower risk of death.

To be specific about moderate, the lowest risk of death was in those people who consume three to four servings (or a total of 375 to 500 grams) of fruits, vegetables and legumes a day, with little additional benefit from more.”

“As well, contrary to popular belief, consuming a higher amount of fat (about 35 per cent of energy) is associated with a lower risk of death compared to lower intakes. However, a diet high in carbohydrates (of more than 60 per cent of energy) is related to higher mortality, although not with the risk of cardiovascular disease.”

Online headlines tell how the papers were received:

European Society of Cardiology:  Revisiting dietary fat guidelines? (PURE)

CardioBrief:  Huge Diet Study Questions Conventional Wisdom About Carbs And Fats

TCTMD: PURE Investigators: Rethink Diet Guidance to Plug More Fats, Fewer Carbs

STAT:  Huge new study casts doubt on conventional wisdom about fat and carbs

The Lancet: PURE study challenges the definition of a healthy diet: but key questions remain  (paywalled)

Jo Nova: Low Fat consensus was wrong: High carb diets increase death rates

Two and three days later, the backlash has begun to appear in the press and on the web:

The Atlantic:  New Nutrition Study Changes Nothing (James Hamblin)

HuffPost: Diet And Health: Puzzling Past Paradox To PURE Understanding (Dr. David Katz)

The PURE study warrants some skepticism (by Marion Nestle)

American Council on Science and Health: Fruit And Veggies Beneficial For Heart Health, But Carbs Aren’t. What?

Those readers who have been following this series on Science Wars will recognize the pattern immediately.  A new finding is published that challenges an existing consensus in a scientific or medical field.  Almost immediately, within days, the new findings are attacked (there is no other word for it), denigrated, and downplayed by advocates of the consensus position with supporting salvos from their allies.    If you think this sounds like politics, you are right.

The first PURE paper itself gives this simple language summary:

“Consistent with most data, but in contrast to dietary guidelines, we found fats, including saturated fatty acids, are not harmful and diets high in carbohydrate have adverse effects on total mortality. We did not observe any detrimental effect of higher fat intake on cardiovascular events. Our data across 18 countries adds to the large and growing body of evidence that increased fats are not associated with higher cardiovascular disease or mortality. …

Removing current restrictions on fat intake but limiting carbohydrate intake (when high) might improve health. Dietary guidelines might need to be reconsidered in light of consistent findings from the present study, especially in countries outside of Europe and North America.”

The PURE Study’s first paper covers two points:

  1. Increased fats in the human diet do not lead to increased cardiovascular disease and do not cause increased mortality.
  2. Diets too high in carbohydrates (starches and sugars), above 60-70 % of total calories, increase mortality. (“Carbohydrates are the sugars, starches and fibers found in fruits, grains, vegetables and milk products.”)

and thus concludes that dietary guidelines, especially outside of the US and Europe, might be reconsidered in light of this new evidence.

The second PURE paper covers dietary intake of vegetables, fruits and legumes (peas and beans), finding:

“The results showed that non-cardiovascular mortality and total mortality are decreased with high intake of fruits, vegetables, and legumes compared with low intake. …

Many dietary guidelines recommend a minimum of 400 g/day of fruits and vegetables, which might not be achievable globally since fruits and vegetables have previously been shown to be unaffordable in low-income and lower-middle income countries. Our findings that even three servings per day (375 g/day) show similar benefit against the risk of non-cardiovascular and total mortality as higher intakes indicates that optimal health benefits can be achieved with a more modest level of consumption, an approach that is likely to be more affordable in poor countries.”

This is, at first glance, an entirely noncontroversial finding.  Eating more fruits, vegetables, and legumes is better for your health.  Here’s the “but”….

  1. Eating more fruits, veggies, and legumes is better…but…
  2. Just three servings a day maxes out the benefit and is an achievable target for the poor, eating more is not that much better.  (These are also primarily carbohydrates.)

These two papers have stepped on a lot of toes and caused quite an uproar.

The consensus positions in human diet, set by such august bodies as the American Heart Association, the FDA, and the Health Fad Industry maintain, we could say “insist”, that:

  1. Fat is bad and should be nearly eliminated from human diets — meats must be lean, dairy must be low- or non-fat.
  2. Grains, vegetables and fruits should be the bulk of human diet — over 3/4s of total diet in both the US FDA and the Australian governmental recommendations.

Thus, these two papers directly contradict the consensus positions on fats, carbs in general, and vegetables and fruit.

