[ed. note: Michael Jorrin, who I like to call Doc Gumshoe, is a longtime medical writer (not a doctor) who writes about non-financial health and medical issues for us a couple times a month (past submissions can be found on his author page here). Like all of our authors, he chooses his own topics and his words and opinions are his alone. Enjoy!]
When I first started doing this kind of thing – by which I mean writing about health and medical subjects – I used to have to make my way to the New York Academy of Medicine Library, at Fifth Avenue and 103rd Street, to do my research. There I would consult Index Medicus, a huge, comprehensive, multivolume index of medical journals all over the world. I would quickly find the journal papers my particular project required, request those volumes of the journals from the library circulation desk, read those papers, request photocopies of those papers that I felt I would need to refer to in my mission, pay the 10 cents per page fee, and depart, feeling that I had accomplished the crucial first step in my task.
No more. Index Medicus ceased publication in 2004, because, apparently, nobody but nobody used it anymore. All research was being done on line. And, in the meantime, the internet has deduced that I am interested in matters medical, and swamps my inbox with emails alerting me to every sort of medical and health news. I welcome this, up to a point. But it requires me to weed my inbox assiduously. If I don’t keep on top of it, it will become disastrously overgrown. Sometimes I miss the old way – I could skim Index Medicus a whole lot faster than PubMed or Medline. I could decide in an Augenblick if a paper might be worth reading. “Yes” to papers in Lancet or the New England Journal, “no” to papers in the Pseudomedical Consortium of Lower Slobbovia.
But among the daily internet weeds there are flowers of interest, and some of these merit, I hope, inclusion in Doc Gumshoe dispatches. Here are a few.
Is there a link between elevated cholesterol intake and dementia or Alzheimer’s?
Based on a study in Finland (Ylilauri MPT, Am J Clin Nutr 2017), the answer appears to be no. Whether this is good news or not good news depends on your appetite for meat, eggs, butter and cheese.
In the past, an association has been noted between elevated cholesterol levels and dementia. In particular, a focus of attention has been the APOE4 gene, which appears to increase the risk of late-onset Alzheimer’s disease (AD), and also plays a role in the processing and use of cholesterol and other lipids in the brain. However, elevated cholesterol is frequently observed in persons with high blood pressure as well as diabetes, so it is difficult to pinpoint cholesterol as the factor that contributes to AD. The data that tends to support the link between elevated cholesterol and dementia is that persons who take statins have a somewhat lower risk of developing dementia. But, as Doc Gumshoe never tires of pointing out, that is an association and not a proof of causation. It’s possible that the population that takes statins is different from the non-statin users in other respects than having a high cholesterol level. And it’s also possible that statins reduce the deposition of whatever brain-crud results in dementia or AD in a way that’s independent of their effect on cholesterol synthesis.
The study in Finland, however, is nothing if not robust. It followed 2,497 men, ages 42 – 60 years, who were free from dementia at baseline, for a total of 21.9 years, and found no association whatever between the intake of dietary cholesterol and the development of dementia or AD. Both total diet and egg intake were measured, and increased egg intake was associated with better performance on neuropsychological tests and executive function. Better, not worse!
What this seems to say is that we cannot reduce our risk of developing dementia or AD by cutting back on dietary cholesterol. I would, however, introduce a small Note of Caution: dietary cholesterol as cholesterol is by no means the only culprit in elevated cholesterol levels in the bloodstream. Remember, we ourselves make somewhere around 80% of the cholesterol in our systems, and we need to keep doing it, because cholesterol is a key component of many of our bodily tissues. So questions about the link between cholesterol and dementia are definitely still open.
Coffee, tea, and cardiovascular events
This was a substantial study (Miller PE, Am J Med 2016) in 6,508 persons described as “multi-ethnic” who were classified according to coffee and/or tea consumption. The background to this is that the health effects of coffee drinking in particular are somewhat controversial. Caffeine is known to increase heart rate, peripheral vasoconstriction, and blood pressure. At the same time, coffee consumption has definitely been linked with decreased risk of developing diabetes. The studies that demonstrated that link showed that diabetes benefit occurred with bona fide caffeinated coffee, but not with decaf. Doc Gumshoe, ever the skeptic, had wondered whether it was because at least some of the non-coffee drinkers might