Plant Based Diet Meal Plans for Calcium Requirements
There is no question that calcium is an important nutrient.
Growing up, we were told to drink milk to grow big and tall. However, you are now an adult, having opted for a plant-based diet and questioning how to get enough calcium from your diet. Fear not, because I am going to give you a run down on your calcium requirements, the best sources and the best practises to help calcium absorption on a plant-based diet.
Calcium is the most abundant mineral in the human body and is essential for the normal development and maintenance of the body’s skeleton and for proper functioning of nervous, muscular and cardiac systems. Clearly, calcium has an important role in the human body and an inadequate intake can contribute to the progression of serious disorders such as osteoporosis and osteopenia.
To achieve an adequate amount of calcium depends on multiple factors such as absorption, bioavailability (the proportion of an nutrient that is absorbed and utilised), excretion, variation in food sources and inhibitory factors.
The recommended daily intake (RDI) for calcium for males and females, aged 19-30 and 19-50, respectively, is 1000mg per day. Different life stages requires a higher intake. Over the age of 30 for females and 50 for males and adolescents between 12-18 years of age increases to 1300mg per day. Calcium is particularly important for growing children so they can reach their full potential height as adults. Older adults require a higher intake because calcium absorption decreases with advancing age. A particular interest is within older women, aged 50 and above, given their increased risk for osteoporosis and osteopenia in their postmenopausal stage.
Hypercalcemia is the condition where calcium intake and levels in the blood is too high and can cause serious complications such as weakened bones, kidney stones and calcification in blood vessels and soft tissue. Excessive intake of calcium from foods alone is rare and is generally associated with the use of calcium supplements. The Upper Level (UL) of calcium in Australia is set at 2500mg per day.
Plant Based Calcium vs. Dairy Calcium
To state the obvious plant based calcium comes from plants, such as broccoli, kale, spinach and bok choy. When manufacturing plant based milk, the material is extracted from plants such as soybeans and rice, immersed in water and undergoes a series of processing and fortification that results in a similar milky substance to that of cow’s milk. The nutritional values of plant base milks varies, with soy milk, a product originating hundreds of years ago in Asia, having comparable nutritional values to that of cow’s milk. Plant base milk have a number of added benefits such as fibre, folate, vitamin B2, vitamin B12 and antioxidants and is almost absent of saturated fat.
On the other hand we have calcium from dairy products that comes from mammals, mainly cows. Cow’s milk has a good bioavailability of calcium that can be attributed to the presence of other components such as lactose, casein phosphopeptides and vitamin D. Cow’s milk can come in a variety of forms such as skim, whole and reduced fat and with varying nutritional values. In general, cow’s milk contain fats, including saturated fat, lactose, protein and some vitamins and minerals.
Absorption of Calcium
The efficiency of calcium absorption varies among foods and can be effected by the presence of other factors in foods, or what I like to call calcium culprits.
Studies show that a higher load of calcium intake negatively effects the efficiency of calcium absorption. What I am suggesting here is that you should be spacing your calcium intake throughout the day rather than in one sitting.
Calcium absorption can be decreased due to the inhibitory effect of phytates and oxalates, commonly known as ‘anti-nutrients’. These anti-nutrients can bind to calcium, forming insoluble complexes, thus decreasing calcium absorption. Oxalates are highest in certain dark leafy greens. That's not to say we shouldn't eat them - we just need to be aware of how they affect calcium absorption.
To limit high-oxalate greens, choose low-oxalate vegetables such as kale and broccoli. Phytates are also found in whole grains, nuts, seeds and legumes. There are plentiful food preparation and processing methods you can do to reduce the phytate content in the household that includes soaking, heating, germination, fermentation and pounding. If you are unable to perform these methods there are plenty of alternative foods available that are low in phytates and oxalates that I will touch on in this blog.
The other two calcium culprits to keep an eye out for are sodium and protein. Sodium and calcium excretion are linked in the kidneys and for every 2300mg of sodium consumed takes out roughly 40mg of calcium. A diet high in protein can promote urinary calcium excretion and each gram of protein takes out 1mg of calcium. To complicate things, adequate protein is essential for bone growth, maintenance and renewal.
You can be chowing down as much calcium as possible, but it won’t be effective without its trusty friend vitamin D. Numerous studies have been conducted on the relationship between calcium and vitamin D.
A study in 2015 evaluated fractional calcium absorption from a green leafy vegetable vs. milk in relation to vitamin D status of postmenopausal Thai women. They found that vitamin D status had a significant impact on fractional calcium absorption in both the plant-based diet and dairy diet postmenopausal women. The RDI for vitamin D is 5µg per day and increases in adults over 50 and over 70 to 10 per day and 15µg per day, respectively.