On the “this is big important news” and “a paradigm changing study” side comes the always insightful Jo Nova from down under:  “Low Fat consensus was wrong: High carb diets increase death rates.  How many people have died prematurely because they swapped their fats for carbohydrates?  New research published in the Lancet shows that low fat diets could increase your risk of death.”

On the other side, the Health Triad — David Katz, Marion Nestle, and James Hamblin — immediately issued Rapid Response attacks, in the Atlantic and the Huffington Post.  They quote one another, of course.  David Katz, promoter of “integrative medicine” and plant-based diets, infamously accused of writing positive book reviews for the HuffPost under a pseudonym for his own Sci-Fi novels  — Marion Nestle, prolific author on Food Politics with a blog by that name, active anti-sugar, anti-soda campaigner — James Hamblin, media darling doctor and health writer for The Atlantic.

Katz says “I appreciate the good intentions- but the message is, simply, wrong.”

Hamblin, whose discussion is the best from the consensus viewpoint, in the end  insists “People are complex, and the ways we perceive and communicate and relate to one another are complex… But the basic agreement on what to eat for the health of people and the planet is not: diverse, naturally high-fiber, minimally processed foods, mostly plants.”

Nestle quotes both Hamblin and Katz and tries the “wrong by association” attack:   “Drug companies have a big interest in this topic, especially if dietary approaches to heart disease prevention aren’t proven.” (The PURE Study is funded by hundreds of groups, from many nations, starting with lots of governmental agencies and ending with “unrestricted grants from several pharmaceutical companies”). (List of funders in .docx format)


Bottom Line: 

  1. Prospective epidemiological health studies cannot, do not, say anything about causes. They can, however, be used to rule out public health issues — like the demonized high-fat diets, as the PURE study does in this case.  These types of studies cannot be adjusted for all confounders, despite all claims of authors and statisticians to the contrary, thus their findings are best taken ONLY as indicators of overall health outcome trends and point to interesting areas for further investigation.
  1. The PURE study found that internationally, poor and wealthy, rural and urban, humans are not harmed by higher fat diets — they do not die prematurely and do not suffer from more cardiovascular disease.

My opinion?:  The low-fat diet mantra has always been bias-driven.  This is just one more large study confirming this point.

  1. Overall, diets above 60-70% carbohydrates can lead to premature death.

My opinion?:  Diets that high in carbohydrates lack other important foods and are unbalanced, leading to poorer health.  The nit-picking “good carbs, bad carbs, processed carbs” is just that – nit-picking.

  1. Three to four servings of VFL (veggies, fruits, legumes) is generally sufficient for good health.

My opinion?:  Probably correct.  The western idea of “more is always better” is nonsensical – in the US fresh apples and oranges cost $1.50/lb, tomatoes and broccoli almost $2.00/lb  (June 2017 average) — out of reach for many low income families.

  1. The response to the studies indicates that what we see as Human Nutrition is not real science — it is yet another Science Controversy, The Nutrition Wars. All public information about human nutrition should be viewed with this in mind.
  1. In the United States, Europe and ANZO, the major diet problem is that people generally eat too much of everything — there is almost zero incidence of clinical deficiencies of any vitamin, mineral, fat, protein, or carbohydrate — despite the constant clamoring cacophony of alarm from the Food Faddists.



The Salt Wars Continue

Back in May 2017, Gina Kolata wrote an article for the New York Times’ Health section titled:  “Why Everything We Know About Salt May Be Wrong”.   It is very well done and is a fascinating read — and represents a new beginning for the study of salt (sodium chloride, table salt) in the human diet.   It details the years-long quest of a little known German scientist, Dr. Jens Titze.  Kolata relates this story:

“In 1991, as a medical student in Berlin, he took a class on human physiology in extreme environments. The professor who taught the course worked with the European space program and presented data from a simulated 28-day mission in which a crew lived in a small capsule.

The main goal was to learn how the crew members would get along. But the scientists also had collected the astronauts’ urine and other physiological markers.

Dr. Titze noticed something puzzling in the crew members’ data: Their urine volumes went up and down in a seven-day cycle. That contradicted all he’d been taught in medical school: There should be no such temporal cycle.”

Dr. Titze followed-up his interest in 1994, with the Russian cosmonaut program, sbtudying salt in the diets of simulated space travelers, and found:

a 28-day rhythm in the amount of sodium the cosmonauts’ bodies retained that was not linked to the amount of urine they produced. And the sodium rhythms were much more pronounced than the urine patterns”…… The conclusion, he realized, “was heresy.”

