Table 5.
Synthesis of the nutrients in breast milk responsive to maternal diet
| Nutrients | Number of articles | Relevance | Quality of evidence | Observations |
|---|---|---|---|---|
| PUFA/SFA | ||||
| DHA | 29 (15 exp, 14 obs) | Essential for optimal brain and visual system development | High quality | DHA levels in BM proportional to maternal dietary DHA intake Maternal diet quality affects the fatty acid composition of breast milk. Lower DHA and long-chain fatty acids proportion in vegan BM For RCT, supplementation ranged from 200 mg to 1200 mg/d EFSA adequate DHA intake: 100–200 mg/d |
| EPA | Important for cardiovascular function and precursor of bioactive mediators with anti-inflammatory and pro-resolving properties | High quality | EPA levels in BM less proportional to maternal dietary EPA intake Effect of maternal EPA supplementation on BM concentration is more modest than DHA For RCT, supplementation ranged from 70 mg to 300 mg/d EFSA adequate EPA intake: 100–200 mg/d |
|
| ALA | Precursor of longer-chain n-3 PUFA and may have independent roles | Low quality | BM ALA content correlated with intake of rapeseed and soyabean oils; seeds and nuts such as flaxseed, chia and walnuts and some green leafy vegetables (kale and spinach) For RCT, supplementation was 10·1 g/d EFSA adequate intake: 0·5 % Energy intake of ALA |
|
| ARA | Essential for brain development and immune system function | Low quality | No effect observed in studies, but very low doses provided Same proportion of ARA in omnivores and vegans’ BM For RCT, supplementation was 54 mg/d EFSA adequate intake: Not available |
|
| SFA/TFA | High quality | Total trans acids (TFA) in the milk appeared to follow dietary trans changes after a 12–36 h lag period. No association between TFA consumption and BM TFA level Overweight women’s BM compared with normal-weight women’s BM contained higher amount of SFA, lower ratio of unsaturated to saturated FA than those of normal weight EFSA adequate intake: not applicable |
||
| Vitamins | ||||
| A | 8 exp | Optimum visual, growth, immune system and cognitive development | High quality | Vitamin A level in BM is responsive to maternal intake Higher deficiency risks in developing countries For RCT, supplementation was either 30 mg/d, 54 mg/d or 60 mg single dose EFSA average requirement: 1020 µg RE/d |
| B1, B2 and B9 | 6 (5 exp, 1 obs) | B1 deficiency can cause gastrointestinal symptoms, cardiac failure, and lactic. B2 deficiency can cause anaemia and cataracts can develop if riboflavin deficiency is severe and prolonged B5 deficiency may include symptoms such as fatigue, insomnia, depression, irritability and vomiting B9 plays an essential role in the development of a baby’s brain and spinal cord during pregnancy. |
Very low quality | Thiamine supplementation did not significantly affect the thiamine concentration in BM Riboflavin supplementations seem to have a positive impact on BM riboflavin concentration No evidence found on folic acid and pantothenic acid For RCT, vitamin B1 supplementation was 1·7 mg/d For RCTs, vitamin B2 supplementation was 2 mg/d EFSA average requirement vitamin B1:0·072 mg/MJ Thiamin requirement is related to energy requirement and therefore expressed in mg/MJ. Values expressed in mg/d can be calculated based on the energy requirement of the group considered (EFSA NDA Panel, 2013) EFSA adequate requirement vitamin B2:1·7 mg/d EFSA adequate intake vitamin B5:7 mg/d EFSA adequate requirement vitamin B9:380 µg DFE/d |
| B6 | Essential for brain development | Moderate quality | Vitamin B6 supplementation seems to impact vitamin B6 breast milk concentration positively For RCT, Vitamin B6 supplementation ranged from 2·5 to 20 mg/d EFSA average requirement: 1·4 mg/d |
|
| B12 | Essential for brain development | Moderate quality | Maternal vitamin B12 supplementation may prevent declines in BM content For RCT, Vitamin B12 supplementation was 8 µg/d EFSA adequate intake: 5 µg/d |
|
| C | 3 exp | Essential for collagen formation, and role in immune system and nervous system function | Moderate quality | BM vitamin C levels responsive to maternal supplementation only when lactating mothers have low intake. Overall, vitamin C levels appear responsive to intake, but levels are regulated, as response to a highest dose of vitamin C was modest in European women in contrast with the 3-fold increase in African women. For RCT, Vitamin C supplementation ranged from 90 mg/d to 1000 mg/d EFSA average requirement: 140 mg/d |
| D | 5 exp | Essential for Ca absorption and skeletal growth, deficiency can cause nutritional rickets | Moderate quality | BM vitamin D levels responsive to maternal supplementation. Higher effect when high unique dose supplementation (150 000 μg) For RCT, vitamin D supplementation ranged from 50 µg/d to 3750 µg single dose EFSA adequate intake: 15 µg/d |
| E | 6 (5 exp, 1 obs) | Deficiency can compromise immune system and affect lung development. Premature infants are more susceptible to deficiency and can cause thrombocytosis, haemolytic anaemia and interventricular haemorrhage | High quality | Dose–response relationship, and supplementation effects are confirmed for α-tocopherol Milk total tocopherol found to be associated only with mother’s total fat and saturated fat dietary intake An increase in PUFA content may increase peroxidation and therefore increase vitamin E requirements. For RCT, Vitamin E supplementation ranged from 40 mg to 536 mg single dose EFSA adequate intake: 11 mg/d |
