Calcium plays a crucial role in various physiological processes within our bodies. Calcium ions not only affect cellular metabolism and signaling but are also particularly important for bone growth and metabolism[1]. The amount of calcium intake from our diet directly impacts our health.
Insufficient calcium intake has been linked to conditions such as osteoporosis, cancer, cardiovascular diseases, and obesity. There’s a correlation between these conditions and calcium intake[2]. Given that many individuals in our population have inadequate calcium intake, calcium supplements have become a common household staple for maintaining overall health.
Why should you take calcium supplements?
In the elderly and postmenopausal women, bone loss tends to occur faster than bone formation. Insufficient calcium intake over time can increase the risk of osteoporosis[4]. Calcium supplementation has been shown to promote bone growth in children and adolescents and to effectively support bone consolidation and maintenance in adults. It also reduces the risk of fractures in the elderly, slows down the rate of bone loss, and benefits postmenopausal women’s health[3].
The 6 Key Benefits of Calcium:
1. Maintaining Normal Physiological Functions
Calcium is the most abundant mineral element in the human body, accounting for about 2% of body weight[2]. The concentration of calcium ions in the body is tightly regulated to maintain a specific range in the blood, preventing high or low blood calcium levels.
Calcium is involved in various physiological functions, including vascular contraction and relaxation, muscle function, nerve transmission, cellular signal conduction, and hormone secretion. Only less than 1% of total body calcium is required for these functions, while the remaining 99% is stored in bones and teeth to support their structure[4].
2. Maintaining Bone Health and Preventing Osteoporosis
Around the age of 30, bone density reaches its peak and then begins to decline with age. This is especially pronounced in postmenopausal women. Osteoporosis is a serious public health issue, affecting over 10 million Americans, with 80% of cases occurring in women[6]. Each year in the United States, osteoporosis leads to at least 1.5 million fractures[7].
Studies show that supplementing with calcium and vitamin D significantly increases total bone density and reduces the incidence of hip fractures in postmenopausal women[8]. Exercise can also reduce the risk of osteoporosis in the elderly[9].
3. Blood Pressure Regulation
Calcium intake is generally considered to assist in blood pressure regulation. Research on American women aged 45 and above found that a higher intake of dietary calcium is negatively correlated with the risk of hypertension in middle-aged and elderly women[10].
This suggests that women with higher dietary calcium intake are less likely to develop hypertension. In another study, hypertensive participants who took calcium supplements experienced a reduction in systolic blood pressure, but calcium did not significantly affect blood pressure in those with normal blood pressure[11].
4. Neurological Stability and Improved Sleep
Clinical studies investigating the relationship between sleep quality, anxiety, depression, muscle and bone pain, and calcium intake found that poor sleep quality was associated with lower calcium intake. Participants who consumed over 800 mg of calcium daily reported better sleep quality. Therefore, increasing calcium intake is recommended for individuals with sleep quality issues[13].
5. Prevention of Muscle Cramps and Muscle Strain
Up to 30% of pregnant women suffer from leg cramps, often attributed to changes in calcium or magnesium concentrations in the blood[14]. Clinical studies have shown that supplementing with calcium for four weeks significantly reduces the frequency of leg cramps[15]. Similar research in women with leg cramps found a tendency toward decreased frequency with calcium supplementation[16].
6. Alleviation of Premenstrual Syndrome (PMS) Symptoms
During the luteal phase of the menstrual cycle, blood calcium levels decrease, potentially exacerbating premenstrual syndrome (PMS) symptoms. Taking calcium supplements or consuming a calcium-rich diet can help restore blood calcium levels and alleviate PMS symptoms[17]. Another review suggests that supplementing with 1200-1600 mg of calcium daily can be considered as an adjunctive therapy for women experiencing PMS[18].
What are calcium-rich foods?
Milk, yogurt, and cheese are natural sources rich in calcium. Non-dairy sources include dark leafy vegetables such as bok choy, kale, broccoli, and spinach. However, the calcium provided by vegetables has lower bioavailability.
