Replacing refined wheat with whole grain wheat led to 0.9% less body fat, according to results of a study with 79 overweight or obese postmenopausal women published in the Journal of Nutrition.
“Serum total and LDL cholesterol, two important risk factors of cardiovascular disease, increased with refined wheat but not whole grain wheat consumption, which may suggest a cardioprotective role for whole grain,” wrote researcher led by Mette Kristensen from the University of Copenhagen in Denmark.
The study also involved scientists from the Nestlé Research Center (Switzerland), Italian food company Barilla, and the Danish Technical University, Lyngby.
Whole grain success
The 2010 Dietary Guidelines for Americans recommend Americans consume at least half of all grains as whole grains, which include the entire grain seed (kernel), which consists of bran, germ, and endosperm.
Refined grains have been milled to remove the bran and germ, which creates a finer texture and improves their shelf life, but also removes dietary fiber, iron, and B vitamins. Enriched grains are grain products with B vitamins and iron added.
On-product whole grain claims have soared since the introduction of the Whole Grain Stamp in 2005. Market research organization Mintel says that since 2005, more than 4,000 new products carry the claim. It appeared on 2.3% of products launched in 2005 – rising to 5.6% in 2010.
The Whole Grain Stamp program provides manufacturers with two different versions: one that indicates that a product is made with 100 percent whole grain and provides a full 16-gram serving of whole grain per portion; and a basic Whole Grain Stamp that requires a product to provide at least eight grams of whole grain per portion, equivalent to a half serving of whole grains.
New data
Kristensen and her co-workers recruited 79 overweight or obese postmenopausal women and randomly assigned them to consume an energy-restricted diet containing refined or whole grain wheat products.
After 12 weeks of consuming the diets, results revealed that both diets produced weight loss, but the greater loss was observed in the whole grain group with 3.6 kg lost on the whole grain diet, compared with 2.7 kg on the refined wheat diet. However, these changes were not deemed to be statistically significant.
Changes to the percentage of body fat were significantly different between the diet groups, however. The whole grain diet group experienced an average reduction in body fat of 3%, compared with only 2.1% in the refined wheat diet group.
In addition, total and LDL cholesterol levels increased by about 5% in the refined wheat diet group, whereas no such changes were observed in the whole grain group, added the researchers.
Source: Journal of Nutrition
Published online ahead of print, doi: 10.3945/jn.111.142315
“Wholegrain Compared with Refined Wheat Decreases the Percentage of Body Fat Following a 12-Week, Energy-Restricted Dietary Intervention in Postmenopausal Women”
Authors: M. Kristensen, S. Toubro, M.G. Jensen, A.B. Ross, G. Riboldi, M. Petronio, S. Bugel, I. Tetens, A. Astrup