A very simple concept here. Grass fed beef has more omega 3 and the correct ratio of omega 6 to omega 3 fats. ref Plus, grass fed beef has a much higher content of CLA. WHY? Grass feeds certain bacteria in the cows intestinal tract that produce more omega 3 fats as well as greater quantities of CLA.
Cows fed grains in feed lots develop different bacteria in their guts that do not produce the same amount of omega 3 or CLA. It is just that simple. The bacteria grown on grains pushes the omega 6 to omega 3 ratio to over 15 - 1 while cows eating pasture grass have within a 4-1 ratio. This is very significant to health. The cattle research industry knows this is a problem and has developed methods (back grounding) to slightly lower this ratio. This also significantly lowers the pathogenic e-coli bacteria count from grain feeding.
Could grains have a similar affect on human intestinal bacteria types? And could this lead to digestive problems? VERY INTERESTING! Could this be one of the positive aspects of gluten free programs?
A connection has been discovered between good bacteria acting on certain fecal enzymes to lower the colon cancer risk. Giving Lactobacillus acidophilus significantly reduced the activity of these 3 enzymes known to increase colon cancer, B-glucuronidase, nitroreductase, and azorductase. These 3 enzymes can catalyze procarcinogens into a proximal carcinogen (direct cancer causing element). It takes 4 weeks after discontinuing Lactobacillus for these enzymes to return to their pre-bacteria levels. AJCN, 39: May 1984, pp 756-761. ref ref < check date, new study