In general I think we should try to meet most of our nutrient needs by eating fresh foods.
After all, that’s the the way humans are adapted to absorbing nutrients. Isolated, synthetic nutrients don’t have the same effect on our bodies, because most nutrients require co-factors and enzymes to be properly absorbed and activated. These are not often present in supplements.
Cod liver oil is a notable exception. In fact, even though most people think of it as a supplement, it’s more accurate to refer to it as a food – or perhaps “superfood”.
In particular, I recommend that all men and women trying to get pregnant, and all women that are pregnant and breastfeeding, take fermented cod liver oil (sold by Green Pastures – I have no affiliation with them).
Why cod liver oil?
- It has large amounts of pre-formed vitamin A (retinol). Vitamin A plays several crucial roles in reproductive health. It promotes full-term pregnancy, proper development of the face, kidneys and lungs and prevents prolonged labor, deafness and internal organ displacement – among other things. As I mentioned in a previous article Why You Can’t Get Vitamin A From Vegetables, animal foods like liver and cod liver oil are the only significant sources of vitamin A in the diet.
- It has more vitamin D per unit weight than any other common food. Vitamin D is another important nutrient for fertility and pregnancy that up to 50% of women are deficient in. Vitamin D promotes proper development of the bones, especially in the 3rd trimester when the fetal skeleton begins to grow rapidly. It also plays a role in the development of the lungs, and protects newborns from tetany, convulsions and heart failure.
- It has vitamin E, vitamin K2 (mk-7 form) and various quinones. These fat-soluble vitamins are important to health and, in the case of K2 especially, aren’t commonly found in foods.
- It has healthy amounts of the long-chain omega-3 fatty acids, EPA & DHA. DHA is particularly important for fertility (both male and female) and pregnancy. DHA is preferentially incorporated into the rapidly developing brain during pregnancy and the first two years of infancy, concentrating in the grey matter and the eyes. It’s also crucial to the formation of neurons – the functional cells of the brain – and to protecting the brain from oxidative damage.
Why do I specifically recommend Green Pastures fermented cod liver oil?
- It is cold-processed through fermentation. This is important because processing with heat (which is what almost all other brands do) can damage the fragile long-chain omega-3 fatty acids, which in turn makes them potentially harmful to ingest.
- It contains naturally occurring fat-soluble vitamins. Most companies bleach and deodorize the cod liver oil in processing it, and before they do that, they have to remove the naturally occurring vitamins to prevent them from becoming damaged. Then they add the vitamins back in afterward – except that when they do, they add back synthetic vitamins instead of the naturally occurring ones.
I recommend a dose of between 5 mL to 10 mL per day for women trying to get pregnant or who are already pregnant or breastfeeding, and a dose of 5 mL per day for men.