Calcium is the most abundant mineral in the human body, serving as a major building block for bones and teeth. It also plays a vital role in muscle contraction, blood clotting, nerve transmission, and blood pressure regulation. While dairy products are often the first foods that come to mind when considering calcium intake, many plant-based options can provide sufficient amounts of this essential mineral for those following a vegan diet.
Why is Calcium Important?
Calcium is indispensable for overall health at every stage of life. It is essential for forming and maintaining strong bones and teeth. It also facilitates blood clotting and regulates muscle contractions, including that of the heart.
Recommended Daily Allowance
The recommended daily allowance (RDA) for calcium varies depending on age and sex. The NIH recommend that men consume 90 mg and women consume 75 mg of the vitamin C per day. Adults aged 19 to 64 and over need 700mg daily. Older adults, especially women, often require slightly more calcium due to the increased risk of weakened bones.
The Body's Calcium Regulation System
Calcium is so indispensable that your body has a backup system to keep a steady amount of it in your blood to maintain those vital functions, in case of a calcium deficiency. If you don't get enough calcium in your diet, a complex series of reactions will release calcium from your bones into your bloodstream, to go where it's needed.
Calcium in Vegan Diets: Addressing Common Concerns
Studies suggest that calcium intake tends to be lowest for those following a vegan diet, often falling below dietary reference intakes. This may increase the risk of bone fracture. However, with careful planning and attention to calcium-rich plant foods, vegans can meet their calcium needs.
Read also: Sources of Calcium on Carnivore
Bioavailability Considerations
Some plant foods contain compounds such as insoluble fiber, oxalates, and phytates that can bind with calcium and hinder its absorption. For example, some greens like spinach and chard are higher in oxalic acid, which reduces our ability to access calcium. It’s therefore important to look for calcium-fortified plant foods and to ensure you are achieving adequate amounts in your regular diet.
The Role of Vitamin D
Vitamin D, often referred to as the 'sunshine vitamin,' plays an important role in calcium absorption. However, it is difficult to get adequate amounts of this from food. When the strength of the sun isn’t enough to give you the correct amount, it is important to make sure you are taking a regular vitamin D supplement.
Excellent Vegan Sources of Calcium
Here are some of the best vegan food sources of calcium:
1. Fortified Plant-Based Milk Alternatives
Plant-based milk alternatives are often fortified with calcium and vitamin D. One cup of fortified soy milk contains about the same amount of calcium as the equivalent of cow’s milk. It is important to choose a product that is fortified with calcium carbonate. Soy milk is also rich in vitamin D, and it contains less saturated fat than whole milk with lactose.
A 200ml portion of fortified plant-based milk alternative provides approximately 240mg of calcium. Popular options include:
Read also: Calcium D-Glucarate Precautions
- Unsweetened almond milk (calcium fortified)
- Soya milk (calcium fortified)
- Oat milk (calcium fortified)
- Coconut milk (calcium fortified)
However, organic versions and some brands are not, so always check labels.
2. Fortified Plant-Based Yogurt Alternatives
Similarly, a 125g portion of a plant-based yogurt alternative, fortified with calcium and vitamin D, provides around 150mg of calcium. Plain soya yogurt and coconut yogurt are common choices.
3. Green Leafy Vegetables
Often cited as being useful food sources of calcium, it’s worth remembering that the calcium these vegetables provide is less bio-available. So, although an 80g portion of each cooked green leafy veg contains the following you may not be accessing it all:
- Spinach = 128mg
- Kale = 120mg
- Turnip greens/tops = 110g
- Okra = 96mg
- Mustard Greens = 94mg
- Purple sprouting broccoli = 88mg
- Pak choi = 74mg
- Spring greens = 60mg
- Swiss Chard = 46mg
- Broccoli = 28mg
- Brussels sprouts = 16mg
Low- and moderate-oxalate vegetables like turnip greens, broccoli, and kale are considered better sources than higher-oxalate vegetables, such as spinach, beet greens, and Swiss chard. Boiling is one way to reduce oxalate levels by 30 to 87%. Interestingly, it appears to be more effective than steaming or baking.
