Relations between nutrient intake and serum lipid and apolipoprotein levels

Relations between nutrient intake and serum lipid and apolipoprotein levels Angel Gonzalez-Requejo, MD, M a r c i a n o Sanchez-Bayle, MD, Jose Baeza, MD, Pilar Arnaiz, MD, Santiago Vila, MD, Julia Asensio, MD, a n d Consuelo Ruiz-Jarabo, PhD From the Working Group of Cardiovascular Risk Factors in Childhood and Adolescence, Hospital "Nifio Jes0s," Madrid, Spain

Objective: To study the relation between diet and serum lipid and apolipoprotein levels in a large, homogeneous group of Spanish children. Design: Survey. Setting: Eleven schools chosen at random in Madrid City and the surrounding area. Subjects and methods: Subjects comprised 1682 children, 2 to 12 years of age. Dietary data were obtained with a 24-hour record performed by the child's main caregiver. For statistical analysis the sample was divided into tertiles on the basis of calorie-adjusted consumption of dietary components. Results: Children in the highest tertile of total fat consumption, compared with children in the lowest tertile, had significantly higher mean serum levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), apolipoprotein A-I (Apo A) and apolipoprotein B- 100 (Apo B). When compared with children in the lowest tertile, children in the highest tertile of saturated fat consumption had significantly higher mean levels of TC, LDL-C, and Apo B, and lower mean levels of HDL-C and Apo A. Children in the highest tertile of monounsaturated fat consumption, compared with children in the lowest fertile, had significantly higher mean levels of HDL-C and Apo A, and lower mean levels of TC, LDL-C, and Apo B. Conclusions: Our findings suggest that diet composition strongly influences lipid profile in children and point out the importance of monounsaturated fatty acids as modulators of serum lipid and apolipoprotein levels. (J PEDIATR1995; 127:53-7)

To reduce the incidence of adult coronary artery disease, the 1984 National Institutes of Health Consensus Conference, the American Heart Association (AHA), and the American Academy of Pediatrics have recommended that healthy children more than 2 years of age should adopt a diet with an average total fat intake of less than 30% of total calories, saturated fat intake of less than 10% of total calories, and dally dietary cholesterol intake of less than 300 mg. They also have issued statements recommending strategies for the Submitted for publication July 11, 1994; accepted Jan. 30, 1995. Reprint requests: Marciano Sanchez-Bayle, MD, Hospital "Nifio Jestis," Avda. Menendez Pelayo 65, 28009 Madrid, Spain. Copyright © 1995 by Mosby-Year Book, Inc. 0022-3476/95/$3.00 + 0 9/20/63772

detection and treatment of children with high cholesterol levels, in whom dietary restriction should be the first step. 1-3 Thus a considerable body of public health policy rests on the Apo A ApolipoproteinA-I Apo B ApolipoproteinB-100 HDL-C High-densitylipoprotein cholesterol LDL-C TC

Low-density lipoprotein cholesterol Total cholesterol

link between dietary fat intake and serum lipid levels in children. In adults, data from observational studies, 4 from dietary manipulation in controlled groups, 5, 6 and from clinical trials 7, 8 indicate that dietary fat intake, particularly saturated fat intake, influences total cholesterol and low-density lipo-

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Gonzalez-Requejo et al.

