Preheat the oven to 350 degrees F. Use a 8 1/2 by 4 1/2 by 2 1/2 inch , grease and flour the pan, placing parchment paper on the bottom.
Sift together the flour, salt, baking powder into one bowl and add the berries, chia seeds and hemp hearts. In a second bowl, mix the yogurt, eggs, vanilla, sugar and zest.
Whisk the dry ingredients into the wet ones and with a rubber spatula, fold the oil into the batter until is well incorporated. Pour batter into the prepared pan and bake for 55 minutes, or until tester comes out clean.
While the cake is in the oven, cook the 1/3 cup of lemon juice with 1/3 cup of sugar until the sugar dissolves and the mixture is clear. Set aside.
Once the cake is done, allow it to cool in the pan for 10 minutes. Place on a baking rack over a sheet pan and while the cake is still warm, pour the lemon - sugar mixture over the cake and allow it to soak in. Let cool.
For the glaze, and this is an optional step, combine the confectioners sugar with the lemon juice and pour over the loaf.