Dairy consumption has taken quite a hit in the past few years as more and more people opt to cut it out, by choice or necessity. Many of my patients have tried cutting out dairy for various different reasons. One of the things I often find with these patients is that they have not appropriately planned their no-dairy diet so that they can still get all of the nutrients they need, the main one being calcium.
It’s no secret that calcium is important for bone health. It’s stored in our bones and teeth, providing them with structure and strength. In order to avoid developing osteoporosis and frail bones, two of the most important things we can do are engage in regular activity and ensure we get enough calcium. Compared to other minerals, our daily calcium requirements are very high (adults aged 19-50 need 1000mg/day). Calcium is especially important for men over 70 and post-menopausal women, who start gradually losing bone mass (their requirements go up to 1300mg/day). But calcium isn’t only important for our older population. It’s also very important for pregnant and lactating women, and adolescents, who need to build up their bone mass before they reach peak mass in early adulthood.
Calcium isn’t just an issue in dairy-free diets. Even amongst dairy consumers, most Australians aren’t reaching their recommended intakes of calcium each day. So, initial planning and awareness are required to ensure you’re getting enough calcium no matter what diet you follow.
Calcium supplements are often recommended to help us reach our calcium needs. Recently, studies looking at the effectiveness of calcium supplements have shown some surprising results. Smaller doses have been shown to provide no protection against bone fractures, but taking higher dose supplements (with 1000mg calcium or more) may increase our risk of certain conditions like heart disease and kidney stones. Because of this, obtaining calcium from food is highly preferable to supplementing. Also, when we take a calcium supplement, rather than getting our calcium from food sources, we also miss out on all of the other valuable nutrients in a food. Let’s take a high-calcium food like broccoli for example: aside from providing calcium, it also provide lots of fibre, iron, zinc, potassium and antioxidants (amongst other things), and eating it has been scientifically shown to strengthen the immune system, slow ageing and reduce our risk of a multitude of diseases including diabetes, cancer and heart disease. How’s that for superfood?!
There are many different plant-based sources of calcium. These include (in order of highest-lowest calcium content):
Chia seeds* (631mg/100g)
Sesame seeds and tahini* (330mg/100g for hulled seeds)
Calcium-set tofu (check the ingredients list for calcium sulphate/coagulant (516) or calcium chloride/mineral salt (509)) (usually has around 320mg/100g)
Curly parsley* (245mg/100g)
Blackstrap molasses* (205mg/100g)
Dried figs (200mg/100g)
Brazil nuts (150mg/100g)
Green vegetables: spinach (136mg/100g (1/2 cup) cooked), kale (135mg/100g raw), Chinese cabbage (105mg/100g raw), silverbeet (87mg/100g cooked), bok choy (86mg/100g raw), cabbage (48mg/100g cooked), broccoli (40mg/100g cooked)
Calcium-fortified soy milk and other plant milks** (check that they have at least 120mg calcium per 100mL or 100g added)Tempeh (111mg/100g)
Dried apricots (70mg/100g)
Legumes (e.g. kidney beans, chickpeas, soy beans) (~50mg/100g cooked)
Some dried herbs also contain quite a lot of calcium. Per tablespoon, the richest sources are oregano (85mg), dill (55mg), thyme (51mg) and basil (42mg).
An important thing to remember:
One of the reasons our calcium requirements are so high is that calcium is not well absorbed by our bodies (the body doesn’t necessarily need ~1000mg, but we likely need to be eating that much to ensure we absorb enough). There are various things that impair calcium absorption:
Caffeine (found in coffee, black and green tea, chocolate)
Phytates in cereals, nuts and seeds (concentrated in the husk/coating of the grain/seed) (soaking these foods can reduce the phytate content)
Oxalates in spinach, rhubarb, beet greens, silverbeet
High salt/sodium foods
Alcohol & smoking
Vitamin D deficiency
Some medications, like corticosteroids (e.g. Prednisolone)
For this reason, it’s best to choose more easily absorbed food sources of calcium. It is most easily absorbed from the low-oxalate green cruciferous vegetables: broccoli, cabbage, kale, and Asian greens (e.g. bok choy) (these have an absorption rate of about 50-65%). The next most easily absorbed sources of calcium are calcium-fortified soy products like soy milk and tofu (with an absorption rate of about 25-30%). Interestingly, the calcium in low-oxalate greens is more easily absorbed than calcium from dairy foods!
As a general guide to achieving adequate calcium intake on a plant-based diet, I recommend including at least 1 cup of cooked low-oxalate greens and 1.5 cups/250g of plant-based milk/tofu with added calcium per day, and avoiding having them with caffeinated drinks, salty foods or alcohol. Without adequate intake, a calcium supplement should be considered. Despite the apparent health risks of calcium supplementation, not getting enough calcium can be more of a health risk than taking calcium supplements. It’s important to weigh up if a calcium supplement would be more useful than potentially harmful for you.
*Keep in mind that with these foods you probably aren’t going to be consuming 100g, so although they’re high in calcium they’re not likely to provide much in the context of your overall diet.
**Tip: Before drinking, shake plant-based milks! The calcium tends to settle at the bottom of the carton.