Research Article

Fish Preparation as a Predictor of Cardiovascular Activity in African American Men and Women

Vernessa R. Clark*, Larry Keen, Jessica Brooks, Kimberly Boyd and Brittany Watkins

Department of Psychology, Virginia State University, USA

*Corresponding author: Vernessa R. Clark, Department of Psychology, Virginia State University, USA

Received Date: 05 Dec, 2019 ; Accepted Date: 02 Jan, 2020 ; Published Date: 08 Jan, 2020

Abstract

Objective: The purpose of this study was to determine the ability of fish preparation to predict to predict cardiovascular reactivity to stress in African American men and women.

Hypothesis: It was hypothesized that fish preparation would significantly predict cardiovascular reactivity to stress. Specifically, consumptions of fish prepared in a healthy manner (grilling and baking) would be associated with lower cardiovascular activity and consumption of fish prepared in an unhealthy manner (frying) would be associated with greater cardiovascular activity.

Methods: One hundred and thirty-one African-American students (30 men and 101 women) between the ages of 18 and 28 years participated in the study. Heart rate, cardiac output, stroke volume, mean arterial pressure and systolic and diastolic blood pressure were measured as the participants viewed a racially noxious scene on a digital video. Cardiovascular measurements were taken prior to the scene (pre-stressor period), during the scene (stressor period), and after the scene (recovery period).

Results: Multiple regression analyses revealed that fish preparation significantly predicted diastolic blood pressure and mean arterial pressure. These findings revealed that consumption of fish prepared in an unhealthy manner was associated with lower levels of cardiovascular activity in this African American college sample.

Keywords

Cardiac Output; Fish Preparation; Heart Rate; Stroke Volume; Systolic And Diastolic Blood Pressure; Mean Arterial Pressure

Introduction

In recent years, research on omega-3 fatty acids found in fish and their benefits of preventing cardiovascular disease have increased. For example, according to Nestel, consuming one to four servings of fish per week significantly prevented coronary heart disease in comparison to no fish intake [1]. Similar findings were reported by Orencia AJ, et al., who examined fish consumption and susceptibility to stroke in a sample of middle aged men and reported that men who ate the highest levels of fish had a higher age adjusted death rate from stroke compared to men who ate moderate to small amounts of fish [2]. Low quantities of omega-3 fatty acids, such as two to three servings per week or two fish oil capsules per day, have also been found to decrease the prevalence of unexpected deaths caused by irregular heartbeats, as well as reduce systolic blood pressure by 5 millimeter of mercury (mm Hg) [3,4]. Though fish consumption does increase omega-3 fatty acid intake, fish with high mercury levels have been shown to negatively affect health outcomes. The consumption of fish with high levels of mercury may result in mercury toxicity, which decreases the benefits of omega-3 fatty acids and increases blood pressure [5]. Nahab et al. examined mercury levels in deep fried fish (with and without breading) compared to raw fish [6]. They found that mercury levels were higher in fried fish. Mercury increased by 45% in breaded fried fish and by 75% in fish fried without breading. The investigators also reported that the median mercury levels from fried breaded and non-breaded fish were twice as high for African American men and women compared to White men and women. Omega-3 fatty acids in fish have been shown to have favorable effects on cardiovascular disease in Caucasians, but the effects on African Americans’ cardiac health is not as promising. For example, Nahab examined racial and geographic differences in fish consumption among African American and Caucasian men and women and found that although African Americans ate significantly more fish, they had significantly less omega 3 fatty acids than Caucasians [7]. The beneficial effects of omega-3 fatty acids may differ depending on the way the fish is prepared. Since many African Americans prepare their fish through frying, this method of cooking may decrease the beneficial effects of omega 3 fatty acids on health outcomes in this group [7,8]. The purpose of the present study was to examine the ability of fish preparation to predict cardiovascular reactivity to stress in African American men and women. It was hypothesized that fish preparation would significantly predict cardiovascular activity. Specifically, consumption of fish prepared in a healthy manner (grilling and baking) would be associated with lower cardiovascular activity and consumption of fish prepared in an unhealthy manner (frying) would be associated with greater cardiovascular activity.

Method

Study Design

The ability of fish preparation to predict cardiovascular activity was examined. The cross-sectional study protocol was approved by the University’s Intuitional Review Board. Upon completion of the study, participants were given course credit for their participation.

