Wednesday September 3 2014
Type 2 diabetes is increasingly common in young people
"Skipping breakfast in childhood may raise the risk of diabetes," the Mail Online reports. A study of UK schoolchildren found that those who didn’t regularly eat breakfast had early signs of having risk markers for type 2 diabetes.
The study found that children who did not usually eat breakfast had 26% higher insulin resistance than children who always ate breakfast. High insulin resistance increases risk of type 2 diabetes, which is why the results of this study are important. It should be pointed out that while the levels were higher in children who skipped breakfast, they were still within normal limits.
The researchers questioned more than 4,000 children aged nine and 10 about whether they usually ate breakfast, and took a fasting blood sample for a variety of measurements, including their blood sugar level and insulin level.
The results suggest that eating breakfast may reduce the risk of higher insulin resistance levels, but due to the cross-sectional design of the study (a one-off assessment), it cannot prove that skipping breakfast causes higher insulin resistance or type 2 diabetes. And, as the researchers point out, even if a direct cause and effect relationship was established, it is still unclear why skipping breakfast would make you more prone to diabetes.
Despite this limitation of the study, eating a healthy breakfast high in fibre has many health benefits and should be encouraged.
Where did the story come from?
The study was carried out by researchers from St George’s University Hospital in London, the University of Oxford, the Medical Research Council Human Nutrition Research in Cambridge and University of Glasgow School of Medicine. It was funded by Diabetes UK, the Wellcome Trust, and the National Prevention Research Initiative. The authors declared no conflict of interest.
The study was published in the peer-reviewed medical journal PLOS Medicine. This is an open access journal so the study is free to read online.
The UK media generally reported the study accurately, although claims the study “tracked” children over time are inaccurate. Researchers used a one-off questionnaire and blood test, and none of the results showed that the children were insulin resistant – they just had higher levels within the normal range.
Also the Mail Online’s headline “Youngsters who don't eat morning meal more likely to be insulin dependent” appears to be written by someone without any grasp of human biology. All humans are insulin dependent.
What kind of research was this?
This was a cross-sectional study of nine- and 10-year-old children in England. It aimed to see if there was a link between eating breakfast and markers for type 2 diabetes, in particular insulin resistance and high blood sugar levels. Higher fasting insulin levels are seen when the body becomes insulin resistant, which is a risk factor for developing type 2 diabetes. As this was a cross-sectional study, it cannot prove that not eating breakfast causes children to be at higher risk of type 2 diabetes, but it can show that there is an association.
What did the research involve?
The researchers used information collected from 4,116 children who had participated in the Child Heart And health Study in England (CHASE) between 2004 and 2007. This study invited children aged nine and 10 from 200 randomly selected schools in London, Birmingham and Leicester to take part in a survey looking at risk factors for type 2 diabetes and cardiovascular disease.
This included questionnaires, measures of body fat and a fasting blood sample, taken eight to 10 hours after their last meal.
One of the questions related to how often they ate breakfast, with the following possible responses:
- every day
- most days
- some days
- not usually
Children from the last 85 schools were also interviewed by a research nutritionist to determine their food and drink intake in the previous 24 hours.
They analysed the data looking for an association between breakfast consumption and insulin resistance and higher blood sugar levels adjusting the results to take into account age, sex, ethnicity, day of the week and month, and school.
What were the basic results?
Of the 4,116 children:
- 3,056 (74%) ate breakfast daily
- 450 (11%) had breakfast most days
- 372 (9%) had breakfast some days
- 238 (6%) did not usually have breakfast
Compared to children who ate breakfast every day, children who did not usually have breakfast had:
- 26% higher fasting insulin levels
- 26.7% higher insulin resistance
- 1.2% higher HbA1c (number of red blood cells attached to glucose, which is a marker of average blood glucose concentration, higher numbers increase the risk of diabetes) 1% higher glucose (blood sugar) level
These results remained significant even after taking into account the child’s fat mass, socioeconomic status and physical activity levels.
In the subset of children asked about their food intake over the previous 24 hours, children eating a high fibre breakfast had lower insulin resistance than those eating other types of breakfasts such as toast or biscuits.
How did the researchers interpret the results?
The researchers concluded that “children who ate breakfast daily, particularly a high fibre cereal breakfast, had a more favourable type 2 diabetes risk profile. Trials are needed to quantify the protective effect of breakfast on emerging type 2 diabetes risk”.
This well designed study found that children who did not usually eat breakfast had 26% higher insulin resistance than children who always ate breakfast, though the level was still within normal limits.
Higher levels indicate a risk of type 2 diabetes, which is why the results of this study are important.
Strengths of the study include the large sample size, multi-ethnicity of the participants and accuracy of the body fat measurements rather than just relying on body mass index (BMI).
A limitation of the study is that due to the cross-sectional design it cannot prove that not eating breakfast would cause diabetes, but it does show that this may begin to increase the risk. The study is also reliant on self-reporting of usual breakfast intake.
Eating a healthy breakfast rich in fibre has been linked to many health benefits and is thought to contribute to maintaining a healthy weight. As the researchers point out, further studies will be required to verify the link, such as through following children over time to see which ones develop diabetes.
Analysis by Bazian. Edited by NHS Choices. Follow Behind the Headlines on Twitter. Join the Healthy Evidence forum.