Thursday, 1 August 2013

What can we learn for breast milk? Part 2: Micronutrients

All these calculations use 84 grams of protein worth of breast milk, to normalise it to the minimum needed for an adult (see part 1).

I'm also aware that the nutritional content of breast milk varies depending on the mother's diet but using the USDA data for it means we get a nice average of an American (which I'm aware may not be the best nutritionally).

Here's my CRONometer print out for the breast milk at 84g of protein (ignore chromium, there's just no data for it):


Let's start with vitamin A, this amount of breast milk provides ~16.5kIU vitamin A which is quite a bit and more than what I or the WAPF recommend (10kIU). Infants are growing rapidly and so need more vitamin A though, so this is fine.

With the B vitamins everything is in normal meaty amounts, except the B2 is slightly higher and B5 is a lot higher. B5 is needed for forming acteyl-coA so may be high due to the infant's high energy requirement, it's also used in the synthesis of fatty acids and cholesterol so again good reasons for it to be high. B6 is also fairly low, but the milk provides huge amounts of folate and choline instead so homocysteine levels will be fine. The WAPF comments that most mothers are also deficiency in B6 due to low meat consumption  The amount of choline is so incredibly high due (9 large eggs worth) to its other use for helping the developing brain. As previously discussed the amount of choline/folate/B6 needed are all interrelated.

Vitamin C is higher than would be gotten eating a carnivorous diet, but the protein needs for infants is very high and so little is left over to make uric acid, so breast milk supplies ascorbic acid instead.

Vitamin D is fairly low but almost all mothers are deficient in this vitamin. It's one of two supplements I recommend to everyone (the other being magnesium as soils are depleted), and should be supplemented based on your blood levels rather than a set IU amount.

The vitamin K is K1, as the USDA doesn't measure K2. It's quite low compared to the RDA and about twice the amount in 2000 calories worth of grain-fed rib-eye (grass-fed meat would have more K1 though), but as previously discussed K2 can do clotting like K1 so this is no problem.


As previously discussed in my post about calcium, breast milk in the amount an infant drinks (rather than 84g of protein worth) only provides ~320mg calcium a day and this should be fine for an adult too.

Magnesium is lower than the RDA but still about double provided by just meat. Again I'll note that most mothers are deficient in magnesium due to the soil being depleted and that's why I recommend supplementing it.

Phosphorus is at about half the level of calcium which is why I originally recommended a 2:1 calcium:phosphorus ratio but further research shows our calcium needs are lower. The total amount is similar to that found in 2000 calories of rib-eye so I'm happy that this amount is ideal for an adult.

The level of potassium is almost at the USDA RDA which is interesting and may warrant the use of more potassium in a carnivore diet. But the ideal potassium:sodium depends on whether you're in ketosis or not, with ketosis meaning more sodium is needed per potassium. Infants, as far as I'm aware are not in ketosis due to the lactose in breast milk and so have more potassium and less sodium (or at least only mild ketosis). Additionally the level of sodium in breast milk is quite low as infant's kidneys struggle somewhat with sodium initially and slowly improve as the infant grows. This means that an adult in ketosis needs much more sodium and less potassium.

With selenium, the level is almost three times the RDA, but similar to the amount recommended by most for proper thyroid health (200ug), again American mothers are likely to be slightly deficient in this so 150-200ug is properly the best amount.

The manganese is quite high in breast milk, and is needed for mitochondrial functioning so may be high due to an infant's high energy requirements.

The iron in breast milk is very low, as it is in all mammal milks, as iron interes with zinc absorption and zinc is needed for the developing brain. Infants have large iron stores when born (or at least they should do if the placenta is allowed to return the infant's blood back to its body after birth and not clamped early like is usually done in the developed world; as much as half an infant's total blood can be lost to the placenta with early cord clamping, which is a huge amount!) so little is needed in the diet until at least 6 months old (older if delayed clamping) and the first weaning foods should be high in iron such as meat or liver.

The copper in breast milk is actually pretty low, only ~0.6mg total a day (rather than per 84g protein) and an infant will slowly run down the coper stored developed before birth similar to what it does for iron, again meaning the best weaning food would be liver (from beef or lamb, not pork) as it's rich in copper too. This means that our copper requirement is more than ~0.6mg per day, and as discussed in the phytic acid nutrients post I recommend 1-2.4mg of copper a day.


We can see that looking at the vitamins and minerals of breast milk, again in the context of the body it's designed to nourish, gives is good insight into the nutrition of an adult. I points to us needing more retinol, calcium, magnesium, potassium, sodium, selenium, and copper than is normally achieved just eating fatty meat. This points to the need include a few other choice animal foods in our diets for optimal health.


  1. I have a question about PUFAs.

    PUFAs should be no more than 5% of our daily calories, correct? Does this mean that 5% of our daily calories are literally a combo of omega 3 and 6, or that 5% of our calories are the fat from fowl or fish.

    I'm asking because omega 3/6 are already 5% of the calories in even the least polyunsaturated animal fats like beef tallow or lamb tallow. What exactly is a polyunsaturated fat, is it just the omega 3/6 part of a fat? or does it refer to the whole fat, ie chicken fat is a 'polyunsaturated fat' and that should be 5% of our calories?

    1. I mean that total omega-3 and omega-6 calories should be no more than 5% of total calories.