Wheat is consumed in large amounts in the U.S. and it lessens the ability to metabolize D3 even from sunlight. If you live above the 38th parallel you already have lower than optimum levels. Trying to get someone to give up wheat (not gluten) however is not easy.
Off topic, but wheat consumption is supposedly why Europeans evolved to have lighter skin pigmentation. The lack of melanin allows the skin to better absorb vitamin D from the sun.
Wheat is consumed in large amounts in the U.S. and it lessens the ability to metabolize D3 even from sunlight. If you live above the 38th parallel you already have lower than optimum levels. Trying to get someone to give up wheat (not gluten) however is not easy.
If you supplement with D3, be sure to take K2 with it as it enhances the absorption.
Off topic, but wheat consumption is supposedly why Europeans evolved to have lighter skin pigmentation. The lack of melanin allows the skin to better absorb vitamin D from the sun.
Gluten is IN wheat, the cause of allergic reactions.