For all of those on the Paleo diet, watch your iodine levels:
According to a recent study conducted in Sweden, women who ate according to a modified Paleo diet over a two year period experienced mild to moderate iodine deficiency, compared to other subjects who were following a "Nordic Nutrition" guidelines-based diet, which recommends:
Sufficient intake of monounsaturated fats
Limiting of saturated fats
25-35 grains daily of dietary fiber
Sufficient but not excessive protein
Limited added sugars
Increased vitamin D and selenium rich foods
Regular moderate intensity activity weekly
A group of researchers from Sweden presented these results at the annual meeting of the American Thyroid Association in 2013. The Paleo dieters were eating a high-protein, high-fat, low-carbohydrate diet focusing on lean meat, fish, fruits and vegetables, egss and nut. They excluded all gluten, grains, beans, refined foods, sugar, salt, and sodas.
The Paleo group's iodine levels decreased significantly at the two year point. In addition, median TSH levels rose after 2 years, and the Free T3 levels decreased in the Paleo group after six months, while those in the Nordic diet group did not.