Journal of Gerontological Nursing

Feature Article 

Effects of Green Tea Ingestion on Postprandial Drops in Blood Pressure in Older Adults

Jung Tae Son, PhD, RN; Eunjoo Lee, PhD, RN

Abstract

The purpose of this study was to examine whether drinking green tea can prevent postprandial drops in blood pressure in older adults. Participants included 29 older adults who had experienced postprandial drops in systolic blood pressure of more than 15 mmHg in a previous study. During the experimental phase, each participant drank 400 mL of green tea before lunch; during the control phase, participants ate lunch without any tea. Blood pressure and heart rate were measured during both phases before lunch and at 15-minute intervals for 90 minutes after lunch. Drinking green tea before lunch elicited significant pressor effects by increasing systolic and diastolic blood pressure an average of 15.1 mmHg and 5.7 mmHg, respectively. It had no significant effect on heart rate. Drinking green tea before meals is recommended for older adults who experience postprandial hypotension; however, the appropriate volume and time of green tea ingestion to prevent a postprandial drop in blood pressure should be further studied.

Abstract

The purpose of this study was to examine whether drinking green tea can prevent postprandial drops in blood pressure in older adults. Participants included 29 older adults who had experienced postprandial drops in systolic blood pressure of more than 15 mmHg in a previous study. During the experimental phase, each participant drank 400 mL of green tea before lunch; during the control phase, participants ate lunch without any tea. Blood pressure and heart rate were measured during both phases before lunch and at 15-minute intervals for 90 minutes after lunch. Drinking green tea before lunch elicited significant pressor effects by increasing systolic and diastolic blood pressure an average of 15.1 mmHg and 5.7 mmHg, respectively. It had no significant effect on heart rate. Drinking green tea before meals is recommended for older adults who experience postprandial hypotension; however, the appropriate volume and time of green tea ingestion to prevent a postprandial drop in blood pressure should be further studied.

Dr. Son is Professor, College of Nursing, Catholic University of Daegu, and Dr. Lee is Professor, College of Nursing, Research Institute of Nursing Science, Kyungpook National University, Daegu, Korea.

The authors have disclosed no potential conflicts of interest, financial or otherwise. This work was supported by a Korean Research Foundation Grant (KRF-2007-531-E00090) from the Korean Government (MOEHRD).

Address correspondence to Eunjoo Lee, PhD, RN, Professor, College of Nursing, Research Institute of Nursing Science, Kyungpook National University, 101 Dong-in Dong Jung-gu, Daegu, Korea, 700-422; e-mail: jewelee@knu.ac.kr.

Received: April 17, 2011
Accepted: November 29, 2011
Posted Online: February 15, 2012

Falls are one of the most common problems among older adults and are frequently related to postprandial hypotension (PPH) (Le Couteur, Fisher, Davis, & McLean, 2003; Puisieux et al., 2000). The prevalence of PPH has been thoroughly addressed since the first report on this phenomenon (Seyer-Hansen, 1977), although recent studies on PPH are relatively sparse (Luciano, Brennan, & Rothberg, 2010). Older adults who experienced a reduction in blood pressure (BP) of at least 15 mmHg were shown to have an increased incidence of falls (Le Couteur et al., 2003) and syncope (Jansen, Connelly, Kelley-Gagnon, Parker, & Lipsitz, 1995; Kim & Noh, 2008; Puisieux et al., 2000), both of which cause a deterioration in quality of life. Other studies have reported that PPH is associated with new coronary disease, new strokes, and total mortality at long-term follow up (Aronow & Ahn, 1997; Fisher, Davis, Srikusalanukul, & Budge, 2005).

Postprandial Hypotension

PPH is defined as a reduction in systolic BP (SBP) by more than 20 mmHg within 2 hours after a meal (Jansen & Lipsitz, 1995). Among 162 older adults (mean age = 79.8, SD = 6.6 years) in Korea, 96% were found to experience a postprandial reduction in BP (Son & Lee, 2009), and in several studies, 26% to 36% of older adults had a SBP drop of more than 20 mmHg within 90 minutes after a meal (Son & Lee, 2009; Vaitkevicius, Esserwein, Maynard, O’Connor, & Fleg, 1991; Yu, Song, & Kim, 2002). Another study reported a 67.6% incidence of PPH (Grodzicki et al., 1998). The incidence of PPH was found to be even higher in individuals with hypertension (Le Couteur et al., 2003), particularly those taking antihypertensive medications (Luciano et al., 2010; Puisieux et al., 2000; Rakic, Burke, & Beilin, 1999).

