1 August 2009

News Briefs

Artificial sweeteners linked to diabetes
People who use artificial sweeteners are heavier, more likely to have diabetes, and more likely to be insulin-resistant compared with non-users, according to data presented at ENDO 2009 (the annual meeting of The Endocrine Society) and reported in Medscape Medical News. The researchers reported they found an inverse association between obesity and diabetes, on one side, and daily total caloric, carbohydrate, and fat intake, on the other side, when comparing artificial sweetener users and control subjects.

Lead author Kristofer Gravenstein said ‘We cannot say that artificial sweetener use causes obesity, we can say it is associated with it.’ However, the researchers suggest that artificial sweeteners may modulate metabolic rate through enteroendocrine cells, therefore contributing to the development of diabetes and/or obesity. This hypothesis needs further testing they say.

‘More research is definitely warranted,’ says the GI Symbol Program’s Dr Alan Barclay. ‘This is not the first study to show this effect. We don’t really know if it is just a spurious association because this particular study is a cross-sectional study, so it may simply be that people who are overweight/obese or have diabetes use more artificial sweeteners to try and reduce their calorie intake. On the other hand, it may be that some artificial sweeteners are adversely affecting the regulation of appetite. Aspartame, for example, contains the large neutral amino acid phenylalanine that may have an effect on our brain. The same coincidental increase in obesity started when aspartame was introduced into Australia too.

Mediterranean diet and GI
'The Mediterranean diet may be a good way of achieving low GI eating,' says Dr William Neville commenting on an article in the British Medical Journal that discussed the benefits of the Mediterranean diet.

Eco Atkins
In June 2008, we reported on Dr David Jenkins’ Eco Atkins diet, first presented as a paper at the 5th International Congress of Vegetarian Nutrition. The study has now been published in Archives of Internal Medicine. The one-month study compared a low-carb (27% carbs, 30% protein and 43% fat) vegan ‘eco Atkins’ diet with a high-carb (58% carbs, 17% protein and 25% fat) vegetarian one that included dairy foods and eggs.

Prof David Jenkins

What were the diets? The ‘test’ vegan diet provided the minimum level of carbs recommended by the National Academy of Sciences Institute of Medicine –130 g/day – by eliminating bread, rice, and potatoes but including high-fibre oat bran cereal and vegetables such as okra and eggplant. Protein sources included nut bread and tofu. Fats included olive oil, nuts, and avocados. The control diet simply extended the DASH diet in that it allowed low-fat dairy foods, egg substitutes, and whole-grain foods but eliminated (rather than reduced) meat consumption. All the dieters were provided with prepared foods.

The results. Everyone was a winner when it came to weight loss. All the dieters lost around 4 kg (8.8 lbs). However, that’s not surprising since both diets were low in calories – calculated to provide about 60% of the calories a person would need to maintain their weight. What does this mean? Well if your weight is stable on 2000 calories per day, you would have been given a daily food plan with 1200 calories in it.

Reductions in ‘bad’ LDL cholesterol levels and improvements in the ratios between total cholesterol and HDL cholesterol were greater for the low-carb vegan diet. Greater improvements in blood pressure were also seen in the low-carb group, although the difference was of borderline significance.

To answer questions about long-term results when people are not provided with prepared meals, the researchers are currently conducting an ongoing 7-month study reports Jenkins. Preliminary results show that while body weight reduction is maintained, long-term differences in LDL cholesterol are not as dramatic he says.

You lost it, but how do you keep it off?
As any dieter will tell you, keeping it off is the hard bit. The results of a small study published in the June 2009 issue of the British Journal of Nutrition, suggests that what’s needed are some really good strategies for appetite control to help you keep the pounds (kilos) off after you have lost weight on a really restricted energy diet. The study also showed there are benefits on the right diet that don’t show up on the scales.

In this Danish study, the volunteers were assigned to one of three weight maintenance diets after an 8-week low energy diet where they had all lost lots of weight: a low GI diet rich in monounsaturated fats, a low fat diet and a control diet that you could describe as being typically Western – high in saturated fats and high GI carbs. After 6 months, all the volunteers had regained 4–5 kg. But the typical Western diet resulted in significantly different glucose, insulin, glucagon and HbA1c values, indicating that it could lead to decreased insulin sensitivity long term.

How do you cook your carrots?
Results of a UK study due to be published later in 2009 could have a big impact on how we cook our carrots – and other vegetables too. Carrots are a popular topic here at GI News. Not only are they low GI (41) raw or cooked, they are rich in beta-carotene, have some vitamin C and fibre too. They are also rich in a nutrient you may never ever have heard of, falcarinol.


According to one of our favourite websites, NHS Choices Behind the Headlines, UK University of Newcastle researchers say that although eating carrots is strongly tied to reduced risk of cancer, the active ingredient is unknown and that the common belief that beta-carotene in carrots prevents cancer is untrue. They say that their previous experiments have shown that falcarinol slowed the growth of isolated cancer cells and tumours in rats, and that this may be the active ingredient in carrots. To see how different cooking methods alter levels of falcarinol the researchers:

  • Boiled carrots then cut them into 1 cm (1/2 in) cubes
  • Steamed carrots then cut them into 1 cm (1/2 in) cubes
  • Cut carrots into 1 cm (1/2 in) cubes then boiled them
  • Cut carrots into 1 cm (1/2 in) cubes then steamed them
Except for the ‘steamed then cut’ group, all the cooked carrots lost some water-soluble falcarinol. The ‘cut then boiled’ group lost most, almost 25% more than the ‘boiled then cut’ group.