Table I. Sample distribution according to age and gender Gender

Age(¥O

2-5 6-9 10-12 TOTAL

Male

Female

Total

473 212 222 907

400 178 197 775

873 390 419 1682

protein cholesterol levels. In children, uniform and significant associations between nutrient intake and serum lipid levels have not been demonstrated within large groups: Nicklas et al. 9 found few significant correlations between dietary components and serum lipids; Glueck et al. 1° described some significant relations between diet and lipid levels, but the relations were limited to age and sex subgroups. Shea et al.n found that children with higher intakes of either total fat or saturated fat had significantly higher levels of TC and LDL-C, but the sample was small. In the past few years several intervention studies have shown that dietary modifications produce changes in blood lipid levels in children. 1214 The aim of this work was to study the relations between diet and values for serum lipids and apolipoproteins in a large, homogeneous group of Spanish children. METHODS Subjects and setting. As previously described, 14 from 1989 to 1992 the Nifio Jesds Group conducted an epidemiologic study of cardiovascular risk factors in childhood and adolescence in the city of Madrid and the surrounding area. The study design was approved by the ethics and scientific committee of the Hospital "Nifio Jesds"; 11 schools in this area were randomly selected with a random-number table. These schools hold a total of 3534 pupils from 2 to 18 years of age (many schools in Spain offer preschool courses for children 2 to 4 years of age). For the purpose of this study and to improve compliance in food records, we included only children from 2 to 12 years of age. All pupils from this age group (2271 subjects) were invited to participate. Parents received written information about the objectives and methods of the study and were asked to give consent, which was obtained in 1774 cases. Of these children, 92 were excluded because of unreliable or incomplete answers in questionnaires or food records. Thus 1682 children had complete data. Measures. The children' s diet was estimated by a 24-hour record: the child's main caregiver was asked to measure carefully, with scales and household measures, all foods and beverages consumed by the child on the day before blood samples were collected. On the study day a team of pedia-

tricians, nurses, and laboratory technicians went to the school. Weight was measured with a calibrated balance scale, and height was evaluated with a stadiometer. Body mass index was calculated as the weight (in kilograms) divided by the height (in meters) squared. Antecubital venous blood was taken after an overnight fast (10 hours) and tested for lipids and apolipoproteins within 2 hours. Foods were converted to nutrient intakes with U.S. Department of Agriculture sources of nutrient values. 15, 16 Laboratory procedures. Triglycerides and TC were measured by an enzymatic method with a commercial kit (Boehfinger Mannheim, Mannheim, Germany). 17, 18 The level of high-density lipoprotein cholesterol was determined in the supernatant obtained after precipitation of very low density lipoprotein cholesterol and LDL-C by phosphotungstic acid-magnesium chloride. 19 Level of LDL-C was calculated according to the formula of Friedewald et al. 2° Values for apolipoproteins A and B were determined, with the use of specific antibodies, by kinetic nephelometry in an Array protein system kit (Beckman Instruments Inc., Fullerton, Calif.). Statistical analysis. The study population was divided into tertiles on the basis Of calorie-adjusted consumption of total fat, saturated fat, monounsaturated fat, and carbohydrates. Differences in mean serum lipid levels among tertiles were evaluated by the Student t test. Data were processed in a PC-compatible Norgate AT286 computer system with the Statistical Package for the Social Sciences, a commercially available software program (SPSS Inc., Chicago, Ill.). 21 RESULTS Sample distribution according to age and sex is shown in Table I, Mean lipid and apolipoprotein levels for the entire sample were as follows: TC, 4.5 + 017 mmol/L (175.3 -+ 28 rng/dl); triglycerides, 0.4 + 0.2 mmol/L (32.6 -+ 16 mg/dl); LDL-C, 2.9 + 0.6 mmol/L (114 +-22 mg/dl); HI)L-C, 1.5 + 0.4 mmol/L (56.8 + 16 mg/dl); Apo A, 140.1 -+ 31 mg/dl; and Apo B, 64.2 -+ 26 mg/dl. Mean consumption of total fat accounted for 35.9% of total calories. Mean consumptions of saturated, monounsaturated, and polyunsaturated fat were 21.1%, 9.2%, and 5.6%, respectively. Protein and carbohydrate consumption accounted for 14% and 49.1% of the total caloric intake, respectively. The sample was divided into tertiles on the basis of calorie-adjusted consumption of several dietary components. In each case, no statistically significant differences in sex, age, and body mass index were found among tertiles. Lipid and apolipoprotein levels in the lowest, middle, and highest tertiles of total fat consumption are displayed in Table II. When compared with children in the lowest tertile of total fat consumption, children in the highest tertile had higher mean levels of TC, LDL-C, HDL-C, Apo A, and Apo B. Tables

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Gonzalez-Requejo et aL

55

Table II. Serum lipid and apolipoprotein levels by tertiles of calorie-adjusted total fat consumption per day Lipids, mmoI/L (mg/dl)

Apolipoproteins (mg/dl)

Tertile

Total fat intake (% of total kcai)

