HEP 491 PAPER v5 JC

AN EVALUATION OF A THREE-DAY DIET AND HYPERTENSION
Cruz, HEART Laboratory, Ursinus College1
An evaluationof a three-day diet and hypertension
Joseph A. Cruz1 & Deborah L. Feairheller, PhD1
1The HEART (Hypertension and Endothelial function with Aerobic and Resistance Training)
Laboratory, Health & Exercise Physiology Department, Ursinus College, Collegeville, PA.
Funding: No external financial support.
Author Correspondence:
Deborah L Feairheller, PhD
The HEART (Hypertension and Endothelial function with Aerobic and Resistance Training)
Laboratory, Health & Exercise Physiology Department, Ursinus College,
601 E. Main Street, Collegeville, PA 19426
Tel#: 610.409.3256
Email: dfeairheller@ursinus.edu
Disclosure: We have no conflicts of interest to declare.
Introduction
Overview
There has always been a light of hope in the advancing research of the medical field for
new approaches to diagnose, cure and prevent individuals from developing cardiovascular
disease (CVD). CVD is referred to as an umbrella that covers a variety of diseases that involve
the cardiovascular system and overall the entire homeostatic environment of the human body.
Hypertension, or high blood pressure, is classified as one of the many manifestations within this
CVD umbrella and is usually defined as abnormal elevated pressure exerted on the walls of the
blood vessels. Inadequate control of blood pressure can progress to more serious cardiovascular
(CV) diseases such as atherosclerosis, myocardial infarction, stroke and death.
There have been several variations to dietary guidelines suggested that may prevent CVD
and promote improved health in individuals. Each of these has been researched prospectively and
proven effective (Lane, 2008). Within these guidelines, vitamin D has been researched
extensively and has been reported to lower blood pressure in hypertensive adults, but there has
yet to be a large randomized control trials to prove the accuracy of these findings. Along with the
lack of evidence of the antihypertensive effects of vitamin D, there is also little research on
three-day diet and the information that can be retrieved from an analysis. There is limited
research of the effects that vitamin A may have on cardiovascular risk markers. Further, dietary
fiber has been researched and continues to be researched. There are proposed effects that
adequate dietary fiber can lower blood pressure as well as decreasing other cardiovascular and
inflammatory risk levels. Iron is also associated with the cardiovascular system and the
pulmonary system in terms of its function. Inadequate levels of iron are seen in all populations
and is the reason for being the most common dietary deficiency. The risk of deficiency in this
daily nutrient may cause an increase risk in cardiovascular disease. The purpose of this study is
to conduct a cross-sectional study and to observe self-reported three-day diets and any

