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Showing posts from September, 2011

Calling self-experimentation N=1 is incorrect and misleading

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This is not a post about semantics. Using “N=1” to refer to self-experimentation is okay, as long as one understands that self-experimentation is one of the most powerful ways to improve one’s health. Typically the term “N=1” is used in a demeaning way, as in: “It is just my N=1 experience, so it’s not worth much, but …” This is the reason behind this post. Using the “N=1” term to refer to self-experimentation in this way is both incorrect and misleading. Calling self-experimentation N=1 is incorrect The table below shows a dataset that is discussed in this YouTube video  on HealthCorrelator for Excel (HCE) . It refers to one single individual. Nearly all health-related datasets will look somewhat like this, with columns referring to health variables and rows referring to multiple measurements for the health variables. (This actually applies to datasets in general, including datasets about non-health-related phenomena.) Often each individual measurement, or row, will be associated with

Being glucose intolerant may make you live only to be 96, if you would otherwise live to be 100

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This comes also from the widely cited Brunner and colleagues study , published in Diabetes Care in 2006. They defined a person as glucose intolerant if he or she had a blood glucose level of 5.3-11 mmol/l after a 2-h post–50-g oral glucose tolerance test. For those using the other measurement system, like us here in the USA, that is a blood glucose level of approximately 95-198 mg/dl. Quite a range, eh!? This covers the high end of normoglycemia, as well as pre- to full-blown type 2 diabetes. In this investigation, called the Whitehall Study, 18,403 nonindustrial London-based male civil servants aged 40 to 64 years were examined between September 1967 and January 1970. These folks were then followed for over 30 years, based on the National Health Service Central Registry; essentially to find out whether they had died, and of what. During this period, there were 11,426 deaths from all causes; with 5,497 due to cardiovascular disease (48.1%) and 3,240 due to cancer (28.4%). The graph be

Fasting blood glucose of 83 mg/dl and heart disease: Fact and fiction

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If you are interested in the connection between blood glucose control and heart disease, you have probably done your homework. This is a scary connection, and sometimes the information on the Internetz make people even more scared. You have probably seen something to this effect mentioned: Heart disease risk increases in a linear fashion as fasting blood glucose rises beyond 83 mg/dl . In fact, I have seen this many times, including on some very respectable blogs. I suspect it started with one blogger, and then got repeated over and over again by others; sometimes things become “true” through repetition. Frequently the reference cited is a study by Brunner and colleagues , published in Diabetes Care in 2006. I doubt very much the bloggers in question actually read this article. Sometimes a study by Coutinho and colleagues is also cited, but this latter study is actually a meta-analysis. So I decided to take a look at the Brunner and colleagues study. It covers, among other things, t

Evolution of the "Hero's Journey"

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When I was a child, my father told me stories of his time spent working for a gold mining company in the Amazon jungle. He brought home tales of fishing for piranhas, evading giant venomous snakes, and nearly being eaten alive by a swarm of ants. Dad also traded with indigenous tribes. My curiosity was piqued by photos of those natives, so shockingly naked, and their beautifully crafted bows and arrows. Dad had one on display that he had acquired in exchange for a pair of jeans, which my brother and I used to play with until it almost broke (leading to a stern warning). Dad's stories have stuck with me to this day and I've often reflected on the influence they’ve had on my life. Each story had a some sort of moral in it, although I didn't know it. They’ve guided me in all sorts of situations, be they social, financial or otherwise. Now, as if following wise ancient tradition, he tells these same stories to my children and nephews, his grandchildren. Evolution of storytellin

What chimpanzee predatory behavior can tell us about early human diets

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Among primates, we humans are unique in how much meat we eat. On average we eat 10 times as much meat as chimpanzees, who eat the most meat among wild apes. And, unlike any other primate, humans specialize in eating big-game animals (larger than ourselves) like reindeer and mammoths.  Because of how much meat humans eat, a few major questions are under discussion among biologists and anthropologists:  What role did meat play in human evolution?   How much meat did human ancestors really eat early on? Cutmarks on bones, unfortunately, don't say much about whether meat was eaten once a day, once a week, or once a month. But could a few clues into early human diets be gleaned from the extensive field research into the predatory nature of wild chimps? Biological anthropologist Craig Stanford says he gained a research window into studying chimpanzee meat-eating because Jane Goodall, a committed vegetarian, found the chimp's brutality too morally repugnant and awful to watch. He has

Nonlinearity and the industrial seed oils paradox

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Most relationships among variables in nature are nonlinear, frequently taking the form of a J curve. The figure below illustrates this type of curve. In this illustration, the horizontal axis measures the amount of time an individual spends consuming a given dose (high) of a substance daily. The vertical axis measures a certain disease marker – e.g., a marker of systemic inflammation, such as levels of circulating tumor necrosis factor (TNF). This is just one of many measurement schemes that may lead to a J curve. J-curve relationships and variants such as U-curve and inverted J-curve relationships  are ubiquitous , and may occur due to many reasons. For example, a J curve like the one above may be due to the substance being consumed having at least one health-promoting attribute, and at least one health-impairing attribute. The latter has a delayed effect, and ends up overcoming the benefits of the former over time. In this sense, there is no “sweet spot”. People are better off not co