Updated: Mar 3
I’ve always been a fat lover.
Yes, you heard me: I love fat. Even when the low-fat craze was in full swing back in the early 2000’s and I went to school to study nutrition, I always tired to buy full fat dairy (hard to find back then!), I didn’t skip the butter on my veggies or the oil in my salad and I sure as hell ate my egg yolks. Skim milk? Forget about it. I know this got me lots of side eye from my roommates….
Fast forward to 2019, we now know, fat is actually really important for us. It serves hundreds of important functions, including brain health, transport of fat-soluble vitamins, hormone regulation, optimizing our metabolism and more. Some go as far as speculating we are getting fatter not in spite of but because of our low fat craze (source)!
Now, I’m not advocating for a Keto or Atkins diet while breastfeeding (I will cover the 'why' in a later blog post). However, fat is important for any human, but especially for breastfeeding moms and their babies.
Let’s look at breast milk specifically.
How much Fat is in Breast Milk?
Breast milk is not a ‘low fat’ food by any means. About 50% of calories in breast milk come from fat (source)! Fat is generally higher in human than cow's milk, at around 3.8 – 4.2% milk fat (whole cow's milk has 3.5% milk fat), although there are factors which influence its total fat content and it is therefore difficult to say how much fat is in your specific breast milk at any given time (see below).
But the point is: your baby is definitely not on a ‘low fat diet’. Nor should they be!
Fat serves crucial roles in your baby’s development, especially for the brain and central nervous system: (If you’re not much into scienc-y stuff, skip these next few bullet points)
Your baby’s brain doubles in weight over the first 6 months of life. New synapses are formed at rates of up to 40 000 per second (!) through the first year after birth (source). DocosahexaenoicAcid (DHA), a fatty acid found in fish and fish oil, is a necessary part of these neural synapses and signaling membranes and therefore plays extremely important roles in your baby's development of the brain, the eyes and the central nervous system. This continues way beyond the time your baby is born, so DHA is not only important during pregnancy, but also for the first years of life and beyond.
HAMLET (human α-lactalbumin made lethal to tumor cells) is the name of a substance present in your milk that has been shown to selectively kill tumor cells (yes, your milk can kill cancer cells!). HAMLET needs a very specific fatty acid - Oleic Acid - to be formed (source). Oleic Acid can be found in olive oil, nuts and high oleic sunflower oil.
Medium and Short Chain Fatty Acids enable your breasts to secrete its milk fat as droplets, the so called Human Milk Fat Globule (HMFG). Aside from transporting milk fat and several other important nutrients, the HMFG helps to mature baby's gut and fight off microbes, bacteria and viruses (source).
Medium Chain Fatty Acids in breast milk also increase the absorption of Calcium and Magnesium, serve as precursors for important biological molecules and may have a positive effect on the prevention of obesity (source).
The omega-6 fatty acids Arachidonic Acid (ARA) plays important roles as a component in the cell membranes of muscles, heart, kidneys and liver and as a precursor to eicosanoids (source). So yes, not just omega-3 fatty acids, but omega-6 fatty acids are also important!
These are just a few select examples where different fatty acids serve different (and highly important!) functions - not just in your baby's brain, but in virtually all aspects of your baby's development!
Can I increase the fat in my breast milk?
No, your diet does not affect the total amount of fat in your diet. Your breast milk contains roughly 11 grams of fat per cup (about 3 grams more per cup than whole cow's milk!), but it is not primarily your diet that influences your breast milk's fat content.
Rather, your age and weight, the time of day, your baby's age and how 'empty' your breast is (because hindmilk is higher in fat than foremilk) determine its fat content.
However, your diet is the most important factor in the composition of the different fatty acids in your milk.
A Little Explanation on Fats and Fatty Acids
Every fat, also known as a "Triglyceride", consists of three of those fatty acids and a glycerol backbone. The fatty acids differ greatly in their structure and function. They can be saturated or unsaturated, have a short, medium or long chain, have their (first) double bond at the third ('omega-3'), sixth ('omega-6') or ninth ('omega-9') carbon atom from the end of the chain, or have a cis or trans configuration ("Trans Fat").
Essentially, fat is made up of different fatty acids, and each has a different effect on the body.
The composition of all of those different fatty acids in your breast milk primarily depends on your diet. And that's where you have the ability to positively change your breast milk's fatty acid composition and your baby's development and lifelong health (and not just with fish oil)!
4 Ways to Add Healthy Fats to Your Breast Milk
1. Mix and Match "Healthy Fats" with every meal!
Make it a point to include at least one 'Healthy Fat' into every meal.
Studies have shown, the fatty acid composition of your breast milk is primarily influenced by the fatty acids in your diet. Within just a day or two, you can positively influence your breast milk's fatty acid composition by including Healthy Fats into your meals! But don't forget:
Mix it up. Different foods contain different healthy fats that serve different functions in the body. Also, some fatty acids share some of the same enzymes, such as the omega-3 series with the omega-6 series. Too much of one type of fatty acid may therefore suppress the synthesis of others.
Be creative with meal planning! You could, for example, add walnuts to your morning smoothie, spread mashed avocado instead of mayo on your sandwich for lunch and serve vegetables sautéed in olive oil with your dinner. The following day, switch the walnuts for flax seed in your smoothie, eat salad with a boiled egg for lunch (be sure to also eat the egg yolk that contains most of the fat!) and serve low-mercury fish for dinner.