correlations seen within the individual’s diet and the necessary macro- and micronutrients,
specifically vitamin D, vitamin A, dietary fiber, and iron.
Guidelines
Dietary guidelines have been generated to give the population recommendations of
healthy habits on daily nutritional consumption. Most dietary guidelines are similar in their key
recommendations internationally (Hansen, 2014). The guidelines call for a diet that accounts for
all macro- and micronutrients that are within appropriate calorie limits, reducing sodium, added
sugar, saturated fatty acids and trans fatty acids, while increasing potassium and fiber intakes
(Reidlinger, 2015). Healthy eating patterns suggested by the present 2015-2020 Dietary
Guidelines include increasing whole grains, whole fruit and vegetable consumption. Low-fat, or
fat free dairy products are preferred. Protein food should include high amount of seafood, lean
meat, legumes, nuts, and seeds. Also the guidelines state to avoid foods that contain high
amounts of trans fat, saturated fats, added sugars, and sodium by reducing intake to 10 percent of
calorie limit each. If alcohol is consumed, recommendations state that it should be consumed in a
timely manner as well as limiting consumption to 1 or 2 drinks for women and men, respectively
(US Dept. of Heath and Human Services and US Dept. of Agriculture, 2015).
Vitamin A
Not much research has been conducted on vitamin A and it’s affects on cardiovascular
risk markers. Vitamin A is a nutrient that can be either consumed through animal or plant
sources or be converted from other carotenoids; such as beta-carotene and beta-cryptoxanthin.
Carotenoids, such as beta-carotene and beta-cryptoxanthin, are consumed through plants and can
be converted to vitamin A (Bates, 1995). Dark green, yellow, and orange fruits and vegetables
are rich sources of these provitamin A carotenoids. Bates also states that there may be immunity
improving effects, prevention of degenerative diseases, and decrease in overall mortality.
Vitamin D
Vitamin D is a necessary dietary component in the body’s homeostatic environment. This
nutrient has had several claims and suggestions that it plays a vital role in the prevention of many
chronic diseases including cardiovascular disease, one of the top leading causes of death in the
United States. Vitamin D exists in two forms; vitamin D2 is derived from plant sources where
vitamin D3, or the “sunshine vitamin”, is synthesized from the ultraviolet irradiation, or from
oily fish or supplements (Mozos, 2014). Recently in the United States, there has been an
increase in the number of outpatients who can be classified as vitamin D deficient from 2007 to
2010 (Huang, 2015). To define vitamin D deficiency, Mozos (2015) stated that most experts
define vitamin D deficiency and insufficiency as a concentration level of calcidiol, which is
generated from the substrate 25-hydroxyvitamin, of <20 ng/mL and 21 – 29 ng/mL. If vitamin D
is >30 ng/mL it is classified as sufficient and if concentrations are >150 ng/mL, then the patient
can be classified to have vitamin D intoxication. Vitamin D can be consumed through protein
sources, specifically fish, fortified cereals, and dairy products.
Dietary Fiber
Dietary fiber has been seen to have protective and preventive properties from the risk of
developing hypertension. It has been reported to have an inverse relationship with Peripheral
Artery Disease (PAD), a major cause of mortality which results from atherosclerosis, coronary
artery disease, hypertension, and cigarette smoking (Merchant, 2003). The intake of adequate

levels of dietary fiber have proposed roles of decreasing blood pressure, cholesterol levels, and
inflammation biomarker levels (Grooms, 2013). Fiber can be consumed from whole grains,
especially fortified cereals, fruits, vegetables and supplementation.
Iron
Iron is a vital element within the cardiovascular and pulmonary systems of the body. It
aids in the important transport of oxygen within the blood to the other organs and tissues within
the body as well as cell growth and proliferation. Iron deficiency, assumed to be the most
common dietary deficiency, is a prime cause of worldwide anemia (Ponikowska, 2013). Food
fortification, dietary diversification and iron supplementation are strategies that aim to control
adequate iron levels, however it has been seen that higher food intakes can lead to increased risk
of CVD (Geissler, 2011). Rich sources of iron exist in protein sources including red meat, pork,
poultry and seafood, dark leafy vegetables and iron-fortified cereals.
Diet Interventions
Most diet interventions performed in prospective studies applied either one or a
combination of multiple interventions including the Dietary Approaches to Stop Hypertension
(DASH) diet, Mediterranean diets, low-sodium diets, low-calorie diets, and low-fat diets (Gay,
2016). Most of these diets mimic dietary guidelines and aim to reduce the amount of proposed
nutritional components that may increase risk for CVD or other chronic diseases. The DASH diet
is aimed to increase fruit, vegetables, low-fat dairy, whole grains, lean meat and fish, along with
nuts and oils; while avoiding red meat, added sugars, and increased sodium (Wengreen, 2013).
The Mediterranean diet is more focused on increased vegetables, fruits, nuts, legumes, cereals,
high intake of oils (especially olive oil), low-moderate intake of dairy and alcohol, and a
preference of fish over meat and poultry (Leblanc, 2015). Low-sodium diets aim to reduce
amount of sodium consumed. Similarly, low-calorie diets aim to reduce calories and low-fat
diets aim to reduce mostly saturated or all fat intake. In respect, there have been reports of
combinations of more than one of the diets listed.
Methods
Participants
Young participants were recruited from the Ursinus College area. Specific criteria for
inclusion for all participants were: non-diabetic, non-smoking, no medications that affect
cardiovascular hemodynamics, no more than one anti-hypertensive medication, and no evidence
or history of CVD, hypercholesterolemia, or renal disease. Each participant gave written
informed consent and completed a health and exercise history questionnaire. The protocol was
approved by the Ursinus College Institutional Review Board, and all procedures were in
accordance with the ethical standards of the Helsinki Declaration.
Blood Pressure Measurements
Clinic BP measurements were obtained in accordance with JNC-7 guidelines on three
separate visits in a quiet (5min rest), temperature controlled room, using an aneroid
sphygmomanometer (Medline Industries, Mundelein, IL) (Chobanian, Mozaffarian, Roger, et al.,
2003). BP measurements were performed in triplicate with the average of the three values used
as the representative BP

