Although formulas have been around for decades, the value of breast milk for babies is still irreplaceable. There are thousands of nutrients in the mother’s milk, many of which are beneficial to the development of the brain and nervous system, and are most effectively absorbed by the baby. Also, compared to formula, breast milk is relatively safe and non-polluting. After nine years of research on the growth patterns of young children in six very different countries (Brazil, Ghana, India, Norway, Oman and the United States), the United Nations World Health Organization (WHO) has set international standards for children under age of 5, which is applicable for children worldwide. WHO believes that beyond genetic and ethnic factors, the major differences in the growth for children under five years of age are influenced by nutrition, feeding methods, environment and health care, and WHO's conclusion is "Breastfeeding is recommended!"

Breastfeeding has all sorts of benefits for both mother and baby. While breastfeeding, a healthy diet will provide a mother with the energy she needs to care for herself and her baby. More importantly, eating healthy foods could help mothers shed the pregnancy weight faster. Breast milk is very nutritious, it contains everything a baby requires for proper development during the first six months of life. The World Health Organization and UNICEF recommend that breastfeeding begin within one hour after delivery; exclusive breastfeeding should be carried out during the first six months of life; adequate nutrition and safe non-staple foods should be added at the age of six months, while continuing breastfeeding for two years or more.

The composition of breast milk is dynamic. From the first day of birth to the last day of breastfeeding, the fat, carbohydrate and protein composition of breast milk will change with the growth and development of newborns to meet the special needs of individual infant’s demand. The ingredients of breast milk change along with the time of breastfeeding. The milk at the beginning of a feeding is more watery, and the milk that comes later is thicker, higher in fat and more nutritious. The pre-milk allows the baby to quench his thirst, while the high-fat post-milk is the food for the baby and gives the baby a message to stop sucking. Generally, an ounce (28 ml) of breast milk contains 19–23 calories, with 3.6–4.8% from protein, 28.8–32.4% from fat and 26.8–31.2% from carbs, mostly lactose. Moreover, breast milk also contains a variety of vitamins and minerals, such as vitamins A, D, E, K, beta carotene, calcium, potassium, chlorine, iron, zinc and so on. Breast milk can fully meet the nutritional needs of infants for the first 6 months. After 6 months, even if adding non-staple foods to the baby’s diet, breast milk can continue to provide important nutrients and growth factors for up to 2 years. Therefore, breast milk is considered to be the Godsent perfect food for the baby.

Breastfeeding mothers require 500 more calories per day than non-breastfeeding mothers, but each mother is different and your energy needs change with the breastfeeding process. The number of calories you need will depend on your baby’s age, size and appetite, as well as your own body BMI, exercise volume, and other factors, such as whether your baby is exclusively breastfed, or whether you are feeding twins or multiple births. As the demand for calories increases, the nutritional needs of women during breastfeeding will also increase. In fact, many of the nutritional needs during lactation are actually higher than during pregnancy, and your breastmilk are a reflection of the nutrients in your diet, including fat-soluble vitamins and some B-vitamins (see Group 1 nutrients). This means that if your diet does not provide these nutrients, then your baby won’t get them either.

For other nutrients, the levels in your breastmilk are not directly correlated to your diet, including important minerals such as folic acid, calcium, iron and zinc (see Group 2 nutrients). Even if they are not in your diet, these nutrients will be present in your breast milk. However, if these nutrients are low in your diet, your body will transfer these nutrients from your bones and tissues to your breast milk for delivery to your baby. Therefore, your baby will always get the nutrition she or he needs, but this may come at the cost of leaving you depleted.

Group 1 Nutrients 
Below are the group 1 nutrients and some common food sources :
Vitamin B1 (Thiamin) : Fish, pork, seeds, nuts and bread.
Vitamin B2 (Riboflavin) : Cheese, almonds, nuts, red meat, oily fish and eggs.
Vitamin B6 : Seeds, nuts, fish, poultry, pork, bananas and dried fruit.
Vitamin B12 : Shellfish, liver, oily fish, crab and shrimp.
Choline : Eggs, beef liver, chicken liver, fish and peanuts.
Vitamin A : Sweet potatoes, carrots, dark leafy greens, organ meats and eggs.
Vitamin D : Cod liver oil, oily fish, some mushrooms and fortified foods.
Selenium : Brazil nuts, seafood, fish, whole wheat and seeds.
Iodine : Dried seaweed, cod, milk and iodized salt.

If you are deficient or don’t get adequate amounts Group 1 nutrients in your diet, the amount of Group 1 nutrients in your breast milk will be substantially reduced. Therefore, it is important for you and your baby to get sufficient amounts of these nutrients from your diet or supplement.

Group 2 Nutrients 
Below are the group 2 nutrients and some common food sources :
Folate : Beans, lentils, leafy greens, asparagus and avocados.
Calcium : Milk, yogurt, cheese, leafy greens and legumes.
Iron : Red meat, pork, poultry, seafood, beans, green vegetables and dried fruit.
Copper : Shellfish, whole grains, nuts, beans, organ meats and potatoes.
Zinc : Oysters, red meat, poultry, beans, nuts and dairy.

The amounts of nutrients in Group 2 in breast milk are not affected by your dietary intake or body stores. If your intake is low, your body will take these nutrients from your own bones and tissue stores to secrete them into your breast milk. Therefore, your baby will always get the right amount of nutrients. However, if you don’t have enough from your diet, your body will be suffered and depleted. To avoid deficiency, these nutrients must come from your diet or supplements.

For most women, while it may seem intuitive to stop taking prenatal vitamins after birth, continuing to take them postpartum can help ensure that you get the nutrients you need during lactation. In fact, taking a prenatal while nursing may be especially important given that many nutrient demands increase while breastfeeding. In other words, you should not rely on your prenatal vitamins to meet all your nutritional needs. Here are some of the specific nutrients that many breastfeeding women are lack, and you should know which nutrients to supplement to help you and your baby get the best nutrition.

1. Make sure you get enough Vitamin D while breastfeeding –

The amount of vitamin D found in breast milk is directly related to the level of vitamin D in the mother. Unfortunately, common factors such as lack of sun exposure and limited fish intake may affect the adequate vitamin D stores of a new mother’s. As a result, the amount of vitamin D provided by breast milk is generally insufficient to meet the dietary needs of a developing infant. So what should breastfeeding mothers do to help solve this problem? In order to transfer enough vitamin D to breast milk, research reports that breastfed mothers need to take enough Vitamin D per day. Pediatricians also strongly recommend supplementing infants with vitamin D. However, even if you supplement your baby with vitamin D, it’s still important for you, a breastfeeding mother, to supplement yourself in order to prevent the depletion of your own vitamin D stores.

2. Obtaining a sufficient amount of Omega-3s fatty acids EPA and DHA during breastfeeding is critical –

DHA is very important for both mother and baby during pregnancy, and in order to provide enough amount for her fetus, a mother’s DHA stores can easily become depleted. Unfortunately, this cycle continues when you are breastfeeding. In short, if your DHA intake is low, then the amount in your breast milk will be low. American Pregnancy Association recommended that pregnant and lactating women take at least 300 mg of DHA per day. Meanwhile, don’t forget other key omega-3s, EPA. More importantly, the consumption of sufficient amounts of EPA and DHA has also proven beneficial to body composition. Some studies have shown that supplementation with Omega-3s fatty acids can help women recover to pre-pregnancy weight more quickly, especially combine with breastfeeding.