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.