Calcium Natural Sources

Of all the micro nutrients in our diet calcium is one of the big ones, requiring a whopping 1000mg per day. Although milk is often thought of the premium calcium source it is relatively low on these list of calcium rich foods. For calcium sources choose hard cheeses, seeds like sesame – tahini, chia, poppy, flax, nuts like almonds and brazil as well as dark leafy greens such as kale.

Daily Calcium Requirements

Infants       0-1            210-270mg

Children    1-3 yrs     500mg / 4-8yrs     800mg / 9-18yrs  1300mg

Adults                       1000mg

Pregnancy               1000mg

Lactation                 1300mg


Calcium Rich Foods

Spices, poppy seed: 1438mg  

Cheese, parmesan, hard: 1184mg

Cheese, romano: 1064mg

Cheese, gruyere: 1011mg

Tahini: 960mg

Cheese, goat, hard type: 895mg  

Cheese, swiss: 791mg

Cheese, provolone: 756mg  

Cheese, monterey: 746mg  

Cheese, edam: 731mg  

Cheese, cheddar: 721mg

Cheese, gouda: 700mg  

Cheese, colby: 685mg

Seeds, chia seeds, dried: 631mg  

Seaweed, agar, dried: 625mg

Cheese, blue: 528mg  

Cheese, mozzarella, whole milk: 505mg

Cheese, limburger: 497mg  

Cheese, feta: 493mg  

Sardine, with bone: 382mg 

Sesame seeds: 330mg

Carob, unsweetened: 303mg  

Cheese, goat, semisoft type: 298mg 

Almond butter: 270mg 

Almonds: 266mg 

Flaxseed: 255mg

Fish, anchovy, european, canned in oil, drained solids: 232mg 

Fish, salmon, pink, canned, solids with bone and liquid: 213mg 

Cheese, ricotta, whole milk: 207mg  

Kale, scotch, raw: 205mg  

Molasses: 205mg

LSA (miled linseed, sunflower seed and Almond): 202mg 

Dandelion greens, raw: 187mg

Yoghurt, natural: 185mg 

Cheese, brie: 184mg

Seaweed, kelp: 168mg  

Brazilnuts: 160mg  

Fungi, Cloud ears, dried: 159mg

Seaweed, wakame, raw: 150mg  

Taro, cooked: 149mg  

Cocoa powder: 149mg

Bok choy: 123mg

Milk, regular fat: 98mg


Calcium Supplements

Some calcium supplements are very hard to digest, while others are easier. Best forms – Calcium citrate, calcium citrate malate and calcium gluconate. Natural seaweed based calciums are also easily absorbed and used by the body.

Forms such as calcium orotate and carbonate are cheap, very hard to digest and should be avoided.

Also calcium carbonate from oyster shells or dolomite may be contaminated with heavy metals such as lead and aluminium.

Calcium hydroxyappetite is made from crushed bones and has been found to be more easily absorbed than carbonate and orotate.


Calcium absorption inhibited by:

Phytate: (phytic acid) inhibits calcium absorption. 

Some fibres – bind to calcium and decrease absorption.

Oxalate – chelates calcium and increases fecal calcium excretion. Oxaltes are found in – spinach, rhubarb, swiss chard, celery, beets, eggplant, green okra, squash, blueberries, strawberries, blackberries, gooseberries, nuts – peanuts, pecans, tea, ovaltine, cocoa.

Magnesium, zinc and iron all compete with calcium for absorption.

Unabsorbed fatty acids in significant quantities in the gastrointestinal tract, form insoluble calcium soaps which cannot be absorbed and are therefore excreted in faeces.

Caffeine; produces small increases in urinary calcium excretion. It may also increase secretion of calcium into the GIT increasing fecal loss.

Alcohol; It is not known how, probably through increased urinary excretion due to increased urination.

Boron supplements greater than 3mg given with magnesium supplements greater than 200mg increase urinary calcium loss.

Age, due to decreased renal calcitriol production. 

High plasma phosphorus concentrations may also decrease renal calcitriol production.

Estrogen deficiency at menopause decreases vitamin D mediated calcium absorption. This is why it is really important to make sure your calcium stores are high before menopause begins.



Calcium absorption improved by;

Vitamin D – stimulates absorption, in small intestine.

Fructose oligosaccharides, inulin and other non digestible saccharides enhance paracellular Calcium absorption.

Ingesting food or lactose (especially in infants and children) with calcium improves absorption.

Sugars, sugar alcohol (such as xylitol) and protein improve absorption.

Bacteria in the colon help to release calcium that is bound to some fermentable fibres such as pectins, releasing 4% to 10% of Calcium absorbed in a day. 

The more you need the more you absorb, children absorb up to 75% of calcium ingested, whilst non lactating, non pregnant adults absorb only 30%.

Absorption increased with increases in parathyroid hormone.

It is estimated that 20% -50% of calcium from diet is absorbed, and 20%-35% form dairy products is absorbed (g). Absorption increases during pregnancy.