Plasma and red blood cell fatty acids of low-birth-weight infants fed their mother's expressed breast milk or preterm-infant formula
Article Abstract:
Long-chain polyunsaturated fatty acids (LCPs) are vital parts of the structure of membranes which surround every living cell, and also serve as precursors for important hormone-like molecules such as prostaglandins. LCPs are made in the human body from linoleic acid and linolenic acid, two fatty acids that are essential, meaning that they must be obtained from the diet because humans do not have the capacity to manufacture them. Breast milk from women who give birth prematurely appears to contain enough LCPs to meet their infants' needs, while infants given formula (which contains less LCPs) need to meet LCP requirements by synthesizing them themselves. Linoleic and linolenic acid differ structurally in the position of their double bonds (unsaturation); the formula for linoleic is 18:2(n-6), while that for linolenic is 18:3(n-3). Fatty acids that have the n-6 configuration cannot be converted to the n-3 configuration, and studies suggest that infant formulas that have an excess of n-6 over n-3 fatty acids may cause depletion of n-3 fatty acids and replacement by n-6 fatty acids in liver and brain cells but not the red blood cells. The health effects of this replacement are unclear. The effect of increasing the amount of n-3 fatty acids in infant formula fed to low-birth-weight infants on the levels of LCPs in red blood cells was studied. Nine infants were fed breast milk, 16 infants were fed formula in which the ratio of n-3 to n-6 fatty acids resembled breast milk (2 percent n-3, 20 percent n-6 fatty acids), and 11 infants received breast milk with formula supplements. The levels of n-3 and n-6 LCPs were similar among all infant groups on the first and twenty-eighth day of the study (also the first and twenty-eighth day of life). The data suggest that formula with at least 2 percent n-3 fatty acids such as linolenic acid, in a ratio with n-6 fatty acids that is similar to that found in breast milk, may allow for incorporation of n-3 fatty acids into the body tissues of low-birth-weight infants that is equivalent to the incorporation when such infants are fed breast milk. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Clinical Nutrition
Subject: Health
ISSN: 0002-9165
Year: 1990
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Brain synaptosomal, liver, plasma, and red blood cell lipids in piglets fed exclusively on a vegetable-oil-containing formula with and without fish-oil supplements
Article Abstract:
Long-chain polyunsaturated fatty acids (LCPs) are part of the structure of the membranes which enclose all living cells. LCPs are made by humans from linoleic and linolenic acid, two fatty acids that are essential, meaning humans cannot make them so they must be obtained from the diet. Breast milk appears to contain enough LCPs to meet infants' needs, while infants given formula (which contains fewer LCPs) need to meet their LCP requirements by synthesizing them themselves. Both linoleic, an n-6 fatty acid, and linolenic, an n-3 fatty acid, are needed, as they differ structurally and cannot be interconverted. Studies have shown that the fatty acid content of cell membranes affects the function of the brain, and so it is important that infant formula contains appropriate levels of n-3 and n-6 fatty acids. Fish oil, which is high in n-3 fatty acids, has effectively prevented the loss of n-3 fatty acids in premature infants. But whether fish oil is beneficial to rapidly growing infants is unclear, since its high content of n-3 fatty acids may alter the body's use of n-6 fatty acids. The effect of fish oil supplementation on the fatty acid composition of lipids (fats) in brain, liver, and red blood cells of piglets was evaluated. Groups of six piglets each were fed sow milk (M), vegetable-oil-based formula (F), or vegetable oil plus fish oil-based formula (FF). Animals fed F had low levels of n-3 fatty acids compared with M-fed pigs, and FF feeding corrected this deficiency. The F-fed animals compensated for low n-3 levels by synthesizing more n-6 fatty acids, and this was not seen in FF-fed piglets. However, the ratio of n-3 to n-6 fatty acids in some lipids in certain tissues of FF-fed piglets was lower than in M-fed piglets, and the authors urge caution as to the dosage and universal usage of fish oil. The effects of fish oil supplementation on the function of the developing brain need to be studied further. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Clinical Nutrition
Subject: Health
ISSN: 0002-9165
Year: 1990
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Comparison of breast-feeding and formula feeding on intestinal and hepatic cholesterol metabolism in neonatal pigs
Article Abstract:
Manufactured infant formulas have a much lower cholesterol content than breast milk. Cholesterol is required for many body functions, including maintenance of the membranes that surround every cell. Levels of dietary cholesterol may affect intestinal cholesterol production; the intestines, as well as the liver, have the ability to make cholesterol. The effect of differing levels of dietary cholesterol on cholesterol production by the liver and intestines was investigated in newborn piglets. The physiology of pigs closely resembles that of humans in crucial areas. In all piglets, plasma (blood) cholesterol levels rose with age, but plasma cholesterol levels were higher in breast milk (BM)-fed animals on days 15 and 25 postpartum than in formula-fed animals. In animals fed formula, cholesterol synthesis by the liver increased as a response to their low cholesterol diet, while intestinal cholesterol synthesis was not affected. The cholesterol synthesis in the livers of BM-fed animals was low, presumably because their diets supplied more cholesterol. In addition, cholesterol contained in intestinal cells was depleted following birth, probably for use in making bile acids and other important body compounds. The results indicate that in newborn piglets, liver cholesterol production can compensate for low cholesterol levels in the diet. (Consumer Summary produced by Reliance Medical Information, Inc.)
Publication Name: American Journal of Clinical Nutrition
Subject: Health
ISSN: 0002-9165
Year: 1990
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