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The effect of dietary calcium on post prandial lipaemia
Nutrition Research, Vol. 14, No. 10, pp. 1601-1603, 1994 Copyright 9 1994 Elsevier Science Ltd Printed in the USA. All rights reserved 0271-5317/94 $6.00 + .00
Pergamon
0271-5317(94)E00080-8
THE EFFECT OF DIETARY CALCIUM ON POST PRANDIAL LIPAEMIA B. Marshall, MNut Diet and S. Samman*, PhD Human Nutrition Unit, Department of Biochemistry University of Sydney, NSW 2006, Australia
ABSTRACt To test the hypothesis that increasing the level of dietary calcium will reduce the absorption of fat at a constant dietary fat content, the effect of dietary calcium on post prandial lipaemia was determined. Nine healthy subjects, in the fasted state, were given test meals on two different occasions in which the calcium content was set at 288 or 1328 mg of elemental calcium. The subjects served as their own control. Blood samples were collected before the ingestion of the test meal and then hourly for 7 hours. No significant differences were found between the post prandial response to the low calcium (mean area under plasma triacylglycerol curve: 1.90 _+1.66 mM.hr) and the high calcium test meals (2.24 _+ 1.91). The results show that under physiological conditions, fat absorption is not affected by dietary calcium. Key words: dietary calcium, post prandial lipaemia, humans.
INTRODU(7I'ION Supplements of calcium, equivalent to 1-3 times the RDI, have been shown to reduce serum cholesterol (1-3) and triacylglycerol (TAG) concentrations (4). The effect is pronounced in hyperlipidaemic subjects (2-5) and when consuming a diet that is high in saturated fats (1,4). Less is known about the acute effects of dietary calcium on fat absorption. This may be particularly important as it has been hypothesized that atherogenesis is a post prandial phenomenon (6). The aim of this study was to determine the effect of dietary calcium on serum TAG concentrations following the ingestion of a test meal, with the hypothesis being that increasing the amount of dietary calcium will reduce the absorption of fat.
MATERIALS AND METHODS Nine healthy male volunteers, average age of 24 years (+ 4.5, SD) and BMI 22.5 kg/m 2 (+ 2.4), were recruited for this study; all were non-smokers. They were asked to maintain their usual dietary and exercise habits but to avoid the consumption of alcohol and to avoid strenuous exercise for 24 hours before the experimental period. The study protocol was approved by the University of Sydney Ethical Review Committee. * For all correspondence
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B. MARSHALL and S. SAMMAN
The test meal was designed to supply the amount of fat (0.8 g/kg body weight) that would be supplied by the main meal of the day. The ingredients were natural skim yoghurt, cream, peanut oil, artificial sweetener (Equal, 38 mg aspartamine, 956 mg lactose; Searle Consumer Products, Crows Nest, NSW) and vanilla essence (Queen Fine Foods, Aldedey, Qld) (7). The test meal had a P:S ratio of 0.4 and contained 288 mg elemental calcium (low calcium test meal). This was supplemented with 1000 mg of calcium (high calcium test meal) in the form of calcium citrate powder (Bioglan Laboratories, Marrickville, NSW). Calcium citrate was chosen as it is the most common form of calcium in milk (8).The subjects consumed 0.78 _+0.01 g and 0.80 ___0.01 g of fat/kg body weight for the low and high calcium test meals respectively. After a 12 hour fast, a capillary blood sample was collected from each individual, into tubes containing NaEDTA (lmg/ml). The test meal was given to the subjects, in a randomised single-blind manner. The meal was consumed within 15 minutes, between 8:00 and 8:30 AM. Within two weeks, the study was repeated in the same subjects but the test meal provided was altered. The order of test meals was randomised. During the study, the subjects were not allowed any food or drink other than sips of water or weak jasmine tea without milk or sugar, as described previously (7). Zero time was taken from when the subjects began consuming the test meal and blood samples were collected hourly for 7 hours. Serum TAG was analysed on the same experimental day using an automated enzymatic method (Uni Kit III Triglycerides PAP, Roche Diagnostica, Basel, Switzerland). The area under the plasma TAG curve (AUC) was determined by triangulation with the baseline taken at the fasting concentration.
RESULTS The subjects were apparently compliant with requests including fasting, avoidance of alcohol and strenuous exercise before the study periods, and remaining sedentary during the study periods. No significant differences were found between markers of post prandial lipaemia following the ingestion of the low or high calcium test meals (Table 1). Table 1. Post prandial triacylglycerol response to low calcium (288 mg) and high calcium (1328 mg) test meals4.
