Calcium is a mineral which is essential for strong bones and teeth. In fact, almost 99% of the calcium in our bodies forms the structural component to our bones and skeletal system. If calcium levels in the blood drop, the body will restore them by drawing calcium from the bones.
Calcium also plays a vital role in heart, muscle, nerve and blood function.
When you don’t consume enough calcium from your diet, your body will withdraw calcium from the bones and overtime this can reduce bone mineral density, lead to bones becoming brittle and increase the risk of osteoporosis.
Osteoporosis is the most common bone disease in humans and is categorised by low bone mass, structural deterioration and decreased bone strength. A lower bone mineral density increases the risk of fractures. In the five to ten years following menopause, women can lose up to 20% of their bone mass and 50% of these will experience an osteoporotic fracture at some point in time. This is because levels of the hormone, oestrogen, drop after menopause. Oestrogen plays an important role in maintaining bone strength, so a drop in oestrogen levels may result in increased bone loss.
How much calcium do you need?
Recommended Dietary Intake (RDI) for adults:
- Females & males aged 19-50: 1000mg / day
- Females aged >70 years (post-menopausal): 1300mg / day
- Males aged >70 years: 1000mg / day
People with osteoporosis or osteopenia should aim to consume 1300mg calcium per day (or at least 1000mg), ideally from the diet. If this cannot be achieved through diet alone, speak to your health care practitioner to assess if calcium supplements and appropriate for you.
Food sources of calcium:
Dairy foods are the main sources of dietary calcium however calcium can also be obtained from other foods, from fortified foods and from supplements. The calcium is milk is generally well absorbed in the body. A cup of milk (250mL) contains 310mg calcium and 100mg (30%) of this is absorbed in the body.
What if you’re dairy free or lactose free?
You can still reach your calcium target if you are following a lactose-free, vegan or dairy free diet, however you do need to know what your best food sources are.
Bioavailability of calcium:
The absorption rate of calcium from different foods is called ‘bioavailability’. Dairy foods have a high bioavailability, compared to some other plant-based foods, such as spinach, which can have a low bioavailability. However, there are a number of plant-based foods which provide a good source of bioavailable calcium.
Low FODMAP Calcium-Rich Food Lists
From Dairy and Seafood:
Food source | Average serve size | Calcium content (mg) per average serve size |
Dairy | ||
Lactose Free Cow’s Milk | 1 cup (250mL) | 310 |
Cheese – Cheddar, Colby, Tasty | 2 slices (40g) | 300 |
Cheese – Parmesan | 20g | 190 |
Cheese- Feta | 40g | 160 |
Plain Lactose Free Yoghurt | 200g | 300 |
Lactose Free Kefir (fermented milk) | 200mL | 200
|
Seafood | ||
Tuna fortified with calcium (John West) | 90g tin | 800-1000 |
Sardines with bones | 100g | 270 |
Sardines without bones | 100g | 80 |
Canned salmon with bones | 100g | 190 |
From Plant Foods:
Food source | Average serve size | Calcium content (mg) per average serve size |
Dairy Alternatives | ||
Calcium-fortified low FODMAP Plant Milk
Choose almond, rice or soy-protein milk (eg. So Good) for low FODMAP options. |
1 cup (250mL) | 300
Shake well before pouring as calcium can separate to the bottle of the bottle. |
Calcium-set Firm Tofu
(calcium-set contributes more calcium than magnesium-set) |
125g | 170 – 400
*Look for calcium sulfate / gypsum / e516 OR magnesium chloride / nigari / e511 on ingredients list |
Vegetables | ||
Bok Choy | 1 cup cooked | 170 |
Kale | 1 cup | 120 (Note: lower bioavailability than bok choy) |
Broccoli | 100g | 200
(Note: lower bioavailability than bok choy, broccoli heads are lower in FODMAPs than broccoli stalk) |
Chinese mustard greens | 100g | 280 (Well absorbed) |
Seeds – check your FODMAP Friendly App for low FODMAP serve sizes | ||
Chia seeds | 40g (2-3 tbsp) | 175 |
Sesame seeds / unhulled tahini | 20 g | 170 |
Hulled tahini | 20g | 65 |
Poppy seeds | 10g | 145 |
Written by Rebecca Ponsford, Accredited Practising Dietitian, FODMAP Nutrition & Dietetics