Can 2
apples a day help keep the doctor away?
"Core
Blimey eating two apples a day boosts health of your heart by slashing high
levels of cholesterol," reports The Sun.
The story
is based on a small trial that found that eating 2 apples a day for 8 weeks can
slightly reduce high cholesterol levels, by up to 4%. Apples are high in
fibre and polyphenols (chemicals thought to have various health benefits).
The trial
included 40 healthy volunteers with slightly raised cholesterol. When they ate
2 apples a day for 8 weeks, total cholesterol and LDL ("bad")
cholesterol levels reduced slightly compared with when they consumed the same
number of calories from apple juice concentrate mixed with water.
It's
important to note that after eating the apples their cholesterol levels were
still higher than what is considered to be healthy. Eating apples should not be
seen as a substitute for cholesterol-lowering drugs such as statins for people who need them.
Eating
apples contributes to our recommended 5 fruit or vegetables a day. Achieving this target will help to ensure
adequate vitamin and mineral intake, to reduce the risk of bowel cancer and to
help maintain a healthy weight.
Where did
the story come from?
The study
was carried out by researchers from the University of Reading, and the
Fondazione Edmund Mach in Italy. It received internal funding grant from the
European Union, and a grant from AGER (Agribusiness and research) – an
organisation funded by banking institutions and supporting research in the Italian
food industry. The study was published in the peer-reviewed medical journal The American Journal of
Clinical Nutrition.
The media
in general have reported the study accurately and included expert opinion
advising against trading in statins for apples.
What kind
of research was this?
This was
a randomised crossover
trial comparing
apple consumption with calorie-matched apple juice. Participants switched from
fruit to juice halfway through the trial. As the same people were exposed to
both interventions, this reduces the risk of patient variation affecting the
results and means a smaller number of participants can be involved. However, in
this case there were only 40 participants, so the results may not be
representative of what would be seen in the population as a whole.
What did
the research involve?
The
researchers recruited 23 women and 17 men from Reading who had slightly high
cholesterol. For 2 weeks before the study started, they were asked to avoid
apples, apple juice and any probiotics such as live yoghurts. They were then
split into 2 groups. The first was asked to consume 2 apples a day for 8 weeks.
This was followed by a "washout" period of no apples for 4 weeks and
then an apple substitute for 8 weeks.
The apple
substitute had the same number of calories as the fresh apples but was made up
of apple juice concentrate and water. The second group consumed the apple
substitute for the first 8 weeks, had the 4 week washout and then ate 2 apples
a day for 8 weeks. Apples are high in fibre and polyphenols (chemicals thought
to have various health benefits).
What were
the basic results?
After 8
weeks, the group on 2 apples a day had better cholesterol readings compared
with the group on apple juice:
- total
cholesterol level was lower, at 5.89mmol/L compared to 6.11mmol/L
- LDL
("bad") cholesterol was slightly lower at 3.72mmol/L compared to
3.86mmol/L
- triglyceride
(another type of fat) level was also slightly improved at 1.17mmol/L versus
1.3mmol/L
Eating
apples had no effect on HDL ("good") cholesterol, blood pressure or
other markers of heart health.
How did
the researchers interpret the results?
The
researchers say their "findings show clear cause and effect between
inclusion of 2 Renetta Canada apples into normal diets and improved CVD
[cardiovascular disease] risk factors". They recommend that further
studies look into the mechanisms behind their protective effect and work out
the optimal number of apples to be consumed a day.
Conclusion
This
small study has found that eating 2 apples a day may be beneficial in terms of
reducing total cholesterol, LDL ("bad") cholesterol and triglyceride
levels. The effect was quite small and the participants' cholesterol levels
remained higher than what is considered to be healthy – i.e. less than 5mmol/L
for total cholesterol and 3mmol/L or less for LDL cholesterol.
That
said, any reduction is likely to be worth it in terms of reducing the risk of
cardiovascular disease such as heart attack or stroke. However, eating apples
should not be seen as an alternative to statins, which have been shown to have
a much greater effect in lowering cholesterol.
Though
the study was a randomised controlled trial, there are some limitations such as
the small number of participants and the short length of the trial. It is not
clear whether further reductions in cholesterol levels would occur over a
longer period of time. There were some suggestions of different effects in
women compared with men, but there were not enough participants to be sure.
Nevertheless,
eating apples is not only likely to reduce cholesterol, but also contributes to
the consumption of dietary fibre, which reduces the risk of bowel cancer.
Consuming a variety of fruit and vegetables to achieve our 5 a day is likely to be better than focusing on
just the 1 fruit.
Analysis
by Bazian
Edited by NHS Website
Edited by NHS Website
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