Download Fiber Intake and Cardiovascular Disease Risk Factors

Running Head: 611 PICO
1
Nurs 611 PICO: Fiber Intake and Cardiovascular Disease Risk Factors
Erica Prince
University of New Hampshire
611 PICO
2
Abstract
This paper reviews three research articles that examine the relationship between fiber
intake and cardiovascular risk factors. The three studies all had subjects increase their
fiber intake and then measured how the selected risk factors changed in response to this
diet. The results showed that increasing fiber intake can decrease certain cardiovascular
risk factors like cholesterol and arterial stiffness. Further research should be done,
however. No negative effects were noted.
611 PICO
3
Nurs 611 PICO: Fiber Intake and Cardiovascular Disease Risk
In patients aged 13-adult, how does increased fiber intake compared with lower
fiber intake affect risk for cardiovascular disease?
Heart disease is the number one cause of death for Americans. Patient teaching is
an important part of nursing practice, so information on how to reduce risk factors of
cardiovascular disease is essential information. Evidence based practice is necessary in
order to provide support for nursing interventions. Research studies test theories and help
provide this evidence. By looking at these articles and considering the specific patient’s
needs, nurses can use evidence based practice to teach and intervene about the patient’s
health. Instructing a patient to eat a higher fiber diet can be an intervention that reduces
risks of cardiovascular disease, which includes elevated blood lipid levels, artery
stiffness, and increased weight.
To find evidence, CINAHL was accessed through the UNH Library Database
search. The key words entered in the search were, “fiber intake, cardiovascular disease.”
This resulted in 51 articles, with a majority of them seeming relevant to the topic at hand.
The results were then limited to articles that had the full text available, those that had
been published within that last 10 years, and those that were in English. This refined the
results to 17 articles. Articles were eliminated if they didn’t directly address
cardiovascular disease risk. This left seven articles. The final three articles were selected
because they allowed examination of a wide variety of risk factors that can be affected by
fiber intake.
611 PICO
4
The first study examined whether a lower intake of dietary fiber contributed to
arterial stiffness. It was a longitudinal cohort study with 373 participants whose fiber
intake was assessed from ages 13-36. Then at age 36, stiffness of 3 large arteries was
measured using ultrasonography. Results showed, after accounting for sex, height, total
energy intake and other lifestyle factors, those with the lowest fiber intake had stiffer
arteries than those with higher fiber intake (Laar et al., 2012). The study boasted a large
number of participants which allowed for more accurate data. The researchers also used
confidence intervals to assess the accuracy of the data. The participants met with
researchers once a month for a face to face interview where they listed what and how
much they generally ate. This is not the most accurate measurement of fiber intake and
leaves room for error. So, while this study does show that fiber can reduce this certain
risk factor, it is still important to take into account other preventative measures like
exercise, blood pressure control and low fat diet.
The second study examined the effects of a diet supplemented with soluble versus
insoluble fiber on plasma lipid levels through a randomized, crossover, controlled, singleblind design. Twenty eight men with cardiovascular disease (CVD), which the authors
defined as stable angina or past myocardial infarction, consumed a controlled, low fat
diet that was supplemented with either soluble or insoluble fiber over an 8 week period.
Results showed that ingestion of either type of fiber resulted in a decreased waist
circumference by an average of 2cm. The soluble fiber showed a more favorable effect
on the lipid levels than the insoluble fiber did. The soluble fiber reduced plasma
611 PICO
5
triacylglycerol concentrations by 6.7% and apo B:apo A-I by 4.7% and increased the apo
A-I concentration by 4.3% in comparison with insoluble fiber. Also those that ate the
soluble fiber rather than the insoluble fiber had increased HDL-cholesterol concentrations
by 6.7% (P <0.006) and decreased the ratio of LDL to HDL cholesterol by 14.2% (P
<0.003) (Solà et al., 2007). While this study did blind its participants and calculate the
significance of the data for accuracy, there were a couple limitations. Twenty eight
subjects is a small sample size, which could have affected the results. The authors also
discussed that different people have varying genes that affect their metabolism of lipids
and fiber. So, while this method may be useful for some, it might not be as helpful for
others. It will be important to take into account the patient’s history and preferences
before suggesting this intervention. The study did not find any significant increase in
cardiovascular disease risk by ingesting this diet, so it is a relatively safe intervention
patients could try.
