1 June 2010

News Briefs

Whole fruit not juice does the trick
The health benefits of eating plenty of fruit and vegetables are already well known but a study published in Diabetes Care reports that you need to be a bit choosy if your goal is to reduce your diabetes risk. When researchers from the Harvard Medical School looked at the diets of more than 71,000 women to see if there was a link between developing type 2 diabetes and fruit and vegetable consumption they found:

  • An increase of 3 servings a day of whole fruit was associated with an 18% reduced risk of type 2 diabetes.
  • An increase of 1 serve of green leafy vegetables a day was associated with a 9% reduced risk of diabetes.
  • An extra serving of fruit juice a day was associated with an 18% increase in diabetes risk.
The take home message to reduce your diabetes risk, they say is to eat whole fruit not juiced and plenty of green leafy vegetables.

Bitter melons and better blood glucose
Bitter melons

Bitter melon (also called bitter gourd and balsam pear) is a cousin of squash, watermelon and cucumber and is long associated with treating diabetes in Asia where it’s widely cultivated for its ‘bubble-wrap’ textured, green, immature fruit (12–30 cm long) that’s stuffed, pickled, and sliced into various dishes, hot and cold.

Writing in Chemistry and Biology a team from Australia’s Garvan Institute of Medical Research along with the Shanghai Institute of Materia Medica, report that it has bioactive compounds that appear to activate the enzyme AMPK, a protein that regulates the body’s metabolism and affects glucose uptake. While there are well known diabetes drugs on the market that also activate AMPK, they can have side effects. ‘The advantage of bitter melon is that there are no known side effects. Practitioners of Chinese medicine have used it for hundreds of years to good effect,’ said Drs Jiming Ye and Nigel Turner, the Garvan scientists involved in the project.

GI Group: Bitter melon comes under the ‘vegetable fruits’ umbrella. Yes, anything with a seed is a fruit (botanically speaking) including avocado, eggplant/aubergine, capsicum/pepper, cucumber, pumpkin (GI 65), butternut pumpkin/squash (GI 51) and tomatoes along with all those lovely legumes – beans and peas and other members of the legume family where the seed is enclosed within a pod.

Get a boost from a banana
‘You may have seen cyclists eating bananas one-handed as they speed down the road or a tennis pro eat a banana between sets,’ says Gold Medal Nutrition author and dietitian. ‘That’s because they are very good for energy. The average banana (GI 52) provides around 20g carbohydrate, which is then digested and converted to muscle fuel (glucose). A banana is also a source of some resistant starch that works like dietary fibre in the large intestine. Many athletes also eat bananas to re-fuel their body after sport as their muscle stores of glucose will be low. That’s why they are very popular in the change rooms after a game of football or netball. But you don’t have to be an athlete to get a boost from a banana. It works for the deskbound too. Consider eating a banana to help get you out of the mid-afternoon slump at work. It will perk you up far better than any cake, biscuit or pastry.

So grab a banana and get even more benefits. It:
  • provides around 350mg of potassium (about 10% of your daily needs). Our Dietary Guidelines say: “Because plant foods contribute significantly to the intake of potassium and magnesium – both of which have been proposed to be associated with a lower blood pressure – diets high in fruits and vegetables will increase the daily intake of both minerals and may help prevent and control hypertension.” (my emphasis says Glenn).
  • helps you maintain a healthy weight as a medium banana has less than 100 cals (420kJ), about a third of what you get from a 50g pack of potato crisps and half of what is in a couple of chocolate biscuits.
  • helps to keep you regular and healthy on the inside. The average banana provides around 3g of fibre plus some resistant starch, so called because it is resistant to digestion and therefore acts like fibre.’
Glenn Cardwell is an Accredited Practising Dietitian who also consults with industry (including Australian Banana Growers). Check out Glenn's website HERE

More nuts, less cholesterol
Consuming more nuts appears to be associated with improvements in blood cholesterol levels, according to a pooled analysis of data from 25 trials reported in Archives of Internal Medicine. When Dr Joan Sabaté and colleagues pooled data from 25 nut consumption trials (yes, such thing exist) they found that eating around 67 grams (about 2.4 ounces) of nuts a day was associated with an average 5% reduction in cholesterol levels. And if a participant also had high triglyceride levels it dropped too by around 10%. ‘… different types of nuts had similar effects on blood lipid levels,’ the authors write. ‘Nuts are a whole food that has been consumed by humans throughout history. Increasing the consumption of nuts as part of an otherwise prudent diet can be expected to favorably affect blood lipid levels (at least in the short term) and have the potential to lower coronary heart disease risk.’

Mixed nuts
Mixed nuts
Photo courtesy http://www.nutsforlife.com.au/

GI Group: What’s a nut? It’s the seed of a fruit with a thick hard shell (pericarp). But there are several types of nuts. ‘True nuts’ (the ones with a cap at the stem) are oak acorns, chestnuts (GI), hickory and hazel. Almonds, coconuts, pecan and walnuts are drupe ‘fruits’ like peaches, plums and cherries. Other nuts are ‘seeds’ – Brazil nuts cashews (GI 22) and pine nuts. Peanuts (GI 14) aren’t actually nuts, they are a legume. (Source Edible, Cameron House 2008)

‘Deli’ meats and diabetes risk
Eating processed meats (preserved by smoking, curing or salting, or with the addition of chemical preservatives), such as bacon, sausages, hot dogs or processed deli meats but not unprocessed red meats, may raise risk of diabetes and heart disease according to a systematic review and meta-analysis published in Circulation that included 20 studies and 1,218,380 individuals.

Researchers from the Harvard School of Public Health found that, on average, each 50 gram (1.8 oz) daily serving of processed meat (about 1–2 slices of deli meats or 1 hot dog) was associated with a whopping 42% higher risk of developing heart disease and a 19% higher risk of developing diabetes.

‘When we looked at average nutrients in unprocessed red and processed meats eaten in the United States, we found that they contained similar average amounts of saturated fat and cholesterol. In contrast, processed meats contained, on average, 4 times more sodium and 50% more nitrate preservatives,’ said lead researcher Renata Micha PhD. ‘This suggests that differences in salt and preservatives, rather than fats, might explain the higher risk of heart disease and diabetes seen with processed meats, but not with unprocessed red meats,’ she said. ‘Based on our findings, eating one serving per week or less [of processed meats] would be associated with relatively small risk.’


Cath said...

I like the *idea* of eating a banana in the mid-afternoon. But unfortunately this is one of my (very few) food aversions. What would you suggest as a good alternative for a similar effect? I tend to keep dried apricots and dates in a jar at work.

GI Group said...

Dried apricots are a good option (they have a low GI of 31) but they are incredibly easy to OVER CONSUME. They are so more-ish. Other snacks people on a low GI diet tell us that they enjoy and find satisfying are small tubs of low fat yoghurt, or a crunchy apple or juicy pear ...

Daniela said...

I read on the Diabetes UK website that it would be impractical to eat enough bitter melon (kerala) for it to have a significant effect in stabilising blood glucose. Do you have an opinion on this?

GI Group said...

Hi Daniela, We will do a bit of research on this and get back to you in the next few days.