4. Fresh Fruit
Fruit, including rhubarb, is rich in oxalates, so may limit the amount of calcium you are able to absorb. However, an 80g portion of each fruit provides:
Read also: Understanding Low Calcium Diets
- Blackberries = 33mg
- Rhubarb (cooked) = 26mg
- Kiwi = 20mg
- Oranges = 19mg
- Tangerines = 14mg
- Pear = 6mg
- Apple = 4mg
One large orange contains 74 mg of calcium, while a single glass of calcium-fortified orange juice contains 300 mg
5. Dried Fruit
Dried fruits, like other fruit and veg, are a source of oxalates so may limit calcium intake. However, a 30g serving of each dried fruit provides:
- Figs = 69mg
- Apricots = 28mg
- Dates = 14mg
- Raisins = 14mg
About eight figs, or 1 cup, provides 241 mg of calcium. Figs make a great sweet treat and are rich in fiber and antioxidants. Try them as a midday snack or crush them into a creamy jam.
6. Beans and Pulses
Soaking and cooking helps reduce levels of anti-nutrients, like oxalates, in beans, pulses as well as fruit and vegetables. An 80g portion of each cooked bean or pulse provides:
- Soya beans = 66mg
- Chickpeas = 37mg
- Aduki beans = 31mg
- Kidney beans = 30mg
- Broad beans = 14mg
- Black-eyed beans = 17mg
- Lentils = 18mg
One cup of white beans yields 161 mg of calcium. White beans are a low-fat food and are also rich in iron. Add them to a favorite soup or salad, eat them in a side dish, or use them in hummus.
7. Nuts and Seeds
Nuts and seeds can be useful sources of minerals, including calcium, a 30g portion provides:
- Sesame seeds = 201mg
- Chia seeds = 189mg
- Almonds, whole kernels = 72mg
- Brazil nuts = 51mg
- Sunflower seeds = 33mg
- Walnuts = 28mg
- Pumpkin seeds = 12mg
- Pine nuts = 3mg
A single ounce, or 2 tablespoons, of chia seeds provide 179 mg of calcium. Chia also contains boron, which promotes the health of bones and muscles by helping the body to metabolize calcium, phosphorous, and magnesium. Add chia seeds to smoothies or mix them into oatmeal or yogurt for a little added crunch.
Eating just 1 tablespoon of sesame seeds adds 88 mg of calcium to a person’s diet. Try toasting them and sprinkling the seeds over a salad or baking them in bread for a nuttier flavor. Sesame seeds also contain zinc and copper, and both are beneficial to bone health.
Just 1 cup of whole almonds contains 385 mg of calcium, which is more than one-third of the recommended daily amount. However, the same serving also contains 838 calories and almost 72 grams of fat. While the fat is mostly healthful and monounsaturated, the calorie count is high, and a person should limit their intake to smaller portions of a quarter cup per serving, for example.
A single cup of sunflower seed kernels contains 109 mg of calcium. These seeds are also rich in magnesium, which balances the effects of calcium in the body and regulates nerve and muscle health. In addition, sunflower seed kernels contain vitamin E and copper. Together, these nutrients can promote bone strength and flexibility and prevent bone loss. However, sunflower seeds can contain high amounts of added salt, which depletes the body’s levels of calcium. For optimal health benefits, choose raw, unsalted seeds. Also, consider a single serving to be about one handful of kernels, to avoid excessive calorie intake.
8. Baked Products
In the UK, white and brown breads are required by law to be fortified with calcium. Here is how an 80g portion (roughly two thick slices) of each bread compares:
- Wheatgerm bread = 170mg
- Malted wheat bread = 167mg
- Brown bread = 149mg
- White bread = 142mg
- Naan bread = 138mg
- Seeded bread = 120mg
- White pitta bread = 110mg
- Wholemeal bread = 85mg
9. Dried Herbs
Dried herbs are a useful way to increase your intake of micronutrients including minerals such as calcium. One teaspoon of each dried herb provides:
- Dried basil = 63mg
- Dried marjoram = 60mg
- Dried thyme = 57mg
- Dried dill = 53mg
- Celery seeds = 53mg
- Dried mixed herbs = 50mg
- Dried sage = 50mg
- Dried oregano = 48mg
10. Other Vegan Foods
A 100g serving of the following foods, on average (depending on the brand), provides:
- Tofu (calcium fortified) = 350mg
- Vegan sausages = 136mg
- Tempeh = 120mg
- Veggie burger = 100mg
Tofu tends to be an excellent source of calcium. However, the calcium content varies, depending on the firmness and the brand, and it can range from 275-861 mg per half cup. To receive the benefits of the calcium, read labeling carefully and only select tofu that contains calcium salt, which manufacturers use as a coagulant.
