Diet and Observational Studies

Woody Allen, Sleeper:

Dr. Melik: This morning for breakfast he requested something called "wheat germ, organic honey and tiger's milk."
Dr. Aragon: [chuckling] Oh, yes. Those are the charmed substances that some years ago were thought to contain life-preserving properties.
Dr. Melik: You mean there was no deep fat? No steak or cream pies or... hot fudge?
Dr. Aragon: Those were thought to be unhealthy... precisely the opposite of what we now know to be true.
Dr. Melik: Incredible.

Two more pieces of traditional dietary advice take a beating.

Article #1: Trans fats, but not saturated fats like butter, linked to greater risk of early death and heart disease

Contrary to prevailing dietary advice, a recent evidence review found no excess cardiovascular risk associated with intake of saturated fat. In contrast, research suggests that industrial trans fats may increase the risk of coronary heart disease. 

Saturated fats come mainly from animal products, such as butter, cows' milk, meat, salmon and egg yolks, and some plant products such as chocolate and palm oils. Trans unsaturated fats (trans fats) are mainly produced industrially from plant oils (a process known as hydrogenation) for use in margarine, snack foods and packaged baked goods. 

To help clarify these controversies, de Souza and colleagues analysed the results of 50 observational studies [ed., emphasis added; see below] assessing the association between saturated and/or trans fats and health outcomes in adults.

Or: Butter Good, Margarine Bad

Article #2: The science of skipping breakfast: How government nutritionists may have gotten it wrong

Researchers at a New York City hospital several years ago conducted a test of the widely accepted notion that skipping breakfast can make you fat. 

For some nutritionists, this idea is an article of faith. Indeed, it is enshrined in the Dietary Guidelines for Americans, the federal government’s advice book, which recommends having breakfast every day because “not eating breakfast has been associated with excess body weight.” 

As with many nutrition tips, though, including some offered by the Dietary Guidelines, the tidbit about skipping breakfast is based on scientific speculation, not certainty, and indeed, it may be completely unfounded, as the experiment in New York indicated.

The scientific speculation was based on some concept of how metabolism might work.

This is not some moldy, old-wive's tale piece of advice that has been hanging around for decades (like needing to drink 8 glasses of water a day). This was only added to the guidelines in 2010.

The advice was based on "observational studies." That is, researchers simply observe people behaving naturally. The self-selected "fasters" where more likely to obese than those who ate breakfast.

However, if "observational studies" are replaced by actual experiments, with randomized controlled trials and all the rest of the modern scientific method, the experiments disprove the conclusions of the observational studies 90% of the time.

[Note: the study in the first article was an "observational study".]

This may be due to "confounders."

One of the primary troubles in observational studies is what scientists refer to as “confounders” — basically, unaccounted factors that can lead researchers to make mistaken assumptions about causes. For example, suppose breakfast skippers have a personality trait that makes them more likely to gain weight than breakfast eaters. If that’s the case, it may look as if skipping breakfast causes weight gain even though the cause is the personality trait.

And moralizing the dietary guidelines creates problems.

Allison attributes the widespread adoption of the breakfast hypothesis at least in part on researchers who read too much into observational studies, and wrongly ignore the stronger evidence from the randomized controlled trials. In addition, he speculates that there “maybe some sense that eating breakfast is ‘moral’ and ‘upstanding,’” and that makes people more willing to believe it’s good for you.

For the record, most of the hypothesis of catastrophic anthropogenic global warming is based on observational studies that have been moralized.

Article: The U.S. government is poised to withdraw longstanding warnings about cholesterol

The original research (1915) on the issue of dietary cholesterol was done in rabbits and rats. Rabbits showed an adverse effect with a high cholesterol diet; the rats did not. The obvious lesson of being cautious because we could not test, and therefore could not know, how humans reacted to a purely high cholesterol diet was missed.

Additional research, and the knowledge that atherosclerosis was caused by cholesterol deposits, implied that high dietary cholesterol was a problem. More recent research implies that diets high in saturated fats and carbohydrates are more of a problem.

The paradigm shifts.

The nation’s top nutrition advisory panel has decided to drop its caution about eating cholesterol-laden food, a move that could undo almost 40 years of government warnings about its consumption. 

The group’s finding that cholesterol in the diet need no longer be considered a “nutrient of concern” stands in contrast to the committee’s findings five years ago, the last time it convened. During those proceedings, as in previous years, the panel deemed the issue of excess cholesterol in the American diet a public health concern. 

The finding follows an evolution of thinking among many nutritionists who now believe that, for healthy adults, eating foods high in cholesterol may not significantly affect the level of cholesterol in the blood or increase the risk of heart disease. 

The greater danger in this regard, these experts believe, lies not in products such as eggs, shrimp or lobster, which are high in cholesterol, but in too many servings of foods heavy with saturated fats, such as fatty meats, whole milk, and butter. 

The new view on cholesterol in food does not reverse warnings about high levels of “bad” cholesterol in the blood, which have been linked to heart disease.  

[snip]

 Rudel and his colleagues have been able to breed squirrel monkeys that are more vulnerable to the cholesterol diet. That and other evidence leads to their belief that for some people -- as for the squirrel monkeys -- genetics are to blame. 

[snip] 

“These reversals in the field do make us wonder and scratch our heads,” said David Allison, a public health professor at the University of Alabama at Birmingham. “But in science, change is normal and expected.” 

When our view of the cosmos shifted from Ptolemy to Copernicus to Newton and Einstein, Allison said, “the reaction was not to say, ‘Oh my gosh, something is wrong with physics!’ We say, ‘Oh my gosh, isn’t this cool?’ ” 

Allison said the problem in nutrition stems from the arrogance that sometimes accompanies dietary advice. A little humility could go a long way. 

“Where nutrition has some trouble,” he said, “is all the confidence and vitriol and moralism that goes along with our recommendations.”

"Confidence and vitriol and moralism." People get emotionally bound up in their own opinions and beliefs. And once that happens, it is hard to shift them. It is one of the reasons that paradigm shifts, even in science, begin in the young and are completed when the holders of the old paradigm die out.

[See also the recent shifts concerning dietary salt, as well.]

These belief systems substitute for religion, and all that religion implies.

"Health Nazi's." "Food fascists." "Vegetarian separatists."

And the analogy to the catastrophic anthropogenic global warming hypothesis is clear.

Science Links - 7/16/15

Article: Natural contaminants, arsenic and uranium, in one-fifth of California's groundwater

Natural contaminants are more prevalent than human-made contaminants in California groundwater used for public supply, is the conclusion of a decade-long study by U.S. Geological Survey scientists. The study evaluated the quality of nearly all of the groundwater used for public supply in California and is the most comprehensive assessment of groundwater in any state to date. Groundwater provides about one-third of California's drinking supply in a typical year, but more during drought conditions.

There is more uranium and arsenic in the water supplies than nitrates (from fertilizers) and various organics.

Article: Old astronomic riddle on the way to be solved: Absorption of starlight in space

The absorption is due to a complex carbon molecule nicknamed, "buckyballs."

Scientists were able to identify for the first time a molecule responsible for the absorption of starlight in space: the positively charged Buckminsterfullerene, or so-called football molecule.

Article: Climate Scientists’ Road to Hell

Amusing, but 3 years old.

Article: Better chocolate with microbes: Same yeast used in beer, wine and bread

Best flavor from the common bread yeast.

Did you know that chocolate is fermented? So is coffee.

Article: New Horizons: Images reveal ice mountains on Pluto

Ice mountains 10000 ft (slightly less than 2 miles) high.

And no impact craters which implies enough geologic activity to smooth out the surface.