Read the entire Article
5 on Bb before answering these questions, as information relevant to them
is found in many places throughout the article.
Gudden J, Vasquez AA and Bloemendaal M. The Effects of
Intermittent Fasting on Brain and Cognitive Function. Nutrients 2021, 13, 3166.
https://doi.org/10.3390/nu13093166
Do not copy
any parts from the article. Each answer should be
between 200-250 words (use Word Count to check). Be sure to correct grammar and
spelling, or you will lose points.
1. Through
what metabolic mechanisms could an IF protocol promote brain health even
if weight was not lost? (1)
Intermittent
fasting has shown promise for improving outcomes in several neurological
disorders and has underlying mechanisms that could support brain health.
Fasting regimens cause metabolic shifts like decreased insulin and increased
ketone circulation that may benefit neuronal function and survival. However,
more research is still needed. Longitudinal clinical trials directly comparing
effects of starting intermittent fasting at different ages could help determine
optimal dosing. Placebo-controlled studies are also lacking, and controlled
trials should account for potential confounding from calorie reduction or
rhythmic eating changes accompanying various fasting models. Further exploring
intermittent fasting applications and optimizing protocols through rigorous
human studies remains an important area for future research.
2.Would you
expect that a change from three meals a day to a TRF would increase microbiome
diversity? Defend your answer (1)
3. Some of
the studies reported improvements in symptoms of neurogenerative disease using FMD.
(1)
a) briefly describe one such disease situation; if the subjects
were animals, describe the model of the disease. What was improved by the FMD?
b) Is FMD really intermittent fasting? Would you expect the same
effects with other low-calorie diets? Defend your answer.
a) One study
used a multiple sclerosis animal model where mice were induced with EAE to
mimic MS. These mice were given 3 cycles of FMD, which completely reversed
disease progression as measured by clinical scoring compared to ad libitum fed
mice.
b) While FMD
does involve periods of low-calorie intake, it differs from simple calorie
restriction in that the fasting mimicking diet aims to lower protein/amino acid
content specifically to reduce IGF-1 levels. Studies comparing FMD to CR or
unrestricted diets found reductions in IGF-1 and markers of aging and disease
with FMD that were not seen with long term CR. So, the composition changes
aimed at lowering IGF-1 distinguish FMD and suggest its effects may not be
replicated by other generally low calorie diets without attention to
macronutrient balance.
4. The
authors do not state how severe or how long-term the diets must be in order to
produce positive effects on neurological function. Based on Table 1, what can
you say about: (1)
a)
the length of the diets needed to produce improvement in symptoms and risk
factors in humans.
b)
the severity of the diets needed to produce improvement in symptoms and risk
factors in humans.
a) Based on
Table 1, the majority of studies that showed improvements in humans used diet
lengths ranging from 2 months to 3 years. No studies with durations under 2
months showed effects.
b) The
severity of diets associated with improvements varied. Studies using TRF, ADF
or PF generally did not aim for calorie reduction. FMD was more restrictive at
very low-calorie intake for 5 days per month but produced benefits. Ramadan
fasting showed some improvements and relapses depending on variables,
suggesting a mild intermittent fast may work for some but requires careful
variables management. Overall improvements were seen with protocols ranging
from mild TRF to medically supervised very low calorie FMD but not with
constant severe calorie reduction.
5. The
effects reported in studies where subjects followed IF vs their previous ad libitum diets could be due to many
differences between the two situations, which may not be specific to an IF.
Discuss TWO
differences in the dietary situations (e.g. protocol, composition–not their
effects) that could be responsible for the results. (1)
Two
differences in the dietary situations between IF and ad libitum protocols that
could contribute to results include:
– Timing of
eating – IF protocols restrict eating to specific windows each day while ad lib
usually allows grazing. This impacts circadian rhythms and hormone levels.
– Feeding
frequency – Most IF calls for 1-2 meals per day vs spreading foods across the
day with snacking in an ad lib plan. This changes digestion patterns and
substrate availability.
The changes
in circadian impact, feeding frequency and other aspects of the overall dietary
pattern from IF, not just its effects, could drive some results seen versus
unstructured ad lib eating. Strict controls are needed to isolate the
intermittent fasting variable.
