Sabtu, 31 Juli 2010

GI Symbol News with Dr Alan Barclay

[ALAN]
Dr Alan Barclay

Why you don’t need to keep count of the GI values of your meals and snacks
With the current trend to count each and every gram of carbohydrate (or every calorie/kilojoule) in a food or beverage, it is easy to understand that some people feel that they should be adding up the GI values of their meals or even keep count of the total GI value of all the meals and snacks they have in a day.

Relax. You absolutely don’t need a calculator nor a pen a paper when you eat the low GI way. It’s not necessary, nor is it a good idea for a number of reasons.

Firstly, unlike grams of carbohydrate and other nutrients or calorie (kilojoule) counts, the GI is a measure of quality – not quantity. A useful analogy is that of mixing paints – the final colour will reflect the dominant colour used, not simply the sum of its parts.

It’s true that researchers sometimes calculate what is called the average dietary GI, or to be more precise, the weighted average GI – where the weighting is a percentage value representing the proportion of total carbohydrate contributed by each individual food and beverage. But this is for studies to be published in peer-reviewed scientific journals. For everyday use, this is simply not necessary as we know from what’s called ‘dietary modelling’ that simply replacing most of the high GI carbs you eat with with medium or low GI ones will lower the GI of the average person’s diet sufficiently to reduce their risk of developing type 2 diabetes and will also help them achieve and maintain a healthier weight.

In addition, numerous studies have shown that people with diabetes can improve their glycated hemoglobin (a measure of their average blood glucose level over a 3–4 month period) simply by lowering the GI of their diet. In these studies, the people did not have to calculate their daily GI values– it was not necessary: they just used the substitution model (look how easy it is):

The low gi substitution model

Secondly, we also know that you don’t have to sweat over making sure every meal you eat is low GI. This is due to what’s known as the second meal effect: if you eat a low GI meal, you reduce the glycemic impact of the carbohydrates eaten at the following meal. Research has found this applies to a high GI breakfast eaten after a low GI dinner the night before, or a high GI lunch, after tucking into a low GI breakfast.

Finally, like grams of carbohydrate and other nutrients and calories/kilojoules, GI values aren’t 100% accurate – for all of the same reasons: foods are grown in different soils, under different weather conditions, and consequently, all have a slightly different nutrient composition – so it is pointless to try and be too precise with GI (or any other nutrient) values.

So ‘don’t sweat the small stuff’ and add stress to your life. Simply swap the high GI carbs you eat at most meals for low or moderate GI counterparts and you will achieve a low(or lower) GI diet overall. And don’t forget about the total calories/kilojoules, type of fat and sodium content of your meals – GI is only one part of healthy eating.

For more information on GI values and why you don't need to keep count, please feel free to contact me: alan@gisymbol.com

New GI Symbol

For more information about the GI Symbol Program
Dr Alan W Barclay, PhD
Chief Scientific Officer
Glycemic Index Foundation (Ltd)
Phone: +61 (0)2 9785 1037
Mob: +61 (0)416 111 046
Fax: +61 (0)2 9785 1037
Email: alan@gisymbol.com
Website: http://www.gisymbol.com/

GI Update

GI Q&A with Prof Jennie Brand-Miller

Jennie

What’s ‘available’ carbohydrate?
When we talk about available carbohydrate (also called glycemic, net or usable carbohydrate), we mean the carbohydrate that is absorbed into the bloodstream and directly affects blood glucose levels. It excludes the escapees like fibre, and some sugar alcohols, that are not completely digested in the small intestine.

How is carbohydrate measured?
The carb content of foods can be calculated in a couple of ways. Many countries including the US and Canada determine it indirectly or ‘by difference’. First they measure the amount of protein, fat, water and ash in 100 grams of a food, they then tot up the numbers and subtract the total from 100. What's left over is called carbohydrate. This means that the carbohydrate content figures on their food labels and in their food tables includes both available and unavailable carbs (the ones which cannot be absorbed into the bloodstream). In Europe, Australia and New Zealand on the other hand, the food labels and food tables only includes available carbs (the ones that are absorbed into the bloodstream).

