Your Mother Made You Fat!

September 09, 2010

Your Mother Made You Fat! 

 ReferenceJournal of Nutrition 140(9) 1595 2010 Competency: Good Fats, Bad Fats 

 Here is the experiment just published in the Journal of Lipid Research (what, you didn’t read that one!) that gives another piece of evidence that you can blame it all on your mother.  If you give four generations of rats a diet in which you mimic our modern American diet of lots of omega-6 fatty acids (otherwise known as vegetable oil, corn oil, soybean oil, and most vegetable oils) with a deficiency in omega-3 fatty acids (otherwise known as fish oil, DHA and EPA), you see a gradual increase in body mass from generation to generation.  

Each generation of rats in this experiment had the exact same food and were able to eat whatever they wanted.  And their food had the same balance of omega 3 to omega 6 fatty acids we have in America: about 1:15.  And each generation then got fatter than the prior generation.  That means that the diet one generation eats gradually turns into a genetic effect. 

 How can that happen?  Our genes are fixed!  Aren’t they?  Well, yes and no.  The field of nutrigenomics is emerging and really is just about that: how does what you eat affect how your genes are affected.  We are pretty sure that you have about 10 times the number of combinations of genes because of the way we can add methyl groups to our DNA and to the histone proteins that protect our DNA.  The basic DNA doesn’t change, but the way the gene is expressed changes, one generation to the next. 

And this research shows exactly that effect.  The CSG-3 gene (colony-stimulating factor-3) and the nocturnin gene both steadily increased each generation.    This could lead to an altered expression of how fat is stored that is then passed on to the next generation, not on the DNA itself but on the proteins that line DNA and the chemical groups attached to the outside.  It works like a gene, but only takes one generation to make the change. 

 How did that happen?  Well, in the last 100 years our intake of omega fats, derived primarily from grass-raised animals has dropped as our meat is mostly raised on grains like corn and beans.  Feedlot-raised animals have dramatically lower levels of omega fats in their tissue.  And, in the same time period, the industrial production of vegetable oils made them much cheaper.  We love fried food and oil of any kind.   The ratio of omega 3 to 6 was probably about 1:1 or 1:2 in our Paleolithic days.  Today, in America it is usually around 1:15.   In urban neighborhoods where cheap fast food is a norm, ratios as high as 1:50 are common.  And obesity is just taking off.  

Conclusion: the ratio of omega fats in our diet not only affects us in the short term but may be contributing to the obesity of our children in the longer term.  We know from the Lyon Heart study that reducing your ratio to 1:4 lowers your risk of heart disease by more than the effect of a statin drug. At least we don’t have to blame it on ourselves.  Our mother takes another guilt trip for the cause. 

 WWW. What will work for me.  Well, we now have two generations to think about when we eat.  How you eat affects you, and maybe your kids too.  The only way to gradually reverse this is to start changing your ratio of omega fats in your diet.   Eat more fish oil, avoid vegetable oil in all it forms.   An alternative tactic is just to attack the research and state that it was all done in mice.  No way, Jose, am I going to change.   I personally take a gram a day of fish oil.  I’m raising that to two.  Morning and evening, three big pills.

Column written by Dr. John E Whitcomb, MD, Brookfield Longevity, Brookfield, WI 53045 (262-784-5300.