2. Eat Fish from the Sea!
Eat fish low in mercury and other contaminants 2 to 3 times per week, such as Salmon, Herring, Sardines or Pacific Mackerel.
The long chain omega-3 fatty acids DHA (Docosahexaenoic Acid) and EPA (Eicosapenaenoic Acid), which are important for baby's brain and visual development, are pretty much only sourced from Marine Fish and Microalgae.
Two to three portions of fish equal just about 8 to 12 ounces per week, or 228 to 340 grams, which is what is recommended by the Dietary Guidelines for Americans. However, the content of DHA and EPA, as does mercury contamination, varies between species, so choose wisely! The handout "Your Best Choice of Fish during Pregnancy and while Breastfeeding" can help you select Fish with the least amount of Mercury and most amount of DHA and EPA.
Why not just take Fish Oil?
You can certainly take Fish Oil if you absolutely hate fish, can't afford fish or for any other reason. However, I do recommend eating the 'real deal' at least once in a while.
Why? The healthy DHA fat works together with other nutrients which are found in fish (but not in supplements), such as Choline, to support baby's brain development (source). Fish is also is a great source of Vitamin D, Selenium, Zinc and other nutrients important in baby's development, which you'd be missing out on if you only took isolated Fish Oil Supplements. Those nutrients are hard to find in other foods!
3. Balance your Macros
Aim for a macronutrient distribution somewhere around 50% (of calories from) carbohydrates (288 grams), 30% fat (77 grams) and 20% protein (115 grams).
The reason? Your diet's fat to carbohydrate ratio influences your breast milk's fatty acid composition as well! The mammary gland starts making her own fatty acids under low fat and high carbohydrate conditions - and it prefers to make short and medium chain fatty acids, which we learned are super beneficial.
Researchers at Baylor College of Medicine found that milk samples expressed after high carb/low fat meals were much higher in Medium and Short Chain Fatty Acids - 2 and a half times as much - compared to the low carb/high fat meals (source).
The composition of your breast milk's fatty acids changes, depending on whether your meal contains more carbohydrates or more fat. But don't just go 'low carb' or 'high carb'. We need the right balance of short, medium and long chain fatty acids, as they each have distinct functions.
I recommend for you to balance your Macronutrients to a ratio somewhere around 50:30:20. Neither a high fat nor a high carbohydrate diet is a good approach while breastfeeding.
The "Plate Method" is a great way to balance your meals without having to do some major calculations before each meal.
What is the "Plate Method"?
It is a tool Dietitians often use to 'simplify' healthy eating. Not everybody has time to check every food and label for calorie content and grams of fat, carbs and protein - let alone calculate the calorie distribution for each macronutrient. In any case, the 50/30/20 'rule' is just a ballpark, and doesn't have to be followed to a 'T'.
With the Plate Method, envision every meal you eat, separated on a plate in front of you. With the exception of Breakfast, load half of your plate with non-starchy vegetables. Load another quarter with your grain or starchy food, and the other quarter with your protein source (meat, fish, eggs, etc.). Include a Healthy Fat with every meal, such as Olive Oil on your veggies, butter or coconut oil on your toast or a whole milk product. That way, you'll automatically land in the ballpark of a 50/30/20 ratio.
4. Scratch Man Made Trans Fats from your Diet
In my opinion, all fats are part of a healthy diet (including saturated fats from butter etc.). However, there is one type of fat which we should avoid like the plague, especially while pregnant or breastfeeding: Trans fats. Specifically, man made trans fats (there are some naturally occurring trans fats which are beneficial).
Trans fats are fatty acids which are formed when hydrogen is added to vegetable oil during a process called 'hydrogenation'. Hydrogenation makes a fat more solid. Hence, you can find trans fats mostly in baked goods (Cakes, Donuts, Bread , Cookies etc.), fried foods (French Fries, Chicken Nuggets etc.), Fast Food (Pizza, Burgers etc.), Potato Chips, Mayonnaise, Shortening, Ice Cream and pretty much anything made with (partially) hydrogenated vegetable, corn or soybean oil.
Trans fats have a whole list of negative effects on the body. They raise the level of LDL ("bad" cholesterol), increase the risk of chronic diseases, such as cardiovascular disease and diabetes, and may trigger allergic symptoms, such as asthma, allergic rhinitis and atopic eczema. Since they transfer into breast milk, they decrease the level of other (essential!) fatty acids and can decrease the formation of DHA and ARA from their precursors (source).
Because man made trans fats have a bunch of negative and no positive effect on your breast milk's fatty acid composition, eliminate trans fats from your diet as best as you can. You can start by choosing mostly unprocessed foods and cooking your foods at home, rather than eating out (trans fats are often found in commercial frying and cooking oil, especially the type that is reheated over and over such as in fast food places).
But packaged foods aren't completely off the table. Look for the word "Trans Fat" in the Nutrition Facts Label. If it contains even small amounts of trans fats, scratch it! Nowadays, even processed foods can easily be made without 'trans fats' without affecting their taste, so simply choose products without trans fats. But caution: A product can contain up to 0.5 grams of trans fat per serving, and still be labeled as having "0 grams trans fats". Therefore, if you are unsure about a product, scan the ingredients list for the word 'partially hydrogenated oil', as this means the product may still contain small amounts of trans fats.
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