GI testing by an accredited laboratory
North America

Dr Alexandra Jenkins
Glycemic Index Laboratories
36 Lombard Street, Suite 100
Toronto, Ontario M5C 2X3 Canada
Phone +1 416 861 0506
Email info@gilabs.com
Web http://www.gilabs.com/

Australia
Fiona Atkinson

[FIONA]

Research Manager, Sydney University Glycemic Index Research Service (SUGiRS)
Human Nutrition Unit, School of Molecular and Microbial Biosciences
Sydney University
NSW 2006 Australia
Phone + 61 2 9351 6018
Fax: + 61 2 9351 6022
Email sugirs@mmb.usyd.edu.au
Web http://www.glycemicindex.com/

See The New Glucose Revolution on YouTube

Making the Most of GI News

Subscribe - it's free!
To subscribe to GI News, simply click on the SUBSCRIBE link in the top right-hand column. Help us be sure our email newsletter isn’t filtered as spam. Add "gifeedback@gmail.com" to your address book to ‘whitelist’ us with your filter, helping future issues of GI News get to your inbox.

Your questions answered
If you have posted a question in GI News, be assured that the GI Group will answer this as soon as possible. We welcome your views about our articles and other reader’s suggestions. Please POST your comments and questions on the site.

Want to search past issues of GI News?
Want to search the GI News Archive for a particular topic, food or recipe? Make the most of our search feature with Google. Simply enter the term in the space provided and press SEARCH.

Want to print a copy of this GI News edition?
Download and print the PDF.

Copyright
This website and all information, data, documents, pages and images it contains is copyright under the Copyright Act 1968 (Commonwealth of Australia) (as amended) and the copyright laws of all member countries of the Berne Union and the Universal Copyright Convention.

Copyright in the website and in material prepared by GI News is owned by GI News, Human Nutrition Unit, University of Sydney. Copyright in quotations, images from published works and photo libraries, and materials contributed by third parties including our regular contributors Alan Barclay, Jennie Brand-Miller, Johanna Burani, Diane Temple, Emma Stirling and Nicole Senior is owned by the respective authors or agencies, as credited.

GI News encourages the availability, dissemination and exchange of public information. You may include a link to GI News on your website. You may also copy, distribute, display, download and otherwise freely deal only with material owned by GI News, on the condition that you include the copyright notice “© GI News, Human Nutrition Unit, University of Sydney” on all uses and prominently credit the source as being GI News.

You must, however, obtain permission from GI News if you wish to do the following:
  • charge others for access to the work
  • include all or part of the work in advertising or a product for sale, or
  • modify the work.
To obtain such permission, please contact gifeedback@gmail.com

This permission does not extend to material contributed and owned by other parties. We strongly recommend that you refer to the copyright statements at their respective websites and seek their permission before making use of any such material, whether images or text. Please contact GI News if you are in doubt as to the ownership of any material.

Disclaimer
GI News endeavours to check the veracity of news stories cited in this free e-newsletter by referring to the primary source, but cannot be held responsible for inaccuracies in the articles so published. GI News provides links to other World Wide Web sites as a convenience to users, but cannot be held responsible for the content or availability of these sites.

© ® & ™ The University of Sydney, Australia

Rabu, 30 Juni 2010

Paleolithic diet

This diet consists mainly οf сеrtаіn varieties οf vegetables, fruits, meat, berries аnԁ nuts. It advocates eating foods thаt ԁο nοt need tο bе cooked аnԁ аrе consumed іn thе way thаt foods wеrе eaten before fire wаѕ invented. Whеn уου follow thе diet, іt іѕ nοt nесеѕѕаrу tο eat thе foods whеn thеу аrе uncooked, bυt уου ѕhουƖԁ eat οnƖу those foods thаt саn bе eaten whеn thеу аrе raw. A person οn thе Paleolithic nutrition diet саn eat three vegetables аnԁ three fruits аnԁ ѕοmе meat іn one meal. Thе Paleolithic diet food list comprises mainly οf meats (thаt include seafood) аѕ well аѕ eggs.