However, the mechanisms causing PPH remain unclear. An older adult may have an impaired compensatory response to decreased blood flow in systemic circulation because of splanchnic blood pooling after a meal or the release of gastrointestinal hormones (Jansen & Hoefnagels, 1991). Although PPH develops frequently in older adults, it has not been shown to occur in healthy young individuals (Masuo, Mikami, Ogihara, & Tuck, 1996).

Regardless of the high incidence and serious consequences of PPH among older adults, geriatric assessments of drops in postprandial BP have not been commonly performed (Jansen, 2005), nor have effective nursing interventions been developed to prevent this condition. Thus, such interventions to prevent PPH in older adults are warranted. The nursing role in managing health problems in older adults has become larger and will increase even more due to the rapid increase in this population.

Review of Interventions

Various pharmacological and nonpharmacological interventions have been used to manage severe drops in BP after meals, with conflicting results (Jansen & Lipsitz, 1995). Some pharmacological agents—although they may be active for several hours—may take an hour or more to take effect (Jordan, Shannon, Grogan, Biaggioni, & Robertson, 1999). However, PPH has been reported to develop almost immediately after mealtime with the nadir in BP at 30 to 45 minutes after a meal. Approximately 15% of older adults were found to reach their lowest point within 15 minutes, 70% in 30 to 60 minutes, and the remaining 15% in 75 to 90 minutes (Jansen & Lipsitz, 1995; Son & Lee, 2009). This rapid drop in BP after mealtime requires an equally rapid countermeasure.

Some cross-sectional and randomized controlled studies have reported an association between coffee drinking and increased BP (Rakic et al., 1999), possibly due to caffeine. Caffeine may function to attenuate the magnitude of drops in BP, but in the long run, coffee drinking may aggravate hypertension (Rakic et al., 1999). Green tea also has caffeine, and so ingesting green tea before meals may be helpful for those prone to PPH. Green tea is one of the most frequently consumed beverages in Asia (Ji et al., 1997) and has a long history of use. In Korea, the beneficial effects of green tea have long been recognized. For example, consumption of tea may be associated with a reduction in heart disease (Antonello et al., 2007; Stangl, Lorenz, & Stangl, 2006; Yang, Lu, Wu, Wu, & Chang, 2004).

The purpose of this study was to examine the preventive effects of green tea drinking on postprandial drops in BP in older adults who are at risk for PPH. A secondary purpose was to examine any effects of green tea ingestion on heart rate (HR), because a raised HR could negate any beneficial effects on BP. The specific study questions were as follows:

  • Does green tea ingestion before meals prevent postprandial drops in SBP in older adults?
  • Does green tea ingestion before meals prevent postprandial drops in diastolic BP (DBP) in older adults?
  • Does green tea ingestion before meals change the postprandial HRs of older adults?

Method

Study Design

A within-subjects repeated measures (crossover) design was used to control the various extraneous differences that might occur between the control and experimental groups. Thus, all participants were part of the experimental and control groups at different times.

Participants

Approval was granted by the Institutional Review of C University Hospital in Daegu, Korea, and all participants gave their informed consent to participate in the study. The number of participants needed for sufficient power was calculated using the G*Power 3.1 program ( http://www.psycho.uni-duesseldorf.de/abteilungen/aap/gpower3). We used an alpha = 0.05, middle effect size, and power (1-β) = 0.80. Based on this power analysis, 28 participants were needed.

First we sent official letters to a community center and a nursing home located in the city of Daegu, asking them to participate in the study. After both sites gave their approval, we conducted BP screenings on the community center members and nursing home residents to determine which participants had PPH. Of 162 people screened, 72 (44.4%) had postprandial BP drops >15 mmHg within 90 minutes after a meal.