TC

LDL-C

HDL-C

Apo A

Apo B

Lowest Middle Highest

30.4 _+ 1.4 36.4 _+0.8 42.7 ± 2.1

4.4 _+0.4* (170 _+ 15) 4.6 -+ 0.6 (177 ± 24) 4.7 _+0.8 (183 _+32)

2.6 _+0.5* (100 _+20) 2.9 + 0.6 (111 + 24) 3.8 _+0.8 (145 _+ 30)

1.5 _+0.3? (58 -+ 12) 1.5 + 0.3 (58 --- 10) 1.6 + 0.3 (60 + 11)

138.9 ± 19~: 140.1 _+ 18 146.4 _+ 20

60.9 -+ 10:~ 62.4 -+ 12 68.3 -+ 14

Values expressed as mean + SD. Comparisons between highest and lowest tertile values are as follows: *p <0.001. tp <0.05. ~p <0.01.

Table Ill. Serum lipid and apolipoprotein levels by tertiles of saturated fat consumption per day Lipids, mmol/L (mgldl)

Apolipoproteins (mgldl)

Tertile

Saturated fat intake (% of total kcal)

TC

LDI.-C

HDL-C

Apo A

Apo B

Lowest Middle Highest

14.5 _+ 1.l 20.3 _+0.5 24.5 _+2

4.4 + 0.7* (170 _+28) 4.6 + 0.6 (176 + 22) 4.9 _+ 0.8 (188 ± 30)

2.7 _+0.4* (106 + 14) 2.9 _+0.5 (112 _+20) 3.6 _+0.7 (138 + 28)

1.5 -+ 0.4? (60 + 16) 1.5 -+ 0.3 (57 + 12) 1.4 -+ 0.3 (54 -+ 10)

139.6 _+25:) 133.4 _+20 130.6 _+ 18

60.1 ± 8:~ 63.2 _+ 12 65.3 _+ 18

Values expressed as mean + SD. Comparison between highest and lowest tertile values are as follows: *p <0.001. tp <0.05. :~p <0.01.

Table IV. Serum lipid and apolipoprotein levels by tertiles of monounsaturated fat consumption per day

Tertile

Monounsaturated fat intake (% of total kcal)

Lowest Middle Highest

8.5 + 1 9.4 + 1.7 11.3 _+ 2

~

Lipids, mmol/L (mg/dl)

Apolipoproteins (mg/dl)

TC

LDL-C

HDL-C

4.7 _+ 0.6* (183 _+24) 4.7 + 0.5 (180 -+ 20) 4.6 _+0.5 (178 _+ 19)

3.4 _+ 0.5* (131 _+ 18) 2.9 _+0.6 (112 _+23) 2.7 _+0.6 (103 _+ 25)

1.4 -+ 0.3? (53 -+ 12) 1.4 -+ 0.3 (54 + 10) 1.6 + 0.3 (61 + 12)

Ape A 136.3 _+24? 140.1 _+ 18 146.3 _+24

Apo B 64.2 _+ 14" 61.1 _+ 12 61 _+ 14

Values expressed as mean ± SD. Comparison between highest and lowest teilile values are as follows: *p <0.01. tp <0.001. III and IV show lipid and apolipoprotein levels for the lowest, middle, and highest tertiles of saturated and monounsaturated fat consumption. When compared with children in the lowest tertile, children in the highest tertile of saturated fat consumption had significantly higher mean levels of TC, LDL-C, and Apo B, and lower mean levels of HDL-C and Apo A. Children in the highest tertile of monounsaturated fat consumption had higher mean levels of HDL-C and Apo A, and lower mean levels of TC, LDL-C, and Apo B. As to carbohydrate intake, children in the highest tertile had lower levels of TC (4.4 vs 4.8 mmol/L [170 vs 186 mg/dl]; p <0.001), L D L - C (2.8 vs 3.1 mmol/L [107 vs 118 mg/di]; p <0.001), H D L - C (1.4 vs 1.5 mmol/L [55 vs 59 mg/dl]; p <0.001), Apo A (138 vs 144 mg/dl; p <0.01), and Apo B (62 vs 69 mg/dl; p <0.01). No significant relation between dietary protein intake and lipid levels was found.

