References used for all of the nutrient pages can be found at the bottom of the Nutrition Facts page. Click here.

How Much Calcium Do I Need?

  • RDA for Adults 19-50 is 1000 mg/d

  • RDA for Adults >50 is 1200 mg/d

  • Upper Safe Limit for Adults 19-50 is 2500 mg/d

  • ​Upper Safe Limit for Adults >50 is 2000 mg/d

Why Do I Need Calcium?

Calcium is well known for its important role in bone health and 99% of our calcium resides in our bones. The other 1% of our body's calcium is in our blood where it plays a critical role in the following:

  • Regulation of muscle contraction

  • Clotting of blood

  • Transmission of nerve impulses

  • Secretion of hormones

  • Activation of  some enzyme reactions​

The 1% of calcium in our blood is so important to life that our bones act as a bank that the body can use to withdraw and deposit calcium as needed to maintain adequate levels. A diet that is consistently low in calcium will not be reflected in low blood calcium levels because this level is kept constant by taking calcium from bone. This means that a calcium deficiency will likely go unnoticed until it shows up as osteoporosis later in life.

Plant-Based Sources

  • The best absorbed plant-based sources of calcium are leafy greens such as kale, collard greens, bok choy, mustard greens and turnip greens

  • Other good sources include fortified soy milk, calcium set tofu, fortified orange juice and broccoli

  • There is calcium in beans, almonds, sesame seeds and greens such as spinach, chard and beet greens but the calcium in these foods is poorly absorbed


Calcium Content (mg)

Collard greens, cooked, 1 cup


Kale, cooked, 1 cup


Bok choy, cooked, 1 cup


Mustard greens, cooked, 1 cup


Turnip greens, cooked, 1 cup


Broccoli, cooked, 1 cup


Tofu, firm, calcium-set, 1/2 cup


Soy milk, fortified, 1 cup


Almond milk, fortified, 1 cup


Orange juice, fortified, 1 cup


Soy yogurt, 6 oz


Deficiency Symptoms

  • Bone loss (osteoporosis)

Toxicity Symptoms

  • Constipation

  • Increased risk of kidney stones

  • Interference with absorption of other minerals

How to Assess Status

  • As mentioned before, blood calcium is not a good indicator of dietary intake because blood calcium is tightly regulated by the body and the bones give up calcium as needed to replete blood levels

  • ​Talk to your physician about appropriate tests to screen for osteoporosis and pay attention to your diet to ensure that you are including several calcium rich sources in your diet each day to meet the RDA


  • Obtaining adequate calcium on a plant-based diet is not hard but you do need to know which foods are good sources and make sure you are getting enough each day
  • There is a common myth among vegans that they have lower calcium needs than those following the standard American diet due to the protective factors in the alkaline nature of a plant heavy diet
  • However, new evidence debunks this long-standing theory as is discussed in Dr. Greger's video below


Please check out the following videos and article related to calcium:


Kristen Zaier, ​​Plant-Based RD