Most of us understand the importance of
a normal blood glucose level. If our blood glucose level goes very low we
might become unconscious; if our blood glucose level goes very high we develop
a problem called diabetes. Now diabetes is serious: it can cause damage to the
larger blood vessels in our body, so diabetic patients have a very high
incidence of heart attack, stroke as well as amputation; but diabetes can also
cause problems to the very small blood vessels in the body so called micro
vascular problems, resulting in damage to the retina - diabetics have a high
instance of blindness - it can also cause problems with the very small blood
vessels supplying the kidney. So diabetics have a high incidence of
kidney failure. Now what exactly is a normal blood glucose level? Well to put it
in terms that most people can understand including myself, I have here a container
with five litres of water within it and the reason I've chosen five litres is
because the average person has about five litres of blood circulating around
the body. I have also a container of glucose - a white crystalline powder - and
you might be surprised to know that the amount of glucose that I would need to
add to this container to give a similar concentration of glucose in my blood is
only one teaspoon. In fact, it's slightly less; it's about 4.5 grams. So here's the
glucose and if I add that to this container the concentration in there is
approximately the same as the blood glucose level in my blood right now,
talking to you. Now, if I were to add another teaspoonful the concentration of glucose now in this water is that of a diabetic. So as
you can see, the blood glucose level is very tightly controlled and the
difference between a normal blood glucose and that of a diabetic person is
only an additional one teaspoonful of glucose - quite surprising really. So how
do we maintain normal blood glucose levels during the course of the day? Well
many people are advised to eat small frequent meals throughout the day,
consisting or having as part of that meal or snack, a complex carbohydrate
which releases glucose very slowly into the bloodstream. However, more recently,
many experts have challenged this view and I'm of the view, as well, that we
don't actually need frequent meals, containing complex
carbohydrates. In fact Professor Tim Noakes in his excellent book "The real
Meal Revolution" has suggested that actually there's no requirement for us
to eat carbohydrates at all and certainly the liver has an amazing
ability to manufacture glucose should it be required. Certainly for people with
type 2 diabetes, in which the main problem is too much glucose in the
bloodstream, many experts and myself included believe that the way to tackle
this issue is to eat meals which have a restricted amount of carbohydrate within
them. Because all carbohydrates when they're eaten are digested and
they have to enter the bloodstream as glucose and, as you can see, it doesn't
take very much glucose entering the bloodstream to turn a normal blood
glucose level into that of a diabetic. So it seems sensible if you have a risk of
diabetes, then to restrict the amount of carbohydrate that you're eating. We don't
need - there's no essential requirement - for carbohydrates, in fact. We can exist
very happily with proteins and fats. We don't actually need to eat carbohydrates,
and, as I say the liver has an ability to manufacture glucose and release it into
the bloodstream - a process called gluconeogenesis. So that's a normal blood glucose level: only one teaspoon in five litres gives a concentration of glucose
which is equivalent to that of a normal person. It doesn't take very much more to
tip one into a high blood glucose level the same as that of a diabetic - and so
for those who are at risk of developing type 2 diabetes - in fact some would say
for all of us - it's sensible to restrict the amount of carbohydrates that we eat.
