1 August 2013

What’s New?

Diet soft drinks – is it the drink or what you eat with it that’s the problem? 
An opinion article published by Cell Press in Trends in Endocrinology & Metabolism reviews evidence on the negative impact of artificial sweeteners on health, raising red flags about all sweeteners – even those that don't have any calories. ‘It is not uncommon for people to be given messages that artificially-sweetened products are healthy, will help them lose weight or will help prevent weight gain,’ says author Susan E. Swithers of Purdue University. ‘The data to support those claims are not very strong, and although it seems like common sense that diet sodas would not be as problematic as regular sodas, common sense is not always right.’

‘Rather than just focus on soft drinks whether artificially or naturally sweetened,’ says Dr Alan Barclay, ‘let’s look at the whole shebang – people’s dietary patterns: what people who drink soft drinks regularly are eating with them. ‘Generally speaking, we tend to drink soft drinks with certain types of foods like potato chips, pizza, hamburgers, or we mix them with alcohol like bourbon or vodka (and help ourselves to crisps and salty nuts). People are still eating pretty poorly overall and unless they change their dietary patterns they are not going to see any benefits.

The bottom line re diet soft drinks and weight benefits: ‘If you chose an artificially sweetened product to reduce your overall energy intake in the context of a very healthy diet with plenty of fruits, veggies, whole grains etc... you probably would see some overall benefits. But if you’re simply swapping from one to the other and still having deep fried chicken and a large chips, you probably aren't going to see any real belt tightening benefits.’

Diet drinks

Exercise, even in small doses, changes the expression of our DNA. 
‘Our study shows the positive effects of exercise, because the epigenetic pattern of genes that affect fat storage in the body changes’, says Charlotte Ling, Associate Professor at Lund University Diabetes Centre. We inherit our genes and they cannot be changed. The genes, however, have methyl groups attached which affect what is known as gene expression – whether the genes are activated or deactivated. The methyl groups can be influenced in various ways, through exercise, diet and lifestyle, in a process known as DNA methylation. This is epigenetics. In this study, the researchers investigated what happened to the methyl groups in the fat cells of 23 slightly overweight, healthy men aged around 35 who had not previously engaged in any physical activity, when they regularly attended spinning and aerobics classes over a six-month period.

‘They were supposed to attend three sessions a week, but they went on average 1.8 times’, says Tina Rönn, Associate Researcher at Lund University. Using technology that analyses 480,000 positions throughout the genome, they could see that epigenetic changes had taken place in 7,000 genes (an individual has 20,000 genes). They then went on to look specifically at the methylation in genes linked to type 2 diabetes and obesity. ‘We found changes in those genes too, which suggests that altered DNA methylation as a result of physical activity could be one of the mechanisms of how these genes affect the risk of disease’, says Rönn, adding that this has never before been studied in fat cells and that they now have a map of the DNA methylome in fat. – A Six Months Exercise Intervention Influences the Genome-wide DNA Methylation Pattern in Human Adipose Tissue, PLOS Genetics, June 2013

What’s new? 
#1 Edible walls: Sydney Design 2013, Powerhouse Museum 3–18 August. Edible walls are about growing things in spaces that have previously been ignored. Bringing together design, technology, sustainability, environment and education, researchers and students from the University of Technology, Sydney will build a series of edible walls at the Powerhouse Museum as part of the Sydney Design 2013 exhibition. Several leading Australian green wall companies will also showcase vertical garden designs that can turn small and otherwise difficult-to-use outdoor spaces into mini vertical fruit and vegetable gardens. PS: We hope the urban foragers don't forage your crop for their table.

#2 Healthy Kids Lunch Boxes BakeClass: Saturday 10 August, 9.30–12.30 – a three-hour workshop where you will discover how easy (and enjoyable) it is to fill lunch boxes with Anneka Manning’s ‘better for you’ sweet and savoury snacks that you will feel good about serving and your kids (and their friends) will enjoy. You can find out more about this workshop here.

#3 Nutritionism (Allen and Unwin/Columbia University Press): From the fear of ‘bad nutrients’ such as fat and cholesterol, to the celebration of supposedly health-enhancing vitamins and omega-3 fats, our understanding of food and health has been dominated by a reductive scientific focus on nutrients according to Dr Gyorgy Scrinis. In this book he argues that this 'nutritionism' has narrowed our appreciation of food quality, while promoting confusion and nutritional anxieties. His alternative? A food quality paradigm based on respecting traditional dietary patterns and reducing technological processing. ‘It may offend nutritionists and will upset the food industry, but it could also herald a delicious revolution in our ability to eat well.’ (Rosemary Stanton)

There’s certainly food for thought in this provocative critique of the science of nutrition. The problem of course in such a comprehensive book is fact checking. We wonder, for example, where he plucked the ‘71’ for the GI of carrots from. Certainly not the GI database. Finding errors and out-of-date information in a topic one knows well (and there are several in his critique of GI) does make one question the reliability of his facts in other areas. And that’s a pity, because we are certainly not fans of the ‘ideology of nutritionism’ here at GI News.