Multivitamins are great maintenance tools to supplement a healthy balanced diet and to top up our vitamins and minerals from any gaps in nutrition. However, we don’t all fit into one box. We require different nutrients and in some cases, there are nutrients we need to avoid.
Some individuals have certain sensitivities to vitamins, and mainly minerals.
According to the NHS women require approximately 14.8mg of iron per day where as men require only 8.7mg.
There is no easy way to dispose of iron other than blood loss, which is why toxicity is less likely for women due to their monthly period.
Free iron can be toxic in high amounts. Normally, iron can circulate when bound safely to proteins like transferrin, however toxicity can increase free iron which results in pro-oxidant damage.
Some genetic disorders can result in excess asboprtion of iron. Hemochromatosis (which involves excessive uptake of iron from food) would result in the need to avoid iron in multivitamins.
Some individuals can suffer from choline metabolic disorder which would require avoiding supplementation. In instances like this, choline supplementation can cause a fishy body odour due to intestinal metabolism of choline to trimethylamine.
Wilson’s disease is a genetic disorder which is characterised by excess copper stored in parts of the body such as the liver, brain and eye tissue. Similarly, people with liver or kidney issues may have to avoid copper supplementation.
Generally, iodine consumption is not harmful, especially below 150mcg a day in adults who aren’t pregnant or lactating. However, excess iodine can negatively impact someone with a thyroid condition, especially if it is driven by an existing iodine overload.