Calcium
The most abundant mineral in the body, essential for strong bones and teeth, but also for muscle contraction, blood clotting and nerve transmission.
~99% of the body’s calcium is in the bones and teeth, which also act as a reservoir. The remaining 1%, in the blood and cells, is vital for muscle contraction (including the heart), blood clotting and nerve signalling. Blood calcium is very tightly regulated.
The original angle (misdirected calcium): the message “drink milk for calcium” is incomplete and sometimes misleading. Two major caveats:
- The calcium paradox: countries that consume a lot of dairy (the Nordic ones) paradoxically have some of the highest fracture rates. Calcium alone does not “make” strong bones: you need the cofactors.
- Calcium needs to be properly directed: without vitamin K2, absorbed calcium can be deposited in the arteries (calcification, cardiovascular risk) instead of the bones. K2 activates proteins that “steer” calcium towards the bone. It is the often-forgotten link.
The calcium team:
- Vitamin D: enables its absorption in the gut
- Vitamin K2: directs it to the bones and away from the arteries
- Magnesium: cofactor, balances calcium
- Protein and weight-bearing exercise: build the bone matrix
Sources beyond milk: sardines (with the bones), almonds, green vegetables (kale, broccoli), tofu, calcium-rich mineral waters, sesame seeds. Vegans can meet their needs with care.
The over-supplementation trap: taking large supplements of calcium alone (without K2, without the food context) could increase cardiovascular risk (arterial calcification). Calcium from food is preferable to isolated mega-doses.