Estimation of Arachidonic Acid Synthesis in Full Term Neonates Using Natural Variation of 13 C Content

BackgroundAnimal and human studies have suggested that trans fatty acids might alter some physiological functions and adversely affect the growth and essential fatty acid balance of infants. In this context it is important to know the fatty acid composition, including the levels of trans isomers of oleic, linoleic and α‐linolenic acids in infant formulas.MethodsTen liquid and fourteen powdered formulas for term infants were purchased from retail stores in Canada. The fatty acid composition of each formula was determined by capillary gas‐liquid chromatography.ResultsAll the formulas met the mimimum content of 500 mg of linoleic acid/100 kcal formula (equivalent to 4.5% of energy) specified under current Canadian regulations. The formulas all met the minimum energy levels of 3% as linoleic acid and 0.7% as α‐linolenic acid recommended recently by an ad hoc committee of Health Canada. However, in nine formulas, the proportion of linoleic acid was more than 20% of total fatty acids, and consequently, in five of them, the ratio of linoleic acid to α‐linolenic acid exceeded the maximum ratio of 16:1 recommended by the ad hoc committee. Trans fatty acids were present in all the samples, and generally the liquid formulas displayed a higher total trans content (mean 1.9%, range 0.9‐3.1%) than powdered formulas (mean 1.4%, range 0.6‐2.5%). The amounts of trans isomers of linoleic and α‐linolenic acids and the degree of isomerization of these fatty acids were also higher in liquid formulas than in powdered formulas.ConclusionsA few of the Canadian infant formulas would provide one‐third of α‐linolenic acid as trans geometric isomers.

Essential Fatty Acids and Their Trans Geometrical Isomers in Powdered and Liquid Infant Formulas Sold in Canada

Ratnayake,

Chardigny,

Wolff

et al. 1997

Intake and Blood Levels of Fatty Acids in Treated Patients With Phenylketonuria

Acosta,

Yannicelli,

Singh

et al. 2001

BackgroundInvestigators in Italy and Spain have suggested that therapy for patients with phenylketonuria (PKU) may result in essential fatty acid (EFA) deficiency. Objectives of this study were to determine if the diets of patients with PKU in the United States provided adequate EFA intakes and whether patients could form long‐chain polyunsaturated fatty acids.MethodsPatients (1–13 years of age) with classic PKU undergoing therapy and their non‐PKU sibling closest in age were compared. Nutrient intakes were calculated from 3‐day diet diaries. Fatty acids in plasma and erythrocytes were identified and quantified. Paired t tests compared results for the patients and their non‐PKU siblings.ResultsTwenty‐eight patients and 26 siblings were studied. Mean fat intake was greatest by siblings (34.8 ± 1.3% of energy) and lowest by Phenyl‐Free–fed patients (19.5 ± 1.2% of energy;P < 0.05). Fat intake (30.4 ± 1.8% of energy) by Phenex‐fed patients did not differ from that of siblings. Percentage of energy ingested as C18:2n‐6 and C18:3n‐3 did not differ significantly between patients and siblings. No clinically significant, consistent differences were found in fatty acid levels (wt%) in plasma or erythrocytes between patients with PKU and siblings.ConclusionsNo patient in this study exhibited a Holman index of EFA deficiency. Siblings ingested animal protein containing C20:5n‐3 and C22:6n‐3 fatty acids, and this may account for their greater wt% of these plasma and erythrocyte fatty acids. Because patients with PKU do not ingest fatty acids >C18 but C20:4n‐6, C20:5n‐3, and C22:6n‐3 were found in their plasma and erythrocytes, in vivo synthesis from C18:2n‐6 and C18:3n‐3 appears to occur. Lack of EFA deficiency in patients in this study may be the result of the use of canola and soy oils containing C18:2n‐6 and C18:3n‐3 rather than olive oil in the diets.

Role of Intestinal Transporters in Neonatal Nutrition: Carbohydrates, Proteins, Lipids, Minerals, and Vitamins

Boudry

David

Douard

et al. 2010

To support rapid growth and a high metabolic rate, infants require enormous amounts of nutrients. The small intestine must have the complete array of transporters that absorb the nutrients released from digested food. Failure of intestinal transporters to function properly often presents symptoms as "failure to thrive" because nutrients are not absorbed and as diarrhea because unabsorbed nutrients upset luminal osmolality or become substrates of intestinal bacteria. We enumerate the nutrients that constitute human milk and various infant milk formulas, explain their importance in neonatal nutrition, then describe for each nutrient the transporter(s) that absorbs it from the intestinal lumen into the enterocyte cytosol and from the cytosol to the portal blood. More than 100 membrane and cytosolic transporters are now thought to facilitate absorption of minerals and vitamins as well as products of digestion of the macronutrients carbohydrates, proteins, and lipids. We highlight research areas that should yield information needed to better understand the important role of these transporters during normal development.