Calcium is the most abundant mineral in the body that is predominantly stored in the skeleton.
Despite its importance, it is estimated that over 3.5 billion people are deficient worldwide.
- What Is Calcium and Why Is It Important?
- What Foods Are High in Calcium?
- Healthy High Calcium Recipes
- Satiety Response to High Calcium Foods
- Multivariate Satiety Analysis
- Optimal Calcium Intake
- Calcium Availability in the Food System and Relationship to Obesity
- Symptoms of Calcium Deficiency
- Risks of Calcium Supplementation
- Do I need to take calcium with D3 and K2?
- Absorption and Bioavailability of Calcium
- Synergistic Nutrients with Calcium
- The Calcium: Magnesium Ratio
What Is Calcium and Why Is It Important?
But why is calcium an important nutrient?
- Calcium is perhaps most well-known for its importance in the healthy development and maintenance of bones and teeth, blood clotting, and nerve transmission.
- The body requires minerals like calcium for muscle contraction. Magnesium is the mineral that works alongside calcium in this process, allowing for muscle relaxation.
- Calcium is essential for children as they grow and develop. Children who don’t get enough calcium may not grow to their full potential height and may develop other health issues.
- Calcium is a nutrient necessary in the breakdown of histamines.
- We need calcium for cell signalling and stabilising enzymes and other proteins necessary for human metabolism.
- The body needs adequate calcium to detoxify oxalate and heavy metals like lead.
- Calcium helps regulate blood pressure and has been shown in studies to reduce hypertension and preeclampsia in pregnant women.
- Hormone balance is partly regulated by calcium, and calcium can reduce premenstrual syndrome (PMS) and associated symptoms.
- Too little calcium can increase the risk of developing osteoporosis in older people. Osteoporosis is prevalent in older women, meaning the calcium demand in postmenopausal women is greater. Fractures from falls are common in older people with low muscle mass and fragile bones and are often difficult to recover from.
What Foods Are High in Calcium?
Calcium is found readily in plant and animal foods, although it is arguably more bioavailable in animal foods. Some popular high calcium foods are listed below.
While calcium is present in some plant foods, how much is absorbed is questionable because of phytates, oxalates, and other antinutrients found in some of them. These compounds are known to antagonise the absorption of minerals like calcium.
While these plant-based foods tend to have high levels of calcium per calorie, they tend to also have a very low energy density, so it can be hard to consume enough of them to get significant amounts of calcium.
- cream cheese
- salmon (with bones)
- sardines (with bones)
Animal foods, specifically dairy, are the most calcium-dense and bioavailable sources of calcium. These foods also include minimal amounts of vitamin D, which can be helpful in the intestinal absorption of calcium.
- Brazil nuts
Similar to vegetable sources of calcium, nuts contain antinutrients that can inhibit calcium absorption too.
Healthy High Calcium Recipes
Some of our NutriBooster recipes with the highest calcium include:
- red nutrient boosting smoothie
- low calorie panna cotta
- Greek yogurt veggie smoothie
- chocolate nutrient boosting smoothie
- Hulk green smoothie (pictured below)
Satiety Response to High Calcium Foods
Our satiety analysis shows that foods with more calcium tend to be more satiating. As shown in the chart below, Optimisers who consume food and meals that contained more calcium per calorie tended to consume 36% fewer calories.
The average intake for Optimisers was 1.1 g (1100 mg) per 2000 calories with the 85th percentile of 1.8 g per 2000 calories. This is higher than the Estimated Average Requirement of 0.84 g per day and the Daily Recommended Intake of 1.0 g per day, but less than the upper limit of 2.5 g per day. This limit has been set for calcium supplements because of the increased risk of kidney stones.
Multivariate Satiety Analysis
The multivariate analysis of our Optimiser data below shows that calcium has the third-largest impact on calories of all the micronutrients, following methionine and potassium. People who consume more calcium eat 5% fewer calories than those who consume less calcium.
Based on our satiety analysis, we have set a stretch target of 1.65 g/2000 calories for men and 1.32 g/2000 kcal for women.
Calcium Availability in the Food System and Relationship to Obesity
The chart below shows that the calcium content of commonly available foods has decreased significantly since the 1940s with the widespread introduction of chemical fertilisers and modern farming practices (data from USDA Economic Research Service). This decrease in calcium is closely correlated with the rise in obesity. Therefore, today, you will need to consume a lot more food to get the same amount of calcium you would have in the 1940s.
It’s interesting to note that calcium intake and obesity have an inverse relationship, or the decrease in calcium in the food system strongly correlates with increasing obesity. As you can see in the table below, a decrease in sodium and calcium in the food system strongly correlates with rising obesity rates over the past half-century.
|nutrient||correlation with obesity|
|sodium (g/2000 cal)||-96%|
|calcium (g/2000 cal)||-96%|
|cholesterol (g/2000 cal)||-96%|
|saturated fat (%)||-92%|
|potassium (g/2000 cal)||-91%|
|vitamin A (RAE/2000 cal)||-81%|
|phosphorus (g/2000 cal)||-80%|
|vitamin B12 (mg/2000 cal)||-70%|
|magnesium (mg/2000 cal)||-33%|
|vitamin C (g/2000 cal)||-3.4%|
Because calcium is used in so many bodily processes, too little of this mineral is associated with symptoms like:
- muscle pain,
- brittle fingernails,
- cognitive impairment,
- heart palpitations and atrial fibrillation,
- histamine intolerance and mast cell disorders,
- menstrual cramps,
- numbness and tingling,
- osteoporosis, and
- tooth decay and loss.
