Are we suppressing one of Mother
Nature’s oldest and most effective bug-fighting mechanisms by force-feeding
patients when they have lost their appetite during an infection?
A PhD student in physiological
sciences from Stellenbosch University, Gustav van Niekerk, argues this might be
the case and is calling for a reassessment of this standard medical practice.
In an article published in the
high-impact journal Autophagy this week (6 April 2016), Van Niekerk and
researchers from the Department of Physiological Sciences at SU argue that
appetite loss during infection or sickness has a very important function. And
that is to enhance the ability of cells to perform autophagy, a process which
literally means “eating of self”.
Read: Chemicals that control appetite
Under normal circumstances the cells
in your body use autophagy (a kind of cellular ‘recycling process plant’) to
clear the garbage generated by the wear and tear of the parts in a cell.
Through autophagy, the cell is able to recycle the debris or junk that could
otherwise have caused damage to the cell.
The degraded material is then used as
fuel to generate new parts. In other words, all the cells in your body are
continuously being regenerated in order to function optimally.
Van Niekerk and co-authors argue that
short-term fasting during an infection can be beneficial, since cells which are
deprived of nutrients are forced to upregulate the recycling process
(autophagy). In turn, bacteria and viruses invading the cell can be degraded by
the very same recycling process.
A cell’s self-defence mechanism
Van Niekerk explains: “The immune
system is often seen as the ‘army’, while ‘normal’ cells such as liver cells
and neurons are seen as ‘civilians’. In this view, invading bacteria or viruses
harm the ‘unarmed civilian’ while the ‘military’ (the immune system) are
dedicated to fight off an infection.”
However, "normal" cells are not quite
“We argue that an upregulated
autophagy acts as a cell’s self-defence mechanism and that it plays a critical
role in the body’s immune system.
“In this way, ‘civilian’ cells are in
fact acting like ‘partisan forces’ halting the spread of the infection while
the ‘professional forces’ (immune cells) are mobilised.”
Read: 10 immune system boosters
Prof. Anna-Mart Engelbrecht, head of
the Department of Physiological Sciences and one of the co-authors, says this
new way of understanding the role of autophagy has important implications for
the medical field: “It has also been shown that
cancer patients who fasted before chemotherapy experienced less harmful side
effects usually induced by chemotherapy such as fatigue, weakness, headaches,
nausea, vomiting and diarrhoea.”
Shorter-term nutritional withdrawal
Firstly, the researchers argue for a
re-evaluation of nutritional support in the context of controlled underfeeding,
where enhanced autophagy may provide superior support.
Upregulating autophagy may also have
additional benefits. Chunks of bacteria and viruses processed by the cell’s
recycling plant can also be passed on to immune cells. In turn, the immune
cells can be "trained" to recognise the bacteria and viruses and form
antibodies against them. This would suggest that upregulating of the recycling
plant (autophagy) may be an effective way to enhance vaccine efficacy.
Read: Vaccine breakthroughs
The researchers stress, however, that
shorter-term nutritional withdrawal should not be confused with the
well-established immune-inhibiting effect of long-term starvation. They also
point out that there are a number of circumstances in which nutritional
supplementation may provide a therapeutic benefit. As an example, some
pathogens are able to "hijack" certain steps in the autophagic proses.
Therefore, evaluating patients according to pathogen-type may indicate
infections in which permissive underfeeding as opposed to aggressive
supplementation may prove more effective.
Fasting protects against chemo
Periodic fasting good for health
Fasting boosts longevity in animals
The co-authors on the article are
Prof. Anna-Mart Engelbrecht, Dr. Ben Loos and Dr Theo Nell. The work was
supported by the Cancer Association of South Africa (CANSA), the National
Research Foundation (NRF) and the Medical Research Council (MRC).
Gustav van Niekerk
076 801 7048
by Wiida Fourie, media: Faculty of Science, Stellenbosch University
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