Dietpill Nuratrim

Thе animals thаt wе ɡеt meat аnԁ eggs frοm аrе usually fed a natural аnԁ organic diet. Meats ѕhουƖԁ bе free οf artificial flavoring аnԁ preservatives οf аnу sort. Sіnсе thе vegetables thаt аrе a раrt οf thіѕ diet аrе those thаt саn bе eaten іn thе raw form, potatoes аnԁ green beans аrе nοt included. Mοѕt types οf fruits саn bе included іn thіѕ diet tοο. Hοwеνеr, fruits thаt аrе high іn sugar ѕhουƖԁ bе avoided.

GI News—July 2010

[COLLAGE]

  • 7 steps to better blood glucose
  • Rice: it’s not the colour or size, it’s the GI that counts
  • Why you should check your vitamin B12
  • The scoop on chromium
  • Does sugar cause diabetes?
  • Starchy vegetables – 10 things you need to know
  • Prof Jennie Brand-Miller on carbs and blood glucose
In Food for Thought in this issue, we outline 7 steps to better blood glucose. You have probably never given your blood glucose a second thought unless you have diabetes. But out-of-control blood glucose is emerging as a major health crisis around the world. Our love affair with soft white bread, French fries, crispy breakfast flakes, sugary baked goods (all high GI foods) has led to an outbreak of insulin resistance – essentially, what happens when the body’s system for handling blood glucose spikes gets worn out from overwork. In Australia for example, one in four people now has some impairment in glucose tolerance or insulin secretion. (The chances are nearly one in two for the overweight, over 45s.) Left unchecked, the result is metabolic syndrome – a precursor to heart disease, stroke and type 2 diabetes. Ask your doctor to measure your blood glucose levels next time you visit.

Good eating, good health and good reading.

Editor: Philippa Sandall
Web management and design: Alan Barclay, PhD

Food for Thought

7 steps to better blood glucose
1. Eat more regularly whether you have three meals a day or have three smaller meals plus snacks. If you use insulin or take medication that stimulates insulin production from your pancreas, it is helpful if you can maintain some consistency in the times you eat your meals. Make meals a time to relax and enjoy food – you are more likely to feel satisfied if you do. Just remember to put your knife and fork down when you are full (not stuffed).
2. Switch to low GI foods – the ‘smart’ carbs (‘tricklers’) that are slowly digested and absorbed when you eat them producing only gentle rises and falls in your blood glucose and insulin levels. A Cochrane review that analysed 11 randomised controlled trials found that following a low GI diet significantly helps people with type 1 and type 2 diabetes improve their blood glucose levels. In fact, the researchers found that HbA1c (A1c) levels decreased by 0.5% with a low GI diet, and point out that the findings are significant both statistically and clinically. (HbA1c gives a picture of a person’s average blood glucose levels over several months.) You can check out our 10 tips to reduce the overall GI of your diet HERE.
3. Keep carb portions moderate – 50–60g of carbohydrate at any one sitting is a good average. On your dinner plate, that’s the equivalent of 1¼ cups of cooked (al dente) pasta – measure it out and see what it looks like. And in this super-sized world, eat smaller portions for your meals and snacks overall. Using smaller plates and bowls is a help.
4. Eat more fruits and vegetables. You see, it isn’t all about cutting back. Most people don’t eat anywhere near enough of them. Fresh, frozen, dried and canned (in juice not syrup) fruits are all suitable. And when it comes to non-starchy vegetables (leafy greens, tomatoes, onions, etc), you can eat as much as you like. As bonus, toss your salad in a vinaigrette dressing – adding acid to your meals can help reduce your blood glucose response. In GI Symbol News in this issue, Alan Barclay talks about serve sizes for starchy veggies.
5. Favour the good fats. The type of fat can make a big difference to your health and waistline. Cut back on saturated fat and focus on the good fats – monounsaturated fat (found in olive oil, nuts and avocados), omega-3 fatty acids (fish is the best source) and polyunsaturated fats (in vegetable oils). Fat doesn’t raise your blood glucose and it doesn’t require insulin in order to be metabolised so it doesn’t raise insulin levels either. And because it slows the rate at which food leaves your stomach it can blunt the blood glucose effect of a whole meal.
6. Eat more protein at every meal. It won’t increase your blood glucose levels and keeps hunger pangs at bay as it helps you feel fuller for longer. There’s no need to go overboard – a small (100g/3½oz) piece of lean chicken or steak, a little can of fish, a side dish of legumes, an egg, a tub of skinny yoghurt or a handful of nuts will do it.
7. Get regular physical activity. Exercising muscles need fuel and the fuel they prefer is glucose. So as soon as you start moving your muscles they’ll start burning up glucose. First they’ll use their own stores of glucose (that’s glycogen); then they’ll call on the liver for some of its stores, all the time drawing the glucose out of the blood and lowering your blood glucose levels.