Other calcium-rich foods include various fruits, tofu, and some grains[19]. Dark leafy vegetables, fruits, and legumes may play an important role as sources of calcium in the Mediterranean diet, with the bioavailability of dietary calcium depending on physiological and dietary factors[2].
| Calcium content (calcium content per 100 grams) |
Foods high in calcium |
| More than 500 mg | Small dried fish, black sesame, lettuce, dried shrimp |
| 200-500 mg | Tofu, milk, cheese, nuts, oysters, edamame, black beans |
| 50-200 mg | White sesame, shrimp, white sesame, okra, kale, amaranth |
Recommended Calcium Intake?
According to professional organizations, the Recommended Daily Intake (RDI) and the Upper Limit (UL) for calcium per person per day can be referred to in the table below[20]. It’s important to note that many people believe that pregnant or lactating women require more calcium supplementation, but in reality, their calcium needs are the same as those of the general adult population.
While calcium deficiency is a concern among our population, it’s worth noting that excessive calcium intake over the long term can still lead to adverse effects. Having an excessively high level of calcium in the blood (known as hypercalcemia) due to excessive calcium intake could lead to kidney dysfunction, vascular and soft tissue calcification, hypercalciuria (excess calcium in the urine), and kidney stones. Additionally, it can affect the absorption of other minerals[4].
| Male/Female | RDI, milligrams | UL, mg |
| 0 month- | 300 | 1000 |
| July- | 400 | 1500 |
| 1 year old- | 500 | 2500 |
| 4 years old- | 600 | 2500 |
| 7 years old- | 800 | 2500 |
| 10 years old- | 1000 | 2500 |
| 13 years old- | 1200 | 2500 |
| 16- | 1200 | 2500 |
| Over 19 years old | 1000 | 2500 |
| Pregnancy | 1000 | 2500 |
| Lactation | 1000 | 2500 |
How to Effectively Supplement Calcium? When to Take Calcium Supplements?
Calcium Form and Absorption Rate
Calcium supplements come in various forms, including calcium carbonate, calcium phosphate, calcium citrate, seaweed calcium, and calcium malate.
- For those with poor digestion, it’s best to avoid calcium carbonate and opt for sources like calcium citrate or seaweed calcium.
- Take calcium supplements with meals: If the supplement contains calcium carbonate, taking it with meals can aid in absorption by utilizing stomach acid. However, if it’s calcium citrate, it can be taken without meals and still have good absorption rates[21].
- Take calcium supplements before bed: Calcium and magnesium can enhance sleep quality and relax muscles. Individuals with sleep disturbances can take calcium supplements two hours after dinner or before bedtime.
- Calcium powder has better absorption than calcium tablets: Powder allows for greater surface area contact with the intestines, leading to improved absorption efficiency.
Further Reading: How to Choose Calcium Supplements? Significant Variations in Absorption Rates: Calcium Carbonate, Calcium Citrate, Seaweed Calcium
Benefits of Small, Frequent Calcium Intake
The absorption rate of calcium in the intestines decreases as the intake of calcium increases. The highest absorption percentage is achieved when a single calcium intake is ≤500 milligrams[4].
For individuals aiming to reach the recommended daily calcium intake of 1,000 milligrams, it’s advisable to take calcium supplements at different times throughout the day using the small, frequent dose approach to achieve optimal calcium absorption[20].
Pair with Vitamin D to Enhance Calcium Absorption
Vitamin D assists in opening calcium ion channels in the intestines, increasing calcium absorption, and regulating calcium transport proteins to enhance calcium ion transmission. Therefore, combining calcium and vitamin D improves calcium absorption[22].
The Ideal Calcium-to-Magnesium Ratio of 2:1
Research indicates that culturing human bone cells with a calcium-to-magnesium ratio of 2:1 promotes positive effects on cell adhesion, proliferation, differentiation, and compatibility. This ratio encourages cell growth and enhancement in human bone cells[23].
Which Groups Need Calcium Supplements?
- Children and Adolescents during growth and development
- Individuals who don’t consume dairy products, have limited vegetable intake, or regularly consume coffee
- Women, especially postmenopausal women, should consider calcium supplementation
- Pregnant and lactating women
- Elderly individuals to prevent osteoporosis
