I came across this story earlier this week. It concerns a study presented at a Associated Professional Sleep Societies in Minneapolis in the US. The details are somewhat sketchy from the report, but here’s what I think the researchers did and what their findings were.
262 teenagers with an average age of 17 were rated on measures of daytime sleepiness, depression and cravings for carbohydrate.
The main reported finding was that the more sleepy individuals were, the more the craved carbohydrate, and the greater the risk of them being depressed was.
In the report I link to, there is comment from one of the authors in which he refers to ‘sleep deprivation’ as an important factor. Yet, there is no mention that sleep per se was assessed. I don’t know what precisely has gone here, but I have a feeling that in the author’s mind, daytime sleepiness is a proxy for sleep deprivation. If that’s the case, then I think this is an over-simplistic view, because there’s lots of things that can cause people to be sleepy that have nothing directly to do with sleep deprivation.
The number one offender that I have on my own personal list is blood sugar imbalance, and specifically episodes of low blood sugar (hypoglycaemia). This problem, clinically, is very common, which is one of the reasons I mention it quite often in my writing and lectures.
Here’s the thing, when individuals drop their blood sugar level, not only can they feel sleepy, but they can crave carbohydrate too. Oh, and seeing as brain function generally depends on a good supply of sugar (glucose), we won’t be too surprised to learn that low blood sugar can cause problems with mood, including low mood and depression.
In other words, the one thing that could explain the constellation of sleepiness, carb cravings and depression may not be sleep deprivation, but blood sugar imbalance.
However, could there be a link between blood sugar imbalance and poor sleep? The answer to that question in my view is an unequivocal ‘yes’.
One of the effects of low blood sugar is to cause the body to attempt to top up blood sugar levels internally, through the release of sugar from the liver. To do this, the body can ramp up activity in the so-called ‘sympathetic nervous system’, which plays an integral part in the stress response. The body can also release stress hormones such as adrenaline (epinephrine) that simulate sugar release too.
An activated stress response ain’t so good for sleep. At the very best it will impair the depth of sleep and our ability to feel truly rested. Worse than that, though, is its habit of waking people up at about 3.30 – 4.00 am and then not letting them get back to sleep again until about half an hour before their alarm goes off.
I’ve found in practice that rectifying blood sugar imbalance with a ‘primal’, relatively low-carb diet does wonders for improving energy and mood. And within a couple of weeks, it will have usually sorted out any craving for the carbohydrate-rich foods that usually are the cause of the problem in the first place.