Fasting TAG concentration (raM) Peak TAG concentration (raM) Time to peak (hr) Area under curve (mM.hr)
Test Meals Low Calcium High Calcium 1.06 _+0.35 0.96 _+ 0.49 1.64 _+ 0.51 1.64 _+0.85 3.5 + 1.2 3.7 + 0.9 1.90 + 1.66 2.24 _+ 1.91
# Values expressed as means _+SD, n=9. The variation in fasting plasma TAG levels for individual subjects was small (9.4%) and no difference was found between the individual fasting levels on the two occasions. A positive correlation was found between the fasting and peak TAG concentrations (rE = +0.66, P < 0.05).
DISCUSSION Under physiological conditions, the post prandial lipaemic response is not affected by realistic amounts of dietary calcium. The lack of effect on plasma TAG in the short term is consistent with long term studies in healthy adults (5,9,10) and infants (11). Although supplementation with higher
CALCIUM AND POSTPRANDIAL LIPAEMIA
1603
levels of calcium in hyperlipidaemic subjects results in a reduction in plasma lipids (2,3,5), it is possible that higher levels of calcium may affect the post prandial response to the test meal, however such amounts are unlikely to be ingested under normal circumstances. The total calcium content of the high calcium test meal was 1328 rag, though this is greater than the RDI for calcium it is still within achievable levels by dietary means. The post prandial lipaemic response to the test meals varied in magnitude and pattern between subjects. On the basis of 7 time points post prandially, six subjects had a monophasic and three subjects a biphasic response. Within the same subjects, the pattern of response was similar on both occasions. Contrary to reports showing a positive correlation between fasting TAG concentration and AUC (7,12), such a relationship was not found in this study possibly due to the small post prandial response shown by several of the subjects. However, consistent with some reports (12,13), a positive correlation was found between fasting and peak TAG levels.
REFERENCES 1.
Bhattacharyya AK, Thera C, Anderson JT, Grande F and Keys A. Dietary calcium and fat. Effect on serum lipids and fecal excretion of cholesterol and its degradation products in man. Am J Clin Nutr 1969; 22:1161-74.
2.
Carlson LA, Olsson AG, Oro L and Rossner S. Effects of oral calcium upon serum cholesterol and triglycerides in patients with hyperlipidemia. Atherosclerosis 1971; 14:391-400.
3.
Bierenbaum ML, Fleischman AI and Raichelson RI. Long term human studies on the lipid effects of oral calcium. Lipids 1972; 7: 202-6.
4.
Yacowitz H, Fleischman AI and Bierenbaum ML. Effects of oral calcium upon serum lipids in man. Brit Med J 1965, 1: 1352-4.
.
Karanja N, Morris CD, Illingworth R and McCarron DA. Plasma lipids and hypertension: response to calcium supplementation. Am J Clin Nutr 1987; 45: 60-5.
6.
Zilversmit DB. Atherogenesis: A postprandial phenomenon. Circulation 1979; 60: 473-85.
7.
Brown AJ and Roberts DCK. Moderate fish oil intake improves lipemic response to a standard fat meal. A study in 25 healthy men. Arteriosclerosis and Thrombosis 1991; 11: 457-66.
8.
Scott R. Cheesemaking practice, 1st edn, London: Applied Science Publishers Limited, 1981:p60-61.
9.
Mitchell WD, Fyfe T and Smith DA. The effect of oral calcium on cholesterol metabolism. J Atheroscler Res 1968; 8: 913-22.
10.
Bierenbaum ML, Wolf E, Bisegeier G and Maginnis WP. Dietary calcium. A method of lowering blood pressure. Am J Hypertens 1988; 1: 149S-152S.
11.
DeVizia B, Fomon SJ, Nelson SE, Edwards BE and Ziegler EE. Effects of dietary calcium on metabolic balance of normal infants. Pediatr Res 1985; 19: 800-6.
12.
Nestel PJ. Relationship between plasma triglycerides and removal of chylomicrons. J Clin Invest 1964; 43: 943-49.
13.
Cohn JS, Lain CWK, Sullivan DR and Hensley WJ. Postprandial concentrations of potentially atherogenic triglyceride-rich lipoproteins in plasma are significantly correlated with fasting plasma triglyceride concentration. Clin Biochem Rev 1990; 11:116 (abstract).