Body Composition Measurements
Body composition was measured by whole-body bioelectrical impedance (BIA) using the
single frequency impedance instrument (ImpediMed DF50, San Diego, CA) following an
overnight fast in a quiet, temperature controlled room. Participants were asked to refrain from
salty foods, exercise, medication, alcohol, and caffeine for at least 10 hours prior to the test.
Height and weight were measured using a calibrated electronic scale without shoes. BIA was
measured in accordance with the manufacturer’s instructions at 50 kHz on the right side of the
body. Two electrodes were placed on the dorsal right hand and foot while the athletes were lying
in a supine position. Three measurements were taken, and the mean values of impedance, phase,
resistance, and reactance were used for calculations of total fat and fat free mass.
Diet Analysis
Self-report three-day diet logs were collected. We requested that they include two
weekdays (and one weekend day. Diet logs were assessed by the Diet Analysis Pus software
(Cengage Learning, Stamford, Connecticut) for calculation of daily kilocalorie, nutrient, and
mineral content. An average was then calculated for the three-day period.
Statistics Analysis
Data are expressed as mean ± the standard deviation (SD). Distribution of all variables
was examined using the Shapiro-Wilk test of normality. Pearson correlation was used to
determine if there were relationships between the variables and was further examined by linear
regression analysis. Statistical significance was set at P < 0.05. All statistical analyses were
performed using SPSS version 19.0 (SPSS Inc., Chicago, IL, USA).
Results
Participant Characteristics
There was a total of 92 relatively young participants that had three-day diet included into
the statistical analysis. The mean age of all participants was 23.61  9.3 years old, and were
predominated by males (65.2%, n = 60) and of the Caucasian ethnicity (87%, n = 80). The
participants seemed to be healthy since mean systolic blood pressure (SBP) and diastolic blood
pressure (DBP) were recorded as 120.91  9 mmHg and 73  6.8 mmHg, respectively. Mean
body fat% was 27.10 8.68 and the mean Body Mass Index (BMI) was 26.36  3.58. The
participant characteristics can be seen in Table 1.
Diet Characteristics
In Table 2, mean diet characteristics of the self-reported three-diet of all the participants
is presented. Mean average of all patient’s kilocalorie (kCal) was 2470.13  758.66. Out of the
averaged patient consumption, intake carbohydrates consisted of 47.32%, protein was 18.86%
and fat 33.79% of averaged kCal. Average Cholesterol (mg) intake was observed at 520.07 
527.26; average dietary fiber (g) was 23.40  8.62; and average sodium intake (mg) was
measured at 4298.88  2064.96. Sugar (g) consumption was measured at 104.41  41.44

