Fish or Nuts? Dietary Effects on Cardiometabolic Risk Factors and Persistent Organic Pollutants

At inclusion demographic information recorded, including length of breastfeeding for women. Thereafter, participants will start with a run-in period of two weeks where they will be asked not to consume salmon, mackerel, sardines or other fatty fish or nuts providing a dietary baseline. At baseline, subjects will be randomized to a fish, nuts or control group. The fish group will be asked to consume three to four portions weekly. The fish will be eaten at the main meal and in sandwiches for a total of 600 grams weekly for 6 months. This group will avoid eating nuts. The nut group will consume equal amount of energy (\~1400 kcal ) for weekly use for 6 months. This group will avoid eating fatty fish. The control group will consume their usual diet, but asked to avoid fatty fish and nuts.

At baseline (conditions for baseline are the same in all three groups) the nut group will consume equal amount of energy (\~1400 kcal \~100 grams walnuts, \~50 grams hazelnuts and \~50 grams almonds/week).The nuts will be provided free of charge for the six months. This group will avoid eating fatty fish.

After the baseline the control group will consume their usual diet, asked to avoid fatty fish and nuts.