November 21, 2013

The Latest Scare Study: Or Why Eating Meat Does Not Cause Diabetes

I've received several worried emails over the past week written in response to a study which is being highlighted by the vegan/low fat/low-carb-diet-haters, who are using it to supposedly prove that eating a low carb diet rich in meat will acidify your blood and give you diabetes.

This article is summarized here:

http://www.medindia.net/news/higher-dietary-acid-load-increases-diabetes-risk-127666-1.htm

Dr. Weil, who has earned millions promoting his own brand of faddish health advice summarizes it here: http://www.drweil.com/drw/u/WBL02378/Surprise-Diabetes-Threat.html

I went and read the actual study, which you can find in its full form here:

Dietary acid load and risk of type 2 diabetes: the E3N-EPICcohort study

Here's my take on it:

I am always very suspicious of the findings of any large study that draws its conclusions from questionnaires purporting to measure what people are supposed to have eaten over a set period of time. And it turns out that this is exactly what was done here.

The measures of blood acidity used in this study, PRAL and NEAP, are not determined by measuring blood acid in the participants. Instead, they are computed using a formula which was  applied to the answers given in response to a standardized dietary questionnaires filled in by study participants.  You can read a critique of the methodology used to establish the forumulas used to convert these questionnaire responses to estimated blood acidity here: Critique on equations of net endogenous acid production (NEAP) and indirect proof of constant organic acid excretion

But even if this study is wrong that the formulas are flawed, since the level of blood acids are not actually measured, the reliability of the study result all comes down to the quality of the questionnaires used. And that is something I have personal experience with, as I was a subject years ago in a study of low carb dieters, a study that used one of these standardized nutritional survey questionnaires.

As the study proceeded I filled out this multiple-choice questionnaire several times. At one point, the nutritionist running the study mailed me my personal dietary analysis based on the answers I had given. Since this occurred during the year when, to lose weight successfully, I had taken to actively logging every bite I ate using LifeForm software, and carefully measuring portion sizes, too, I was able to compare my actual intake, as tracked in my log with what the questionnaire said I had eaten.

The questionnaire's results weren't even close. It ascribed to me a much higher calorie intake than what I was actually eating, and even more significantly, came up with  a completely different breakdown of carbs, protein, and fat--one that gave me a much higher carb intake than what I was actually eating. One that would have completely knocked me out of the ketogenic state that random tests with ketone strips confirmed I was maintaining.

The total failure of the questionnaire to reflect my dietary intake didn't surprise me, though, because the multiple choice questions that made up the questionnaire were written in such a way that it was impossible for me to give accurate answers.  For example, there was no option to answer "never" to many of the questions about my intake of high carb foods like potatoes. Instead I had a choice of reporting I had eaten potatoes "1 to 5" times in the previous month.

And though the questionnaire might ask about how often I had eaten red meat, or even about how often I had eaten "hamburger" it did not ask any questions that would make it possible to determine whether the "meat" I reported eating was the pink slime laced with MSG eaten at McDonalds or a home cooked burger made of high quality ground sirloin.

Even worse, there was no way that the questions posed by the questionnaire could determine if the "red meat" I had eaten had been accompanied by a big white bread bun and a big serving of fries. A person eating a stack of pancakes with syrup, eggs, and ham for breakfast who fills in this questionnaires is scored as eating "meat", in these questionnaires, though any future sorry metabolic outcome linked to eating this kind breakfast more likely to be due to its high carb intake, the high fructose in the syrup and the phosphates and other chemicals in the ham.

So these fatally flawed questionnaires will point the finger at "meat" when the real nutritional culprits may be something else entirely.

That's why I would not don't take this study too seriously. If you had a study where blood acid levels were actually measured in a large population over a long period of time and the measured high blood acids were found to be correlated with a nasty health outcome, it would be worth thinking about, but the costs of that kind of study are prohibitive, so it isn't likely to happen.  But as we have no way of even knowing if the participants in this study really had high levels of acid in their blood, and if the higher level of diabetes found in people who said they ate a lot of meat was caused by the meat or what they ate alongside of the meat, the rest of the study's conclusions are really a stretch.

