Healthnotes Newswire —Reducing saturated-fat and cholesterol intake during early childhood may decrease the risk of subsequent heart disease without adversely affecting neurological development, according to a study published in the current issue of the Journal of the American Medical Association (JAMA).1
While earlier studies have shown that consuming a low-fat diet does not impair the growth of children, there is little information about whether such a diet would adversely affect the development of the brain and nervous system. Therefore, in the study published in JAMA, researchers from Finland studied neurological development in a group of five-year-old children who had been randomly assigned at age seven months to receive either a standard diet (control group) or one that was low in total fat, saturated fat, and cholesterol (study group).
The main difference between the two diets was that the study group consumed about two glasses per day of skim (fat-free) milk and were supplemented with a source of unsaturated fat (usually 2–3 teaspoons per day of canola oil or soft margarine), whereas the control group consumed either whole milk or reduced-fat (1.5 to 1.9% fat) milk. At age five years, the average serum cholesterol level was significantly lower in the study group compared with that in the control group. Moreover, neurological development was at least as good in the former as in the latter.
Many nutrition experts advise both adults and children older than two years of age to consume a low-fat diet, in order to help prevent atherosclerosis (hardening of the arteries). Current recommendations are to restrict the intake of fat to less than 30% of total calories, saturated fat to less than 10% of calories, and dietary cholesterol to less than 300 mg per day. In the standard American diet, which contains closer to 35% of total calories from fat, saturated fat comes mostly from meat and dairy, and much of the dietary cholesterol comes from eggs.
The importance of starting a low-fat diet early in life can be inferred from the fact that early signs of atherosclerosis have been found in autopsies of children who had had high serum cholesterol levels. However, concerns have been raised that a diet too low in fat could interfere with the normal growth and development of children. It is crucial that an adequate amount of essential fatty acids (components of dietary fat) be consumed during the first few years of life, because these fatty acids play a key role in the development of the brain and of visual function.
While this newly published study will be encouraging to those who have been warning of the dangers of excessive dietary fat, it would be premature to conclude that young children should be switched from whole or reduced-fat milk to skim milk. In the Finnish study, total fat intake was only slightly lower in the study group (an average of 30.6% of calories) than in the control group (33.4% of calories). Thus, the “low-fat” diet failed to achieve the currently recommended target of less than 30% of calories from fat. The main reason this target was not met was that the children in the study group were supplemented with about 80–120 calories of vegetable fat per day.
A skim milk–based diet that is not supplemented with vegetable fat would provide only about 20–25% of total calories in the form of fat, a level of intake that has not been demonstrated to be sufficient to promote normal brain development. Indeed, the possible nutritional inadequacy of low-fat milk for children was suggested by an earlier study. In that report, children who consumed low-fat milk had an increased risk of suffering acute gastrointestinal illness, compared with those drinking whole milk.2 In some countries such as Japan, until recently, most children consumed diets containing much less than 20–25% of total calories from fat. However, despite historical precedence, the effects of such diets on brain development have not been adequately studied.
While children should be discouraged from consuming excessive amounts of fat, additional research is needed to determine whether restricting fat intake to less than 30% of calories is safe for children. Until more is known, young children who drink fat-free milk should probably receive small amounts of supplemental vegetable oil, preferably oils that contain both the omega-3 and omega-6 essential fatty acids, such as canola or soybean oil.References