W e also considered the children whose diets met the recommendations of the A H A (i.e., an intake of total fat -<30% of total calories and an intake of saturated fatty acids <10% of total calories). These children (154 subjects), when compared with those whose diet did not meet the A H A recommendations, had a better lipid profile, with lower levels of TC (4.2 vs 4.5 mmol/L [161 vs 175 m g / d l ] ; p <0.001), triglycerides (0.5 vs 0.6 mmol/L [45 vs 50 mg/dl]; p <0.001), L D L - C (2.5 vs 3.1 mmol/L [97 vs 121 mg/dl]; p <0.001) and Apo B (58 vs 63 mg/dl; p <0.001), and higher levels of HDL-C (1.6 vs 1.4 mmol/L [61 vs 53 mg/dl]; p <0.001) and Apo A (149 vs 139 mg/dl; p <0.01). DISCUSSION Food records have been shown to be an accurate method for diet assessment 22-25 and avoid the cost of an interviewer.

56

GonzaIez-Requejo et al.

The major disadvantage of a 24-hour record is the inability of a single day' s intake to represent the usual diet, but it does foster good compliance (poor compliance is one of the main problems of longer food records). We have found significant relations between diet composition and lipid levels. Shea et al. 11 found that children in the highest tercile for total and saturated fat consumption had higher mean levels of TC and LDL-C. However, no relations between unsaturated fat consumption and lipid levels, or between dietary fat intake and HDL-C, were found. Apolipoprotein determinations were not included. In our work a high consumption of total fat was associated with an increase in serum levels ofTC, LDL-C, HDL-C, Apo A, and Apo B. These data support the conclusion that a high consumption of fat increases levels of all cholesterol fractions. Children with higher intakes of saturated fat had higher levels of TC because of an elevation in the LDL fraction (the HDL fraction was significantly lower), whereas children with higher intakes of monounsaturated fat had lower mean levels of TC because of a lower LDL fraction (the HDL fraction was significantly higher). These data are in agreement with epidemiologic studies that point out the importance of monounsaturated fatty acids as modulators of serum lipid and lipoprotein levels. A high consumption of monounsaturated fat as a percentage of total fat intake has been found to be associated with lower levels of TC and LDL-C, and higher levels of LDL-C and Apo A. 2628 Children with higher intakes of carbohydrates have lower levels of all cholesterol fractions and apolipoproteins, probably because the increase in carbohydrate consumption is associated with lower total fat intake. Frank et al. 29 and Morrison et al. 3° also found that TC was negatively correlated with dietary carbohydrate. Mean levels of TC, LDL-C, and Apo B have been found to be very high among Spanish children: 12% have cholesterol levels greater than 5.2 mmol/L (>200 mg/dl), and more than 11% have LDL-C levels greater than 3.4 mmol/L (> 130 mg/dl). These findings are in agreement with the data of Plaza Perez et al.,31 who evaluated data from 21 epidemiologic studies of blood lipid levels in Spanish children and adolescents from 1980 to 1990. They found that levels of TC and LDL-C were higher than expected and that TC levels had been increasing throughout the decade. These authors suggested that modifications in lipid profiles could be due to changes in dietary patterns: the Spanish diet has evolved within the last two decades from a traditional Mediterranean diet to one characteristic of industrialized countries, rich in saturated fats. Children from our sample not only have a high intake of total fat (35% of total caloric intake) but an extremely high consumption of saturated fat, which accounts for 21% of the total caloric intake. Our data indicate that the

The Journal of Pediatrics July 1995

high levels of TC and LDL-C found in our study may be related to the composition of diet. Our findings strengthen existing data that support both the role of diet in determining lipid levels in children and the beneficial effect of monounsaturated fatty acids on the serum lipid profile. Long-term studies of a diet with no more than 10% of calories from saturated fat, with a judicious consumption of total fat and a high percentage of this fat as monounsaturated fatty acids, are needed to determine the effect on atherosclerosis in adult life. We are grateful to A. Aranguren, P. Cabello, C. Huertas, O. Lera, N. Roman, and M. A. Herrero, and to the nurses and laboratory technicians from the Hospital "Nifio Jestis," for their help in data collection and sample processing. REFERENCES

