Posts

Showing posts from July, 2010

Resveratrol blocks weight gain in primate study

Image
Gray mouse lemur Resveratrol—a natural red-wine compound previously shown to protect mice against excess weight gain when fed a high-fat diet—has now been found to reduce seasonal weight gain in gray mouse lemurs in a primate model of obesity. The study was published in BMC Physiology by a team of researchers from the Centre Nationale de la Recherche Scientifique, Museum National d’Histoire Naturelle, of Paris, who wrote that they had “demonstrated for the first time the short-term effects of resveratrol on the metabolism of an heterothermic [with varying body temperatures] primate.” Gray mouse lemurs are a species of prosimian primate that can double in weight (seasonal fattening) within a matter of weeks. This increase in energy reserves is induced by the arrival of shorter days and longer nights (shorter photoperiod), which serves as a means of adapting to the long dry winters in its natural environment in Madagascar. When given four weeks of resveratrol supplementation at the ti

If You Ever Had Doubts About Our Ancestors Eating Shellfish, See Curtis Marean's Feature

Image
When the Sea Saved Humanity Powered by Ergo:Ux

Too much complexity! I like the simplicity of Ricky’s Weather Forecasting Stone

Image
Too much complexity in the last few posts and related comments: multivariate analyses, path coefficients, nonparametric statistics, competing and interaction effects, explained variance, plant protein and colorectal cancer, the China Study, raw plant foods possibly giving people cancer unless they don’t … I like simplicity though, and so does my mentor . I really like the simplicity of Ricky’s Weather Forecasting Stone. (See photo below, from … I will tell you in the comments section. Click on it to enlarge. Use the "CRTL" and "+" keys to zoom in, and CRTL" and "-" to zoom out.) Can you guess who the gentleman on the photo is? A few hints. He is a widely read and very smart blogger. He likes to eat a lot of saturated fat, and yet is very lean. If you do not read his blog, you should. Reading his blog is like heavy resistance exercise, for the brain. It is not much unlike doing an IQ test with advanced biology and physiology material mixed in, and a lo

The China Study one more time: Are raw plant foods giving people cancer?

Image
In this previous post I analyzed some data from the China Study that included counties where there were cases of schistosomiasis infection. Following one of Denise Minger ’s suggestions, I removed all those counties from the data. I was left with 29 counties, a much smaller sample size. I then ran a multivariate analysis using WarpPLS ( warppls.com ), like in the previous post, but this time I used an algorithm that identifies nonlinear relationships between variables. Below is the model with the results. (Click on it to enlarge. Use the "CRTL" and "+" keys to zoom in, and CRTL" and "-" to zoom out.) As in the previous post, the arrows explore associations between variables. The variables are shown within ovals. The meaning of each variable is the following: aprotein = animal protein consumption; pprotein = plant protein consumption; cholest = total cholesterol; crcancer = colorectal cancer. What is total cholesterol doing at the right part of the gr

The China Study again: A multivariate analysis suggesting that schistosomiasis rules!

Image
In the comments section of Denise Minger’s post on July 16, 2010 , which discusses some of the data from the China Study (as a follow up to a previous post on the same topic), Denise herself posted the data she used in her analysis. This data is from the China Study. So I decided to take a look at that data and do a couple of multivariate analyzes with it using WarpPLS ( warppls.com ). First I built a model that explores relationships with the goal of testing the assumption that the consumption of animal protein causes colorectal cancer, via an intermediate effect on total cholesterol. I built the model with various hypothesized associations to explore several relationships simultaneously, including some commonsense ones. Including commonsense relationships is usually a good idea in exploratory multivariate analyses. The model is shown on the graph below, with the results. (Click on it to enlarge. Use the "CRTL" and "+" keys to zoom in, and CRTL" and "-&qu

My transformation: I cannot remember the last time I had a fever

Image
The two photos below (click to enlarge) were taken 4 years apart. The one on the left was taken in 2006, when I weighed 210 lbs (95 kg). Since my height is 5 ft 8 in, at that weight I was an obese person, with over 30 percent body fat. The one on the right was taken in 2010, at a weight of 150 lbs (68 kg) and about 13 percent body fat. I think I am a bit closer to the camera on the right, so the photos are not exactly on the same scale. For a more recent transformation update, see this post . My lipids improved from borderline bad to fairly good numbers, as one would expect, but the two main changes that I noticed were in terms of illnesses and energy levels. I have not had a fever in a long time. I simply cannot remember when it was the last time that I had to stay in bed because of an illness. I only remember that I was fat then. Also, I used to feel a lot more tired when I was fat. Now I seem to have a lot of energy, almost all the time. In my estimation, I was obese or overweight f

Anti-Aging with Aubrey de Grey

A couple of weekends ago I was in LA going to a meet-up with biomedical gerontologist Aubrey de Grey to discuss new research on aging. He talked about a new paper he co-authored with a few of his other biogerontologist colleagues. So, I asked him to tell me more. Out of that meeting came a follow-up interview and this article published on KurzweilAI.net. Please read that article as it describes well why we must prevent a "Global Aging Crisis". And for anyone who wants to read the entire interview with Aubrey and the efforts of the SENS Foundation, here it is below: Q. Would you give a brief summary of the new paper of which you are listed as a co-author in Science Translational Medicine? The essence of this paper is that we argue for a more balanced approach to the quest for interventions to postpone age-related ill-health. Specifically, we highlight the fact that there are three general strategies to consider: - promotion of healthy lifestyles (through reduction in environm

Subcutaneous versus visceral fat: How to tell the difference?