Accepted for publication March 30, 1994.
Pergamon
0271-5317(94)E00080-8
THE EFFECT OF DIETARY CALCIUM ON POST PRANDIAL LIPAEMIA B. Marshall, MNut Diet and S. Samman*, PhD Human Nutrition Unit, Department of Biochemistry University of Sydney, NSW 2006, Australia
ABSTRACt To test the hypothesis that increasing the level of dietary calcium will reduce the absorption of fat at a constant dietary fat content, the effect of dietary calcium on post prandial lipaemia was determined. Nine healthy subjects, in the fasted state, were given test meals on two different occasions in which the calcium content was set at 288 or 1328 mg of elemental calcium. The subjects served as their own control. Blood samples were collected before the ingestion of the test meal and then hourly for 7 hours. No significant differences were found between the post prandial response to the low calcium (mean area under plasma triacylglycerol curve: 1.90 _+1.66 mM.hr) and the high calcium test meals (2.24 _+ 1.91). The results show that under physiological conditions, fat absorption is not affected by dietary calcium. Key words: dietary calcium, post prandial lipaemia, humans.
INTRODU(7I'ION Supplements of calcium, equivalent to 1-3 times the RDI, have been shown to reduce serum cholesterol (1-3) and triacylglycerol (TAG) concentrations (4). The effect is pronounced in hyperlipidaemic subjects (2-5) and when consuming a diet that is high in saturated fats (1,4). Less is known about the acute effects of dietary calcium on fat absorption. This may be particularly important as it has been hypothesized that atherogenesis is a post prandial phenomenon (6). The aim of this study was to determine the effect of dietary calcium on serum TAG concentrations following the ingestion of a test meal, with the hypothesis being that increasing the amount of dietary calcium will reduce the absorption of fat.
MATERIALS AND METHODS Nine healthy male volunteers, average age of 24 years (+ 4.5, SD) and BMI 22.5 kg/m 2 (+ 2.4), were recruited for this study; all were non-smokers. They were asked to maintain their usual dietary and exercise habits but to avoid the consumption of alcohol and to avoid strenuous exercise for 24 hours before the experimental period. The study protocol was approved by the University of Sydney Ethical Review Committee. * For all correspondence
1601
1602
B. MARSHALL and S. SAMMAN
The test meal was designed to supply the amount of fat (0.8 g/kg body weight) that would be supplied by the main meal of the day. The ingredients were natural skim yoghurt, cream, peanut oil, artificial sweetener (Equal, 38 mg aspartamine, 956 mg lactose; Searle Consumer Products, Crows Nest, NSW) and vanilla essence (Queen Fine Foods, Aldedey, Qld) (7). The test meal had a P:S ratio of 0.4 and contained 288 mg elemental calcium (low calcium test meal). This was supplemented with 1000 mg of calcium (high calcium test meal) in the form of calcium citrate powder (Bioglan Laboratories, Marrickville, NSW). Calcium citrate was chosen as it is the most common form of calcium in milk (8).The subjects consumed 0.78 _+0.01 g and 0.80 ___0.01 g of fat/kg body weight for the low and high calcium test meals respectively. After a 12 hour fast, a capillary blood sample was collected from each individual, into tubes containing NaEDTA (lmg/ml). The test meal was given to the subjects, in a randomised single-blind manner. The meal was consumed within 15 minutes, between 8:00 and 8:30 AM. Within two weeks, the study was repeated in the same subjects but the test meal provided was altered. The order of test meals was randomised. During the study, the subjects were not allowed any food or drink other than sips of water or weak jasmine tea without milk or sugar, as described previously (7). Zero time was taken from when the subjects began consuming the test meal and blood samples were collected hourly for 7 hours. Serum TAG was analysed on the same experimental day using an automated enzymatic method (Uni Kit III Triglycerides PAP, Roche Diagnostica, Basel, Switzerland). The area under the plasma TAG curve (AUC) was determined by triangulation with the baseline taken at the fasting concentration.
RESULTS The subjects were apparently compliant with requests including fasting, avoidance of alcohol and strenuous exercise before the study periods, and remaining sedentary during the study periods. No significant differences were found between markers of post prandial lipaemia following the ingestion of the low or high calcium test meals (Table 1). Table 1. Post prandial triacylglycerol response to low calcium (288 mg) and high calcium (1328 mg) test meals4.
