Whole Grains Promote Healthy Weight
Bakers, Food makers and nutritionists are warning about the amazing popularity of the Atkins diet have a new tool in their fight against this food fad in a new study that reveals an inverse assocation between whole grains and weight gain.
It found that while women who ate a large amount of refined grain foods were more likely to be obese, those with the greatest whole grain consumption weighed less and are less likely to gain weight.
The study, published in November’s American Journal of Clinical Nutrition (vol 78, no 5, pp 920-927), investigated the relation between intake of dietary fibre and whole- or refined-grain products with weight gain over time.
They used a prospective cohort study on more than 74,000 US female nurses, aged 38-63 years in 1984 and free of known cardiovascular disease, cancer, and diabetes at baseline. Their dietary habits were assessed in 1984, 1986, 1990, and 1994 with validated food-frequency questionnaires.
Average weight, body mass index, long-term weight changes, and the odds ratio of developing obesity (BMI of 30) according to change in dietary intake were recorded.
The researchers from the Brigham and Women’s Hospital and Harvard Medical School found that women who consumed more whole grains consistently weighed less than women who consumed less whole grains.
Over 12 years, those with the greatest increase in intake of dietary fibre gained an average of 1.52 kg less than did those with the smallest increase in intake of dietary fibre independent of body weight at baseline and age.
Women in the highest quintile of dietary fibre intake had a 49 per cent lower risk of major weight gain than did women in the lowest quintile.
The team concludes that “”weight gain was inversely associated with the intake of high-fibre, whole-grain foods but positively related to the intake of refined-grain foods, which indicated the importance of distinguishing whole-grain products from refined-grain products to aid in weight control”".
Science Begins to Add Weight to CLA
The flurry of activity in CLA applications is being backed by a growing body of research to support the ingredient, particularly for its effects on weight loss. A review published in this month’s Journal of Nutrition supports conjugated linoleic acid’s action on weight management, concluding that it is at least in part due to regulation of glucose and fatty acid uptake and metabolism.
Conjugated linoleic acid is the common name of a group of fatty acids found in dairy products and meat. CLA isomers have been studied for their action on an impressive range of diseases, including cancer, atherosclerosis, obesity, and immune function. However as scientists begin to reveal their effects on reduction of body fat, food makers are increasingly looking at the ingredient for the valuable slimming market.
In Canada, where many of the patents for CLA are held, the dairy industry has long been studying the production of high-CLA milk. In Europe, a research centre in Ireland is studying the compound which could add significant value to its dairy industry, while in Italy, Techno Foods introduced a strawberry flavoured yoghurt naturally rich in CLA (conjugated linoleic acid) and omega-3 fatty acids this summer.
Specific CLA isomers have been shown to prevent the development of obesity in certain rodent and pig models and this has been attributed mainly to trans-10, cis-12 CLA, both in vivo and in vitro, write the University of North Carolina researchers in the review. However, CLA’s ability to modulate human obesity remains controversial because data from clinical trials using mixed isomers are conflicting.
In vitro studies by the team demonstrated that while trans-10, cis-12 CLA prevents triglyceride accumulation in human cells, cis-9, trans-11 CLA increases triglyceride content. The team concluded that the isomers’ regulation of glucose and metabolism must partly explain its mechanism on human fat.
The news is also good for supplement marketers who recently learned of research carried out by Cognis backing the long-term safety of its Tonalin CLA.