Subjects: One hundred and thirty-one African-American students (30 men and 101 women) between the ages of 18 and 28 years participated in the study. All students were screened for cardiovascular disorders and prescription medications that could interfere with the functioning of the cardiovascular system. Students under the age of 18, had cardiovascular disorders, and/or who were taking prescribed medications were not allowed to participate in the study. For fish preparation, 11 participants reported eating grilled fish, 14 participants reported eating baked fish, 39 participants reported eating fried fish and 71 reported eating fish that is fried and prepared other ways. The participants were citizens of the United States and were recruited from classes in the Psychology department. All procedures were in accordance with the ethical standards of the University Institutional Review Board. Informed consent was obtained from all participants included in the study.

Procedures

After the informed consent form was read and signed, cardiovascular activity was non-invasively measured as the participants viewed the 3-minute video recorded scene on digital versatile disc (DVD). Cardiovascular measures were taken prior to the scene (pre-stressor period), during the scene (stressor period), and while the participant recovered from the scene (recovery period). Each period lasted three minutes and measurements were taken 80 seconds into the period. The participants completed the seafood survey after all cardiovascular measures were obtained.

Measures

Cardiovascular Functioning: A Hypertension Diagnostics Pulse wave CR 2000 cardiovascular profiling instrument was used to non-invasively assess BMI and cardiovascular responses (heart rate, cardiac output, stroke volume, mean arterial pressure, systolic and diastolic blood pressure). The oscillometric method was used to determine the measures of blood pressure. In addition, cardiac ejection time measured from blood pressure waveforms were used to obtain measures of stroke volume and cardiac output. To provide a clearer picture of the participants’ overall physiological wellbeing, the cardiovascular measures were collapsed across the three periods.

Stressor: Cardiovascular activity was measured as the particpants viewed the racially noxious scene on DVD. The scene depicted the horrendous conditions that Africans experienced as they were transported to America for slavery.

Seafood Survey: A seafood survey was used to assess how the consumed fish was prepared (grilled, baked, canned, or fried).

Data Analysis

Multiple Regression analyses were conducted to examine the ability of fish preparation to predict cardiovascular reactivity to stress during each measurement period and cardiovascular activity collapsed across periods. In addition, Multiple Regression analyses were used to examine the ability of fish preparation to predict cardiovascular activity separately for men and women. Lastly, a Product- Moment correlation analysis was used to examine the relationship between fish preparation and cardiovascular reactivity to the stressor. The Statistical Package for the Social Sciences (IBM Corp., 2016) computer program was used to conduct all data analyses [9]. A 95% confidence interval level was used to determine significance of each statistical analysis. Means for all study variables are in Table 1.

Results

Fish Preparation and Cardiovascular Activity

It was hypothesized that fish preparation and fish would significantly predict cardiovascular activity. Specifically, healthy fish preparations (grilling and baking) would be associated with lower cardiovascular activity and unhealthy fish preparations (frying) would be associated with greater cardiovascular activity. Fish preparation significantly predicted mean arterial blood pressure during the pre-stressor period, Beta = -.275, t(1, 125) = 3.2, p = .002. It also significantly predicted diastolic blood pressure during the stressor period, Beta = -.265, t(1, 125) = 3.07, p = .003, and recovery period, Beta = -.231, t(1,122) = 2.62, p = .010. Lastly, fish preparation significantly predicted diastolic blood pressure collapsed across periods, Beta = -.223, t(1,127) = 2.58, p = .011, and mean arterial pressure collapsed across periods, Beta = -.211, t(1,126) = 2.42, p = .017. These findings indicate that contrary to the hypothesis, participants who prepared their fish in a healthy manner had higher blood pressures.

Fish reparation and Cardiovascular Activity by Sex

Separated by sex, fish preparation significantly predicted diastolic blood pressure during the pre-stressor period, Beta = -.206, t(1,96) = 2.07, p =.042, stressor period, Beta = -.302, t(1,94) = 3.08, p =.003, and recovery period Beta = -.319, t(1,92) = 3.23, p =.002 for women only. In addition, fish preparation significantly predicted mean arterial pressure during the pre-stressor period, Beta = -.302, t(1, 95) = 3.09, p = .003 for women. Lastly, fish preparation significantly predicted diastolic blood pressure, Beta = -.286, t(1, 96) = 2.9, p = .004 and mean arterial pressure, Beta = -230, t(1, 95) = 2.30, p = .023, collapsed across periods for women only. These findings indicate that women who prepared their fish in a healthy manner had higher blood pressures than those who prepared their fish using an unhealthy technique. Fish preparation did not predict any cardiovascular index for men.