To ensure ethical and patient safety, only older adults with adequate physical and cognitive capacities to endure the study protocols were included. Included were individuals who (a) could independently manage their daily activities; (b) agreed to sit in a chair for 90 minutes after a meal; (c) had not been admitted to a hospital for any acute diseases for at least 1 month prior to the study; (d) had a score of 20 or greater on the Korean version of the Mini-Mental State Examination) (Kang, Na, & Han, 1997); and (e) were 65 or older. Exclusion criteria were set by the factors that influence cardiovascular response. Excluded were those who (a) were smoking or taking medications due to cardiovascular disease (except for antihypertensive agents); (b) had regular caffeine ingestion from other sources (coffee, cola, or chocolate); and (c) had renal diseases or urinary problems, as study participants were required to drink 400 mL of green tea. Of the 72 individuals with PPH, 46 volunteered to participate in the study. Fifteen older adults were excluded using the exclusion criteria (smoked [n = 5], drank coffee [n = 4], drank tea [n = 1], had renal disease [n = 2], had ischemic heart disease [n = 4], with 1 older adult overlapping in smoking and ischemic heart disease). Thus, a total of 31 participants were both eligible and agreed to participate in the study. Eligible participants received an explanation of the study design and requirements for study participation. Although the required minimum number of participants was 28, we decided to include all 31 participants considering the possibility of drop-outs during the study process. All participants were informed about their right to withdraw from the research at any time.

Preparation of Green Tea

Coffee is known to be beneficial in attenuating postprandial BP falls (Heseltine, el-Jabri, Ahmed, & Knox, 1991) but is not frequently consumed by older Korean people. Therefore, we chose one of the most popular green teas in Korea (Pungbuhan Mat®, made by the Pacific Green Tea Company of Korea) for the study and determined the amount of caffeine per bag. A tea bag with 1.2 g of pure leaves contained 15.8 mg of caffeine, according to high performance liquid chromatography, whereas one of the most popular brands of coffee (Nescafé Blend 43, made by Nestlé Australia Ltd.) contained 60 mg of caffeine per serving (Rakic et al., 1999). To make the tea similar in strength to coffee, we used three tea bags per serving, which equals the minimal amount of caffeine that has been shown to influence postprandial BP. The total caffeine content was 48 mg when we steeped three tea bags (3.6 g of green tea leaves) for 2 minutes with 400 mL of water heated to 70 °C. We provided the green tea at room temperature (20 to 26 °C) to make it easier for the participants to drink and also so the temperature of the tea would not have an independent influence on their BP (Kuipers, Jansen, Peeters, & Hoefnagels, 1991).

Data Collection

Five research assistants were recruited from a BSN program. They had completed the required theory and practicum courses and had gained sufficient experience measuring patients’ vital signs, especially older patients. All assistants were retrained in BP measurement technique to increase interrater reliability and were then tested on their accuracy in BP measurement. To test accuracy, we entered BPs and HRs into the Nursing Anne with Vital-Sim (Laerdal Medical, Norway) and then compared those numbers with the those the research assistants obtained in measuring the manikin’s vital signs. We continued to provide training to the research assistants until the numbers were within ±2 mmHg agreement.

Participants living in the community were asked to visit a room located in the College of Nursing to participate in the study. The room was specially prepared for the study and equipped with a dining table, chairs, and television to provide a comfortable environment. For the participants living in a nursing home, data were collected in the facility cafeteria. Room temperature in both places was set to 24 °C using air conditioners.

Participants refrained from ingestion of caffeine or alcohol during the study period (i.e., the day of the study, before measurement). Breakfast and daily medications were permitted as usual.

Data collection was performed during lunchtime. On the first day, each participant was randomly assigned to either the intervention or control group. After an interval of 2 days, each participant was assigned to the other group. Thus, participants served as their own controls, and the 2-day interval between measurements decreased any crossover effects. The research assistants were randomly assigned to the participants to measure BP and HR throughout the study period.

Participants were seated for 20 minutes to stabilize their physiological rhythms, which can be disrupted by movement. BP was measured by a mercury sphygmomanometer (Baumanometer® 0320NL, W.A. Baum Co., Copiague, NY) with adult cuff size (25 cm to 35 cm) at the left brachial artery, with the participant in a seated position. Before the meal, BP and HR were measured two separate times with a 2-minute interval. HR was measured at the radial artery for 60 seconds after the measurement of BP. Meals were arranged before the study in consultation with a dietician regarding calories and distribution of nutrients (carbohydrates, protein, and fat). The meal was mainly composed of rice with vegetable soup and three side dishes, which is a very common Korean meal. Each participant was provided the same amount of rice and soup for the 2 days of study participation, and the temperature of the meals was approximately 37 °C.

