Calcium absorption
- The human body contains about 1200 g calcium (99% in the skeleton i.e. bones and teeth & the remaining 1% is found in blood, extracellular fluid, muscle, and other tissue).
- About 30-35% of calcium ingested from dairy products is absorbed at an intake of 400 mg /day depending on the calcium status of the individual.
- A minimum of 140 mg/day of calcium is lost through urine.
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Dietary factors that enhance calcium absorption
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Dietary factors that inhibit calcium absorption
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Stomach acids
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Lack of stomach acids
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Vitamin D and growth hormones
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Deficiency of vitamin D
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Physiological state. Calcium must be in a water-soluble form to be absorbed. Approximately one third of calcium in dairy is in a water-soluble form, thus particularly well absorbed.
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Oxalates. Calcium in plant material is absorbed to a small extent as it contains substances that render the calcium insoluble in water.
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Phosphopeptides and lactose
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High phosphorus intake
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Sodium increases calcium excretion
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High dietary fibre
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Phytates present in beans, seeds, nuts and grains
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Non-dietary factors affecting calcium metabolism
- Age and estrogen status
- Pregnancy and lactation
Sources of High Calcium and Bio-Availability
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SOURCES OF CALCIUM AND BIOAVAILABILITY
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Food Product
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Ca content mg/100g
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Bio-avail Ca mg/100g
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Cheddar cheese
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788
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236
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Gouda cheese
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806
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242
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Feta cheese
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386
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116
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Maas
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162
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49
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Plain yoghurt
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149
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45
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Fruit yoghurt
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145
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44
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Buttermilk
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144
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43
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Low-fat milk
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122
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37
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Full-cream milk
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120
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36
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UHT whole milk
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117
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35
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Cottage cheese: fat-free
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120
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36
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Cottage cheese: full-cream
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111
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33
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Spinach, boiled
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109
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5
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Cauliflower, cooked
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12
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6
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Brussel sprouts
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47
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24
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Broccoli
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36
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18
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Cabbage
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29
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15
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Sardines, with bones
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240
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120
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Sweet potatoes, boiled, no skin
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9
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2
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Baked beans, canned
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34
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7
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Fortified maize meal, super
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5
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*
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Fortified maize meal, special
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9
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*
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Fortified maize meal, sifted
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12
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*
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Fortified white bread
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16
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*
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Fortified brown bread
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14
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*
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References
BHATIA V. 2008. Dietary calcium intake – a critical appraisal. Indian J Med Res (127)
GIBNEY MJ, VORSTER HH & KOK, FJ. 2002. Introduction to Human Nutrition.UK. Blackwell Publishing
WHITNEY EN & ROLFES RR. 2002. Understanding nutrition, 9th Ed. London. Wadsworth.
WARDLAW GM & SMITH AM. 2006. Contemporary nutrition, 5th Edition. McGraw and Hill. USA
HEANY RP, WEAVER CM AND RECKER RR.1988. Calcium absorbability from spinach. Am J Clin Nutr (47): 707
WEAVER CM AND PLAWECKI. 1994. Dietary Calcium: adequacy of a vegetarian diet. Am J Clin Nutr (59): 1238S
WEAVER CM, PROULX WR & HEANY R. 1998. Choices for achieving adequate dietary calcium within a vegetarian diet. Am J Clin Nutr.
KINAYMU HK, GALLAGHER JC, PRAHL JM et al. 1997. Association between intestinal vitamin D receptor, calcium absorption and serum 1.25 dihydroxyvitamin D in normal young and elderly women. J Bone Mineral Res. 12 (6): 922.
KALKWARF HJ, SPECKER BL, BIANCHI DC, RANZ RN & HO M. 1997. The effect of calcium supplementation on bone density during lactation and after weaning. N eng J Med. 337:523
KALKWARF HJ, SPECKER BL, HEUBI JE. VIEIRA NE, YERGEY AL. 1996. Intestinal calcium absorption of women during lactation and after weaning. Am J Clin Nutr. 63 94): 526
http://www.idfdairynutrition.org/. Health Professionals: Fact sheets on: 1) Calcium from milk fact sheet; 2) Osteoporosis:
SMIT LE; SMITH N; SCHÖNFELDT H & HEINZE PH. 1998. The Nutritional content of South African Cheeses. Dairy Industry Centre, Agricultural –Animal Nutrition and Animal Products Institute, Irene.
SMIT LE; SMITH N; SCHÖNFELDT H & HEINZE PH. 1998. The Nutritional content of South African Milk and Liquid Milk products. Dairy Industry Centre, Agricultural –Animal Nutrition and Animal Products Institute, Irene.
SMIT LE & SCHÖNFELDT H. 2006. The Nutritional content of South African Milk and Milk products. Dairy Industry Centre, Agricultural –Animal Nutrition and Animal Products Institute, Irene.
KRUGER M, SAYED M., LANGENHOVEN M. AND HOLING F. 1998. Composition of South African Foods: Vegetables and Fruit. pp 36. UDMS, Cape Town.
SOUTH AFRICAN DEPARTMENT OF HEALTH. 1996. Laboratory reports with analytical data on vegetables and fruits
DANSTER N, WOLMARANS P, BUITENDAG CS, DE JAGER A, 2008. Energy and nutrient composition of South African wheat, wheat flour and bread. Technical report to The Winter Cereal Trust of South Africa. Medical Research Council of South Africa.
WOLMARANS P, DANSTER N & CHETTY J. 2005. Energy and nutrient composition of South African maize meal. Technical report to The Maize Trust of South Africa. Medical Research Council of South Africa
US DEPARTMENT OF AGRICULTURE, Agricultural Research Service. 1998. USDA Nutrient database for Standard Reference, release 12. Nutrient data Laboratory Home page, http://www.ars.usda.gov/nutrientdata (Last update, May 2008)
http://www.roche.com/home/divisions.htm. Dietary antioxidants. Dietary Reference Intakes (DRI) (US Food and Nutrition board)
SOUTH AFRICAN DEPARTMENT OF HEALTH. 2007. Draft Guidelines to the regulations governing the labeling and advertising of foodstuffs, R642 of July 2007