‘My aim is a calm pancreas – avoiding the highs and lows.’ – Dianne
‘I was devastated when I discovered that my fasting blood glucose levels were higher than normal and that I was on the path to type 2 diabetes. I did some research and was delighted to read that I could delay the onset of diabetes by changing my lifestyle and my eating habits. It’s early days yet, but I have lost 6 kilos and I am walking for an hour 5–6 days a week. The Low GI Handbook has helped. I have changed my diet and am feeling so great – no more acid reflux, no more feeling sluggish after lunch. I have so much more energy and feel on top of world. My husband has joined me in support and he speaks volumes for changes he is feeling too. We are eating more fish and I can’t believe how many fresh vegetables we get through in a week. We’ve not eaten white bread, biscuits, cake or sweet desserts now for 103 days! (I keep a diary of my food intake.) Instead, we’ve replaced these with grainy breads, nuts and berries. I can’t wait for that follow up blood test my doctor said I should have a year after the last. I'm expecting a big change. Here’s to a low GI diet for life!

The Low GI Handbook

The Low GI Handbook is available from bookstores and online.
Australian edition
US/Canada edition (available bookshops July13th; or as a pre-order from Amazon)

News Briefs

For better blood glucose, it’s the GI not the colour of rice that counts
Consuming more white rice appears to be associated with a higher risk for developing type 2 diabetes, whereas consuming more brown rice may be associated with a lower risk for the disease, according to a report from researchers at Harvard University published in Archives of Internal Medicine. The NHS Choices Behind the Headlines review of this study makes the point that: 'Despite the quality of the study, the results don't actually prove that eating white or brown rice directly raises or lowers the risk of type 2 diabetes,' as cohort studies like this can draw associations but cannot prove causation. They go on to say that the researchers' conclusions are in line with general recommendations that people should include more wholegrains in their diet because they are thought to have a number of health benefits.

GI Group: While choosing brown rather than white rice may help reduce your risk of getting diabetes (along with being active and eating a healthy balanced diet), it's the GI of the rice that matters. The Harvard researchers said that the average GI for white rice was 64 and for brown rice it was 55. The higher GI of the white rice, and the loss of fiber, vitamins, magnesium and other minerals, lignans, phytoestrogens, and phytic acid, in the refining process are the likely factors for the increased diabetes risk.

However, neither colour nor size are a good guide to the GI of rice. Its amylose content is what counts. Amylose is a kind of starch that resists gelatinisation. Although both white and brown rice are grain foods, when you cook them, millions of microscopic cracks in the grains let water penetrate right to the middle of the grain, allowing the starch granules to swell and become fully ‘gelatinised’, thus very easy to digest. It’s true that popular white rices like jasmine have a high GI. But brown rice often has a surprisingly high GI too. This is because the insoluble fibre around brown rice is not viscous and it’s micro-thin. It’s easy for enzymes to attack the starch in rice because the milling operation has resulted in thousands of minute channels that allow water to hydrate the grain and gelatinise the starch during cooking. Greater gelatinisation of starch means higher GI. Finally, don’t forget that a healthy low GI diet is associated with a lower risk of diabetes than either eating brown rice, or wholegrains in general.

The bottom line: For better blood glucose, opt for the lower GI varieties with a higher amylose content such as Basmati, Doongara Clever Rice, Moolgiri medium grain or the Uncle Ben’s Ready Rice brown rice pouch range. These high-amylose rices stay firm and separate when cooked. But you still need to keep portions moderate, even when you choose a low GI rice as eating too much can have a marked effect on your blood glucose. Here’s our tip: a cup of cooked rice combined with plenty of mixed vegetables can turn into three cups of a rice-based meal that suits any adult’s daily diet.

