Friday, December 18, 2009

More Dairy = Less Inflammation?

Effects of dairy compared with soy on oxidative and inflammatory stress in overweight and obese subjects

Background: We recently showed that calcitriol increases oxidative and inflammatory stress; moreover, inhibition of calcitriol with high-calcium diets decreased both adipose tissue and systemic oxidative and inflammatory stress in obese mice, whereas dairy exerted a greater effect. However, these findings may be confounded by concomitant changes in adiposity.

Objective: The objective of this study was to evaluate the acute effects of a dairy-rich diet on oxidative and inflammatory stress in overweight and obese subjects in the absence of adiposity changes.

Design: Twenty subjects (10 obese, 10 overweight) participated in a blinded, randomized, crossover study of dairy- compared with soy-supplemented eucaloric diets. Two 28-d dietary periods were separated by a 28-d washout period. Inflammatory and oxidative stress biomarkers were measured on days 0, 7, and 28 of each dietary period.

Results: The dairy-supplemented diet resulted in significant suppression of oxidative stress (plasma malondialdehyde, 22%; 8-isoprostane-F2, 12%; P < 0.0005) and lower inflammatory markers (tumor necrosis factor-, 15%, P < 0.002; interleukin-6, 13%, P < 0.01; monocyte chemoattractant protein-1, 10%, P < 0.0006) and increased adiponectin (20%, P < 0.002), whereas the soy exerted no significant effect. These effects were evident by day 7 of treatment and increased in magnitude at the end of the 28-d treatment periods. There were no significant differences in response to treatment between overweight and obese subjects for any variable studied.

Conclusion: An increase in dairy food intake produces significant and substantial suppression of the oxidative and inflammatory stress associated with overweight and obesity. This trial was registered at clinicaltrials.gov as NCT00686426.

8 comments:

Sifter said...

OK, call me totally confused. I've always been taught that dairy actually promotes inflammation. See Roger Cohen interview "Dairy causes heart disease, etc."

http://www.naturalnews.com/002695.html

Chris said...

Dairy is controversial.

zach said...

Dairy is complicated. Unheated, unprocessed dairy from grass fed cows does NOT cause heart disease, quite the opposite. If you have leaky gut, casein might be bad for you. Pastured, uncooked cream and butter are some of the healthiest foods in existence and most people thrive on them. Natural News and Mike Adams promote a more Vegan approach, an approach that is ridiculous. They are correct though that store bought dairy-processed and from very sick cows fed nothing but grains, is bad for you. Realmilk.com is a good site to find real dairy products near you.

Robert McLeod said...

I think the title of this post should be "Soy more inflammatory than dairy."

Mike said...

Well put, Zach.

L. Wu said...

"2. Supported by the National Dairy Council."

"...faculty, staff, and student populations of the University of Tennessee... Subjects were excluded for the following reasons: BMI <25 or ≥30... adverse response to dairy foods"

"Two diets (dairy and soy) in the form of "smoothies" were administered 3 times per day throughout each 28-d treatment period. Each smoothie contained 170 kcal, 10 g protein, 1 g fat, and 30 g carbohydrate...

The dairy smoothies were milk based, with nonfat dry milk as the protein source, and contained 350 mg calcium per smoothie. The placebo smoothies were soy based and contained 50 mg calcium per smoothie. The soy protein isolate was used as the protein source in the placebo smoothies."

So, the study was done on a strictly overweight population which is 83% Caucasian (Wikipedia), comparing nonfat dry milk-based protein shakes to non-fermented soy protein isolate shakes, for people who were pre-screened not to have any adverse reaction to dairy. Hmm.

Chris said...

Great comments - I posted that abstract to prompt some discussion.

Chris said...

Of course I should have spotted that it was supported by the Dairy industry!