The third study was a cross sectional study that included 2532 men and 3429
women. Over a period of 8 years, the subjects were instructed to give a 24 hour food
recall at least every 2 months. The amount of dietary fiber consumed was extracted and
then the subjects were split into fifths based on the amount of fiber consumed. The
authors referred to the divided groups quintiles. The 2nd-5th quintiles were compared to
the 1st quintile, which was the quintile with the lowest intake, to assess cardiovascular
risks. A total increase in dietary fiber by 5 grams per day showed decreases in risk for
overweight BMI by 10.6%, elevated hip to waist ratio by 14.7%, high apo B by 9.2%,
high homocysteine by 15.4% and hypertension by 11.6% (Lairon et al., 2005). This study
611 PICO
6
boasted a large sample size with provides more effective results. However, again, their
method for obtaining dietary fiber measurements left a lot of room for human error. This
study also calculated the statistical significance for its data. This study, like the others,
shows the potential benefits of a high fiber diet in reducing cardiovascular risks.
All together the results show that increased fiber consumption can decrease
cardiovascular risks. Cholesterol levels, especially, seem to be lowered with high fiber
intake. Soluble fiber seemed to be more effective with this. One study even compared
their results to statin use. This intervention could be used as an adjuvant therapy. Arterial
stiffness, which can contribute to cardiovascular disease, seems to be minimized with
fiber intake. Other risk factors, like weight seem to decrease with this type of diet.
Overall, the research as a whole shows that high dietary fiber should be recommended for
those at risk for cardiovascular disease.
After reviewing the evidence, I would recommend this intervention to a patient.
None of the studies I reviewed showed any compelling negative effects. Of course, since
foods like fruits, vegetables, and legumes are typically the foods that are high in fiber,
this isn’t a particularly risky diet change. It would be important to assess the patient’s diet
to make sure that as they increase fiber intake they still receive enough nutrients like
protein. It is also important to know that high fiber intake alone has not been proven to
prevent cardiovascular disease. Low fat diets, exercise, seeing a doctor regularly and
taking medications should still be considered vital pieces. Further research should be
done to look into which interventions are most effective when compared to each other.
611 PICO
7
Also, more research may be necessary regarding fiber intake as it is difficult to measure
people’s fiber intake long term, so there studies could have errors within them. Overall,
the evidence suggests that high fiber can have beneficial effects and when used with other
prevention methods, patients will be reducing their risk of having a heart attack.
611 PICO
8
References
Laar, R., DA Stehouwer, Bas, Saskia, H Prins, WR Twisk, & Ferreira, I. (2012).
Lower lifetime dietary fiber intake is associated with carotid artery stiffness: the
Amsterdam Growth and Health Longitudinal Study. American Journal Of
Clinical Nutrition, 96(1), 14-23.
Lairon, D., Arnault, N., Bertrais, S., Planells, R., Clero, E., Hercberg, S., & BoutronRuault, M. (2005). Dietary fiber intake and risk factors for cardiovascular disease
in French adults. American Journal Of Clinical Nutrition, 82(6), 1185-1194.
Solà, R., Godàs, G., Ribalta, J., Vallvé, J., Girona, J., Anguera, A., & ... Masana, L.
(2007). Effects of soluble fiber (Plantago ovata husk) on plasma lipids,
lipoproteins, and apolipoproteins in men with ischemic heart disease. American
Journal Of Clinical Nutrition, 85(4), 1157-1163.