Image
The photos below, from Wikipedia, show two patterns of abdominal fat deposition. The one on the left is predominantly of subcutaneous abdominal fat deposition. The one on the right is an example of visceral abdominal fat deposition, around internal organs, together with a significant amount of subcutaneous fat deposition as well. Body fat is not an inert mass used only to store energy. Body fat can be seen as a “distributed organ”, as it secretes a number of hormones into the bloodstream . For example, it secretes leptin, which regulates hunger. It secretes adiponectin , which has many health-promoting properties. It also secretes tumor necrosis factor-alpha (more recently referred to as simply “tumor necrosis factor” in the medical literature), which promotes inflammation. Inflammation is necessary to repair damaged tissue and deal with pathogens, but too much of it does more harm than good. How does one differentiate subcutaneous from visceral abdominal fat? Subcutaneous abdominal f

The China Study: With a large enough sample, anything is significant

There have been many references recently on diet and lifestyle blogs to the China Study. Except that they are not really references to the China Study, but to a blog post by Denise Minger . This post is indeed excellent, and brilliant, and likely to keep Denise from “having a life” for a while. That it caused so much interest is a testament to the effect that a single brilliant post can have on the Internet. Many thought that the Internet would lead to a depersonalization and de-individualization of communication. Yet, most people are referring to Denise’s post, rather than to “a great post written by someone on a blog.” Anyway, I will not repeat what Denise said on her post here. My goal with this post is bit more general, and applies to the interpretation of quantitative research results in general. This post is a warning regarding “large” studies. These are studies whose main claim to credibility is that they are based on a very large sample. The China Study is a good example. It p

Free running and primal workouts: Both look awesome, and dangerous

The other day I showed a YouTube MovNat video clip to one of my sons, noting the serious fitness of Erwan Le Corre. I also noted that the stunts were somewhat dangerous, and that they tried to replicate some of the movements that our Paleolithic ancestors had to do on a regular basis. That is, those movements are part of what one could call a primal workout. My son looked at me and laughed, as if asking me if I was really being serious. Why? Well, he is into breakdancing (a.k.a. b-boying), and also does a bit of something called "free running". If you don’t know what free running is, take a look at this Wikipedia article . Here are a couple of YouTube video clips on free running: clip 1 , and clip 2 . The moves do look a lot more hardcore than the ones on the MovNat video clip. (The reason for my son's reaction.) But, to be fair, the environments and goals are different. And, in terms of danger, some of these free running moves are really at the high end of the scale. An

Our body’s priority is preventing hypoglycemia, not hyperglycemia

Image
An adult human has about 5 l of blood in circulation. Considering a blood glucose concentration of 100 mg/dl, this translates into a total amount of glucose in the blood of about 5 g (5 l x 0.1 g / 0.1 l). That is approximately a teaspoon of glucose. If a person’s blood glucose goes down to about half of that, the person will enter a state of hypoglycemia. Severe and/or prolonged hypoglycemia can cause seizures, comma, and death. In other words, the disappearance of about 2.5 g of glucose from the blood will lead to hypoglycemia. Since 2.5 g of glucose yields about 10 calories, it should be easy to see that it does not take much to make someone hypoglycemic in the absence of compensatory mechanisms. An adult will consume on average 6 to 9 times as many calories just sitting quietly, and a proportion of those calories will come from glucose. While hypoglycemia has severe negative health effects in the short term, including the most severe of all - death, hyperglycemia has primarily long

Power napping, stress management, and jet lag

Image
Many animals take naps during the day. Our ancestors probably napped during the day too. They certainly did not spend as many hours as we do under mental stress. In fact, the lives of our Paleolithic ancestors would look quite boring to a modern human. Mental stress can be seen as a modern poison. We need antidotes for that poison. Power napping seems to be one of them. (Source: Squidoo.com) Power napping is a topic that I have done some research on, but unfortunately I do not have access to the references right now. I am posting this from Europe, where I arrived a few days ago. Thus I am labeling this post “my experience”. Hopefully I will be able to write a more research-heavy post on this topic in the near future. I am pretty sure that there is a strong connection between power napping and stress hormones. Maybe our regular and knowledgeable commenters can help me fill this gap in their comments on this post. Surprisingly, jet lag has been only very minor this time for me. The time

Michael Holick on Vitamin D

Michael Holick, MD, PhD, of Boston University Medical Center says he’s “just one of the many scientists” exploring vitamin D, but he easily can be considered the world’s foremost authority on the sunshine vitamin. In the 1970s, it was Dr. Holick who first isolated the major circulating form of vitamin D in plasma, 25-hydroxyvitamin D, as well as the active form produced by the kidneys. He was also one of the first scientists to warn the medical community about the potential implications of widespread vitamin D insufficiency. When asked about the prevalence of low vitamin D status, he answers that it’s the “most common medical condition in the world, believe it or not.” Dr. Holick has championed the cause of bringing vitamin D into the limelight for decades, writing numerous scientific papers as well as two popular books on the subject of vitamin D and health. Getting D Facts from Dr. Holick While seeking the latest findings from vitamin D research, I caught up with Dr. Holick and soug