Important Role of Calcium and Vitamin D in the Body

Humans’ need for calcium to build and maintain strong bones and teeth has long been established. Vitamin D encourages the synthesis of proteins in the body and helps the body absorb calcium. These vitamins and minerals also play vital roles in muscle movement and cardiovascular function.

There are even studies that suggest a beneficial role of calcium and vitamin D in protecting against cancer, diabetes and high blood pressure. These suggest that we need Calcium and Vitamin D3 throughout our lives, although in varying quantities. Greater calcium supplementation is usually recommended for people who are pregnant; have stopped menstruating due to natural, medical or surgical reasons; have milk allergy or intolerance; or on a vegan diet.

As an Obstetrician-Gynecologist, I am most concerned with the calcium needs of women as they go through some of the most significant milestones in their lives, such as pregnancy and menopause.

Calcium is indispensable for normal physiologic function during pregnancy, for both mothers and fetuses alike. There is a natural high fetal demand for calcium during pregnancy as the baby forms. Fetal calcium deposition has been reported to peak in the third trimester. The mother responds by increasing maternal calcium absorption to meet that demand, starting in the second trimester of pregnancy. Greater increases were reported among women with low intakes. Maternal bone turnover also gradually increases during pregnancy. The highest levels of bone turnover markers are measured in the third trimester.

Moreover, maternal calcium levels have also been implicated in hypertensive disorders of pregnancy. There is evidence of an inverse relationship between calcium consumption and preeclampsia. According to studies, increased parathyroid hormone and 1,25-hydroxyvitamin D levels in low calcium-consumption mothers may effect elevation in intracellular calcium that may result in high blood pressure. Hypertensive disorder in pregnancy is one of the leading causes of maternal death.

Thereby, the World Health Organization recommends routine calcium supplementation from 20 weeks of pregnancy at doses of 1.5–2.0 g per day, particularly in a population with low calcium consumption to prevent preeclampsia.

Then there is menopause which usually occurs naturally in a woman’s life around the age of 50- 55 years, or earlier due to medical or surgical reasons. Women lose 10% to 20% of their bone as they pass through this menopausal transition . Once the postmenopausal period has established after about 5 years, the bone loss continues but at a slower rate.

Bone metabolism is under the control of estrogen. As estrogen levels plunge during menopause, there is a resulting reduction in the production of new bone cells, and an increase in bone resorption. Because of this, bones become less dense, generally weaker, and more susceptible to fracture. This is what is commonly referred to as osteoporosis.

The European Menopause Society guidelines 2018 state that an adequate intake of calcium is the mainstay of the prevention of osteoporosis. Before menopause, the recommended calcium supplementation is 1,000 mg of calcium daily. After menopause, the recommended dosage is increased to 1,200 mg of calcium per day.

These manifestations clearly show the importance of Calcium and Vitamin D to bone health and ultimately to the preservation of life and its quality. However, we have to be discerning.

Supplements may contain different forms of calcium that correspond to differing proportions of elemental calcium content. There is also no benefit in taking calcium above the recommended levels.