Is Dairy the Best Calcium Source?

A public light has been shone on dairy as proper source of calcium to build and maintain strong bones. In this case, lactovegetarians are able to easily meet their calcium needs through daily cheese, milk, and yogurt intake. Because dairy is excluded from the vegan diet, all vegans (especially young vegan women) should take note of their calcium sources. To maintain calcium homeostasis the following is required: adequate calcium intake, a proper vitamin D status, and regulation of sodium, alcohol, and caffeine intake.

 

Calcium Homeostasis

If blood calcium concentration falls below its normal level (8.5-10 mg/dl), a mechanism is set into action to bring the blood concentration back to normal in order to achieve calcium homeostasis. One mechanism is to increase calcium reabsorption from the kidney, instead of calcium being excreted through the urine. The second mechanism, however, is to pull calcium from the bone leading to bone breakdown.

 

Is Dairy the Best Calcium Source?

Research has indicated that although dairy is a good source of calcium, the animal protein in dairy may actually be a reason for calcium loss in the urine; similar to alcohol, caffeine, and sodium. In fact, a positive correlation was found between the intake of animal protein and the incidence of hip fractures; plant protein intake was inversely related1. Furthermore, the incidence of hip fractures and osteoporosis was discovered to be more common in locations, which calcium intakes are high and dairy consumption is daily2.

 

Absorption of Calcium from Plant Sources

Just as the past articles about iron and zinc, the absorption of calcium is also inhibited by phytates. Thus, by soaking, sprouting, fermenting, blending, or juicing plant foods, the bioavailability of calcium (the capacity of absorption by the intestine) is significantly increased. Furthermore, calcium absorption is also hindered by a tight bond with oxalic acid, which greatly reduces calcium absorption from foods such as spinach, Swiss chard, amaranth, and whole sesame seeds; making these poor sources of usable calcium. Oxalates can be removed from foods by soaking, however the calcium remains bonded to the oxalate in the surrounding liquid. Boiling however has been shown to reduce the total oxalate content in spinach by 60%.

Nonetheless, the calcium intakes of vegans tend to fall below the recommended intake, so many vegans may find it convenient to use calcium-fortified foods (see list) or dietary supplements to maintain calcium homeostasis.

Final thought by Dr. Campbell, head of nutritional research for the China Project: “[the data collected by the china study] indicate that people need less calcium than we think and can get adequate amounts from vegetable source plant food3.”

 

 

Vegan Friendly Calcium Sources:

Food

Milligrams per Serving

Calcium-enriched orange juice, 1 cup

300

Fortified rice/almond/soy milk, 1 cup

300

Sea cucumber, fresh, 3 oz

285

Amaranth, raw, ½ cup (high oxalate)

150

Seaweed, dry (hijiki), 10 g

140

Tofu, firm, made with calcium sulphate, 3 ½ oz

125

White beans, ½ cup

100

Turnip greens, boiled, ½ cup

99

Almonds, dry roasted, ¼ cup

95

Whole sesame seeds, 1 tbsp

90

Blackstrap molasses, 1 tbsp

80

Mustard greens, boiled, ½ cup

76

Seaweed, dry (agar), 10g

76

Chinese cabbage / Bok choy, ½ cup

75

Okra, frozen, ½ cup

75

Tahini (sesame seed butter), 1tbsp

63

Navy Beans, ½ cup

60

Orange, 1 medium

55

Brazil, hazelnuts, ¼ cup

55

Dried figs, 2 medium

54

Kale, raw, chopped, ½ cup

50

Chinese broccoli (gai lan), ½ cup

44

Almond butter, 1 tbsp

43

Black beans, canned, ½ cup

42

Regular molasses, 1 tbsp

41

Pinto beans/chick peas, ½ cup

40

Whole wheat flour, 1 cup

40

Broccoli, raw, ½ cup

21

Regular rice/almond/soy milk, 1 cup

20

 

Recommended Dietary Allowance (RDA) for Calcium

Age

Male Female Pregnancy

Lactation

14-18 years

1,300 mg

1,300 mg 1,300 mg

1,300 mg

19-50 years

1,000 mg

1,000 mg 1,000 mg

1,000 mg

51-70 years

1,000 mg

1,2000 mg

   

 

Resources:

  1. Frassetto LA , Todd KM, Morris RC Jr. Sebastian A. Worldwide incidence of hip fracture in elderly women: relation to consumption of animal and vegetable foods. J Gerontol A Biol Sci Med Sci. 2000, 55(10):M585-92]
  2. Maggi S, Kelsey JL, Litvak J, Hayes SP. Incidence of hip fractures in the elderly: a cross-sectional analysis. Osteoporosis Int. 1991;1:232-41.
  3. Brody E., Jane. May 8, 1990. Huge Study of Diet Indicts Fat and Meat. The New York Times. http://www.nytimes.com/1990/05/08/science/huge-study-of-diet-indicts-fat-and-meat.html?pagewanted=all
  4. Mahan, L., & Escott-Stump, S. (2011). Nutrition and Bone Health. In Krause’s Food & Nutrition Therapy (13th ed., pp. 614-635). St. Louis, MO: Saunders/Elsevier.
  5. Davis, Brenda, RD & Melina, Vesanto, MS, RD. (2014). Minding Your Minerals. Becoming Vegan Comprehensive Edition (1st ed., pp. 4106-4736). Summertown, TN 38483: Book Publishing Company.
  6. Mangels AR et al. The Dietitians guide to Vegetarian Diets. (3rd ed.). Mississauga, Ontario. Jones and Bartlett Learning.

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