Supplying most of the nutrients a new baby needs, breast milk is highly nutritious. Our nutritionist explores what new mums need to consider when preparing for breastfeeding and beyond.
Eating a balanced and varied diet is key for pre-conception, pregnancy and during breastfeeding. Many mums worry the quality of their milk won’t be sufficient, although their bodies knows exactly what their baby needs at each stage of development, and adapts their breast milk accordingly. It’s no surprise, then, that breast milk varies in composition during feeding and throughout the breastfeeding period. In most cases, a varied, well-balanced diet should provide almost all the nutrients a mum needs.
Your breastfeeding diet
There are two factors which determine the quality of breast milk – a mother's diet and her body’s reserves of key nutrients.
Estimates suggest that breast milk contains as many as 300 different components, so eating a balanced, varied diet is important. Ideally, every day should include two-to-three portions of protein foods such as lean meat, fish, beans, nuts and seeds; a minimum of five portions of fruit and vegetables; wholegrain cereals such as brown rice and oats and enough water to satisfy thirst. Those on a plant-based diet should include fortified foods such as plant milks and spreads.
The good news is that most of the dietary restrictions followed during pregnancy won’t necessarily apply when breastfeeding. However, be aware that caffeine is passed into a mother’s milk and could disrupt a baby's sleep. If this happens, limit or avoid tea, coffee, chocolate and cola. Alcohol is also passed into the milk, so mums will need to wait 2-3 hours per alcoholic drink before breastfeeding.
What you need to know
- When planning a breastfeeding diet, there are a few things to consider. Interestingly, not all the nutrients in breast milk are directly influenced by what you eat, however, some are. These include some of the B vitamins (B1, B2, B6, B12 and choline). This means if a mother’s diet is lacking in any of these vitamins, their baby won’t be getting sufficient amounts either.
- A new mum will have a greater need for certain nutrients. It’s because of these extra requirements that some mums continue to take a pre-natal supplement, this may be especially relevant for a new mum of twins. These are likely to support a woman’s additional nutrient needs, but does not stop the need to eat a well-balanced and varied diet.
- When breastfeeding, a woman’s energy needs will increase by as much as 500 calories per day. If a woman continues to carry baby weight from her pregnancy, some of these stores will be used to support milk production. Otherwise, a woman’s appetite may increase to address these extra needs.
- Some nutrients are present in breastmilk regardless of diet. These include calcium, folate, iron and zinc. If these nutrients are not adequately supplied by the food a mother eats, they will be taken from her own reserves (bone and tissue) leaving her potentially at risk of depletion.
- A mother’s milk supplies the protein a baby needs for growth, so she will need an additional 25g of protein per day from lean meats, fish, beans, pulses, nuts and seeds. This should be possible through dietary means by choosing nutrient-dense foods and including an extra portion of protein per day. Aim for 2-3 protein sources daily to satisfy your own needs and that of your baby – as an example a 100g portion of baked white fish supplies 24g protein whilst two boiled eggs supply 14g protein.
When and what might you need to supplement?
1. Vitamin D is used by the body for a number of different functions, including how a baby utilises calcium for the formation of strong bones and teeth. Vitamin D also helps regulate a baby’s immune and respiratory function. In the UK, the Department of Health recommends all pregnant and breastfeeding women supplement with 10mcg of vitamin D, and an exclusively breastfed baby should receive a daily supplement of 8.5-10mcg vitamin D. This is because vitamin D tends to be low in the UK population, especially in certain groups.
Vitamin D food sources are limited in number and most of our vitamin D is produced by sunlight on the skin. Food sources include oily fish, egg yolks and fortified spreads. Available in two forms (D2 and D3), look for cholecalciferol (D3) because it is considered more stable in supplement form. Vegan mums would need to look for a suitable vegan-friendly version such as that made from lichen.
2. Fats are important to support the absorption of fat-soluble vitamins like vitamin D and also to provide essential fatty acids like docosahexaenoic acid (DHA), which is needed for a baby’s visual and brain development. The best dietary sources of DHA include oily fish like salmon, trout and sardines – but don’t forget, just as in pregnancy, it’s advised to limit fish high in mercury. Whilst breastfeeding, limit oily fish intake to no more than two portions per week.
Plant foods, like walnuts and flaxseeds supply omega-3 in the form of alpha-linoleic acid (ALA), however this requires your body to convert it to DHA. This conversion tends to be quite inefficient which is why vegetarians, vegans and those unable to eat fish should consider a daily omega-3 supplement. During pregnancy and lactation, women are advised to take 2.6mg of omega-3 fatty acids of which 100-300mg is DHA per day. Those who are vegan or avoid fish may supplement with a natural algae formula.
3. The need for vitamin B12 increases during pregnancy and breastfeeding. This vitamin is important for the formation of a baby’s blood cells, as well as their brain development and function. It may help mums with their memory, mood and to support energy levels. Food sources include meat, fish, dairy and eggs, as well as fortified plant milks and yeast extract.
Vegan and strict vegetarians who don’t eat meat, dairy or eggs, should speak with their GP about taking a daily B12 supplement which supplies 10mcg. There are two forms of vitamin B12 – cyanocobalamin, which is a synthetic version, or methylcobalamin, the natural form. Studies suggest both forms are effective.
4. Vitamin C plays an important role in tissue growth and repair, as well as bone and teeth development, so women's needs will increase during breastfeeding. Most mums get good amounts by including plenty of fresh fruit and vegetables such as citrus fruits, kiwis, peppers and tomatoes in their diet. If a GP or dietitian has suggested adding a supplement, look for a ‘buffered’ form of vitamin C. This supplies a highly absorbable vitamin C along with a buffering mineral and is thought to be gentler on the gut. Calcium ascorbate would be an example – ideally aim for a supplement providing 100-250mg.
5. Although a woman's body will ensure adequate calcium is supplied in breast milk, it can be useful for those following a restricted diet, and who do not eat dairy, to increase their intake of calcium-rich foods. Food sources include green leafy vegetables, dried fruit, nuts and seeds, fortified plant milks and calcium-set tofu. Breastfeeding mums have been seen to lose 3-5% of their bone density while breastfeeding, so including plenty of calcium-rich food sources is important.
If advised to supplement, look for a product providing about 700-800mg of calcium. Calcium citrate may be a more convenient form as it can be taken at any time of day, whereas calcium carbonate should be taken with meals.
6. Low levels of iodine during pregnancy and when breastfeeding may cause thyroid problems and impact brain development and cognition. Food sources include seafood, sea vegetables and dairy. Vegans and those on a restricted plant-based diet should seek advice from their GP or dietitian with regards supplementation. Daily requirements in the UK are 140mcg iodine, which for most of us is adequately met by consuming dairy and fish.
If you’re considering any major dietary changes, or are thinking about taking supplements, please consult your GP or registered dietitian to ensure you do so without risk to your baby or your own health. Speak to your midwife, doula or health visitor if you have any concerns about feeding your baby.
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This article was published on 31st July 2020.
Kerry Torrens is a qualified Nutritionist (MBANT) with a post graduate diploma in Personalised Nutrition & Nutritional Therapy. She is a member of the British Association for Nutrition and Lifestyle Medicine (BANT) and a member of the Guild of Food Writers. Over the last 15 years she has been a contributing author to a number of nutritional and cookery publications including BBC Good Food.
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