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Nature Communications published an animal study which found the consumption of comparatively low amounts of sugar decreases the competitive performance and reproductive output in the mice studied.
Catherine Collins, Principal Dietitian, St George’s Hospital NHS Trust, said:
“With an increasingly aging population there’s lots of interest in examining the effect of diet on overall health. The problem with humans is our current lifespan – so animals with a short lifespan, such as mice, are often used to examine dietary effects. This study looked at the effect of a high sugar diet (with 25% of normal calorie intake replaced by sugar) on wild mouse behaviour. On a high sugar diet male mice sired 25% less offspring and had less territorial instinct than male mice on their usual mouse chow. Female mice doubled their mortality risk on the high sugar diet. The researchers state that this diet mimicked the high sugar diet commonly taken by some people in the US.
“In the UK, our food survey studies (NDNS) indicated an average sugar intake of around 11 percent of total calories – far less than half the amount fed to the mice in this study. Dietary surveys with those on low income (LIDNS), where sugar and sugary foods may be expected to be higher, averaged 14% sugar calories in adults and 17% energy intake from sugar in children – both in excess of the 11% calories recommended, but far less than the amount of sugar given to these mice.
“So what can we take from this? Certainly, for swaggeringly territorial wild mice, a high sugar diet made them weaker at defending their homestead, and influenced fertility. Unfortunately the study doesn’t address whether this was due to micronutrient deficiencies, or that well-sugared mice didn’t feel in the mood to recreate. For female mice, a high sugar diet definitely detracts from a long life. Whilst this is all very interesting for the viability of the wild mice population, we’re not at a stage of recommending sugar rather than cheese on mousetraps. Being human, it’s an interesting piece of work on sugar that doesn’t really translate to the diet of an average UK child or adult, perhaps with the exception of elite athletes who use sugar and sugary foods as a means of achieving their body’s high energy demands.”
Additional information from Catherine Collins:
Percentage calories is a way of assessing the quality of a diet related to overall calorie intake/ needs and is scaled according to calorie goals. This avoids the need for absolute values. For example – an intake of 80g sugar a day may be considered far too high in a 6 year old, but not high enough in a very active teenage boy rugby fanatic.
For example, sedentary female 70 years:
Estimated energy needs approximately 1600kcal per day
For ideal sugar contribution, no more than 11% total calories should come from sugar
Eg 1600 (kcals) x 0.11 (percent) = 176kcals
Sugar has 4 kcal a gram
So 176kcal = 176/4 = 44g sugar. So a diet of 1600kcal can include 44g sugar from all sources (bar milk) and be considered healthy.
What about an athlete on 5500kcal a day?
Same principle –
5500 x 0.11 / 4 = 151g sugar is ‘healthy’ on a 5500kcal diet…
In reality, most athletes would take more sugar than this as a high calorie, low fibre, energy source.
References:
http://www.ucl.ac.uk/hssrg/studies/ndns
‘Human-relevant levels of added sugar consumption increase female mortality and lower male fitness in mice’ by James S. Ruff et al. published in Nature Communications on Tuesday 13 August 2013.