I have seen several posts recently written by people who have definite and sometimes severe vitamin deficiencies, particularly Vitamin D, and are hypothyroid (usually with antibodies). This makes me wonder which is the chicken and which the egg. I have heard it said that the low thyroid causes low stomach acid so that nutrients are not properly absorbed, which causes the deficiencies, but I am beginning to wonder whether there is some other mechanism in play. Does our western indoor lifestyle play a part? Is there a lower incidence of hypothyroidism in countries where people have more sunlight or a vitamin-D rich diet? Is the incidence of hypothyroidism lower in places where they have higher B12 levels? Is there something about having healthy levels of these nutrients that helps our bodies keep thyroid antibodies in check?
I know it's popular to blame problems on 'leaky gut' and gluten but it does seem to be anecdotal rather than statistical at present. It would be interesting to know whether there are populations of people around the world who have much lower levels of hypothyroidism, and what we can learn from them.