The debate about Calcium and its best sources for human bodies is continuous and endless.
Below is the complete story and I will leave it to you to make your own closure.
Calcium is the most abundant mineral in the human body and among the most important. It constitutes about 1.5 to 2% of our body weight. 98% is contained in our bones and 1% is in our teeth. The remainder 1% is in our body fluids, soft tissues and membranes.
Calcium makes up about 3% of the earth’s crust and is a basic component of most animals and plants.
Our bones serve as a storage site for the body’s calcium, providing this mineral to the bloodstream for use by the heart and other organs. Eating a diet rich in calcium helps to restore it to the bones.
Maintaining a balanced blood calcium level is essential to life. A normal level is about 10mg% (10mg per 100 milliliters of blood).
Calcium is an essential dietary element required in optimal amounts for:
- Good Bone health
- Efficient Nerve and Muscle function
- Overall Cardiovascular health
Calcium works with Magnesium in its functions in the blood, nerves, muscles and tissues particularly in:
- Regulating heartbeats
- Muscle contraction
- Nerve conduction
Calcium plays a role in:
- Maintaining normal Blood Pressure
- Regulating Blood Clotting
- Preventing Cancers of the Digestive tract (Colon and Rectal cancers)
- Relieving Mood Swings
- Relieving Food cravings
- Decreasing the pain, tenderness and bloating associated with Premenstrual Syndrome (PMS)
- Helping for problems of loose teeth and Gingivitis (gum inflammation)
Calcium and Vitamin D help reducing muscle cramps and leg and foot cramps
Calcium is an absolutely critical nutrient in regulating Acid/Alkaline balance (called pH) in the blood.
Symptoms of Calcium Deficiency:
Calcium deficiency known as Hypocalcemia can cause:
- Nerve Sensitivity
- Muscle Twitching
- Brittle Nails
- Leg and foot or other muscle cramps
- Numbness or tingling in the fingers
- Poor Appetite
- Mental Confusion
- Feeling of Chronic Depression
- Skeletal Malformations
- And in Infants, Delayed Development
What causes the Reduction & Increase of Calcium Absorption?
Calcium is absorbed by all parts of the small intestine, but the most rapid absorption occurs after a meal in the more acidic duodenum.
- During infancy and childhood, 50% to 70% of the calcium ingested may be absorbed. The pre-teen and teen years are the most critical time to meet dietary calcium needs since as nearly as 40 % of the total adult bone mass is established between the ages of 10 and 15 years.
- An adult might use only 30% to 50% of dietary calcium in his body.
- After 65 years of age, calcium excretion decreases most likely because of decreased intestinal absorption of calcium.
- Calcium is often drained from the bones during Pregnancy and Nursing and becomes hard to replace in late years.
In general, the greater the need and/or the smaller the dietary supply, the more efficient the absorption of calcium is.
If there is not enough calcium in the diet to maintain sufficient amounts of calcium in the blood, the Parathyroid glands will release more parathyroid hormone (PTH), which will draw calcium out of the bones as well as increase intestinal absorption of available calcium. So even though most of the body’s calcium is in the bones, the blood and cellular concentrations of this mineral are maintained first.
Blood calcium and phosphorus:
Their levels are both regulated by the parathyroid hormone. However, phosphorus levels are not as tightly regulated as calcium in your blood, and levels can rise quickly if you consume too many high-phosphorus foods such as soft drinks and Meat which contains 20 to 30 times as much phosphorus as calcium.
When the diet is high in phosphorus we can lose extra calcium through the urine, resulting in calcium being pulled out of the bones.
The phosphorus-calcium imbalance can lead to Kidney stones and calcification problems.
Good Calcium to Phosphorus ratio is 1:1 in the diet which can reduce the risk of cancer in the Large Intestine.
Many Nutrients, vitamin D, and certain hormones are important for calcium absorption, function and metabolism.