Better blood glucose for kids with type 2
The incidence of type 2 diabetes and impaired glucose tolerance in young people is sweeping the world at an alarming rate. In Australia for example, nearly 1 in 10 young people with diabetes now has type 2. Twenty years ago it was almost unheard of in this age group. Managing type 2 involves helping the kids normalise their blood glucose levels, reduce their blood fats and blood cholesterol and prevent the progression or development of complications.

Lauren Gellar
Lauren Gellar M.S., M.ED., CHES

A small cross-over pilot study published in the Journal of Pediatrics has found that the average mean daytime blood glucose was significantly lower when the kids ate a low GI diet (GI 40) compared with the day they ate a higher GI diet (GI 64).

For the study, 12 obese young people aged between 7 and 16 with type 2 diabetes or impaired glucose tolerance were served a full day of high GI and a full day of low GI meals (matched for carbs, protein and fat content) in a supervised clinic setting. Participants demonstrated significantly lower mean daytime blood glucose and a trend toward lower variability, suggesting a clinically relevant impact of reducing glycemic index.

In their conclusion, the authors, Lauren Gellar and Dr Tonja Nansel write: ‘Our findings are of particular importance given that children who develop disorders of glucose metabolism are likely to be a particularly high-risk group. Thus the ability to demonstrate substantial differences in blood glucose with a dietary change lasting a single day suggests that a low GI diet is a promising approach for achieving improved health outcomes.’ For reprints of this study contact Dr Tonja Nansel

Resistance exercise better than aerobic for blood glucose
Ten weeks of resistance exercise (3 sessions a week of typically around 35 minutes) were associated with significantly better glycemic control in adults with type 2 diabetes compared with aerobic treadmill exercise although the average energy expenditure for both exercise groups was similar according to a study published in Diabetology and Metabolic Syndrome.

Before each session, participants in both groups performed warm up exercises, consisting of stretching exercises for the major muscle groups and there were no differences between the groups concerning their perceived exertion,’ write the authors. ‘The resistance training group followed an individually monitored progressive resistance training program using multiple-station universal weight machines. Seven exercises were used for resistance training that encompassed knee and hip flexion/extension, shoulder flexion/extension, adduction/abduction, elbow flexion/extension and a chest press. Three sets of 8–10 repetitions were performed for all exercises,’ they report.

If you take metformin, get your B12 checked
If you have diabetes and have been taking metformin (brand names such as Glucophage, Glucophage XR, Fortamet, Riomet, Glumetza, and others) for years, ask your doctor to check the level of vitamin B12 in your blood. A recent study published in the British Medical Journal reports that metformin may lead to a B12 deficiency. We need minute amounts of this vitamin (also known as cyanocobalamin or cobalamin) a day for the production of red blood cells and to maintain healthy nerves and a healthy brain.

‘Our data provide a strong case for routine assessment of vitamin B-12 levels during long term treatment with metformin,’ concludes Coen Stehouwer. The 4-year study tracked 390 people with type 2 diabetes and found that the 196 participants taking metformin had a 19% reduction in their vitamin B12 levels compared with the 194 participants who had taken a placebo, who had almost no B12 change. The reduced levels of vitamin B12 in the metformin group also persisted and became more apparent over time, they said.

Where do you get it? Most of us get plenty of vitamin B12 from our diet as red meat, milk, cheese, eggs, fish, shellfish and fortified breakfast cereals and enriched soy or rice milk. You can also take a supplement. What about mushrooms? Dietitian Glenn Cardwell writes: ‘To accurately establish the levels of B12 in mushrooms, scientists at the University of Western Sydney checked mushroom samples from the major mushroom growing centres around Australia in 2009. Writing in the Journal of Agricultural and Food Chemistry they report that there is a modest amount of B12 in mushrooms, closer to 5% of daily needs in a serve (three button mushrooms). It is the same type of B12 as found in meats and seafood, so it is the type of B12 that the body finds very easy to use.

Mushrooms