Participants ate the meal over a 15-minute period. This was found to be an average duration for mealtime in another study conducted in Korea (Yu et al., 2002). Immediately after participants finished eating, BP and HR were measured and then repeatedly measured at 15-minute intervals over a 90-minute period for a total of seven postprandial measurements. During the BP and HR measurements, participants were asked to remain seated in a chair for 90 minutes.

Both the intervention and control group participants were seated for 20 minutes before the baseline measurements of BP and HR. After these measurements were taken, participants in the intervention group were provided with 400 mL of green tea at room temperature. They drank this over the next 10 minutes and then ate their meals. The total number of participants who drank 400 mL of green tea and ate almost every meal provided was 29. Two participants who could not completely finish their green tea were excluded.

Data Analysis

All statistical analyses were performed using SPSS version 18. Descriptive statistics were generated. To test the homogeneity of the baseline data between groups, an independent sample t test was performed. Repeated measure analysis of variance with time (baseline, immediately after, and six more times at 15-minute intervals) and intervention as within-subject factors was used to differentiate main, interaction, and time effects between groups. In the case of a significant time effect, a paired t test was performed comparing the baseline measurement with each subsequent time point using a Bonferroni adjustment. An independent t test was used to test the difference in BP and HR between groups. P values less than 0.05 were considered statistically significant.

Results

Participant Characteristics

Approximately 60% (n = 17) of the participants were living in a community setting, and the remaining 40% (n = 12) lived in a nursing home; 93.1% (n = 27) were women. Mean age was 82.1 (SD = 6.9 years), and 56% (n = 12) were ages 75 to 84. Mean height was 147.3 cm (SD = 7.5 cm), mean weight was 53 kg (SD = 9.1 kg), and mean amount of rice and soup ingested was 162.6 g (SD = 23.5 g) and 173.7 mL (SD = 49.7 mL), respectively. The most frequent illness was hypertension (51.7%), followed by musculoskeletal disorders (34.5%). More than half of the participants (51.7%) were taking antihypertensive medications, and 20.7% were taking oral hypoglycemic agents (Table 1).

Participant Characteristics (N = 29)

Table 1: Participant Characteristics (N = 29)

Effects of Green Tea on Systolic Blood Pressure

The intervention (F = 28.47, p < 0.001), time elapsed since eating (F = 10.46, p < 0.001), and the time × intervention interaction (F = 10.61, p < 0.001) all had significant effects on SBP. For the control group, SBP was significantly lower at 15, 30, 45, 60, 75, and 90 minutes than at baseline, but no significant changes in SBP were noted in the experimental group during the 90 minutes after the meal.

Additionally, significant differences in SBP were noted between the groups at the following time periods: 30 (t = 2.810, p = 0.007), 45 (t = 4.701, p < 0.001), 60 (t = 3.572, p = 0.007), and 75 (t = 2.975, p = 0.004) minutes after the meal. The largest difference in SBP was observed at 45 minutes after eating, with a difference of 15.1 mmHg (SD = 8.7) between groups (Table 2, Figure).

Effect of Drinking Green Tea Before Mealtime on SBP, DBP, And HR

Table 2: Effect of Drinking Green Tea Before Mealtime on SBP, DBP, And HR

Change of systolic blood pressure (SBP) (top), diastolic blood pressure (DBP) (middle), and heart rate (HR) (bottom) between the meal-only group and the drinking green tea with meal group. Data are given as mean ± standard error.Note. BPM = beats per minute.

Figure. Change of systolic blood pressure (SBP) (top), diastolic blood pressure (DBP) (middle), and heart rate (HR) (bottom) between the meal-only group and the drinking green tea with meal group. Data are given as mean ± standard error.Note. BPM = beats per minute.