Fasting TAG concentration (raM) Peak TAG concentration (raM) Time to peak (hr) Area under curve (mM.hr)
Test Meals Low Calcium High Calcium 1.06 _+0.35 0.96 _+ 0.49 1.64 _+ 0.51 1.64 _+0.85 3.5 + 1.2 3.7 + 0.9 1.90 + 1.66 2.24 _+ 1.91
# Values expressed as means _+SD, n=9. The variation in fasting plasma TAG levels for individual subjects was small (9.4%) and no difference was found between the individual fasting levels on the two occasions. A positive correlation was found between the fasting and peak TAG concentrations (rE = +0.66, P < 0.05).
DISCUSSION Under physiological conditions, the post prandial lipaemic response is not affected by realistic amounts of dietary calcium. The lack of effect on plasma TAG in the short term is consistent with long term studies in healthy adults (5,9,10) and infants (11). Although supplementation with higher
CALCIUM AND POSTPRANDIAL LIPAEMIA
1603
levels of calcium in hyperlipidaemic subjects results in a reduction in plasma lipids (2,3,5), it is possible that higher levels of calcium may affect the post prandial response to the test meal, however such amounts are unlikely to be ingested under normal circumstances. The total calcium content of the high calcium test meal was 1328 rag, though this is greater than the RDI for calcium it is still within achievable levels by dietary means. The post prandial lipaemic response to the test meals varied in magnitude and pattern between subjects. On the basis of 7 time points post prandially, six subjects had a monophasic and three subjects a biphasic response. Within the same subjects, the pattern of response was similar on both occasions. Contrary to reports showing a positive correlation between fasting TAG concentration and AUC (7,12), such a relationship was not found in this study possibly due to the small post prandial response shown by several of the subjects. However, consistent with some reports (12,13), a positive correlation was found between fasting and peak TAG levels.
REFERENCES 1.
Bhattacharyya AK, Thera C, Anderson JT, Grande F and Keys A. Dietary calcium and fat. Effect on serum lipids and fecal excretion of cholesterol and its degradation products in man. Am J Clin Nutr 1969; 22:1161-74.
2.
Carlson LA, Olsson AG, Oro L and Rossner S. Effects of oral calcium upon serum cholesterol and triglycerides in patients with hyperlipidemia. Atherosclerosis 1971; 14:391-400.
3.
Bierenbaum ML, Fleischman AI and Raichelson RI. Long term human studies on the lipid effects of oral calcium. Lipids 1972; 7: 202-6.
4.
Yacowitz H, Fleischman AI and Bierenbaum ML. Effects of oral calcium upon serum lipids in man. Brit Med J 1965, 1: 1352-4.
.
Karanja N, Morris CD, Illingworth R and McCarron DA. Plasma lipids and hypertension: response to calcium supplementation. Am J Clin Nutr 1987; 45: 60-5.
6.
Zilversmit DB. Atherogenesis: A postprandial phenomenon. Circulation 1979; 60: 473-85.
7.
Brown AJ and Roberts DCK. Moderate fish oil intake improves lipemic response to a standard fat meal. A study in 25 healthy men. Arteriosclerosis and Thrombosis 1991; 11: 457-66.
8.
Scott R. Cheesemaking practice, 1st edn, London: Applied Science Publishers Limited, 1981:p60-61.
9.
Mitchell WD, Fyfe T and Smith DA. The effect of oral calcium on cholesterol metabolism. J Atheroscler Res 1968; 8: 913-22.
10.
Bierenbaum ML, Wolf E, Bisegeier G and Maginnis WP. Dietary calcium. A method of lowering blood pressure. Am J Hypertens 1988; 1: 149S-152S.
11.
DeVizia B, Fomon SJ, Nelson SE, Edwards BE and Ziegler EE. Effects of dietary calcium on metabolic balance of normal infants. Pediatr Res 1985; 19: 800-6.
12.
Nestel PJ. Relationship between plasma triglycerides and removal of chylomicrons. J Clin Invest 1964; 43: 943-49.
13.
Cohn JS, Lain CWK, Sullivan DR and Hensley WJ. Postprandial concentrations of potentially atherogenic triglyceride-rich lipoproteins in plasma are significantly correlated with fasting plasma triglyceride concentration. Clin Biochem Rev 1990; 11:116 (abstract).
Accepted for publication March 30, 1994.