Monday, September 8, 2014

Pastured Anti-Obesity Advantage: Lower Body Fat, Reduced Liver Fat and Healthier Guts in French Rodent Study of Health Effects of Pasture vs. Regular High Fat Dairy Diet

Happy dairy, happy tummy. That's maybe not the sexiest, but potentially the most important result of this study.
Yes, it's only a rodent study. And no, rodents usually don't drink cow's milk, but the fact that  a pastured dairy diet leads to improved metabolic outcomes and to a stronger gut barrier compared with a standard dairy diet in rodents on an obesogenic high fat diet, is still - in my humble opinion - newsworthy!

As Bérengère Benoit and colleagues point out in their latest paper in the British Journal of Nutrition, "this may be due, at least in part, to the protective mechanisms induced by specific lipids" (Benoit. 2014).
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Before we are dealing with implications and conclusions, though, let's briefly take a look at what exactly it was the French researchers did.

As Benoit et al. point out, dairy products derived from the milk of cows fed in pastures are characterized by higher amounts of conjugated linoleic acid (CLA) and α-linolenic acid (ALA, the major short-chain omega-3 fatty acid, not alpha-lipoic acid). As a SuppVersity Reader you will know that several studies have shown that these "good fats" have the ability to reduce cardiovascular risk and lower the risk of metabolic defects. Whether the latter can be said of plain dairy, when it is produced by pasture-fed cows and thus high(er) in CLA and ALA, however, remains largely unknown.

In the study at hand, a team of researchers from the Lyon University, INSA-Lyon, INRA, and the  INSA-Lyon did thus focus on the specific metabolic effects of pastured compared with standard dairy in a high-fat diet (HFD) context. In that, their focus was on the metabolic and intestinal health effects of the two different types of dairy.

Table 1: Composition of experimental diets (Benoit. 2014)
The experimental animals were fed for 12 weeks with a high fat + energy diet containing 20 % fat in the form of a pasture dairy cream (PDC) or a standard dairy cream (SDC). Samples of plasma, liver, white adipose tissue, duodenum, jejunum and colon were analysed. The

PDC mice, despite having a significantly higher food intake, exhibited lower fat mass, plasma and hepatic triglyceride concentrations, a lower level of inflammation in the adipose tissue than the mice on conventional dairy. Furthermore, the rodents with the pastured dairy in their diet exhibited a higher expression of hepatic PPARα mRNA and adipose tissue uncoupling protein 2 mRNA, suggesting an enhanced oxidative activity of the liver.

As you may remember from previous articles about CLA (specifically "CLA Destroys Body Fat & Increases Endurance! But at Which Costs" | read more), these results may be a direct consequence of the increased amounts of CLA in the pastured dairy diet (PCD) and its metabolic consequences on liver and body fat.

Gut health, again - can pastured dairy render your gut bulletproof?

Moreover, the PDC diet was found to increase the proportions of two strategic cell populations involved in the protective function of the intestinal epithelium, namely Paneth and goblet cells in the small intestine and colon, compared with the SDC diet.
Figure 1: Relative body composition and liver lipids (expr. in % of control; left) and fatty acid and sterol profiles of the regular and pastured dairy (Benoit. 2014)
That's particularly interesting in view of the ever-increasing rates / numbers of patients with (autoimmune) diseases of the gut and potential downstream systemic (ill) health effects of having a leaky gut (learn more). With the accumulating evidence of the far-reaching impact the health of our digestive tract has on the human metabolism, this finding may eventually even be more important than the increase in fatty acid oxidation (assuming it translates to humans, of course).
Do you want to learn the "Fat Truth Behind the Alleged Dairy Weight Loss Miracle"? Go ahead and go back to a previous article of mine to find out if it's calcium, protein, or healthy fats... or, if the whole thing is just another health hoax | read more
Bottom line: In spite of the fact that we still don't know if we'd see the same or even more pronounced health benefits with pastured vs. regular dairy in a human studies, my friend Alex Leaf who actually bet me on announcing the main results of the study at hand on Facebook weeks ago was right, when he states: "This is a study that supports that spending the extra bucks on pastured vs. regular dairy may be worth it."

Human subjects and a regular, not high fat (in rodents this is high fat + high carb = extremely high energy) diet are yet things I would like to see in a follow study, before I fully subscribe to the "pastured dairy hysteria". In the mean time, I would like to draw your attention to the deliberately underlined word "may" from the previous sentence ;-) | Comment on Facebook!
  • Benoit, Bérengère, et al. "Pasture< i> v. standard dairy cream in high-fat diet-fed mice: improved metabolic outcomes and stronger intestinal barrier." British Journal of Nutrition 112.04 (2014): 520-535.