Relationship with Cardiovascular Markers
There were only three significant relationships seen through all correlations. There was a
direct relationship with sodium intake and BMI (p = 0.218), presented in Figure 1. In contrast,
there were two inverse relationships with fiber (p = -.247) and iron (p = -.227) correlating with
SBP. Graphs presenting both the fiber and iron relationships with SBP can be seen in Figure 2
and Figure 3, respectively.
Discussion
The present study was performed to observe any correlations or significant relationships
between diet characteristic components and health among young participants. There were more
specific target nutrients that we hoped to see correlations including vitamin D and A; however
we only found three significant findings which were associated with sodium, dietary fiber, and
iron intakes.
The mean values of the diet characteristics show that the participants within the study
consumed well over in kilocalories (kCal), protein, carbohydrates, fat, saturated fat, cholesterol,
and sodium; whereas the rest of the variables seem to be under or near the recommendations.
Most of the participants within the study are college aged (18-22) with few outside those years.
These years can be considered a transitioning year where adolescents turn to adults and are
required to make challenging lifestyle choices that may affect their health habits. Schweitzer et
al. (2016) explains the “freshman 15” phrase which describes weight gain associated with the
initial years of college. This weight gain can be associated with poor dietary choices and in the
end result in skipping meals, increased frequency of snacks and alcohol, and overall, increased
fat, added sugars, and increased sodium intake. As well as unhealthy eating habits,
environmental factors such as stress can be an indication for the reason for some of the choices
taken by young adults in college years (Nastaskin, 2015). This seems to be typical of most young
adults and we see similar outcomes within our study as well.
The study presented that there was a positive correlation with dietary sodium intake and
BMI. This seems to be a plausible indication due to increased sodium content in foods is linked
to unhealthier foods which overall leads to increased body composition and BMI. However,
there has not been may studies that looked at the effects of sodium on body composition. Sodium
intake has been considered one of the major causes for hypertension among adults, but Shim et
al. (2013) found that, within his study on the association of dietary sodium intake with meal and
snack frequency, dietary sodium was positively correlated with systolic blood pressure for both
males and females and an additional correlation with BMI seen for only males. The participants
were young adults between the ages of 20-26 years old and both males and females had daily
sodium intake percentages well over recommended values, 310% and 245%, respectively. In
contrast, Vaidya and associates (2011), studied associations between adiponectin and 25-
hydroxyvitamin D (25[OH]D) after controlling the influence of the renin-angiotensin-
aldosterone system (RAAS) with dietary sodium equilibration. After all subject performed one
week of a high sodium diet to suppress RAAS and one week of a low sodium diet to stimulate
RAAS, they saw that the sodium intake equilibrium was not associated with BMI.
It was seen in the present study that there was an inverse relationship with dietary fiber
intake and systolic blood pressure. This negative correlation has been reported before in existing

research. In a meta-analysis conducted by Whelton et al. (2005), the authors included 25
randomized controlled trials and assessed the effects of dietary fiber on blood pressure and found
that overall, there was no significant reduction in SBP of -1.15 mmHg, but a significant
reduction in DBP of -1.65 mmHg. Furthermore, Whelton recorded that both SBP and DBP (SBP
-5.95 mmHg; DBP -4.20 mmHg) were significantly reduced in hypertensive patients. It has also
been seen that cereal fiber intake reduced the risk of peripheral artery disease (PAD) in men
(Merchant, 2003). However, there has been research that has recorded no significant effect on
blood pressure with dietary fiber. In a study conducted by He et al. (2004), with 110 patients,
found that there were no significant reductions in both SBP and DPB after after a six-week fiber
intervention. The effects of dietary fiber still seem to be questionable since there have been
recordings of both significant and non-significant effects towards blood pressure. It has been
seen to reduce blood pressure within hypertensive adults but not for young healthy individuals.
A negative correlation was seen with iron intake and SBP. There is a lack of research
performed on the potential effects that dietary iron has on protecting and controlling blood
pressure levels. It has been recorded by Tzoulaki (2008), within a large sample size of 4,680
adults, that both dietary total iron and non-haem, iron found only in plant sources, were inversely
related with blood pressure.
Limitations
Some limitations that could be considered is the lack of variety in population sample.
Most of the participants included in this study were athletes within their in-season period of
sport. This could be a reason why some data seemed to be skewed and showed undesirable data.
Along with sports dominating the sample, a self-reported three-day diet analysis can only show
limited accurate values in an individual’s diet.
Conclusion
In conclusion, examining more population based diets especially younger adults can
provide substantial information in the dietary habits and trends that may lead to causes increased
risk of specific cardiovascular markers. Unfortunately, no significant findings were recorded for
vitamin D and A; however, there was significant correlations that were recorded with a direct
relationship with sodium and body composition along with an inverse relationship of dietary
fiber and iron with SBP. This calls for further research in diet analysis and/or prospective
randomized controlled trials of larger sample size. With this need for further investigation, it can
provide evidence to the proposed allocations.

