Low GI diet, with or without a change in weight, is good for overall health
A randomised controlled trial from the Diogenes study published in Circulation indicates that eating a low GI diet, with or without a change in weight, is good for your overall health and will help prevent the diseases that are linked to inflammation (obesity, diabetes, heart disease, cancer, arthritis). It’s a rather technical report, so we asked Prof Jennie Brand-Miller to explain the results for GI News readers. ‘Inflammation is the result of oxidative stress in the cells,’ she says. ‘Having too much glucose makes the cells see ‘red’. It is well known, that weight loss will reduce inflammation and risk of developing such diseases, now we know that a low GI diet alone (with or without weight loss) will reduce inflammation and risk of inflammatory diseases.’
Regularly eating fish linked to lower diabetes and cardiovascular risk
People who regularly eat fish as their primary source of animal protein have lower blood glucose concentrations and a reduced risk of developing type 2 diabetes are the findings of a study published in Nutrición Hospitalaria, whereas consuming red meat, especially cured meats is related to increased weight gain and obesity. Mercedes Sotos Prieto, lead author of the study which forms part of the Prevention with a Mediterranean Diet study explains how ‘in Mediterranean countries, consumption of foods that typically form part of the diet here has decreased in recent decades. The consumption of saturated fats mainly from red meats and industrial baking has increased and this is really worrying.’ The researcher points out that ‘the red meat consumption of the sample population reaches an average of once a day, which is high in comparison to dietary recommendations.’ Conducted in the Valencian Community on 945 people (340 men and 605 women) between 55 and 80 years of age, the aim of the study was to understand dietary patterns in terms of meat and fish consumption and the correlation between the Mediterranean diet and its association with CVD risk factors.
‘Various hypotheses have been put forward that attempt to explain why the consumption of fish can be related to diabetes,’ they explain. ‘The increase of omega-3 in the cells of the skeletal muscles improves insulin sensitivity.’
AMD-like lesions delayed in mice fed lower GI diet
Prof Allen Taylor
Feeding older mice a lower GI diet delays the onset of age-related, sight-threatening retinal lesions, according to a new study from the Laboratory for Nutrition and Vision Research at Tufts University. We usually prefer to stick to clinical trials and epidemiological studies in humans in GI News, but this research in Aging Cell appears to establish the first mature, mammalian model indicating a delay in the development of AMD-like lesions as the result of a lower GI diet. Prof Allen Taylor says: ‘The only difference between the two groups of mice we studied is the GI of their meals, which suggests that diet alone is enough to accelerate or delay the formation of lesions. These results, coupled with similar observations made by our laboratory in earlier human epidemiologic studies imply that lower GI diets hold potential as an early intervention for preventing onset and progress of AMD.’
The researchers studied middle-aged and older mice that consumed either a higher or lower GI diet. Mice fed the lower GI diet developed fewer and less-severe age-related lesions in the retina than the mice fed the higher GI diet. Compared to the mice on the lower GI diet, mice on the higher GI diet demonstrated elevated accumulations of debris known as advanced glycation end products (AGEs) in the whole retina, particularly in the cells of the RPE (retinal pigment epithelium). The RPE plays a crucial role in maintaining vision and its dysfunction results in the gradual central vision loss that is the hallmark of AMD. AGE accumulation has also been linked to tissue damage in other age-related diseases such as Type 2 diabetes and cardiovascular disease.
Australia’s versatile low GI spud is back in Coles supermarkets (sorry not yet Tasmania) ready for all your holiday cooking for family and friends through December and January. Here at GI News we are tossing up between Roasted Potato Salad with Capers and Turmeric Roasted Potatoes both from the Monday Morning Cooking Club cookbook.
Sadly, there are always naysayers even about spuds! ‘Potato farmer Dave’ posted a comment on Catherine Saxelby’s website review of Carisma potatoes claiming that ‘Carisma is not a potato variety but simply a clever but simple marketing trick of the potato company that sells them to Coles’. Sorry Dave, you are so wrong. Carisma is an Australian first. It is a distinct variety of potato owned by Agrico (a Dutch seed production company) and all the development (several years of it) was done here in Australia by the Mitolo Group with constant GI testing carried out by SUGiRS. If you want to know more about this low GI spud, check out Catherine’s independent Foodwatch Review and see her answer to potato farmer Dave HERE. Tasmania – you’ll have Carisma spuds in your Coles supermarkets early in 2012.
Helping Australian consumers make better choices
Easier-to-understand nutritional labelling for consumers and greater restrictions on the health claims that can be made about that food are among the Australian Government’s response to a national Review of Food Labelling Law and Policy. You can read the full press release HERE. The Government proposes:
- work begin with the food industry and public health groups to develop a single front-of-pack labelling model that will assist Australian shoppers when they make choices about the food they buy
- standards for nutrition and health claims on food labels such as ‘low fat’, ‘high in fibre’, etc be improved to ensure the labels reflect public health goals and provide meaningful information to consumers
- improvements to back-of-pack labelling to provide consumers with better information about added sugars, fats and vegetable oils
- mandating pregnancy warning labels on alcohol that are currently being used voluntarily by industry within two years.
Salt reduction – where’s the jury on this?
Back in August we reported on a recent Cochrane Review that said ‘cutting down on the amount of salt has no clear benefits in terms of likelihood of dying or experiencing cardiovascular disease (CVD).’ The researchers made this finding partly because there just haven’t been large enough trials run for long enough periods of time to prove that sodium reduction really does reduce the risk of heart attack and strokes (CVD).
Now the latest Cochrane Review (on salt) concludes that ‘we do not know if low salt diets improve or worsen health outcomes’. Here’s their plain language summary based on 167 studies between 1950 and 2011 that they reviewed: ‘Low salt diets reduced systolic blood pressure by 1% in white people with normal blood pressure and by 3.5% in white people with elevated blood pressure. The effect was similar in trials of 4 weeks or longer. There were increases in some hormones and lipids which could be harmful if persistent over time. However, the studies were not designed to measure long-term health effects. Therefore we do not know if low salt diets improve or worsen health outcomes. Most of the people who took part in the studies were whites, but in the small number of non-whites the blood pressure reduction was, if anything, greater. More research on reduced salt intake is required, particularly in non-white populations.’
Where does this leave us? First of all, salt reduction is not the only way of lowering blood pressure and reduce your risk of heart disease.
- Losing 10 kg of excess body weight will reduce blood pressure by 5–20 mmHg
- Consuming a diet rich in fruits, vegetables, and low-fat dairy products with a reduced saturated and total fat content (i.e., the DASH diet) will lower blood pressure by 8–14 mmHg
- 30 minutes a day of regular physical activity (a brisk walk will do) will lower it by 4–9 mmHg
Our take-home message: To keep out of the emergency room, being active and enjoying an overall healthy low GI diet that’s moderate in sodium (460 – 2,300 mg a day) and lower in calories and saturated fat is good for your overall health as the latest Diogenes study (see above) has found and will help prevent obesity, diabetes, heart disease, cancer and arthritis (diseases linked to inflammation).