A study in Sweden has shown that iodine deficiency could be a side effect of long-term paleo diet. Use of dietary items with “paleo” on the label has increased by 8% in one year. The study in Sweden used 70 healthy obese women with similar iodine levels at the beginning, and they should decreases of iodine levels in the paleo group versus the NNR (Nordic Nutrition Recommendations) group. Levels increased again at 6 months and 2 years, but not to the previous levels. Therefore, it was recommended to use an iodine supplement while on the paleo diet.