References:
Bates CJ. Vitamin A. MRC Dunn Nutrition Centre. 345(8941): 31-35.
http://dx.doi:10.1016/S0140-6736(95)91157-X
Chobanian AV, Bakris GL, Black HR et al. The Seventh Report of the Joint National Committee
on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure: the JNC 7
report. JAMA 2003; 289(19): 2560-2572.
Gay HC, Rao SG, Vaccarino V, Ali MK. Effects of different dietary interventions on blood
pressure: Systematic review and meta-analysis of randomized controlled trials.
Hypertension 2016; 67: 733-739. doi: 10.1161/HYPERTENSIONAHA.115.06853
Geissler C, Signh M. Iron, meat, and health. Nutrients 2011; 3: 383-316. doi:
10.3390/nu3030283
Grooms KN, Ommerbown MJ, Pham DQ, Djousse L, Clark CR. (2013) Dietary fiber intake and
cardiometabolic risks among US adults, NHANES 1999-2010. American Journal of
Medicine 2013; 126(12). doi: 10.1016/j.amjmed.2013.07.023.
Hansen AL, Dahl L, Olson G, Thornton D, Graff IE, Frøyland L, Thayer JF, Pallesen S. Fish
consumption, sleep, daily functioning, and heart rate variability. Journal of Clinical Sleep
Medicine 2014;10(5):567-575. http://dx.doi.org/10.5664/jcsm.3714
He J, Streiffer RH, Muntner P, Krousel-Wood MA, Whelton PK. Effect of dietary fiber intake on
blood pressure: a randomized, double-blind, placebo controlled trial. Journal of
Hypertension 2004; 22(1):73-80.
Huang KE, Milliron BJ, Davis SA, Feldman SR. Surge in US outpatient vitamin D deficiency
diagnoses: National ambulatory medical care survey analysis. South Medical Journal
2014; 107(4): 214–217. doi:10.1097/SMJ.0000000000000085.
Judd SE, Raiser SN, Kumari M, Tangpricha V. 1,25-Dihydroxyvitamin D3 reduces systolic
blood pressure in hypertensive adults: A pilot feasible study. Steroid Biochemical
Molecular Biology 2010; 121(1-2): 445–447. doi:10.1016/j.jsbmb.2010.04.013
Lan J, Magno C, Lane K, Chan T, Hoyt D, Greenfield S. Nutrition impacts the prevalence of
peripheral arterial disease in the United States. The Journal of Vascular Surgery 2008;
897-904. doi:10.1016/j.jvs.2008.05.014
Lutsey PL, Michos ED. Vitamin D, calcium, atherosclerosis risk: Evidence from serum levels
and supplementation studies. Curr Atheroscler Rep 2013; 15(1): 293.
doi:10.1007/s11883-012-0293-5
Mann MC, Exner DV, Hemelgarn BR, et al. Vitamin D levels are associated with cardiac
autonomic activity in healthy humans. Nutrients 2013; 5, 2114-2127;
doi:10.3390/nu5062114
Merchant AT, Hu FB, Spiegelman D, Willet WC, Rimm EB, Acherio A. Dietary fiber reduces
peripheral arterial disease risk in men. The Journal of Nutrition 2003; 133: 2658-3663.
Mozos I, Marginean O. Links between Vitamin D Deficiency and Cardiovascular Diseases.
BioMed Research International 2015. doi.org/10.1155/2015/109275
Nastaskin RS, Fiocco AJ. A survey of diet self-efficacy and food intake in students with high and

