Doctor Pierce's Notebook

Dr. Oz's Report on Diet and Genes

via www.doctoroz.com

Dr. Oz recently did a show on genetics and weight loss--nutrigenomics, which was a combination of really good information and some not so good information.

There is something to the idea that your genetic make-up has a lot to do with what kind of diet you will respond to and how. While isolating the particular genes that identify which diet is best for you is somewhat new, the general hypothesis has been around for awhile in the form of both anthropological and ethnographic nutrition. Which is to say: we've often looked at our human ancestors in general, and our specific ancestors and their places of origin in order to determine what diets suit which people best.

This is the foundation for the paleolithic diet--eat only what the cave men ate, nuts, berries, leafy greens, and meat--and for the real food movement, which basically says, if it has a food label, you shouldn't eat it.

The nutrigenomic idea is slightly misleading--the report suggests you have a gene that tells us exactly what you should eat.  This is not exactly the case.  You have genes that tell us what sort of disease processes and metabolic tendencies that you've inherited.  What diet that means you should have is, at best, a hypothesis, (what I like to call a SWAG, a scientific, wild-ass guess) much of it based on faulty premises, like the idea that low-fat dieting has a positive effect on stroke and heart-attack, or the idea of a calorie and its relationship to nutrition and obesity. 

For that is the most potentially misleading part of Dr. Oz's report: the idea that the bottom-line is "calories in, calories out"--the laws of thermodynamics tell us that this is not the case. It takes more energy to process a protein "calorie" than a carbohydrate "calorie". I use calorie in quotes, because even the concept of a calorie is rather bizarre and very flawed.

Quality of calories matter more than quantity, and it seems that all calories are not created equal.

It's not just calories in, calories out.  Not by a long shot. 

More on Animal Protein

This study explains the possible link between saturated fats and inflammatory processes which are linked to several diseases.  Note that it is not so much the fat itself but the ratio of "bad fats" to good fats. 

For the past century, changes in the Western diet have altered the consumption of omega-6 fatty acids (w6, found in meat and vegetable oils) compared with omega-3 fatty acids (w3, found in flax and fish oil). Many studies seem to indicate this shift has brought about an increased risk of inflammation (associated with autoimmunity and allergy), and now using a controlled diet study with human volunteers, researchers may have teased out a biological basis for these reported changes.

Anthropological evidence suggests that human ancestors maintained a 2:1 w6/w3 ratio for much of history, but in Western countries today the ratio has spiked to as high as 10:1. Since these omega fatty acids can be converted into inflammatory molecules, this dietary change is believed to also disrupt the proper balance of pro- and anti- inflammatory agents, resulting in increased systemic inflammation and a higher incidence of problems including asthma, allergies, diabetes, and arthritis.

Floyd Chilton and colleagues wanted to examine whether theses fatty acids might have other effects, and developed a dietary intervention strategy in which 27 healthy humans were fed a controlled diet mimicking the w6/w3 ratios of early humans over 5 weeks. They then looked at the gene levels of immune signals and cytokines (protein immune messengers), that impact autoimmunity and allergy in blood cells and found that many key signaling genes that promote inflammation were markedly reduced compared to a normal diet, including a signaling gene for a protein called PI3K, a critical early step in autoimmune and allergic inflammation responses.

Relating to the previous post, the balance of these fats is significantly altered in a positive direction when animals are freely pastured, eat a natural diet of grass, and treated humanely.    Eat grass fed beef whenever possible and make sure to eat cold water fish twice a week.  Non meat-eaters and meat eaters can also use free-range eggs, brussel sprouts, nuts, and flax seed as a natural supplement, or take three fish oil capsules a day.  Note: inflammation is also related to CAD (coronary artery disease).  

Protein and Fat: the Basics

from aftb's photo stream in Flickr.  Used here under a Creative Commons License.

Fat and protein are the essential macro-nutrients for optimal health and wellness.  By essential, I mean they are absolutely necessary--we can live without carbohydrate (thrive, in fact) but if we do not get enough fat and protein, we cannot maintain proper cellular function and the result is certain disease and eventual death.  

So a diet that uses meat as a fat and protein source is close to being optimal and, certainly, our paleolithic ancestors subsisted on bursts of feeding upon the fat and protein of wild game, interspersed with periods of gathering nuts and berries.  

That being said, we can't just turn a blind eye to the fact that meat and animal fat also present health risks.  We now know that dietary fat does not build up in the arteries the way we once thought; once we no longer have to worry about where our next meal is coming from, a grain-based diet, low in essential fatty acids creates an inflammatory state that puts one at higher risk of heart disease. However, the Archives of Internal Medicine recently published a study that shows a small increased risk of coronary artery disease (CAD) in those who report frequent meat eating.  The question is: why?  This is what we call a correlational study.  It demonstrates a relationship but does little to analyze cause and effect.  Here are several possible hypotheses that have yet to be thoroughly studied: 

• It could be something inherent to meat, in any form
  
  
• It could be something inherent to cooking the meat (see prior post on grilling)
  
  
• It could be due to the widespread use of antibiotics and growth hormones in commercial meat industries
  
  
• It could be due to the pro-inflammatory grain (ie, corn) diet we force on these animals in place of their natural diet (grass, clover, etc.)

The last two are interesting to me in terms of health and medicine but also in terms of philosophy and ethics.  When animals are "factory farmed" and treated inhumanely, the nutritional value of their meat is compromised.  When fed, for instance, the instantly fattening, cheaply produced corn and grain-based diet, it increases the ratio of saturated fat to oleic acid and increases the inflammatory properties of meat.  So the question is, would these findings have been different if these were either a.) wild game animals or b.) pastured, humanely treated, domesticated animals?  

Though these are still only working hypotheses my family and I have been slowly converting to the "locavore" philosophy of eating, focusing on locally grown produce, wild caught fish, locally raised, free-range poultry, eggs, and grass-fed beef.  It is certainly difficult and costly to make these switches--but as our friend Rebecca is fond of saying, we vote with our dollars, so it is something we continue to work on, making small changes in our choices of food and where we buy it.   

While the evidence remains to be gathered and tested, it certainly seems rather poetic that being good stewards of the earth, and treating animals humanely, would have broad-ranging health benefits for those who make those choices.  It has a kind of symmetry that makes this nutritional philosophy intuitively the best choice for those seeking optimal health and wellness for themselves and compassionate living for the good of their community.  And in the meantime, I'm working out the details of dietary choices for those who wish to entirely opt out of animal protein for the ethical reasons stated here.  It's difficult because animal protein and fat are optimal sources of our essential macro-nutrients--but there is likely a way that vegetarians and even vegans can eat the low-carbohydrate way, receive optimal nutrition, and live in harmony with their ethical choices.