How does calcium affect our body?

How does calcium affect our body?

Calcium is the most common mineral in the body and is essential for the health of bones and teeth, as well as many bodily functions. Approximately 99% of the body’s calcium is located in the bones and teeth, providing structural support. The remaining 1% is found in the blood and tissues, where calcium plays critical roles in muscle contraction, nerve signal transmission, blood clotting, and heart function.

How much calcium does a person need?

The daily calcium requirement for adults varies, but the recommended amount for both men and women is typically around 950 mg/day. For example, dairy products such as milk, cheese, and yogurt are excellent sources of calcium. Certain vegetables, like kale, broccoli, and almonds, also contain calcium.

Examples of foods providing 200 mg of calcium:

• A glass of milk or buttermilk (1.7 dl)
• A serving of yogurt, viili, or quark (150-200 g)
• 2-3 thin slices of cheese (20-30 g)
• Tofu (60 g)

Examples of foods providing 100 mg of calcium:

• A handful of almonds (0.5 dl)
• A peeled orange (185 g)
• 3 dl black currants (140 g)
• 200 g broccoli

It’s also important to ensure adequate vitamin D intake, as vitamin D regulates calcium absorption. Therefore, a deficiency in vitamin D will affect calcium absorption. Calcium, in turn, can interfere with the absorption of certain trace minerals and vitamins, such as iron, copper, and zinc, so it’s important to pay attention to timing when taking supplements like iron.

Can you get too much calcium?

No, the kidneys ensure that excess calcium is excreted from the body. Since our body obtains the necessary calcium from food, if intake significantly decreases, the parathyroid hormone responds. Parathyroid hormone regulates calcium metabolism and will take the needed calcium from the bones if it’s not provided through food. This hormone ensures that there is a normal level of calcium in the bloodstream, but it doesn’t consider the health of the bones, which can lead to weakened bones over time. Conversely, if calcium intake is high, excess calcium can be stored in the bones.

The importance of calcium changes with age

• Childhood and Growth: During growth, calcium absorption increases due to hormonal changes and the development of the skeleton. Peak bone mass is reached around the age of 20-30, and after age 40, it begins to gradually decrease.
• Pregnancy and Breastfeeding: During pregnancy and breastfeeding, calcium needs are increased. Calcium absorption becomes more efficient, but additional calcium intake is not necessary if the diet is balanced. Studies have shown that the body utilizes calcium stores from the bones during breastfeeding, and calcium supplementation does not prevent this process. After breastfeeding, the calcium lost from the bones is quickly restored. The need for calcium supplementation during pregnancy and breastfeeding is assessed individually, following Finnish nutrition recommendations.
• Menopause: Estrogen production helps protect bones, but the decline in estrogen during menopause weakens bone density and increases the risk of fractures. Adequate calcium and vitamin D intake, along with physical activity, support bone health. Bone loss accelerates at the onset of menopause but slows down after 3-5 years.
• Aging: As we age, calcium absorption decreases, and the body may use calcium stores from the bones if needed. Calcium supplementation may be necessary if the diet contains few dairy products or fortified plant-based products, or if the need has increased for other reasons (e.g., medication).

Genetics affect calcium utilization

Many genetic factors also influence calcium absorption and utilization. For example, the CASR gene codes for the calcium-sensing receptor (CaSR), which regulates blood calcium levels. When calcium binds to CaSR, it inhibits the release of parathyroid hormone, reduces calcium reabsorption in the kidneys, and helps maintain normal calcium levels.

Mutations in the CASR gene can make the receptor overly sensitive to calcium, causing even low calcium levels to trigger signaling. This prevents the release of parathyroid hormone and calcium reabsorption in the kidneys, which can lead to hypocalcemia (low calcium levels). Symptoms may include muscle cramps and spasms, but some individuals with this mutation are asymptomatic

For the curious

Calcium balance, which is vital for bone health, is carefully regulated by parathyroid hormone, active vitamin D (1,25(OH)2D), and calcitonin. Calcium is regulated by the parathyroid glands and kidneys through the calcium-sensing receptor (CaSR), which detects changes in the levels of ionized calcium and adjusts parathyroid hormone secretion accordingly. In the kidneys, the activation of CaSR promotes calcium reabsorption, while in the bones, it supports the differentiation of osteoblasts and bone formation. Parathyroid hormone increases calcium release from the bones and enhances calcium absorption in the intestines. Active vitamin D (1,25(OH)2D) also aids in calcium absorption in the intestines, as well as bone formation and calcium reabsorption in the kidneys. The calcium balance is further supported by the vitamin D receptor (VDR) and parathyroid hormone receptor (PTHR1), which mediate the body’s calcium regulation functions.

Understanding calcium balance is important in preventing osteoporosis and maintaining strong bones throughout life. Osteoporosis is often referred to as a “silent disease” because it develops gradually and causes no symptoms until the bones weaken and the risk of fractures increases. Known risk factors for low bone density and fractures include age, female gender, genetics, hormonal imbalances, smoking, poor nutrition, lack of physical activity, and certain diseases and medications that affect calcium metabolism.

You can find out your natural calcium levels through Evogenom’s Minerals package. It’s also worth exploring the comprehensive Eat package, developed for nutrition and weight management, which provides insights into your individual nutritional intake.

Lähteet

Laaksonen, M. (2008). Associations of gene polymorphisms and nutrition with calcium homeostasis and bone mineral density: studies on skeletal nutrigenetics. University of Helsinki, Department of Applied Chemistry and Microbiology.

Kestävää terveyttä ruoasta – kansalliset ravitsemussuositukset 2024, Valtion Ravitsemusneuvottelukunta 2024.

Duodecim. Käypä Hoito. Luusto lujaksi 2007, Duodecim terveyskirjasto; kalsium.
Marja Komulainen, Marjo Tuppurainen ja Heikki Kröger, Luut murtuvat ilman estrogeeniä, 2003, Duodecim.

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