In Part II, Peter Bowes presets the results of the clinical trials he underwent during the intermittent fasting. Really interesting, yet to be validated with more clinical and field trials, are these facts:
1. Changes in the levels of a growth hormone known as IGF-1 (insulin-like growth factor).
High levels of IGF-1, which is a protein produced by the liver, are believed significantly to increase the risks of colorectal, breast and prostate cancer. Low levels of IGF-1 reduce those risks. Studies in mice have shown that an extreme diet, similar to the one I experienced, causes IGF-1 levels to drop and to stay down for a period after a return to normal eating.
The author's trial data showed exactly the same pattern.
2. Author's blood tests also revealed that the major inhibitor of IGF-1, which is called IGFBP-1, was significantly up during the fasting period, indicating the body is switching to a healthy and more conducive way of ageing.
Part II of the article:
Many of the changes in
my body when I took part in the clinical trial of an intermittent fasting diet
were no surprise. Eating very little for five days each month, I lost weight,
and I felt hungry. I also felt more alert a lot of the time, though I tired
easily. But there were other effects too that were possibly more important.
During each five-day
fasting cycle, when I ate about a quarter the average person's diet, I lost
between 2kg and 4kg (4.4-8.8lbs) but before the next cycle came round, 25 days
of eating normally had returned me almost to my original weight.
But not all
consequences of the diet faded so quickly.
"What we are
seeing is the maintenance of some of the effects even when normal feeding
resumes," explains Dr Valter Longo, director of USC's Longevity institute,
who has observed similar results in rodents.
"That was very
good news because that's exactly what we were hoping to achieve."
Clinical tests showed
that during the diet cycles my systolic blood pressure dropped by about 10%,
while the diastolic number remained about the same. For someone who has, at
times, had borderline hypertension, this was encouraging. However, after the
control period (normal diet), my blood pressure, like my weight, returned to
its original - not-so-healthy - state.
The researchers will
be looking at whether repeated cycles of the diet could be used to help manage
blood pressure in people over the longer term.
Arguably, the most
interesting changes were in the levels of a growth hormone known as IGF-1
(insulin-like growth factor). High levels of IGF-1, which is a protein produced
by the liver, are believed significantly to increase the risks of colorectal,
breast and prostate cancer. Low levels of IGF-1 reduce those risks.
"In animals
studies we and others have shown this to be a growth factor that is very much
associated with ageing and a variety of diseases, including cancer," says
Longo.
Studies in mice have
shown that an extreme diet, similar to the one I experienced, causes IGF-1
levels to drop and to stay down for a period after a return to normal eating.
My data showed exactly
the same pattern.
"You had a
dramatic drop in IGF-1, close to 60% and then once you re-fed it went up, but
was still down 20%," Longo told me.
Such a reduction could
make a significant difference to an individual's likelihood of developing
certain cancers, he says. A study of a small population of people in Ecuador,
who have much lower levels of IGF-1, because they lack a growth hormone
receptor, showed that they rarely develop cancer and other age-related
conditions.
My blood tests also
revealed that the major inhibitor of IGF-1, which is called IGFBP-1, was
significantly up during the fasting period. Even when I resumed a normal diet,
the IGFBP-1 level was elevated compared with my baseline. It is, according to
Longo, a sign that my body switched into a mode that was much more conducive to
healthy ageing.
Data from other
participants in the study is still being analysed, but if they also show lower
levels of IGF-1 and higher levels of IGFBP-1, it could help scientists develop
an intermittent fasting regime that allows people to eat a normal diet for the
vast majority of the time, and still slow down the ageing process.
One idea being
explored by Longo is that a five-day intervention every 60 days may be enough
to trigger positive changes in the body.
"This is exactly
what we have in mind to allow people, for let's say 55 every 60 days, to decide
what they are going to eat with the help of a good doctor, and diet in the five
days. They may not think it is the greatest food they have ever eaten, but it's
a lot easier, let's say, than complete fasting and it's a lot safer than
complete fasting and it may be more effective than complete fasting."
The very small meals I
was given during the five-day fast were far from gourmet cooking, but I was
glad to have something to eat. There are advocates of calorie restriction who
promote complete fasting.
My blood tests also
detected a significant rise in a type of cell, which may play a role in the
regeneration of tissues and organs.
It is a controversial
area and not fully understood by scientists.
"Your data corresponds
to pre-clinical data that we got from animal models that shows that cycles of
fasting could elevate this particular substance, considered to be stem
cells," said Dr Min Wei, the lead investigator.
The substance has also
been referred to, clumsily, as "embryonic-like".
"At least in
humans we have a very limited understanding of what they do. In animal studies
they are believed to be 'embryonic-like' meaning... they are the type of cells
that have the ability to regenerate almost anything," says Longo.
It would be highly
beneficial if intermittent fasting could trigger a response that enhances the
body's ability to repair itself, but much more research is required to confirm
these observations.
This diet is still at
the experimental stage and data from the trial are still being studied. Other
scientists will eventually scrutinise the findings independently, and may
attempt to replicate them.
"We generally
like to see not only an initial discovery in a trial but we like to see
confirmatory trials to be sure that in the broadest kind of sense, in the
general population that these findings are going to be applicable," says
Dr Lawrence Piro, a cancer specialist at The Angeles Clinic and Research
Institute.
"I do believe
fasting to be a very effective mechanism. They are pieces of a puzzle, that
puzzle is not fully revealed yet, the picture isn't clear yet but there's
enough of the picture clear. I think we can be really excited that there is
some substantial truth here, some substantial data coming forward and something
that we can really be hopeful about."
Future clinical trials
will focus on "at-risk" members of community - those who are obese -
to gauge their response to a severely restricted diet.
But if this diet, or
another intermittent fasting diet, is eventually proven be effective and
sustainable, it could have profound implications for weight loss and the way
doctors fight the diseases of old age.
Insulin-like growth factor 1
·
IGF-1 is a protein
produced by the liver when it is stimulated by growth hormone circulating in
the blood
·
It plays a role in the
growth of muscle, bones and cartilage throughout the body, and is critical to
growth and development during childhood
·
Lower levels of IGF-1,
induced by calorie restriction, have been shown in rodents to slow the ageing
process and protect against cancer
·
IGF-1 levels in adult
humans vary according to age and gender
Credit: BBC News
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