| K1 | 3 exp | Deficiency can lead to classical haemorrhagic disease of newborn with bleeding in the first week of life |
Low quality | Dose–response relationship, and supplementation effects are confirmed For RCT, vitamin K supplementation ranged from 0·5 mg/d to 5 mg/d EFSA adequate intake: 70 µg/d |
| Minerals and others | ||||
| Iodine | 4 (1 exp, 3 obs) | Deficiency can damage the developing brain and increase mortality | High quality | Dose–response relationship, and supplementation effects are confirmed Supplementation effects are immediate (peak 6 h after supplementation) For RCTs, iodine supplementation ranged from 75 µg/d to 150 µg/d. One study administrated 450 µg as a single dose EFSA adequate intake: 200 µg/d |
| Se | 6 (4 exp, 2 obs) | Deficiency associated with increased respiratory morbidity | Low quality | BM Se significantly correlated to current fresh fish consumption, no significant correlation between intake of multivitamin supplements during pregnancy and Se in BM Se maternal supplementation seems to increase Se levels in BM and prevent decline with advancing lactation and also appeared to increase the BM concentration of PUFA (especially LA) and decrease BM SFA. For RCT, Se supplementation ranged from 20 µg/d to 200 µg/d EFSA adequate intake: 85 µg/d |
| Fe | 4 (1 exp, 3 obs,) | Fe deficiency anaemia is associated with long-lasting neurofunctional effects and can affect sleep pattern | Low quality | Fe supplementation to non-anaemic women did not change BM Fe content or prevent a decline. For RCT, Fe supplementation was from 80 mg/d EFSA average requirement: 7 mg/d |
| Zn and Cu | 3 obs | Zn deficiency can lead to cutaneous signs, diarrhoea and alopecia. Cu deficiency can cause bone lesions |
Low quality | Dietary intake of Zn, Cu and Fe did not affect BM Zn, Cu and Fe concentrations. All metals with exception of Cu were found in lower concentrations in transitory milk. EFSA adequate intake Cu: 1·5 mg/d EFSA average requirement: Zn: 2·4 mg/d |
| Ovalbumin | 2 exp | Exposure to ovalbumin may reduce egg allergy development | Moderate quality | Direct dose–response between the amount of cooked egg ingested and the BM ovalbumin For RCT, egg intake ranged from no egg to > 4 eggs/week EFSA adequate intake: Not available |
| Protein and amino acids | 2 (1 exp, 1 obs) | Maternal protein consumption may impact the BM nitrogen content. BM nitrogen is used by beneficial bacteria present in the infant’s digestive system. Taurine has an important role in intestinal fat absorption, hepatic function, and auditory and visual development in preterm and low birth weight infant |
Low quality | Output of lactoferrin, α-lactalbumin and serum albumin seem to be higher when a high protein diet is consumed; however, differences are not significant compared with low protein diet consumption. Mean taurine concentration in the vegan BM 35 mg/dl was significantly lower than in BM of omnivores. EFSA average requirement: Zn: 15 mg/d from 0 to 6 months PP and 10 g/d after 6 months PP |
| Tyrosine | 1 exp | Tyrosine deficiency may increase risk postpartum depression | Low quality | Rise in free, but not total tyrosine, supplementation effects immediate (peak 6 h after supplementation) For RCT, tyrosine supplementation ranged from 2 to 10 g single dose EFSA adequate intake/average requirement: not available |
| Choline | 1 obs | Needed for growth and development, and role in membrane and signalling functions | Low quality | No significant effects by maternal diet pattern. EFSA adequate intake: 520 mg/d |
| Contaminants | ||||
| As, Cd, Pb, Hg | 4 obs | Heavy metals disrupt cellular events including growth can induce cancer | Moderate quality | Factors significantly related to metal levels in BM were area of residence (Hg, Pb), prematurity (Hg), fish consumption (Pb) and cereals (Hg), vitamin supplementation (Hg) and smoking (Pb, Cu). BM Pb positively associated with Fe and Zn but inversely associated with Ca. As in BM associated with Fe and B with Ca. No significant differences were found in BM between fish and non-fish eaters for THg concentrations. Negative association was found between THg concentrations in BM and freshwater fish consumption PTWI (JEFCA): no appropriate safety guidelines for As and Pb; Cd PTWI, 2·5 µg/kg bw/week; Inorganic Hg (IHg), 4 µg/kg bw/weeks. Total Hg (MeHg), 1·6 µg/kg bw/week |
| PCB | 1 obs | PCB can induce skin and liver damage | Moderate quality | Levels were three times higher for very high seafood consumers (300 g/d in average) than for low seafood consumers (12 g/d in average) EFSA tolerable intake: 2 picograms per kg bw |
Based on GRADE rating system.
Obs, observational study; exp, experimental study (randomised control trial); ALA, α-linolenic acid; ARA, arachidonic acid; BM, breast milk, FA, fatty acid; PP, postpartum; DFE, dietary folate equivalent; EFSA, European Food Safety Authority; THg, total Hg; PCB, polychlorinated biphenyls; PTWI, provisional tolerable monthly intake; bw, body weight; JEFCA, joint FAO/WHO Expert Committee on Food Additives; RE, retinol equivalent.