Exhibiting patience and perseverance that would be far beyond me, it was in 2006, twelve years later, that Dr. Titze had the opportunity to carry out the research required to find out what was happening.  “In 2006, the Russian space program announced two more simulation studies, one lasting 105 days and the other 520 days.”  The simulated cosmonauts would be fed diets controlled in all aspects, all intakes carefully monitored, bodily outputs of urine would be monitored, blood samples taken daily.

What he found was: “When the crew ate more salt, they excreted more salt; the amount of sodium in their blood remained constant, and their urine volume increased…..Instead of drinking more, the crew were drinking less in the long run when getting more salt. So where was the excreted water coming from?”  And again, the cyclical nature of salt excretion, regardless of intake.

“New studies of Russian cosmonauts, held in isolation to simulate space travel, show that eating more salt made them less thirsty but somehow hungrier. Subsequent experiments found that mice burned more calories when they got more salt, eating 25 percent more just to maintain their weight.”

Dr. Titze has followed that work up with years of lab experimentation to delve into this mystery.

The results are in these two (admittedly very dense, very technical) papers:

High salt intake reprioritizes osmolyte and energy metabolism for body fluid conservation  (pdf here)

Increased salt consumption induces body water conservation and decreases fluid intake  (pdf  here)

The problem?   These findings kick the underpinnings out from under the Salt Consensus, as  Gina Kolata points out:

“The salt equation taught to doctors for more than 200 years is not hard to understand.

The body relies on this essential mineral for a variety of functions, including blood pressure and the transmission of nerve impulses. Sodium levels in the blood must be carefully maintained.

If you eat a lot of salt — sodium chloride — you will become thirsty and drink water, diluting your blood enough to maintain the proper concentration of sodium. Ultimately you will excrete much of the excess salt and water in urine.

The theory is intuitive and simple. And it may be completely wrong.

The long-taught truth about salt is that too much salt causes the body to take on extra water in the blood, increasing blood volume thus increasing blood pressure.  This “truth” just isn’t so for most people.  Titze’s findings, unchallengeable, show that this is not how the human body regulates salt and fluid.

If we were not stepping in the middle of a long-running Science War — the Salt Wars — this would be hailed as a major advance for medical science and human physiology.  Instead, we get denial, equivocation, and dismissal.

Reduced Salt is a battle cry of nearly every medical association — and they influence the FDA and other governmental agencies, not only in the US, but worldwide, through the UN’s World Health Organization.  All of which have been promoting “reduced salt for all” based on the idea that “too much salt => high blood pressure => heart disease => death”.

It appears, from Titze and earlier studies, that this simply is not true.

As covered in my previous essay on the Salt Wars,  Mente et al., in a 2014 finding based on the PURE data, found the same results.  As an editorial in the highly respected New England Journal of Medicine reported:

“The authors concluded from the findings that a very small proportion of the worldwide population consumes a low-sodium diet and that sodium intake is not related to blood pressure in these persons, calling into question the feasibility and usefulness of reducing dietary sodium as a population- based strategy for reducing blood pressure.” 

Mente et al. agreed with other previous huge salt studies, all of which have been attacked and dismissed by the proponents of “Reduced Salt for All”.

Now, with the twin Titze studies casting (put mildly) very serious doubts on the consensus position on dietary salt, we find that not a single anti-salt advocate organization has made any statement of a change of position.

To the contrary, Gina Kolata reports:

 “This is just very novel and fascinating,” said Dr. Melanie Hoenig, an assistant professor of medicine at Harvard Medical School. [and a go-to expert relied on by many a MSM journalist on the topic of salt] “The work was meticulously done.”

The work suggests that we really do not understand the effect of sodium chloride on the body,” said Dr. Hoenig.

“These effects may be far more complex and far-reaching than the relatively simple laws that dictate movement of fluid, based on pressures and particles.”

She and others have not abandoned their conviction that high-salt diets can raise blood pressure in some people.**

But now, Dr. Hoenig said, “I suspect that when it comes to the adverse effects of high sodium intake, we are right for all the wrong reasons.”

** — this conviction statement does not reflect the actual position of anti-salt advocates — who, like the American Heart Assoc.,  demand lowering salt intake for everyone, not just those sensitive to salt.

Bottom Line:

The Salt Wars roll on, taking their toll on the general public as anti-salt advocates refuse to abandon a public health-policy based on demonstrably false understandings of human physiology that attempts to enforce harmful advice on the broad general public.


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