Effects of Green Tea on Diastolic Blood Pressure

Significant intervention (F = 1.60, p = 0.211), time elapsed since eating (F = 5.85, p < 0.001), and time × intervention interaction (F = 2.69, p = 0.026) effects were also noted for DBP. At 15, 30, 45, 60, 75, and 90 minutes, DBP was significantly lower than at baseline in the control group, but no significant changes were noted in DBP in the experimental group during the 90 minutes following the meal compared with baseline (Table 2, Figure).

Effects of Green Tea on Heart Rate

Length of time after a meal was the only significant effect on HR (F = 5.52, p = 0.001); no intervention or interaction effects were noted. For both groups, HRs were significantly higher immediately after the meal than at baseline, but no significant changes in HR were noted in either group during the 90 minutes after the meal (Table 2, Figure).

Discussion

Since PPH was first reported in older adults, various studies have emphasized its risk because of its prevalence and because it can exacerbate symptoms such as frequent falls, syncope, dizziness, and cardiac or cerebral ischemia. As Jansen and Lipsitz (1995) pointed out, little research has focused on interventions to prevent the development of PPH in older adults. No standardized, clinically meaningful intervention has been developed until now.

Research on the effects of caffeine on PPH has been inconsistent. Traditionally, it has been thought that caffeine induces a pressor effect without causing serious complications and thus could be used to counteract hypotension. Lipsitz, Jansen, Connelly, Kelley-Gagnon, and Parker (1994) reported that a 250-mg caffeine capsule reduced splanchnic blood pooling and therefore could be effective in preventing the development of PPH since caffeine inhibits vasodilatory adenosine receptors in splanchnic circulation. Similarly, Lenders, Morre, Smits, and Thien (1988) reported that oral ingestion of 250 mg of caffeine 60 minutes before breakfast increased preprandial BP, prevented the postprandial BP from dropping below its baseline value, and maintained plasma adrenaline levels. However, Lenders et al. (1988) identified that oral caffeine given with a meal did not reduce splanchnic blood pooling nor did it alter the drop in postprandial BP in older adults. They concluded that oral caffeine alone may have an insufficient pressor effect to prevent drops in postprandial BP.

Green tea, of course, is a source of caffeine. It may have a beneficial effect in limiting drops in BP after meals. However, the efficacy of this simple, safe, and almost cost-free intervention in the management of PPH has not been demonstrated sufficiently until now, and it is why we examined the effects of drinking green tea on postprandial drops in BP.

In this study, participants who ate a meal with no green tea experienced a statistically significant postprandial SBP drop of a maximum of 16.7 mmHg. Among the seven, 15-minute interval BP measurements from immediately after the meal to 90 minutes postmeal, six measurements showed significantly lower average SBP and DBP than the preprandial measurements. However, for the participants who drank 400 mL of green tea before a meal, no significant drop occurred in SBP and DBP in any of the postprandial measurements. The degree of postprandial BP drop in SBP/DBP in the meal-only group averaged 14.2 (SD = 10.8) and 5.7 (SD = 5.1) mmHg, respectively, while those in the green tea group averaged 0.1 (SD = 8.6) and 1.3 (SD = 5.4) mmHg, respectively. Thus drinking green tea before a meal was effective in preventing drops in postprandial BP in older adults at high risk for PPH.

Similar to the current study, another study found that drinking 400 mL of green tea (180 mg caffeine) before a meal was shown to increase BP at 30 minutes after drinking the green tea and to maintain this increased BP beyond 60 minutes (Hodgson, Puddey, Burke, Beilin, & Jordan, 1999). When the researchers compared the effects of coffee and green tea in preventing drops in postprandial BP, green tea had a greater effect than coffee. They concluded that the effect may be induced by the other components of green tea such as theobromine or theanine rather than caffeine, although they could not demonstrate this in their research. Other studies have also reported that the effects of green tea on BP are induced by other green tea components, such as polyphenols, organic acids, lipids, or other related compounds, but those studies did not indicate which of these components had the greatest effect (Ballentine, Wiseman, & Bouwens, 1997; Yokogoshi et al., 1995).

