Israel Medical Association Journal

Objectives: To determine the profile of unsaturated fatty acids in the breast milk of two populations in southern Israel, Jewish and rural tent-dwelling Bedouin women.

Methods: This study involved 48 lactating Israeli mothers, 29 Jewish and 19 Bedouin (16–20 weeks postpartum), whose full-term infants were fed exclusively with breast milk. Total milk lipid extracts were transmethylated and analyzed by using an improved gas chromatographic method.

Results: The breast milk of the Bedouin women contained significantly higher levels of total major saturated fatty acids, lauric acid and palmitic acid (45.2 ± 4.7% vs. 41.0 ± 5.6%, P = 0.005; 5.2 ± 2.1 vs. 6.8 ± 2.0%, P = 0.03; and 22.7 ± 2.4 vs. 20.6 ± 3.8%, P = 0.02) respectively. No difference was found in the myristic acid level between the groups. The level of stearic acid was significantly higher in the Jewish group compared to the Bedouin group (5.7 ± 1.1 vs. 5.1 ± 1.1%, P = 0.04). There was a linear correlation between the levels of C14:0 and C12:0 in the Bedouin and Jewish groups respectively (R = 0.87, R = 0.82, P < 0.001).

Conclusions: Higher levels of saturated fatty acids were measured in the breast milk of Bedouin women, an economically weaker population. The results emphasize the importance of diet among lactating women and its influence on milk quality. 

Background: Human milk produced during prolonged lactation (> 1 year) is extraordinarily rich in fat and has a higher energy content than human milk produced during short lactation.

Objectives: To estimate the fatty acid (FA) profile of human milk and to test the hypothesis that the proportion of C12 and C14 (two dietary saturated FA known to most promote hypercholesterolemia) in human milk during prolonged lactation is similar to that in short lactation.

Methods: We conducted a cross-sectional study of 30 mothers of term infants lactating for more than 1 year as compared with 25 mothers of full-term infants who lactated for 2–6 months. Milk was collected by manual expression in mid-breastfeeding.

Results: The two groups did not differ in maternal height, weight, body mass index, diet, infant birth weight and gestational age, but mothers in the prolonged lactation group were significantly older. There was a significant correlation between lactation duration and C12 or C14. The percentage of all FA combined (except for C12 and C14) decreased significantly over time. In contrast, C12:0 and C14:0 combined increased significantly during lactation (R2 = 10.0%, P < 0.03).

Conclusions: Women who lactated for more than 1 year had higher C12 and C14 FA percentages in their milk than women who lactated for 2–6 months.

Background: As high dietary n-6 polyunsaturated fatty acids and n-6:n-3 PUFA[1] ratio may contribute to many western ailments, increasing n-3 PUFA in foods could be beneficial. The nutritional significance of n-3 PUFA-fortified egg vs. enzymatically competitive high n-6 PUFA diets is debatable.

Objectives: To evaluate the dietary contribution of 'field fortification' of eggs by adding n-3 PUFA to high n-6 PUFA hen feed and whether it meets consumer preferences.

Methods: Laying hens (n=3500) were fed n-3 PUFA-fortified (5% extruded linseed) feed or standard (control) feed for 5 weeks. Nutritional significance was evaluated for western (American, Israeli) populations.

Results: Compared to regular (control) eggs, fortified eggs yielded a 3.8-fold increase in total n-3 PUFA, 6.4-fold alpha-linolenic acid (18:3), and 2.4-fold docohexaenoic acid 22:6). N-6:n-3 PUFA ratio decreased 3.6-fold, and n-6:n-3 long chain PUFA ratio threefold (P < 0.0003). Sensory evaluations were not significantly different. Egg cost increased by 1.0–1.5%. Fortified egg n-3 PUFA content averaged 14.3% of the current intake of Americans and 15.9% of Israelis – 9.8 and 10.5% of upper Dietary Reference Intakes, respectively. Egg DHA content averaged 32.9 and 41.1% of upper DRI[2]. Current cholesterol intakes average 281 and 263 mg/day (median 214 and 184 mg/day) including 0.7 and 0.5 egg/day; reported hypercholesterolemia rates are 17.7 and 16.5%, respectively.

Conclusions: Effective concentration and transformation of supplemental n-3 PUFA/LCPUFA[3] from feed to egg substantially enhanced egg n-3 PUFA %DRI, particularly of DHA[4], critical for health but often deficient. Such land-based n-3 PUFA/LCPUFA fortification may be applicable to high n-6 PUFA diets, fitting within cholesterol limitations and market criteria. It may contribute to general health and specific requirements (i.e., pregnancy and lactation), with possibilities of wide accessibility and standardization.