low perceived stress. Nutrition Journal 2015; 14:42. doi: 10.1186/s12937-015-0026-z
Ponikowska B, Suchocki T, Paleczny B, Olesinska M, et al. Iron status and survival rate in
Diabetic patients with coronary artery disease. Diabetes Care 2013; 36:4147-4156. doi:
10.2337/dc13-0528
Reidlinger DP, Darzi J, Hall WL, et al. How effective are current dietary guidelines for
cardiovascular disease prevention in healthy middle-aged and older men and women? A
randomized controlled trial. American Journal of Clinical Nutrition 2015; 101:922–30.
Robinson JC, Graham BB, Rouault TC, Tuder RM. The crossroads of iron with hypoxia and
cellular metabolism: Implications in the pathobiology of pulmonary hypertension.
American Journal of Respiratory Cellular Molecular Biology 2014; 51(6): 721-729. doi:
10.1165/rmcb.2014-0021TR
Schweitzer AL, Ross JT, Klein CJ, Lei KY, Mackey ER. An electronic wellness program to
improve diet and exercise in college students: A pilot study. JMIR Research Protocols
2016; 5(1): e29. http://doi.org/10.2196/resprot.4855
Shim E, Ryu HJ, Hwang J, Kim SY, Chung EJ. Dietary sodium intake in young Korean adults
and its relationship with eating frequency and taste preference. Nutrition Research and
Practice 2013; 7(3): 192-198. http://dx.doi.org/10.4162/nrp.2013.7.3.192
Tzoulaki I, Brown IJ, Chan Q, Van Horn L, Ueshima H, et al. Relation of iron and red meat
intake to blood pressure: cross sectional epidemiological study. BMJ 2008; 337:a258.
doi:10.1136/bmj.a258
US Department of Health and Human Services and US Department of Agriculture. 2015-2020
Dietary Guidelines for Americans. 8th ed. Washington, DC: US Department of Health
and Human Services 2015; http://www.health.gov/DietaryGuidelines.
Vaidya A, Forman JP, Underwood PC, Hopkins PN, Williams GH, Pojoga LH, Williams JS. A
The influence of Body Mass Index and Renin-Angiotensin-Aldosterone system activity
on the relationship between 25-hydroxyvitamin D and adiponectin in Caucasian men. Eur
J Endocrinol 2011; 164(6): 995-1002. doi: 10.1530/EJE-11-0025
Van Ballegooijen AJ, Gansevoort RT et al. Plasma 1,25-Dihydroxyvitamin D and the Risk of
Developing Hypertension. Hypertension 2015; 66:563-570. doi:
10.1161/HYPERTENSIONAHA.115.05837
Whelton SP, Hyre AD, Pedersen B, Yi Y, Whelton PK, He J. Effect of dietary fiber intake on
blood pressure: a meta-analysis of randomized, controlled clinical trials. Journal of
Hypertension 2005; 23(3):475-81.
Weng S, Sprague JE, Oh J, Riek AE, Chin K, et al. Vitamin D deficiency induces high blood
pressure and accelerates atherosclerosis in mice. PLoS ONE 2013; 8(1): e54625. doi:
10.1371/journal.pone.0054625
Wengreen H, Munger RG, Cutler A, Quach A, Bowles A, Cocoran C, Tschanz JT, Norton MC,
Welsh-Bohmer KA. Prospective study of Dietary Approaches to Stop Hypertension – and
Mediterranean-style dietary patterns and age-related cognitive change: the Cache Country
Study on Memory, Health, and Aging. American Journal of Clinical Nutrition 2013;
98(5): 1263-1271. http://doi.org/10.3945/ajcn.112.051276

Table 1. Study Participant Characteristics
Data are represented as mean of ± SD. *SBP, systolic
blood pressure; DBP, diastolic blood pressure;
BMI, body mass index.

Table 2. Participant Diet Characteristics
Data are represented as mean of ± SD. *kCal,

kilocalories; Sat.Fat, saturated fats; Mono.Fat,
monounsaturated fat; Poly.Fat, polyunsaturated fat;
Trans.Fat, trans fatty acids.
Figure 1.
Correlation of sodium intake and Body Mass Index (BMI)
Figure 2.
Correlation of dietary fiber and systolic blood pressure.

Figure 3.
Correlation of iron and systolic blood pressure.

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