Consuming the dairy-rich diet led to significant reductions in compounds linked to oxidative stress of over 20 per cent in some cases, and reductions in inflammatory markers of between 10 and 15 per cent, according to findings published in the American Journal of Clinical Nutrition.
The blinded, randomised, crossover study, supported by the National Dairy Council, involved 10 overweight and 10 obese people consuming a dairy or soy-rich diet for 28 day periods.
No benefits were observed following consumption of the soy-supplemented diet.
The research highlights the potential dairy and its bioactive constituents, an area described recently as a “high risk – reward business area” by Tage Affertsholt, managing partner at 3A Business Consulting.
3A Business Consulting recently published a report on dairy-derived bioactive ingredients that puts the size of the market at 30, 000 MT, or $700m in value terms. Current market growth is estimated to be 10 to 20 per cent per annum and the expectation is that the market will continue to expand at a high rate.
But making accurate growth forecasts is complicated by the health claims situation in the EU and other regulatory and research uncertainties worldwide. Affertsholt told NutraIngredients.com earlier this month that the feedback from industry is that the very restrictive approach to health claims adopted by the European Food Safety Authority (EFSA) will hamper growth potential.
“Some companies are giving up and leaving the game to concentrate on more traditional dairy ingredients,” said Affertsholt.
Led by Michael Zemel from the University of Tennessee, the researchers examined the effects of two diets of equal energy content, one of which was dairy-rich, while the other was soy-supplemented. The participants adhered to the dietary patterns for a 28-day period, followed by a 28-day washout period, and were then crossed over to the other group.
At the end of the study, levels of markers of oxidative stress, including malondialdehyde and 8-isoprostane-F2{alpha} decreased by 22 and 12 per cent, respectively.
Furthermore, inflammatory markers, including tumour necrosis factor-alpha, interleukin-6, and monocyte chemoattractant protein-1 decreased by 15, 13, and 10 per cent, respectively, following the dairy intervention.
Obese and overweight participants responded similarly during the dairy stage. Soy failed to produce any changes in these biomarkers.
“An increase in dairy food intake produces significant and substantial suppression of the oxidative and inflammatory stress associated with overweight and obesity,” said the researchers.
Source: American Journal of Clinical Nutrition
Published online ahead of print, doi:10.3945/ajcn.2009.28468
“Effects of dairy compared with soy on oxidative and inflammatory stress in overweight and obese subjects"
Authors: Michael B. Zemel, X. Sun, T. Sobhani, B. Wilson