Life
has a certain regularity for most of us and this is based on a twenty-four hour
cycle, more or less. We get grumpy if it’s disrupted, especially if it’s early
in the morning. But our circadian clock is rather more important than effecting
our grumpiness when interfered with. Many other nasty effects have been
indicated, such as cancer or diabetes.
The
key issue here is that our metabolism is linked to our clock. Exactly how much
is the question investigated by Dallmann et
al who reported their findings last week in the Proceedings of the National
Academy of Science (1).
Theirs
was a pretty tough study, especially for their volunteer human lab-rats who
were locked away and kept on a strict 40-hour cycle. They had to eat hourly
isocaloric meals, no exotic menu choices for them. In addition they were shut
away in dim light in enforced positions and kept sleep deprived. This way,
their body would have no clues from TV, soft beds, or bright sunshine as to what it should be doing .
This
meant that their metabolism would be running on the circadian clock only with
no interference from competing stimuli. The only excitement was regular blood
letting and saliva sampling to check the levels of the small molecules from
their metabolic workings.
The
levels of 15% of these small molecules varied in line with the subjects’
circadian rhythm. The molecules in question were fatty acids and amino acids.
These are involved in important metabolic pathways. Think cell membranes and
fatty acids, and DNA or proteins in general for amino acids and their
importance is immediately clear.
What
should we do about this? Clearly the old adage of “Early to bed, early to
rise…” has a lot going for it, but is eating regular meals (like you mom told
you) and not burning the candle at both ends all we need to know? Perhaps we
should dig a little deeper to get in tune with our inner clockwork and fit our
exercise and menus so that they match up.
