Phytates

Phytic acid is a natural compound found in whole grains, legumes, nuts and seeds, where it helps seeds store phosphorus. It can bind calcium, iron, zinc and magnesium in the same meal and reduce how much of those minerals you absorb. In places where diets consist almost entirely of unleavened wholegrain bread with little else, this has caused real mineral deficiencies. But that's quite different from eating a varied diet that includes grains or legumes alongside other foods.

Interestingly, research looking at real-world eating patterns finds that people who eat more whole grains and legumes tend to have neutral or even better bone outcomes, not worse ones. Some studies link higher phytate intake with lower fracture risk, and lab research suggests phytate might even help slow the breakdown of bone mineral. This is likely because foods containing phytate also bring along magnesium, potassium, fibre, protein and vitamin K, which support bone health.

You don't need to avoid these foods. Normal preparation, soaking, sprouting, fermenting and leavening, naturally reduces phytate content; it's part of why traditional sourdough bread and soaked beans exist. Pairing vitamin C with meals can help iron absorption, and it's sensible to avoid taking mineral supplements at the same time as your highest-phytate meal. Cutting out whole food groups over concerns like this often causes more harm than the phytates themselves, through lower calcium, protein and fibre intake.