How about flavour? Well in a blind taste test, most people (some 70%) preferred their carrots cooked whole before being cut. Read more here.


Tina said...

How about the Bodytrim system that has been very popular in the media recently. They promote high protein, low carb and fat diet. I want to go on that to lose weight but I am scared to go on a high protein diet, I dont want to overload my kidneys. I like having starchy carbs (pasta or bread) in my meals and snacks, is switching to low GI carbs enough to lose weight or i have to significantly cut it down eg no starchy carbs for dinner.

GI Group said...

Hi Tina, We don't give weight loss advice -- just information on studies published in peer-reviewed journals. If you want to lose weight and keep it off, why don't you make an appointment to see a registered dietitian (an APD in Australia). She (or he) will be able to help you with a weight loss program that's right for you because it is built around the types of foods (such as some starchy carbs like pasta and bread) that you like to eat. Good luck.

Karlynn Holland said...

Did the artificial sweetener study look at just Aspartame, or were other sweeteners also studied? I am particularly curious if this study found the same correlation with Splenda (Sugar alcohol).

GI Group said...

Hi Karlynn, Here's what they say:
'The major artificial sweetener consumed was aspartame, preferred by 66% of BLSA participants, followed by saccharin (13%), sucralose (1.0%), and combinations of the three (21%).'

If you want to read more, here's the link: http://www.medscape.com/viewarticle/704432

Karlynn Holland said...

Thanks! I did some research of my own. Looks like Splenda is also quite hard on the body. But THIS stuff should, in theory, be absolutely amazing for you, particularly your digestive system: Just Like Sugar; http://www.justlikesugarinc.com/

Review article on Inulin and effects on the colon and gastrointestinal system. It's the main ingredient of Just Like Sugar. Article courtesy of Pubmed: http://www.ncbi.nlm.nih.gov/pubmed/15877886?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=1&log$=relatedreviews&logdbfrom=pubmed

GI Group said...

Hi Karlynn

We have passed this on to Dr Alan Barclay for comment. If we don't get back with his thoughts this month (he is away), we'll do a follow up piece in October.

Karlynn Holland said...

Great! Please also ask him for his thoughts on Stevia rebaudiana (Reb A, etc.) too! Many review articles I glossed over highlight the non toxic nature of stevia as a sweetener (at the bottom), and this article even seems to point at potential antioxidant power of Stevia: http://www.ncbi.nlm.nih.gov/pubmed/19540900?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum

I'd love to have another informed opinion on this. Thank you, so much.




GI Group said...

Hi Karlynn,

Catherine Saxelby did a story on stevia back in May which I'll post here for you. I think Alan is also doing something on it in September. But will pass on your comments anyway.

Zero-calorie sweetener, stevia (Stevia rebaudiana) hit the headlines in the Wall Street Journal in December 2008 with the announcement that the FDA were approving two rebiana-based sweeteners (from rebaudioside A, a highly purified extract of stevia) as being safe for use as a general purpose sweetener in foods and beverages. Australia’s food regulator, FSANZ, had granted approval earlier in 2008.

Cargill is marketing its rebiana-based sweetener Truvia with Coca-Cola; Merisant is working with PepsiCo with their version, Purevia. Both have developed non-nutritive tabletop sweeteners from it.

In what they expect to be the first of many new low- and zero-calorie beverages sweetened with Truvia, Coca Cola has launched a reduced-calorie version of Sprite, called Sprite Green, in the US. Odwalla, also owned by Coke, has added two new reduced-calorie juice drinks to its product line – Mojito Mambo and Pomegranate Strawberry. Apparently not all flavours taste good sweetened with stevia. Citrus flavours taste the best – so we may not see Coke Zero with stevia.

Not to be outdone, Pepsi has three flavors of a stevia-sweetened zero-calorie SoBe Lifewater in Fuji Apple & Pear, Black and Blue Berry, and Yumberry Pomegranate with added vitamins as well. They’ve also just brought out an orange-juice drink called Trop50 with 50% less sugar and calories and the juice of freshly squeezed oranges.

Why the interest in stevia? It’s all part of a move away from aspartame (Equal, Nutrasweet) and acesulphame K towards more ‘natural’ substitutes for sugar for diet drinks. Despite being cleared twice by food authorities, aspartame has been plagued by persistent internet rumours linking it to brain cancer and Alzheimer’s that refuse to go away. Trop50, for example, replaces Tropicana's previous Light 'n Healthy orange juice beverage that was made with an artificial sweetener.

Stevia and blood glucose Stevioside does not appear to affect blood glucose levels, good news for those with diabetes. The human body does not metabolise the sweet glycosides and they pass through and are eliminated, so the body does not obtain any kilojoules/calories. You’ll see it sold as a white powder, a liquid extract or as tablets for tea or coffee. It has a slight liquorice flavour. It works well in beverages or yoghurts but not in biscuits or muffins as it can’t duplicate sugar’s ability to add bulk and contribute to the golden-brown colour of baked goods.

So far, so good. If you’re after a non-kilojoule sweetener that’s more ‘natural’, stevia hits the spot. It will be interesting to see how well its safety remains over time and how consumers take to the taste of these new drinks.

Background on stevia Native to South America, the leaves of this semi-tropical shrub are around 30 times sweeter than cane sugar but without the kilojoules/calories. As a herb, the leaves can be used fresh or dried – less than 2 tablespoons of crushed dried leaves can replace a cup of sugar, although it’s hard to be specific as actual sweetness can vary. You can buy stevia leaf powder online from specialty spice merchants such as Herbies Spices (www.herbies.com.au).