So I can't eat dairy, where's my calcium coming from?

Calcium is a mineral needed for healthy bones, teeth, and proper functioning of the heart, muscles, and nerves. In addition to calcium intake to maintain bone health, the CDC recommends 30 minutes of weight-bearing physical activity each day. Below are good sources of calcium:

• Dairy products
• Dark green leafy vegetables
• Calcium fortified foods
• Nuts

For those of us following the paleo diet, we must rely primarily upon dark green leafy veggies and nuts for our calcium. Additionally, Vitamin D assists the body in absorbing calcium (hence why milk is often fortified with Vitamin D), so we need to make sure that we're consuming enough Vitamin D.

After doing a little research, I've found that adult men (19-70) and adult women (19-50) require 1,000 mg/day of calcium, and adult women (51-70) require 1,200 mg/day. Refer to Dietary Reference Intakes for Calcium and Vitamin D, Institute of Medicine of the National Academies (Nov. 30, 2010).

Here's some information (from the Office of Dietary Supplements) that I've gathered on our alternate sources of calcium:
Turnip greens, fresh, boiled, ½ cup - 99 mg - 10% DV

Kale, fresh, cooked, 1 cup - 94 mg - 9% DV
Kale, raw, chopped, 1 cup - 90 mg - 9% DV

Chinese cabbage, bok choi, raw, shredded, 1 cup - 74 mg - 7% DV
Broccoli, raw, ½ cup - 14 mg - 1%

Almonds, raw, whole, 1 cup - 378 mg, 38%

Macadamia nut, raw, whole, 1 cup - 114 mg, 11%

For your comparison 1 cup of skim/non-fat milk contains 299 mg - 30% DV

Also, people have always told me that spinach is high in iron and calcium. However, thanks to a 7th grade science report, I know that spinach also contains oxalate acid. Oxalate acid binds with calcium, thus decreasing the absorption of calcium from spinach to about 5%, whereas the absorption efficiency of kale is close to 50%, bok choy is about 54%, and milk is 32% (from Calcium in Human Health, by Connie Weaver and Robert Proulx Heaney, 2006, p. 137). See the table below for a visual.

(from Calcium in Human Health, by Connie Weaver and Robert Proulx Heaney, 2006, p. 154)

To be honest, I am a little worried about my calcium. However, all of the paleo information I've read so far doesn't seem to be very concerned about calcium intake, saying that because of the large amount of vegetables and proteins we eat, and the lack of grains, the RDI (recommended daily intake) is overstated. I found these link to be pretty straight-forward and to have good references: http://thepaleodiet.com/faq#calcium-and-bones-paleo-diet-suggestions-for-bone-health, http://stevesoriginal.com/blog/paleo_calcium/

All in all, I'm slightly more comforted about my calcium intake. However I do intend to continue taking my daily vitamin supplement (I know that supplements are not something Paleolithic humans had; don't judge me). Better safe than sorry, eh?