That said, as I have written before, people eating low carb diets should be careful to eat quality, unprocessed meats and, as discussed in an earlier blog post, it is very wise to avoid eating meats laced with the inorganic phosphates that will damage your kidneys and heart. A low carb diet whose protein component is made up largely of fast food burger patties, processed foods, and supermarket bacon is not a healthy diet.

If you are going to eat a lot of meat (which many of us who eat low carb diets do not do) it is a good idea to eat organic meats if you are going to be eating a lot of meat fat,  because pesticides and other environmental toxins do tend to be deposited in animal fat.

Also,because the fatty acid composition of the fat of the animals we eat reflect the fats they eat, the fat from animals fattened on the currently fashionable "vegetarian" animal  feeds made up of corn and corn oil may contain higher levels of inflammation-producing omega-6 fatty acids than meat did in the past.  So it may no longer be a good idea to eat the fat found in supermarket meats. if you can find meat from pastured animals, that would be a better choice. I am coming to think it might be healthier to get the fat component in your diet from butters made from pastured cows and from non-processed imported cheeses rather than from consuming big chunks of animal fat.


9 comments:

Synger said...

My immediate "huh?" when reading these articles about acidity was regarding what causes the acidity. Yes, meat, cheese, and eggs are "acidic" foods. So are sugars and grains, and yet it's meat that painted as the culprit in the news headings. It would be just as accurate to say "cut drastically back on sugar and grains" as to suggest we should cut back on meat and cheese.

v/vmary said...

leaving aside recommendations to eat grains, what do you think of this organization's recommendation to avoid nuts since they are filled with potassium and phosphorous? also, when my mom's kidney function was decreasing, but not to the point of needing dialysis, she would only drink distilled water as all the minerals are removed from it. she was an intensive care unit nurse for 40 + years, and i think she said dialysis patients were advised to drink distilled water, but i can't remember. number one for protecting the kidneys is keeping blood sugar under control, i know. it is possible for someone to have both a genetic predisposition to diabetes and kidney disease, so i am trying to educate myself on this, since i may be one of those people.

v/vmary said...

http://www.uphs.upenn.edu/renal/important%20pdf%20II/HD%20water%20treatment.pdf

this is taking about water purification methods for water used in dialysis. distillation is said to be the best, but too expensive.

Jenny said...

The recommendation to avoid nuts comes from the belief that fat causes heart attacks. Once someone is in full kidney failure and on dialysis there is an issue with these electrolytes building up in the bloodstream. Eating low carb can help with kidney damage much earlier in the progression towards total kidney failure.

milan said...

You must avoid nuts and read a lot about that

Jenny said...

Milan,

Huh? Your comment doesn't make sense.

Betsy said...

Jenny, thank you for your analysis and explanation of this research. I too was concerned when I read other reports about it in the news, and I came here to see what you had to say about it. It's really too bad we can't see the questionnaire used in the study since it plays such an important role. I'm beginning to wonder about the rationale for funding such studies.

Jenny said...

Betsy,

A recent article in Nature disclosed that 90% of early stage research in the cancer field is based on assumptions that have already been disproved. A major reason why there has been such a tiny bit of progress in curing cancers.

Research grants are approved by small groups of senior researchers who are not motivated to prove that the work they have put their lives into came up with faulty conclusions. So they incline towards approving studies that confirm their biases.

http://news.yahoo.com/90-percent-early-stage-cancer-research-wrong-study-174500501.html

Diabetes is just as bad, with the majority of the early stage work done in rodents that are suffering diabetes caused by genetic flaws quite different from those found in humans with diabetes.
Diet research is even worse because it isn't a rigorously scientific discipline--someone can publish diet research after earning a degree in Nutrition a less scientifically demanding discipline than than microbiology or molecular biology.

roadrunner said...

I hope you are following the blogs on resistant starch and scFOS. While the blogs run from flambuoyant to offensive (Dr BG, mrheisenbug, FreetheAnimal), there does seem to be something seriously affecting blood sugar.

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