Other Calcium-Rich Vegan Foods
- Soybeans: One cup (180 grams) of cooked soybeans provides 261 mg of calcium, which is about 20% of the DV.
- Edamame: One cup of frozen, prepared edamame contains 98 mg of calcium. Available fresh or frozen and shelled or in pods, edamame contain high-quality proteins and all nine essential amino acids.
- Kale: Just 2 cups of raw chopped kale provide about 180 mg of calcium. Kale belongs to the cruciferous family of vegetables, which also includes broccoli. The leafy green is loaded with antioxidants, which can prevent or delay cell damage. Kale is also low in calories, with every 100 grams containing only 35 calories. Add chopped kale to a salad or sauté or steam the vegetable as a side dish.
- Sweet potatoes: One large sweet potato contains 68 mg of calcium. These vegetables are also rich in potassium and vitamins A and C. Sweet potatoes are naturally low in fat and calories. They are popular as a side dish in some parts of the world.
- Mustard and collard greens: Raw collard greens contain 84 mg of calcium per cup, and they are rich in other vitamins and minerals. Raw mustard greens are also a significant source of nutrients, and they contain 64 mg of calcium per cup.
- Okra: A single cup of raw okra contains 82 mg of calcium.
- Butternut squash: Butternut squash contains 84 mg of calcium per cup. The same serving also provides 31 mg of vitamin C, which is more than one-third of the recommended daily amount. Butternut squash is also rich in vitamin A, and there are many versatile recipes.
- Arugula: Another cruciferous vegetable, arugula, contains 32 mg of calcium per cup. Arugula also contains high amounts of a compound called erucin, which may combat cancer.
- Blackstrap Molasses: It’s made from sugar cane that has been boiled three times. Unlike sugar, it contains several vitamins and minerals, including 100 mg of calcium - or 8% of the DV - per tablespoon (14 g). That said, blackstrap molasses remains very high in sugar, so you should eat it in moderation.
- Teff and Amaranth: Both are rich in fiber and can be incorporated into a variety of dishes. Teff can be made into a porridge or added to chili, while amaranth provides an easy substitute for rice or couscous. Both can be ground into a flour and used to thicken soups and sauces.
- Seaweed: Adding seaweed to your diet is yet another way to increase your calcium intake. Wakame - a variety typically eaten raw - provides around 120 mg, or 9% of the DV per cup (80 grams). Kelp, which can be eaten raw or dried, is another popular option. One cup (80 grams) of raw kelp - which you can add to salads and main dishes - provides around 10% of the DV. Dried kelp flakes can also be used as seasoning.
Optimizing Calcium Intake on a Vegan Diet
To ensure adequate calcium intake when following a vegan diet:
- Include a variety of plant foods in your daily diet.
- Focus particularly on fortified plant-based milks, yogurts, and breads, as well as calcium-set tofu.
- Consider taking a vitamin D supplement, especially during the winter months (October to March).
- If you have concerns about your calcium intake, consult with a healthcare professional or a registered dietitian.
- If you are planning a pregnancy, pregnant or breast-feeding, or you are responsible for the diet of a young or elderly relative refer to your GP or a registered dietician for further advice and guidance.
Calcium Supplements: A Consideration for Vegans
If meeting calcium needs through diet alone is challenging, calcium supplements may be considered. Summary: Calcium supplements of 1,000 mg per day appear to be safe among healthy people.
Additional Factors Influencing Bone Health
Beyond calcium and vitamin D, other factors contribute to bone health:
- Physical Activity: Weight-bearing exercises, such as running and resistance training, help promote strong, healthy bones and increase bone density.
- Protein Intake: Adequate protein intake is important for bone health.
- Vitamin B12: Low vitamin B12 status can result in elevated homocysteine which might harm bones.
- Selenium: Higher selenium levels were associated with greater bone mineral density.