The product-moment correlations revealed that similar to the regression analysis, diastolic blood pressure and mean arterial blood pressure were negatively correlated with unhealthy fish preparation indicating that lowers blood pressures were associated with unhealthy fish preparation (Table 2).

Discussion

Fish preparation significantly predicted diastolic blood pressure and mean arterial pressure. In contrast to the hypothesis, participants, particularly women, who consume fish using unhealthy preparations (fried fish) had lower blood pressures than those who ate grilled or baked fish. This relationship existed primarily in the women subsample. The decrease in heavy metals such as mercury, lead and cadmium in fish during frying may account for this finding. Research studies found that metal in fish has a negative effect on the functioning of the heart by negatively affecting the endocrine system which ultimately results in increases in blood pressure [10]. Ganbi found that frying fish decreased the amount of lead in fish by 20.7% compared to a decrease of 16.2% from roasting and 13.2% from broiling [11]. Ganbi also found that frying fish decreased cadmium in fish by 100% compared to 20.7% from broiling and 0% from roasting [11]. The association of unhealthy fish consumption and low blood pressures in the present study may be attributed to the eradication or reduction of the perilous effects of heavy metals on health from the frying technique. It is apparent that the effects of fish preparation on cardiovascular health are not clear, particularly for African American women. For example, Belin et al. found that in contrast to White women, baking or broiling fish did not reduce heart failure rates in African American women [12]. The surprising finding that unhealthy fish preparation was associated with lower levels of cardiovascular activity should be explored. An examination of the mechanisms underlying this relationship among fish preparation and cardiovascular disease in African American women is warranted.

Limitations of the Study

A major limitation of the study was the age of the participants (18-28). Since sex differences in cardiovascular functioning may be attributed to estrogen levels in women, future studies should examine women with various estrogen levels. In addition, since older men are more susceptible to cardiovascular disease than their younger counterparts, future research should examine the effects of fish consumption and fish preparation on cardiovascular activity in this group.

Acknowledgments and Compliance with Ethical Standards

Disclosure of potential conflicts of interest: There are no potential conflicts of interests.

Research involving Human Participants: This research project involved human participants and the University Human Institutional Review Board approved the study protocol.

Informed consent: All procedures were in accordance with the ethical standards of the responsible committee on human experimentation (institutional and national) and with the Helsinki Declaration of 1975, as revised in 2000. Informed consent was obtained from all participants included in the study.

Table 1: Means and standard deviations for all cardiovascular measures collapsed across periods.

 

 

 Overall Mean

Women

Men

Heart Rate, b/m (11.05)

70.75 (10.08)

71.75 (9.63)

67.09

Systolic blood pressure, mm H (11.11)

117.29 (10.87)

115.89 (10.48)

122.26

Diastolic blood pressure, mm Hg* (8.48)

 63.00 (8.45)

62.94 (8.50)

62.91

Mean arterial pressure, mm Hg* (9.08)

81.69 (9.00)

81.04 (8.92)

83.73

Cardiac output, L/mm (0.92)

 5.69 (0.94)

5.58 (0.93)

5.97

Stroke volume, mL (17.72)

79.69 (17.53)

 77.26 (17.06)

86.56

*Statistically significant at p < .05

 

Table 2: Significant correlations among fish preparation and cardiovascular indices.

 

All Study Participants

Pearson r

p

Mean Arterial Pressure Pre- Stressor Period

-0.275

0.002

Diastolic Blood Pressure Stress Period

-0.265

0.003

Diastolic Blood Pressure Recovery Period

-0.231

0.01

Diastolic Blood Pressure*

-0.223

0.011

Mean Arterial Pressure*

-0.211

0.017

Women

 

 

Diastolic Blood Pressure Pre-Stressor Period

-0.206

0.042

Diastolic Blood Pressure Stress Period

-0.302

0.003

Diastolic Blood Pressure Recovery Period

-0.319

0.002

Mean Arterial Pressure Pre-stressor Period

-0.302

0.003

Diastolic Blood Pressure*

-0.286

0.004

Mean Arterial Pressure*

-0.23

0.023

*Collapsed across periods.

 

Citation: Clark VR, Keen L, Brooks J, Boyd K, Watkins B (2019) Fish Preparation as a Predictor of Cardiovascular Activity in African American Men and Women. J Clin Nutr Food Chem 1: 001. JCNFC-001.000001