We eat well, very locally and solid nutrition. And my son (autistic) still got deficient in lots of vitamins and minerals. His body has higher needs than food can meet (or at least meet with what he would happily eat). I think that is also true for most pg/nursing mamas, and people dealing with any kinds of health issues.
It *may* be possible to meet all vite/mineral needs through food, but I think you'd need to very specifically concentrate on doing that. For us, I want food to be an enjoyable part of our day - I don't want to obsess about whether my son has gotten enough B3 or magnesium from his food on any given day. So we do supps so I don't need to worry about it.
Also, when you eat locally, and eat what's in season, food intake and vites/minerals can really vary, as can mineral content of local soils. Our local soils are very low in lithium for example, and all 4 of us tested redline low in lithium on a hair test. Lithium is involved in using calcium and magnesium properly in the body. Sun exposure can really vary vite D levels. I know we'd be D deficient if we didn't supp, we don't eat enough fish to maintain levels through an Oregon winter.
The best food sources of mag are also high in omega 6s, which inflammatory (a problem in my family history of autoimmune issues). Most sources strong in zinc are also strong in copper, which is a problem for my son (autism) and my husband (migraines). So sometimes food doesn't provide the optimal balance of vitamins and minerals for every person.
And last consideration for us, if you have any digestive issues, you aren't getting all the nutrition from the food you eat. Lots of people have issues with low stomach acid, bile/pancreatic enzymes not releasing/activating properly, genetics that have trouble digesting fat or carbs or protein, or absorbing B12. High quality vites/minerals are often better absorbed by people with any of these kinds of issues. My son, for example, doesn't digest whole/partial nuts AT ALL - he poops them straight out. So I grind pumpkin seeds to flour and bake with those, and hope he can digest them and get the nutrients - but I can't tell if he's pooping pumpkin seed flour - he may well be.
Obviously my bias comes from a son with clear issues and a family history with plenty as well. Not saying everyone needs to supp, this is just a book
on why we do.
