Monday, May 16, 2011

Vegan Nutrition: Calcium

Calcium is important for bones, which are constantly being broken down and built back up. Vitamin D regulates calcium absorption and excretion, especially when calcium intake is low.

Calcium is a component of bones, but is more immediately needed in the blood to keep muscles, such as the heart, contracting efficiently. The body preserves blood calcium levels at the expense of bone calcium. Calcium alone though is not enough to keep bones healthy. It is combination a of a balanced calcium and Vitamin D intake.

While not found in many foods, vitamin D can be made by the action of sunlight (UV rays) on skin.

If you get exposed to the following amounts of midday sun (10 am to 2 pm), without sunscreen, on a day when sunburn is possible (i.e., not winter or cloudy), then you do not need any dietary vitamin D that day:

Chart below for Calcium content in various vegetarian foods.

Calcium Tips

  • Many non-dairy milks are now fortified with calcium, vitamin D, and/or vitamin B12. Many orange juices are fortified with calcium.
  • Shake calcium fortified non-dairy milks before pouring as the calcium can settle to the bottom.
  • The calcium in kale, broccoli, collard greens, and soymilk is all absorbed relatively well.
  • The calcium in spinach, Swiss chard, and beet greens is not well absorbed, due to their high content of oxalates, which bind calcium.
  • Calcium supplements can inhibit iron absorption if eaten at the same time.
  • In addition to the calcium in the leafy greens listed on the right, leafy greens also contain vitamin K which is good for bones.
  • The Daily Value for calcium on food labels is 1,000 mg. Therefore,if a food label says it has 25% of the daily value, it means it has 250 mg of calcium per serving.
Most people seem to be getting enough calcium, whereas vitamin D is a bigger concern. Hence a lot of the alternative or regular milk is often fortified with Vitamin D. More Detailed research, statistics and the Complete article at

Another link of interest and the calcium content chart from the link.

As mentioned on the chart, Oxalic acid, which is found in spinach, rhubarb, chard, and beet greens binds with the calcium in those foods and reduces its absorption. These foods should not be considered good sources of calcium. Calcium in other green vegetables, like kale, collard greens, Chinese mustard greens, and Chinese cabbage flower leaves is well absorbed. Fiber appears to have little effect on calcium absorption.

The US recommended intake for calcium is 1,000 mg for most adults. The UK's recommended intake is 700 mg. Given the results of the EPIC-Oxford study on vegan fracture rates, it is prudent to get 700 mg per day.
For the average vegan, a well balanced diet can usually take care of the calcium intake. To ensure optimal levels, drinking one glass of fortified milk or orange juice each day in addition to an otherwise balanced diet will work just well!!

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