The Health Benefits of Calcium
Introduction & Biological Role
Calcium is an essential mineral for living organisms and the most abundant mineral in the human body. It is an essential element for development of bones and teeth as well as many intracellular signaling processes. Normal calcium levels are required for normal vascular function, muscle activity, nerve transmission, intracellular signaling and hormonal secretion. More than 99% of calcium is stored in the bones and teeth, and only 1% or less is circulating for other purposes.
Calcium metabolism is tightly regulated by the body and in most healthy individuals, it will not fluctuate much between dietary intakes. Your body depends on magnesium, phosphorous, vitamin D and vitamin K for proper balance of your calcium levels. Because of this, as you can imagine, malnourished individuals are at risk of having low calcium. Other factors, such as age, chronic diseases and certain medications can affect calcium absorption and metabolism.
Certain things may enhance calcium absorption, such as carbohydrates, while others such as coffee and cigarette smoking may impede it. Once absorbed, bone continuously undergoes remodeling, with constant reabsorption of calcium and deposition of calcium into new bone. In children, deposition exceeds resorption, leading to bone growth at the growth plates. In adults, this process is typically in equilibrium until we get into the later years of life, particularly in postmenopausal women where reabsorption exceeds deposition.
Health Benefits/ Uses
Osteoporosis is a disease where the mineralization of your bones becomes abnormal, often associated with aging, which causes bones to become weak and brittle. When this happens, there is a significant increase in fracture risk and the subsequent problems that come with having a fracture at an older age. Osteoporosis occurs when the body can’t produce enough bone to keep up with the natural breakdown and remodeling of our bones that happens every day. After age 30, this process begins naturally. Studies have shown that calcium in combination with vitamin D may help prevent bone loss in men as well as menopausal women.
Hypoparathyroidism means underactive parathyroid hormone, which helps regulate calcium, phosphorus and vitamin D. In this condition, your body does not generate enough calcium in your blood leading to a deficiency in calcium levels. Individuals with this condition, diagnosed and managed by a physician, often require calcium supplements.
Research has shown that women who take 1200 mg of calcium per day reduced symptoms of PMS by up to 50%, including headache, moodiness, food cravings, bloating and menstrual pain.
Calcium has been proposed to reduce the risk of cardiovascular disease by several mechanisms such as decreasing absorption of fats and increasing their excretion as well as lowering cholesterol levels in the blood. Studies have been mixed to say the least. A 2012 review of the available data concluded that calcium intake from diet or supplements had little or no effect on cardiovascular disease risk, but that there remains room for more prospective research. The possibility of harm from supplementation has also been raised, again suggesting we need to better answer this question.
High Blood Pressure (Hypertension)
Studies have shown that calcium deficiency or inadequate calcium intake increase your risk for high blood pressure. Interestingly, supplementing calcium even when deficient does not always lower your blood pressure; studies are mixed. Researchers aren’t sure whether it’s a primary calcium issue or whether it’s something else in the diet, for example dairy products.
High Cholesterol (Hyperlipidemia)
Preliminary studies suggest that calcium supplementation may help lower cholesterol slightly. This combined with exercise and a healthy diet is probably superior to calcium supplementation alone. More research is needed.
Preeclampsia is a condition that occurs during pregnancy where the mother develops high blood pressure, fluid overload, and protein in urine. Normally this is a condition that requires close monitoring by the OBGYN, but occasionally can progress to more severe symptoms. Some studies suggest that taking calcium in addition to other medications may help treat or prevent the development of this condition, but studies are mixed.
Obesity & Weight Loss
There is no good evidence that shows that calcium supplements help with weight loss. Some studies have shown low fat dairy products help, but researchers don’t know why. Other studies have shown no benefit. More research is needed.
Stroke (Cerebrovascular Accident)
In one study, women who had higher calcium intake, both through food and supplementation, had a lower risk of stroke over 14 years compared to women who did not. This suggests a correlation, but does not prove causation. More research is needed.
Some studies show that high calcium, high dairy and high vitamin D diets are linked to a reduced risk of colorectal cancer. Not all studies draw this conclusion, so results are mixed and more research is needed.
Some studies have linked high calcium and dairy intake to an increased risk of prostate cancer, however other studies have found no relationship or even a protective effect. A meta-analysis of all the research suggests that high intakes of dairy products and calcium may slightly increase the risk of prostate cancer. Interpreting the evidence is complicated as it is difficult to separate dairy product intake from calcium intake. More research is needed.
Chronic deficiency in children can lead to something called Rickets, which is primarily a vitamin D deficiency but associated with calcium deficiency too. This deficiency and disease is rare in the western world where we supplement our food with calcium and vitamin D, but still happens in more economically challenged areas of the world. Symptoms include muscle weakness, bone pain, growth delays, bowed legs, thickened wrists and ankles and breastbone projection.
In adults, calcium deficiency can manifest as osteopenia and osteoporosis. Osteopenia is the precursor to osteoporosis. These individuals have increased risk of fractures and bone injuries from trauma and decreased bone mineral density on xrays and other imaging. Individuals at risk include postmenopausal women, female athletes, lactose intolerance or cow’s milk allergy, vegetarians. Treatment is primarily preventative with supplementation, and this process does occur naturally in everyone as we age.
Low calcium in the blood can also be a problem if regulation is abnormal. You can have low blood calcium levels, termed hypocalcemia, without total body calcium deficiency.
Excessive calcium is termed hypercalcemia and is associated with some health risks. High calcium can cause renal disease, vascular problems and kidney stones. The most common causes include cancer and elevated parathyroid hormone.
Although not all kidney stones are composed of calcium oxalate, most are. Research is fairly convincing that supplementation of calcium and/or high calcium levels increase your risk of developing kidney stones, especially if you have a history of them. Interestingly, dietary intake of calcium does not increase your risk, just supplementation. Make sure to talk to your doctor if you have a history of kidney stones.
The best dietary sources of calcium include (all have >25% RDV):
- Cheeses (Parmesan, Romano, gruyere, cheddar, American, mozzarella, and feta)
- Dairy (milk, yogurt)
- Soy milk
- Orange juice
Other good dietary sources include:
- Cereal (varies widely)
- Turnip greens
- Chinese Cabbage
- Tortilla (corn or flour)
- Sour cream
- Calcium carbonate: more commonly available, inexpensive, convenient, absorption is improved when taken with food
- Calcium citrate: doesn’t need to be taken with food
Recommended Daily Allowance (RDA)
Below is the recommended daily allowance for calcium. This will vary somewhat by age, gender and in women whether they are pregnant or lactating. What I will say if you want to remember one number is that most teenagers and adults require at least 1000 mg or 1 gm per day.
- Calcium Benefits: https://youtu.be/DMgKHClea60
- Top 10 Dietary Sources of Calcium: https://youtu.be/Nr9HTFx4978
- Calcium Supplement Options: http://amzn.to/2pjnzVf
- Calcium: https://youtu.be/DMgKHClea60
- Iodine: https://youtu.be/814EptN0GKo
- Manganese: https://youtu.be/5khnELeoUYI
- Chromium: https://youtu.be/bxBmhsga0is
- Copper: https://youtu.be/fJYsfAb0IO8
- Iron: https://youtu.be/Q10_f3aTQm4
- Magnesium: https://youtu.be/a3rYf302Sfc
- Phosphorous: https://youtu.be/qaxzSMnWbp0
- Potassium: https://youtu.be/ZRdg8TfnKxs
- Selenium: https://youtu.be/Qn4EK_twW8o
- Sulfur: https://youtu.be/rnlONWITGC8
- Zinc: https://youtu.be/ZapT_eAgeEU