Risks of Calcium Supplementation
Studies suggest that a diet rich in calcium protects against heart disease, but supplemental calcium may increase the risk.
- A 2010 BMJ study found that those who used calcium supplements had a 139% greater risk of a heart attack, while an increased intake of calcium from food did not increase the risk.
- A meta-analysis of studies involving more than 12,000 people also found that calcium supplementation increased the risk of heart attack by 31%, stroke by 20% and death from all causes by 9%.
- An analysis of 12,000 men found that more than 1,000 mg of supplemental calcium per day from multivitamins or individual supplements was associated with a 20% increase in the risk of death from cardiovascular disease.
As well as adequate calcium, it’s important to note that you also need sufficient vitamin D to ensure the absorption of calcium in the intestines and vitamin K2 to ensure calcium is stored in bones and teeth and not arteries. Ironically, cheese and yogurt are excellent sources of all three nutrients.
Excess calcium can also build up in your kidneys as your body tries to excrete it. Subsequently, calcium and vitamin K2 from food and vitamin D from adequate sun exposure is critical to ensuring your calcium does the right job.
The sudden dump of calcium into the bloodstream from supplements may lead to calcification of arteries when it has nowhere to go. On the contrary, calcium obtained from food is absorbed more slowly and is less likely to build up in places where it doesn’t belong. For example, excess calcium circulating in the blood may attach to sclerotic plaques in your arteries or heart valves.
Extra calcium intake from supplements, beyond what is required to build your bones and teeth, is excreted in the urine, which increases your risk of calcium kidney stones.
Plant foods have questionable amounts of absorbable calcium because they contain phytates. For example, phytates in spinach, rhubarb, chard, legumes, grains and cereals can inhibit calcium absorption. Therefore, a diet high in refined grains not only provides less calcium, but the phytates ensure that it is not adequately absorbed.
Much like phytates, oxalates are compounds found readily in calcium-containing plant foods. These ‘antinutrients’ inhibit calcium absorption in the GI tract.
Around 20 – 25% of the calcium in legumes is absorbed. Therefore, soaking legumes can help remove phytates before eating to improve calcium absorption. A little over 30% and 40 – 60% of the calcium in cruciferous vegetables is absorbed by the body. However, only 5 – 9% of calcium is absorbed from rhubarb and spinach.
Calcium absorption is improved by Vitamin D status and resistance training. At the same time, it is made worse by lead exposure, overconsumption of magnesium and potassium, high alcohol consumption, and low hydrochloric acid (stomach acid) levels in the stomach.
It is possible to overdo it and cause harm with the overconsumption of calcium, but this is rare from whole foods and is only a concern with supplements.
Concerns around calcium bioavailability are likely minimal if you consume a broad range of nutrient-dense, calcium-rich foods and get plenty of sunlight. However, you may be disappointed if you drink a lot of green smoothies expecting to absorb calcium, although most people struggle to consume excess spinach!
Calcium works synergistically with vitamins A, C, E, D, K2, arginine, boron, carnosine, chromium, copper, lysine, magnesium, methionine, phosphorus, potassium, and selenium. For this reason, we recommend getting your calcium from whole food sources that come packaged with other nutrients rather than relying on isolated supplements.
Getting enough dietary calcium means we need less vitamin D. However, getting too much phosphorus, magnesium, or potassium will increase your calcium requirement. While you need to ensure you are getting enough of each nutrient, you also need to ensure you are not getting so much that you overwhelm your body’s ability to use other nutrients properly.
In addition to vitamin D and phosphorus, your body also needs adequate magnesium levels to use calcium properly.
- Magnesium deficiency affects calcium metabolism and alters certain hormones that regulate calcium in the body.
- A high calcium intake may interfere with magnesium levels by reducing intestinal absorption and increasing urinary excretion. Magnesium deficiency is also known to induce calcium deficiency.
- Calcium and magnesium also compete and interfere with one another’s functions if they are out of balance.
- Magnesium may prevent calcium from performing muscular contraction when the ratio of magnesium to calcium is out of balance.
Our analysis suggests that people who consume more calcium than magnesium tend to consume fewer calories. Hence, if weight loss is your goal, you should prioritise dietary calcium even more than magnesium.
Nutrient Profile of High Calcium Foods
The nutrient fingerprint chart below shows that we can obtain plenty of calcium in a nutrient-dense diet.
The best way to check if you are getting adequate calcium is to track your food and supplements. You should dial back any supplements or calcium-fortified foods if you are getting more than the minimum Recommended Dietary Allowance (RDA) of calcium of 1.0 g per day. You can then aim to increase your intake of foods that contain more calcium per calorie.
If you’re interested in checking that you’re getting enough (but not too much) calcium in your diet, you can check your nutrient profile using our Free 7-Day Nutrient Clarity Challenge.
Level Up Your Nutrient Density
The free starter pack includes:
- Maximum Nutrient Density Food List
- Sample Maximum Nutrient Density Recipe Book
- Sample Maximum Nutrient Density Meal Plan.
To get started today, all you have to do is join our new Optimising Nutrition Group here.
Once you join, you will find the Nutritional Optimisation starter pack in the discovery section here.
Nutrient Density Index
- Vitamin A
- Vitamin E
- Thiamine (B1)
- Riboflavin (B2)
- Niacin (B3)
- Pantothenic acid (B5)
- Vitamin B6
- Folate (B9)
- Vitamin B12
- Vitamin C
- Vitamin D
- Vitamin K1