What does ‘eat mostly wholegrain cereals’ mean?
Consume more wholegrains is enshrined in dietary guidelines around the globe and is something of a mantra with doctors, dietitians and nutritionists. Australia’s new draft dietary guidelines released in December 2011 urge us to eat mostly wholegrain’ cereals. So, how much is ‘mostly’ and how strong is the evidence? A Nutrition Reviews study that evaluated 135 articles on refined grain foods (published between 2000-2010) reports that the great majority found no association between the intake of refined grain foods and cardiovascular disease, diabetes, weight gain, or overall mortality whatsoever. A few found that very high intakes might be associated with some types of cancers. The evidence overall shows that consuming of up to 50% of all grain foods as refined grain foods (without high levels of added fat, sugar, or sodium) is not associated with increased risk of disease.
Vegetarian fried brown rice from The Low GI Vegetarian Cookbook available from bookshops and online. Photo: Ian Hofstetter.
GI News asked Prof Jennie Brand-Miller to comment. ‘This paper raises questions about the newest dietary guidelines. When health authorities recommend that we eat most grains as wholegrains, they’d like to think we will be eating more fibre (that’s probably true), more micronutrients (not likely), and lower GI carbohydrates (and that’s definitely not true!). The reality is that for most cereal products today, both the “white” version and the “brown” version have a high GI.
I’d like to suggest that we re-define wholegrains as “foods that not only contain the germ, the endosperm and the bran, but also the GI characteristics of the original grain”. At least then, we might see some real benefits of eating them. Wholegrain products might have started with the germ, the endosperm and the bran of the grain, but in many cases, the finished product has been cooked, flaked, toasted, puffed and popped beyond recognition. It’s a long, long way from the grain that came in nature’s packaging.
There are very few clinical trials that have directly compared a “brown” diet with a “white” diet that was otherwise identical. In the largest clinical trial of its sort to date, UK researchers, found that when they provided 316 overweight men and women with a range of wholegrain foods and asked them to substitute them “like for like” for refined grain foods in their typical diet over a 16 week period, there was not even a hint of difference in heart risk (cholesterol, triglycerides, insulin sensitivity and a range of common inflammatory markers) between those who substituted wholegrain foods into their diet, and those who didn’t (the control group).’
Slowly digested carbs reduce inflammation associated with chronic disease.
A diet rich in slowly digested carbohydrates reduces a marker of inflammation called C-reactive protein (associated with an increased risk for many cancers as well as cardiovascular disease) by about 22% in people who are overweight and obese, according to a study by Seattle’s Fred Hutchinson Cancer Research Center in The Journal of Nutrition.
‘Lowering inflammatory factors is important for reducing a broad range of health risks. Showing that a low-glycemic load diet can improve health is important for the millions of Americans who are overweight or obese’ say lead author Marian Neuhouser PhD, RD and colleagues who also found that among overweight and obese study participants, a low glycemic load diet modestly increased – by about 5% – blood levels of a protein hormone called adiponectin, which plays a key role in protecting against several cancers, including breast cancer, as well as metabolic disorders such as type-2 diabetes, nonalcoholic fatty liver disease and hardening of the arteries.
‘The bottom line is that when it comes to reducing markers of chronic-disease risk, not all carbohydrates are created equal. Quality matters,’ she says. ‘There are easy dietary changes people can make. Whenever possible, choose carbohydrates that are less likely to cause rapid spikes in blood glucose.’ These include legumes such as kidney beans, soy beans, pinto beans and lentils; milk; and fruits such as apples, oranges, grapefruit and pears.
Brief, high-intensity workouts reduce BGLs.
Professor Martin Gibala
Researchers at McMaster University report in Journal of Applied Physiology that brief, high intensity workouts, just six sessions over two weeks, can rapidly lower blood glucose levels in people with type 2 diabetes. They found that just 30 minutes of high-intensity intermittent exercise a week, lowered 24-hour blood glucose concentrations, reduced blood glucose spikes after meals, and increased an important marker of metabolic health called skeletal muscle mitochondrial capacity.
What did the workouts involve? Participants rode a stationary bike for 10 bouts of 60 seconds with 1 minute between each burst of exercise. The routine also included a warm up and cool down so each session lasted 25 minutes in total. Participants showed improved blood glucose levels even though they did not lose weight during the two-week study. ‘The improved glycemic control may be linked to changes in the participants’ muscles, such as an improved ability to clear glucose from the blood after meals,’ says Professor Martin Gibala. ‘We need to conduct further research to identify the mechanisms behind these results.’ Martin Gibala explains the research HERE.