Choline, an essential dietary nutrient for humans, is required for the synthesis of the neurotransmitter, acetylcholine, the methyl group donor, betaine, and phospholipids; and therefore, choline is involved in a broad range of critical physiological functions across all stages of the life cycle. The current dietary recommendations for choline have been established as Adequate Intakes (AIs) for total choline; however, dietary choline is present in multiple different forms that are both water-soluble (e.g., free choline, phosphocholine, and glycerophosphocholine) and lipid-soluble (e.g., phosphatidylcholine and sphingomyelin). Interestingly, the different dietary choline forms consumed during infancy differ from those in adulthood. This can be explained by the primary food source, where the majority of choline present in human milk is in the water-soluble form, versus lipid-soluble forms for foods consumed later on. This review summarizes the current knowledge on dietary recommendations and assessment methods, and dietary choline intake from food sources across the life cycle.

Human milk contains nutritional, immunoprotective and developmental components that support optimal infant growth and development. The milk fat globule membrane (MFGM) is one unique component, comprised of a tri-layer of polar lipids, glycolipids, and proteins, that may be important for brain development. MFGM is not present in most infant formulas. We tested the effects of bovine MFGM supplementation on reflex development and on brain lipid and metabolite composition in rats using the “pup in a cup” model. From postnatal d5 to d18, rats received either formula supplemented with MFGM or a standard formula without MFGM; a group of mother-reared animals was used as reference/control condition. Body and brain weights did not differ between groups. MFGM supplementation reduced the gap in maturation age between mother-reared and standard formula-fed groups for the ear and eyelid twitch, negative geotaxis and cliff avoidance reflexes. Statistically significant differences in brain phospholipid and metabolite composition were found at d13 and/or d18 between mother-reared and standard formula-fed groups, including a higher phosphatidylcholine:phosphatidylethanolamine ratio, and higher phosphatidylserine, glycerol-3 phosphate, and glutamine in mother-reared compared to formula-fed pups. Adding MFGM to formula narrowed these differences. Our study demonstrates that addition of bovine MFGM to formula promotes reflex development and alters brain phospholipid and metabolite composition. Changes in brain lipid metabolism and their potential functional implications for neurodevelopment need to be further investigated in future studies.

Choline has critical roles during periods of rapid growth and development, such as infancy. In human milk, choline is mostly present in water-soluble forms (free choline, phosphocholine, and glycerophosphocholine). It is thought that milk choline concentration is influenced by maternal choline intake, and the richest food sources for choline are of animal origin. Scarce information exists on milk choline from countries differing in animal-source food availability. In this secondary analysis of samples from previous trials, the concentrations of the water-soluble forms of choline were quantified by liquid chromatography-tandem mass spectrometry in mature milk samples collected from lactating women in Canada (n = 301) and in Cambodia (n = 67). None of the water-soluble forms of choline concentrations in milk differed between Canada and Cambodia. For all milk samples (n = 368), free choline, phosphocholine, glycerophosphocholine, and the sum of water-soluble forms of choline concentrations in milk were (mean (95%CI)) 151 (141, 160, 540 (519, 562), 411 (396, 427), and 1102 (1072, 1133) µmol/L, respectively. Theoretically, only 19% of infants would meet the current Adequate Intake (AI) for choline. Our findings suggest that the concentrations in milk of water-soluble forms of choline are similar in Canada and Cambodia, and that the concentration used to set the infant AI might be inaccurate.

Choline is critical for infant development and mother’s milk is the sole source of choline for fully breastfed infants until six months of age. Human milk choline consists to 85% of water-soluble forms of choline including free choline (FC), phosphocholine (PhosC), and glycerophosphocholine (GPC). Donor milk requires safe handling procedures such as cold storage and pasteurization. However, the stability of water-soluble forms of choline during these processes is not known. The objectives of this research were to determine the effect of storage and pasteurization on milk choline concentration, and the diurnal intra- and inter-individual variability of water-soluble choline forms. Milk samples were collected from healthy women who were fully breastfeeding a full-term, singleton infant <6 months. Milk total water-soluble forms of choline, PhosC, and GPC concentrations did not change during storage at room temperature for up to 4 h. Individual and total water-soluble forms of choline concentrations did not change after storage for 24 h in the refrigerator or for up to one week in the household freezer. Holder pasteurization decreased PhosC and GPC, and thereby total water-soluble choline form concentrations by <5%. We did not observe diurnal variations in PhosC and total water-soluble forms of choline concentrations, but significant differences in FC and GPC concentrations across five sampling time points throughout one day. In conclusion, these outcomes contribute new knowledge for the derivation of evidence-informed guidelines for the handling and storage of expressed human milk as well as the development of optimized milk collection and storage protocols for research studies.

Choline is an important nutrient during development. However, there are limited data on dietary choline intake and status in toddlers and the relation to neurodevelopmental outcomes. This study assessed dietary choline intake and status in healthy toddlers at ages 1 and 2 y and determined the relation to neurodevelopmental outcomes. This is a secondary analysis of data from healthy toddlers enrolled in a double-blind, randomized controlled trial of long-chain polyunsaturated fatty acid supplementation between ages 1 and 2 y. Dietary intakes of betaine and choline were estimated by 3-d food records; plasma free choline, betaine, and dimethylglycine were quantified by liquid chromatography–tandem mass spectrometry. Developmental outcomes were assessed at age 2 y with the use of the Bayley Scales of Infant and Toddler Development, 3rd edition (Bayley-III), Cognitive and Language composites, and the Beery-Buktenica Developmental Test of Visual–Motor Integration (Beery-VMI). The mean ± SD daily intake for total choline at age 1 y was 174 ± 56.2 mg/d and increased (P < 0.001) to 205 ± 67.5 mg/d at age 2 y. At ages 1 and 2 y, 71.8% and 55.8%, respectively, of toddlers did not meet the recommended 200-mg/d Adequate Intake (AI) for dietary choline. At age 1 y, mean ± SD plasma free choline, betaine, and dimethylglycine concentrations were 10.4 ± 3.3, 41.1 ± 15.4, and 4.1 ± 1.9 µmol/L, respectively. Plasma free choline (8.5 ± 2.3 µmol/L) and dimethylglycine (3.2 ± 1.3 µmol/L) concentrations were lower (P < 0.001) at age 2 y. Plasma betaine concentrations were positively associated with the Beery-VMI (β = 0.270; 95% CI: 0.026, 0.513; P = 0.03) at age 2 y. These findings suggest that most toddlers are not meeting the recommended AI for dietary choline and that higher plasma betaine concentrations are associated with better visual-motor development at age 2 y. Further work is required to investigate choline metabolism and its role in neurodevelopment in toddlers. The trial is registered at clinicaltrials.gov as NCT01263912.