One form of vitamin D is produced in the human body from sunlight exposure. In Australia we are lucky to experience sunshine majority of the year round and if sunlight exposure is adequate, dietary vitamin D may not be essential. If you are concerned about receiving an adequate amount of vitamin D, there is vitamin D found in fortified milks such as soy and rice, fortified tofu and mushrooms.
Calcium food sources
We all associate cow’s milk with calcium, however, there is a plethora of non-dairy food sources that contain adequate, if not, large amounts of calcium to meet our daily requirements. The key is to eat a variety of sources, throughout the day, so calcium intake adds up to meet your needs. Consumption of non-dairy sources of calcium, such as vegetables low in phytates and oxalates including broccoli, collards, Chinese cabbage, bok choy and kale, tofu containing calcium, fortified plant-based foods such as fortified milks such as almond, cashew and rice and fruit juices and cereals are feasible approaches to ensure intakes of bioavailable calcium is meet. Many studies have been conducted on the bioavailability of calcium in fortified soy milk and fruit juices and find that they are of similar quality to that of the calcium in cow’s milk. One glass (250mL) alone can provide approximately 300mg of calcium alone, achieving 30% of your recommended daily intake.
Other wonderful plant based calcium sources include sesame seeds, brussels sprouts, butternut squash, sweet potato, chickpeas, navy beans, dried figs, dried apricots, and many more.
To reduce the phytate content of a food you can soak your nuts, seeds, legumes and wholegrains. To avoid oxalates don’t eat too much raw dark leafy vegetables or you can lightly steam them to reduce the oxalate content.
Example Menu: Raw
This example menu can be used as a guide for adding rich sources of calcium into you diet. You can adjust it to your own personal preference, or include samples from the Cooked Menu below.
Calcium Rich Smoothie
Raw Pad Thai
Total of 1113mg of calcium
Example Menu: Cooked Vegan
Total of 1110mg of calcium
~ Written by Stephanie Russell, 3rd Year Nutrition Student. Connect with Steph on @LinkedIn
Booth, A., & Camacho, P. (2013). A Closer Look at Calcium Absorption and the Benefits and
Risks of Dietary Versus Supplemental Calcium. Postgraduate Medicine, 125(6), 73-81. doi: 10.3810/pgm.2013.11.2714
Dawson-Hughes, B. (2003). Interaction of Dietary Calcium and Protein in Bone Health in
Humans. The Journal of Nutrition, 133(3), 852-854. doi: https://doi.org/10.1093/jn/133.3.852S
Gibson, R., Bailey, K., Gibbs, M., & Ferguson, E. (2010). A review of phytate, iron, zinc, and
calcium concentrations in plant-based complementary foods used in low-income countries and implications for bioavailability. Food and Nutrition Bulletin, 31(20), 134-146. doi: https://doi.org/10.1177/15648265100312S206
Holick M. (2001). Sunlight "D"ilemma: risk of skin cancer or bone disease and muscle weakness. The Lancet, 357(9249), 4-6. doi: 10.1016/S0140-6736(00)03560-1
Makinen, O., Wanhalinna, V., Zannini, E., & Arendt, E. (2015). Foods for Special Dietary
3Needs: Non-dairy Plant-based Milk Substitutes and Fermented Dairy-type Products. Critical Reviews in Food Science and Nutrition, 56(3), 339-349. doi: 10.1080/10408398.2012.761950
Nutrient Reference Values for Australia and New Zealand. (2014). Calcium. Retrieved from https://www.nrv.gov.au/nutrients/calcium
Nutrient Reference Values for Australia and New Zealand. (2014). Vitamin D. Retrieved from https://www.nrv.gov.au/nutrients/vitamin-d
Ross, A., Taylor, C., Yaktine. A,, & Del Valle, H. (2011). Dietary Reference Intakes for Calcium
and Vitamin D. Washington, D.C: National Academies Press. Retrieved from
Sirichakwal, P., Kamchansuppasin, A., Akoh, C., Kriengsinyos, C., Charoenkiatkul, S., & O'Brien, K. (2015). Vitamin D Status Is Positively Associated with Calcium Absorption among Postmenopausal Thai Women with Low Calcium Intakes. The Journal of Nutrition, 145(5), 990–995. doi: https://doiorg.ezproxy.ecu.edu.au/10.3945/jn.114.207290
Tang, A., Walker, K., Wilcox, G., Strauss, B., Ashton, J., & Stojanovska, L. (2010). Calcium
absorption in Australian osteopenic post-menopausal women: an acute comparative study of fortified soymilk to cows’ milk. Asia Pacific Journal Clinical Nutrition, 19(2), 234-249.
Zaho, Y., Martin, B., & Weaver, C. (2005). Calcium Bioavailability of Calcium Carbonate
Fortified Soymilk Is Equivalent to Cow’s Milk in Young Women. The Jounral of Nutrition, 135(10), 2379-2382. doi: https://doi.org/10.1093/jn/135.10.2379