Green tea drinking has long been postulated to lower BP (Hu, 1986; Yang et al., 2004), although little scientific evidence exists. However, several studies have reported on the relation between green tea and BP. Yang et al. (2004) reported that habitual drinking of moderate-strength green tea significantly reduced the risk of developing hypertension. Hodgson, Burke, and Puddey (2005) reported that one of the long-term effects of drinking green tea would likely be to inhibit development of high BP at later ages. Also, Japanese researchers have consistently noted that green tea exhibits a substantial hypotensive effect. Studies performed in rats have suggested that green tea extracts can lower BP (Hara, 2001; Yokozawa, Oura, Sakanaka, Ishigaki, & Kim, 1994) in the long run. Ikeda et al. (2007) found that in addition to the hypotensive effect of green tea, the catechins it contains possess potent antioxidative properties, protect against various oxidative diseases, and may reduce cardiovascular disease.

We can speculate that both the green tea itself and the water in green tea may have effects. The water in tea will boost its pressor effects. Jones et al. (2005) investigated the volume of water needed to increase BP for orthostatic patients. They found that 600 mL of water was effective in increasing SBP. Since water drinking elicits a rapid pressor response in autonomic failure, it can be effective for the treatment for PPH. Similar to Jones et al. (2005), Son and Lee (2010) reported that drinking 400 mL of water before a meal increased SBP and DBP compared with a control group who did not drink any water. However, there was a significant drop in SBP 30 minutes after the meal for the experimental group. The result of the current study showed that drinking green tea maintained SBP until 90 minutes after the meal.

Lipsitz, Nyquist, Wei, and Rowe (1983) reported that reduced pressor-receptor function affected sympathetic function activity in older adults. They also reported that meal-related syncope in older patients was associated with a failure to maintain compensatory norepinephrine levels and cardio-acceleratory responses. The response to secreted catecholamine and the compensatory response to the decreased blood flow in the systemic circulation were impaired in older adults. Hoeldtke and Carebello (1987) also indicated that the rate of postprandial increase in catecholamines in older adults was insignificant.

Older adults may have dramatic drops in BP after a meal; however, one study found that the majority of participants showed no specific symptoms (Jansen, 2005). Nurses should be aware of PPH when caring for older adults who are at risk for falls and syncope to help them avoid meal-related falls and cardiovascular events. BP screening and monitoring are also important in preventing adverse events. However, as the nadir in BP has been reported to occur between 15 to 75 minutes after a meal (Aronow & Ahn, 1994), measuring BP immediately after a meal does not always catch the lowest point (Kohara et al., 1998). Nurses need to develop guidelines for the management of PPH, including how often and when to measure BP after meals. More studies are needed to identify the most appropriate time for green tea ingestion and amount of water to drink, as well as factors resulting in PPH in older adults.

We also suggest further studies regarding how BP can be influenced by returning to normal activities or exercise immediately after a meal. Oberman, Harada, Gagnon, Kiely, and Lipsitz (1999) reported that postprandial walking was an effective intervention to prevent PPH. However, Jansen (2005) concluded that returning to normal activities after a meal may increase the incidence of falls and therefore was not recommended. Lilley (1997) also recommended that older adults who are at risk of PPH lie down after a meal or avoid prolonged standing or bathing to prevent unexpected postprandial falls. Therefore, we suggest that drinking green tea, as shown in this study, may enhance the self-care ability of older adults and could be an effective intervention for individuals who are at risk for drops in postprandial BP.

Conclusion

PPH is a detrimental geriatric condition that not only results in falls, syncope, stroke, and dizziness but can also be a precursor to hip fracture and immobility in older adults. PPH occurs almost immediately after a meal and commonly reaches a nadir 30 to 75 minutes after a meal. To prevent complications from drops in postprandial BP, nurses should be aware of PPH and carefully monitor older adults’ BP after meals. This study identified that drinking green tea before a meal could be an effective intervention for individuals at risk for drops in postprandial BP. Further studies are needed to identify the appropriate amount of water and caffeine content of the green tea. Additional research should focus on development of guidelines for the management of PPH, including how often and when to measure postprandial BP in older adults.

