Share

How sugar affects sleep duration

Study links shorter sleep and sugar-sweetened drink consumption

If you slept five or fewer hours last night, you’re more likely to drink significantly more sugary caffeinated drinks, such as sodas and energy drinks, today. That is according to a new study led by the University of California, San Francisco, that tracked more than 18,000 adults in the US.

The researchers say it is not yet clear whether drinking sugar-sweetened beverages causes people to sleep less, or whether sleep deprivation makes people seek out more sugar and caffeine to stay awake, though previous research suggests both could be true.

“We think there may be a positive feedback loop where sugary drinks and sleep loss reinforce one another, making it harder for people to eliminate their unhealthy sugar habit,” says lead author Aric Prather, an assistant professor of psychiatry at the university. “This data suggests that improving people’s sleep could potentially help them break out of the cycle and cut down on their sugar intake, which we know to be linked to metabolic disease.”

In the study published in the journal Sleep Health, Prather and his team analysed the 2005-12 sleep and diet records of 18,779 participants in the US National Health and Nutrition Survey. People who regularly slept five or fewer hours per night drank 21 per cent more caffeinated sugar-sweetened beverages than those who slept seven to eight hours a night. People who slept six hours per night regularly consumed 11 per cent more caffeinated sugar-sweetened beverages. On the other hand, the team found no association between sleep duration and consumption of juice, tea or diet drinks.

Previous research has strongly indicated that sleep deprivation increases hunger, particularly hunger for sugary and fatty foods.

Who has the better memory – men or women?

Women say they can remember things better and longer than men can. A new study proves there is some truth in that claim: middle-aged women outperform similar aged men on all memory measures, although memory does decline in women after menopause.

Published in the journal Menopause, the cross-sectional study of 212 men and women aged 45 to 55 years assessed episodic memory, executive function, semantic processing, and estimated verbal intelligence through cognitive testing.

In addition to comparing sex differences, the study also found that premenopausal and perimenopausal women outperformed postmenopausal women in a number of key memory areas. Women report increased forgetfulness and “brain fog” during the menopause transition. The study found declines in levels of estradiol (a form of the female sex hormone oestrogen) in postmenopausal women were specifically associated with lower rates of initial learning and retrieval of previously recalled information, while memory storage and consolidation were maintained.

“Brain fog and complaints of memory issues should be taken seriously,” says Dr JoAnn Pinkerton, executive director of the North American Menopause Society. “This study and others have shown that these complaints are associated with memory deficits.”

Gestational age may impact academic performance

Being born too early or too late may have a long-term effect on children’s academic performance, according to a new study in the International Journal of Epidemiology. Researchers from the University of Manchester used the whole Swedish population, linking more than 2 million live births between 1973 and 1994 to the National School Register and other registers from Statistics Sweden and the National Board of Health and Welfare. Academic performance was measured by the final grade achieved on completing secondary education at 16. The researchers looked across the full range of pregnancy duration (22 to 45 completed weeks), focusing on extremely pre- and post-term births and taking account of possible effects within and between families.

Between 1973 and 1994, 9.4 per cent of Swedish births were post-term and 4.6 per cent preterm. Grade averages were lower for pre- and post-term children than for term-counterparts, and were lowest in children showing evidence of poor fetal growth, irrespective of gestational age. The adjusted grades of extremely preterm children (at 24 completed weeks) corresponded with a 21-point reduction on a 240-point scale, although they had improved over time. The grades of extremely post-term children (at 45 completed weeks) corresponded with an eight point reduction. However, induced post-term deliveries were not associated with reduced school performance.

Among matched siblings, within-family effects were weaker, particularly in the preterm sibling cohort and less so in post-term children. This suggests other unmeasured familial traits could also play a part.