It has recently become evident that calcium and vitamin D supplements don’t prevent osteoporosis, and might actually end up harming the heart and arteries.
Because most people don’t get enough calcium from their diet, and no longer get enough exposure to the sun to produce sufficient amounts of vitamin D, supplements were regarded as a convenient way to compensate for these deficiencies.
Vitamin D and calcium supplements were, and still are, extremely popular and a huge source of revenue to pharmaceutical companies and other supplement manufacturers
Following up on last week’s article that looked at the dangers of calcium supplements, we will now take a look at the dietary sources of calcium, including tips for those people who do not use milk or dairy foods because of religious reasons or because of intolerances and allergies. Dairy foods include yoghurt, amazi/maas, cottage or cream cheeses, and all other cheeses.
Milk and dairy products
Milk and dairy products are the richest sources of bioavailable calcium in the human diet, with most forms of milk supplying about 1 mg of calcium per ml. If you ingest your 3-A-Day servings of milk and dairy a day, you should be getting between 800 to 1000 mg of calcium, as well as high quality proteins and B vitamins. Other foods like canned fish, which includes edible soft bones, will provide the additional calcium you need on a daily basis.
Read: 10 foods rich in calcium
But in view of the fact that many individuals do not use milk or dairy products, it is important to include other foods that provide calcium in order to avoid or reduce the need for supplements.
a) Lactose intolerance
Individuals with lactose intolerance are either born without the ability to produce the lactase enzyme– which digests milk sugar/lactose in milk and foods made with milk – or they lose the ability to manufacture lactase over time (primary vs. secondary lactose intolerance). Secondary lactose intolerance, which is common among Africans, usually prevents older children, teenagers and adults in Africa from drinking or using fresh milk.
Most individuals who are lactose intolerant can, however, use fermented milk products such as amazi or yoghurt without suffering ill effects. This is because the bacteria that ferment milk to produce these products use up the milk sugar for energy while they multiply and the produce acid compounds that give these fermented milk products their characteristic sour taste.
Read: Probiotic yoghurts affect your gut
A 250 ml cup of plain yoghurt contains 350 mg of calcium and a 300 ml glass of amazi provides 490 mg of calcium.
In addition, research has indicated that most people with lactose intolerance can have up to one cup (250 ml) of standard cow’s milk during the course of the day (e.g. a spot of milk in your tea or coffee), without any symptoms.
b) Cow’s milk protein allergy
If you are truly allergic to one or more of the proteins in cow’s milk, you will have to obtain your calcium from other sources, because the fermentation process does not change the protein composition of the milk.
Patients with true cow’s milk protein allergy cannot use milk, yoghurt, amazi, cheese, or any product made with cow’s milk. In such cases, your doctor and dietician will guide you on how to ingest sufficient calcium to prevent osteoporosis.
c) Milk avoidance due to convictions, vegetarianism and eating disorders:
Vegetarians can be classified as:
- Lacto-ovo-vegetarian (individuals who do not eat meat or fish, but use milk, dairy products and eggs together with a plant-based diet). These vegetarians should have no problem obtaining adequate calcium intake from the milk and dairy products in their diets.
- Lacto-vegetarians (as above, but without the inclusion of eggs). No problem with sourcing adequate calcium from their diets.
- Strict vegetarians or vegans (person who do not eat any foods derived from animals at all and only eat foods derived from plant sources). These individuals may find it more difficult to obtain 1000 mg of calcium per day without the use of supplements.
- Fruitarians (people who only eat fruit and nuts, avoiding all other foods) - as above
- Patients with orthorexia, a type of eating disorder which leads to avoidance of any foods they do not regard as healthy and pure. If such patients decide to avoid all milk and dairy foods they may not obtain adequate calcium from the few restricted foods they do regard as acceptable.
- Patients with other eating disorders such as anorexia and bulimia may restrict their total food intake to such an extent that they develop osteopenia and brittle bone disease.
Read: Treating brittle bones
All strict vegetarians, vegans, fruitarians and patients with orthorexia and other eating disorders that involve avoidance of milk and dairy products may need some form of supplementation to ensure that their diets contain adequate quantities of calcium. The use of a calcium supplement that contains vitamins D and F2 is recommended.
Tips to increase the calcium intake of vegetarians
After an in-depth analysis of dietary practices associated with vegetarian eating patterns, the American Dietetic Association (ADA) published a Position Statement in 2009, which included the following tips to boost calcium intake in strict vegetarians and vegans:
- Use foods that are fortified with calcium or calcium supplements. In South Africa relatively few foods are currently fortified with calcium, which may complicate this recommendation for local conditions. Use of a calcium-vitamin blend such as MenaCal.7 as a supplement may be advisable. Always discuss the use of supplements with your dietician or medical doctor.
- Green foods that have a low oxalate content (bok choy, broccoli, Chinese cabbage, kale) are good sources of highly bioavailable calcium. Such vegetables can usually be purchased at speciality green grocers.
- Tofu (made from soybeans) which is set in calcium, has a relatively high calcium content (such tofu may be obtainable through certain health shops).
- Select soy milk and other soy products that are fortified with calcium.
- Imported foods which are fortified with calcium may increase calcium intake, but can be expensive.
- Avoid eating foods that are rich in oxalates such as spinach and Swiss chard in large quantities as the oxalates tend to prevent calcium absorption.
- Foods rich in phytates may also interfere with calcium uptake. Phytates occur in unrefined cereals, red wine and legumes. To counteract the effect of phytates it is important to soak, sprout, ferment and/or cook foods with a high phytate content. Serving phytate-rich foods with foods rich in vitamin C (citrus fruits, guavas, mangoes, tomatoes and the entire cabbage family) can help to improve the bioavailability of minerals like calcium and iron which may be bound by phytates and not easily absorbed.
It is evident that the advice given by Dr Deepak Bhatt, a cardiologist at Brigham and Women’s Hospital, that the diet is the best source of calcium, remains true and is a goal we should all strive to achieve so that we can, as far as possible, cope without supplements.
Calcium supplements may increase your risk of cardiovascular incidents
Weekly tip - Getting calcium the non-dairy way
Eat well without dairy or gluten
- Craig, W J et al (2009). Position of the American Dietetics Association: vegetarian diets. J Am Diet Assoc, 109(7): 1266-82.
- Grey A, Bolland M (2015).Web of industry, advocacy, and academia in the management of osteoporosis. BMJ;351:h3170.
- Mahan L K et al (2013); Krause’s Food & the Nutrition Care Process. 13th Edition. Elsevier Publishers, USA.
- Strawbridge H (2012). Link between calcium supplements and heart disease raises the question: Take them or toss them?
- Wolmarans P et al (2010). Condensed Food Composition Tables for SA. Medical Research Council, Parow Valley, Cape Town.
Image: High in calcium from Shutterstock
Dr Ingrid van Heerden is a registered dietician and holds a doctoral degree in Nutrition and Biochemistry. She believes that "we are what we eat" and offers free nutrition and weight loss advice via her DietDoc service on Health24.com. Read more of her articles.