Taurine in health and diseases: consistent evidence from experimental and epidemiological studies

Abstract

Taurine (T) was first noted as beneficial for stroke and cardiovascular diseases (CVD) prevention in genetic rat models, stroke-prone spontaneously hypertensive rats (SHRSP). The preventive mechanisms of T were ascribed to sympathetic modulation for reducing blood pressure (BP) and anti-inflammatory action. Recent epidemiological surveys revealed the involvement of inflammatory mediators in the pathogenesis of stroke and also atherosclerosis for which T was proven to be effective experimentally. Arterio-lipidosis prone rats, a substrain of SHRSP selectively bred for higher reactive hypercholesterolemia, quickly develop not only arterial fat deposition but also fatty liver which could be attenuated by dietary T supplementation. CARDIAC (CVD and Alimentary Comparison) Study was a WHO-coordinated multi-center epidemiological survey on diets and CVD risks and mortalities in 61 populations. Twenty-four-hour urinary (24U) T was inversely related significantly with coronary heart disease mortality. Higher 24U-T excreters had significantly lower body mass index, systolic and diastolic BP, total cholesterol (T-Cho), and atherogenic index (AI: T-Cho/high density lipoprotein-cholesterol) than lower T excreters. T effects on CVD risks were intensified in individuals whose 24U-T and -magnesium (M) excretions were higher. Furthermore, higher Na excreters with higher heart rate whose BP were significantly higher than those with lower heart rate were divided into two groups by the mean of 24U-T, high and low T excreters. Since the former showed significantly lower BP than the latter, T may beneficially affect salt-sensitive BP rise. Included among the typical 61 populations, were Guiyang, China or St. John's, Newfoundland, Canada where in which the means of both 24U-T and -M were high or low, respectively. The former and the latter had low and high CVD risks, respectively. Australian Aboriginals living at the coastal area in Victoria were supposed to eat T- and M-rich bush and sea foods and be free from CVD 200 years ago, but they presently have nearly the highest CVD risks indicating that T- and/or M-containing seafood, vegetables, fruits, nuts, milk, etc, similar to prehistoric hunters' and gatherers' food should be good for CVD prevention. The preventive effects of T, good for health and longevity, first noted experimentally, were also proven epidemiologically in humans.

Figure 1

Histopathological hallmarks of ALR fed a high fat and high cholesterol diet. Ten-week-old ALR were fed a high fat and high cholesterol diet for 8 weeks. (A, B) Fat deposition in the mesenteric artery of ALR was detected by Oil red O staining and observed under low- and high-power fields. (C, D) Liver fibrosis of ALR was detected by Azan staining and observed under low- and high-power fields.

Figure 2

CARDIAC Study results of structural equation modeling of coronary heart diseases (CHD). Hypothetical pathway of 5 diet-related factors in relation to CHD. T-Cho: total cholesterol, BMI: body mass index (body weight (kg)/height (m)²), Na/Cr: 24-hour urinary (24U) sodium (Na, g) to creatinine (Cr, g) ratio, M/Cr = 24U-magnesium (M, mg) to Cr ratio, T/Cr = 24U-taurine (T, mmol) to Cr ratio. Significant difference: *p < 0.05, **p < 0.01, ***p < 0.001.

Figure 3

Cardiovascular risks in higher taurine-magnesium (T-M) excreters and lower T-M excreters. T/Cr = 24-hour urinary (24U) taurine (T, mmol) to creatinine (Cr, g) ratio, M/Cr = 24U-magnesium (M, mg) to Cr ratio. T/Cr: + ≧ mean (= 639.4), - < mean, M/Cr: + ≧ mean (= 82.8), - < mean. BMI: body mass index (body weight (kg)/height (m)²), SBP: systolic blood pressure, DBP: diastolic blood pressure, T-Cho: total cholesterol, AI: atherogenic index (T-Cho/high density lipoprotein cholesterol). Parenthesis indicates a number of participants. Significant difference: ***p < 0.001.

Figure 4

Cardiovascular disease risks in higher and lower taurine-magnesium excreters with greater or lesser sodium excretion. T/Cr = 24-hour urinary (24U) taurine (T, mmol) to creatinine (Cr, g) ratio, M/Cr = 24U-magnesium (M, mg) to Cr ratio, Na: 24U-sodium (Na as NaCl, g/day). T/Cr: + ≧ mean (= 639.4), - < mean, M/Cr: + ≧ mean (= 82.8), - < mean, Na: + ≧ mean (= 10.14), - < mean. BMI: body mass index (body weight (kg)/height (m)²), SBP: systolic blood pressure, DBP: diastolic blood pressure, T-Cho: total cholesterol, AI: atherogenic index (T-Cho/high density lipoprotein cholesterol). Parenthesis indicates a number of participants. Significant difference: ***p < 0.001.

Figure 5

Cardiovascular disease risks in higher taurine-magnesium-potassium (T-M-K) excreters and lower T-M-K excreters. T/Cr: 24-hour urinary (24U) taurine (T, mmol) to creatinine (Cr, g) ratio, M/Cr: 24U-magnesium (M, mg) to Cr ratio, K/Cr: 24U-potassium (K, milliequivalent) to Cr ratio. T/Cr: + ≧ mean (= 639.4), - < mean, M/Cr: + ≧ mean (= 82.8), - < mean, K/Cr: + ≧ mean (= 46.1), - < mean. BMI: body mass index (body weight (kg)/height (m)²), SBP: systolic blood pressure, DBP: diastolic blood pressure, T-Cho: Total Cholesterol, AI: Atherogenic index (Total cholesterol/HDL cholesterol). Parenthesis indicates a number of participants. Significant difference: *p < 0.05, ***p < 0.001.

Figure 6

Blood pressure in greater or lesser 24-hour urinary sodium. Na: 24-hour urinary (24U) sodium (Na as NaCl, g/day), Na: + ≧ mean (= 10.14), - < mean. SBP: systolic blood pressure, DBP: diastolic blood pressure. Parenthesis indicates a number of participants. Significant difference: **p < 0.01, ***p < 0.001.

Figure 7

Effect of taurine on blood pressure in male greater salt eaters with faster heart rate. Male greater salt eaters were defined as shown in Figure 6 and analyzed only in those whose heart rate (HR) were recorded. T/Cr: 24-hour urinary taurine (T, mmol) to creatinine (Cr, g) ratio. T/Cr: + ≧ mean (= 639.4), - < mean, HR: + ≧ mean (= 72.9), - < mean. SBP: systolic blood pressure, DBP: diastolic blood pressure. Parenthesis indicates a number of participants. Significant difference: *p < 0.05, **p < 0.01, ***p < 0.001.

Figure 8

Food culture, lifestyle and topographic background of Guiyang people in China.

Figure 9

Prevalence of risk of lifestyle-related diseases in populations excreting higher and lower taurine-magnesium. Obesity: BMI (body mass index, (kg)/height (m)²) ≧ 30, Hypertension: systolic blood pressure ≧ 140 mmHg and/or diastolic blood pressure ≧ 90 mmHg, Hypercholesterolemia: total cholesterol ≧ 220mg/dl. Significant difference: *p < 0.05, **p < 0.01, ***p < 0.001.

Figure 10

Prevalence of hypertension and hypercholesterolemia. Hypertension: systolic blood pressure ≧ 140 mmHg and/or diastolic blood pressure ≧ 90 mmHg, hypercholesterolemia: total cholesterol ≧ 220mg/dl.

Figure 11

Magnesium contents of typical dry food.

Figure 12

Taurine contents of typical food.