1. National Institutes of Health Consensus Development Conference statement: lowering blood cholesterol to prevent heart disease. JAMA 1985;253:2080-6. 2. Diagnosis and treatment of primary hyperlipidemia in childhood: a joint statement for physicians by the Committee on Atherosclerosis and Hypertension in Childhood of the Council of Cardiovascular Diseases in the Young and the Nutrition Committee, American Heart Association. Circulation 1986;74: 1181A-8A. 3. National Cholesterol Education Program Coordinating Committee. The report of the Expert Panel on Blood Cholesterol Levels in Children and Adolescents. Pediatrics 1992;89(suppl):525-84. 4. Sacks FM, Castelli WP, Dormer A, et al. Plasma lipids and 11poprotein in vegetarians and controls. N Engl J Med 1975; 292:1148-51. 5. NestelPJ, Havenstein N, White HM, et al. Lowering of plasma cholesterol and enhanced sterol excretion with the consumption of polyunsaturatedruminant fats. N Engl J Med 1973;228:37982. 6. Mensink R, Katan MB. Effect of a diet enriched with monounsaturated or polyunsaturated fatty acids on levels of low-density and high-density fipoproteincholesterol in healthy women and men. N Engt J Med 1989;321:436-41. 7. The Lipid Research Clinics Program. The Lipid Research Clinics Coronary Primary Prevention Trial Results. 1I. The relationship of reduction in incidence of coronary heart disease to cholesterol lowering. JAMA 1984;251:365-74. 8. Amtzenious AC, Kromhout D, Barth J, et al. Diet, lipoprotein and the progression of coronary atherosclerosis. N Engl J Med 1985;312:574-9. 9. Nicklas TA, Farris RP, Smoak CG. Dietary factors relate to cardiovascular risk factors in early life: Bogalusa Heart Study. Arteriosclerosis 1988;8:193-9. 10. Glueck CJ, Waldman G, McClish DK. Relationships of nutrient intake to lipid and lipoprotein in 1234 white children: The Lipid Research Clinics Prevalence Study. Arteriosclerosis 1982;2:523-36. 11. Shea S, Basch CE, Irigoyen M, et al. Relations of dietary fat consumption to serum total and low-density lipoprotein cholesterolin Hispanic preschool children.Prev Med 199I;20:23749. 12. Variarten E, Puska P, Pietinen P, et al. Effects of dietary fat

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23. Barret-Connor E. Nutrition epidemiology: how do we know what they ate? Am J Cfin Nutr 1991;54:182S-7S. 24. Bingham S, Wiggins HS, Englyst H, et al. Methods and validity of dietary assessments in four Scandinavian populations. Nutr Cancer 1982;4:23-33. 25. Pietinen P, Dougherthy R, Mutanem M, et al. Dietary intervention study among 30 free-living families in Finland. J Am Diet Assoc 1984;84:313-8. 26. Keys A, Menotti A, Carvonen MJ, et al. The diet and 15 year death rate in the Seven Countries Study. Am J Epidemiol 1986;124:903-5. 27. Mensink RP, Katan MD. Effect of dietary fatty acids on serum lipids and apolipoproteins: a meta-analysis of 27 trials. Arterioscl Thromb 1992;12:911-9. 28. Mata P, Garrido JA, Ordov~is JM, et al. Effects of dietary monounsaturated fatty acids on plasma lipoproteins and apolipoproteins in women. Am J Clin Nutr 1992;56:77-83. 29. Frank GC, Berenson GS, Webber LS, et al. Dietary studies and the relationship of diet to cardiovascular disease risk factor variables in ten year old children: The Bogalusa Heart Study. Am J Clin Nutr 1978;31:328-33. 30. Morrison JA, Larsen R, Glatfelter L, et al. Interrelationships between nutrient intake and plasma lipids and lipoprotein in schoolchildren aged 6 to 19: The Princeton School District Study. Pediatrics 1980;65:727-34. 31. Plaza Perez I and the Expert Group from the Spanish Societies of Atherosclerosis, Cardiology, Pediatrics, Nutrition and Preventive Medicine. Report on the blood cholesterol levels of Spanish children and adolescents. Rev Esp Cardiol 1991; 44:567-85.

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