Fat content of the diet among preschool children in southwest Britain: II. relationship with growth, blood lipids, and iron status.

OBJECTIVE

In most countries, it is recommended that adults restrict fat intake to 30% to 35% of energy to reduce the risk of coronary heart disease and certain cancers. However, the appropriate level of fat in the diet of children is hotly debated. It has been generally accepted that fat intake by children under 2 years of age should not be limited because of fears that nutrient intakes and thus growth and iron status might be compromised. However, there is very little longitudinal information on the relationship between fat intake and growth in representative populations of free-living children under 2 years old. The objective of this study was to investigate the relationship between fat intake as a percentage of energy, and nutrient adequacy, growth, blood lipids, and iron status in 18- and 43-month-old children.

DESIGN

This study forms part of the Avon Longitudinal Study of Parents and Children (ALSPAC)-a geographically-based cohort study in southwest England. A randomly selected subsample of the ALSPAC cohort attended research clinics approximately every 6 months from birth, at which a variety of anthropometric and other measurements were made. Dietary intakes at 18 and 43 months were assessed using a 3-day unweighed food record. A capillary blood sample was taken at 18 months for measurement of hemoglobin and ferritin levels. Nonfasting venous blood samples were taken at 31 and 43 months and analyzed for total and high-density lipoprotein cholesterol. The children were divided into quartiles of fat intake as a percentage of energy (QFI). QFI groups were compared for the number of children reaching recommended nutrient intakes, and for anthropometry, measures of iron status, and blood lipid levels.

PARTICIPANTS

Nine hundred fifty-one children at 18 months and 805 children at 43 months.

RESULTS

The mean (standard deviation) percentages of energy from fat in each quartile at 18 months were 31.2 (2.8), 36.1 (0.9), 39.1 (0.8), and 43.1 (2.2), corresponding to a fat intake in grams of 37.3 (8.1), 44.3 (8.1), 50.4 (10.2), and 55.4 (12.7). The number of children failing to reach recommended intake levels for zinc and vitamin A fell with increasing fat intake, while the number of children consuming less than the recommendations for iron and vitamin C rose at both ages. Despite this, there was no association between fat intake at 18 months and mean height or body mass index (BMI) at either 18 or 31 months. Fat intake at 43 months was also unassociated with concurrent or subsequent height or BMI. There was also no significant increase in the number of children falling below the tenth percentile for height or BMI as QFI fell. Mean ferritin levels at 18 months fell in both sexes as QFI increased. Total cholesterol levels at 31 months were significantly associated with QFI at 18 months, and rose from 3.99 mmol/l in the lowest QFI in boys, to 4.31 mmol/l in the highest QFI. QFI at 43 months was unassociated with cholesterol levels.

CONCLUSIONS

These data do not suggest that fat intakes are an important determinant of growth in these children, even before the age of 2 years, or that children at the bottom of the range of fat intakes are experiencing delayed growth. On the other hand, there is also no evidence in this study that children on higher fat intakes are at a greater risk of becoming obese. In contrast to a number of US studies, we have not found children on lower fat intakes to have lower iron intakes-indeed higher fat intakes were associated with a greater chance of consuming less than the recommended intake of iron and with lower ferritin levels. The association of higher fat intakes with higher total cholesterol levels among boys is of concern, as there is evidence that the process of atherosclerosis begins during the preschool years.