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Participant Characteristics (N = 29)

Characteristic n(%) Mean (SD)
Place of residence
  Community 17 (58.6)
  Nursing home 12 (41.4)
Sex
  Women 27 (93.1)
  Men 2 (6.9)
Age 82.1 (6.9)
  65 to 74 5 (17.2)
  75 to 84 12 (41.4)
  ⩾85 12 (41.4)
Height (cm) 147.3 (7.5)
  ⩽139 2 (6.9)
  140 to 149 18 (62.1)
  150 to 159 7 (24.1)
  160 to 169 2 (6.9)
Weight (kg) 53.0 (9.1)
  40 to 49 12 (41.4)
  50 to 59 10 (34.5)
  60 to 69 4 (13.8)
  70 to 79 3 (10.3)
Amount of meal eaten
  Rice (g) 162.6 (23.5)
  Soup (mL) 173.7 (49.7)
Illnessa
  Hypertension 14 (48.3)
  Musculoskeletal disorders 10 (34.5)
  Digestive disorders 6 (20.7)
  Endocrine disorders 5 (17.2)
  Nervous disorders 3 (10.3)
  Other 1 (3.4)
Medicationa
  Antihypertensive agents 14 (48.3)
  Musculoskeletal: Analgesic agents 10 (34.5)
  Oral hypoglycemic agents 6 (20.7)
  Digestive: Antacid or prokinetics agents 5 (17.2)

Effect of Drinking Green Tea Before Mealtime on SBP, DBP, And HR

Minutes After Meal
Baseline 0 15 30 45 60 75 90
Variable Intervention Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Mean (SD) Source F pValue
SBP (mmHg) Meal only 133.8 (12.5) 130.4 (17.8) 127.3** (14.6) 121.9*** (15.1) 119.9*** (12.4) 119.6*** (13.2) 121.2*** (13.7) 126.1*** (13.4) Int Time Int × Time 28.47 10.46 10.61 <0.001 <0.001 <0.001
Green tea + meal 131.8 (14.3) 134.9 (12.2) 133.7 (15.6) 132.7 (14.0) 135.0 (12.1) 132.2 (13.6) 131.7 (13.3) 132.4 (14.8)
t testa 2.810 4.701 3.572 2.975
p Value 0.007 <0.001 0.007 0.004
DBP (mmHg) Meal only 71.8 (9.4) 69.3 (9.8) 67.9* (9.4) 66.4*** (9.5) 66.1*** (9.5) 66.8*** (9.0) 66.1*** (8.8) 66.7** (8.6) Int Time Int × Time 1.60 5.85 2.69 0.211 <0.001 0.026
Green tea + meal 70.6 (7.3) 72.0 (9.06) 70.1 (7.6) 70.1 (8.7) 69.6 (7.3) 69.2 (8.8) 69.6 (8.6) 71.0 (9.1)
HR (BPM) Meal only 73.3 (12.5) 77.8* (14.6) 76.4 (14.7) 74.8 (14.4) 75.2 (13.8) 74.5 (14.3) 74.4 (14.9) 74.1 (14.3) Int Time Int × Time 0.06 5.52 0.49 0.815 0.001 0.756
Green tea + meal 73.1 (12.9) 76.7* (13.5) 75.6 (13.5) 75.8 (13.4) 74.2 (12.5) 74.6 (12.5) 74.4 (12.5) 73.9 (13.1)

Keypoints

Son, J.T. & Lee, E. (2012). Effects of Green Tea Ingestion on Postprandial Drops in Blood Pressure in Older Adults. Journal of Gerontological Nursing, 38(3), 30–39.

  1. Older adults may have dramatic drops in blood pressure (BP) after a meal, increasing the risk for falls and syncope.

  2. BP screening and monitoring after a meal are important in preventing adverse events such as meal-related falls and cardiovascular events.

  3. Drinking green tea before a meal could be an effective intervention for individuals who are at risk for drops in postprandial BP.

Authors

Dr. Son is Professor, College of Nursing, Catholic University of Daegu, and Dr. Lee is Professor, College of Nursing, Research Institute of Nursing Science, Kyungpook National University, Daegu, Korea.

The authors have disclosed no potential conflicts of interest, financial or otherwise. This work was supported by a Korean Research Foundation Grant (KRF-2007-531-E00090) from the Korean Government (MOEHRD).

Address correspondence to Eunjoo Lee, PhD, RN, Professor, College of Nursing, Research Institute of Nursing Science, Kyungpook National University, 101 Dong-in Dong Jung-gu, Daegu, Korea, 700-422; e-mail: .jewelee@knu.ac.kr

10.3928/00989134-20120207-01

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