- Vitamin D plays a pivotal role in allowing the body to absorb calcium. It is needed for much calcium (and phosphorus) to be absorbed from the digestive tract. It also helps maintain normal blood calcium levels.
- Vitamin D is synthesized naturally in the skin when it is exposed to sunlight. However, the efficiency of skin production of vitamin D by older adults is considerably lower than that of younger people.
If vitamin D levels are optimal, most adults should be able to meet their daily calcium need via a varied diet that includes a wide variety of calcium-rich foods.
Many dietary factors also reduce calcium absorption:
- A high Sodium intake contributes to higher urinary calcium losses. Reducing sodium intake can reduce bone loss considerably.
- Sugar intake may reduce the reabsorption of calcium and magnesium and cause more to be eliminated.
- Alcohol can decrease the absorption of calcium from the intestine and cause deficiencies in vitamin D and Magnesium- both of which are important to bone health.
- Coffee consumption of more than 2 cups a day may contribute to an accelerated bone loss.
- High Protein diets may increase calcium elimination through the intestines.
- Food that is high in oxalic acids such as spinach, rhubarb, chard and chocolate. Only 5% of the calcium in spinach is absorbed. The unabsorbed forms of calcium are excreted in the feces as calcium oxalates and calcium soaps.
- Phytic acid or phytates found in whole grain foods or foods very rich in fiber may reduce the absorption and other minerals as well. But this happens only when consuming more than 30g/day.
- Food high in Fatty Acids may decrease calcium absorption due to the formation of calcium soaps in the GI tract.
- Medications can affect bioavailability or increase calcium excretion, both of which may contribute to bone loss. One example is the Excessive use of Antacids. Also, certain medications, such as steroids and anticonvulsants, may contribute to bone demineralization.
- Low Stomach acid because gastric hydrochloric acid helps calcium absorption.
- Stress can diminish calcium absorption possibly through its effect on stomach acid levels and digestion.
- At Menopause, calcium excretion increases greatly.
- About 50% of the ingested calcium is excreted in the urine each day but it is typically low during periods of rapid skeletal growth.
- The amount of calcium lost in Sweat is about 15mg/day. Strenuous physical activity with sweating increases the loss.
Various factors can improve calcium absorption:
- Vitamins A & C beside Vitamin D can help support normal membrane transport of calcium.
- Calcium is often chelated with Protein and Amino acids to make it more absorbable but not too much protein
- Some dietary fat may also help absorption but high fat may reduce it
- Exercise has been shown to improve absorption and lack of exercise can lessen it
- Body needs: growth, prepuberty & adolescence, post-menopause, pregnancy, and lactation.
- Milk Lactose
- Calcium supplements tend to stimulate retention of calcium and decrease urinary excretion.
Are there any risks associated with too much calcium?
Symptoms of Excess Calcium:
- Unquenchable Thirst
- Excessive Urination
- Abdominal Pain (one-sided)
- Lack of appetite
- Memory Loss
- Irregular Heart Rhythm
When we increase calcium, we should also increase magnesium intake, about ½ of the calcium supply. It helps calcium stay more soluble and thereby may reduce the risk of Kidney Stone formation and other calcification of the soft tissues.
Studies indicate that men who take too much may have an increased risk of Prostate Cancer, and should limit their dietary intake to 500-600 mg daily from all sources.
How Much Calcium Do We Need?
Dietary Sources of Calcium:
Here I want to start by quoting Dr. Andrew Weil (founder and director of the Arizona Center for Integrative Medicine and clinical professor of medicine at the University of Arizona):
“ The most common perception I hear about bone health is that taking supplemental calcium—or consuming plenty of calcium-rich dairy products—is essential. I think this idea is widespread because it seems so reasonable: Bones get their strength from calcium, so taking calcium pills or drinking milk daily seems like the best routes to building and maintain them.
The problem: Bones are actually made of a complex of minerals (calcium is just one of them) and specialized connective tissue known as collagen. …The populations with the highest calcium intakes actually have the highest rates of hip fractures in later life. I now recommend supplemental calcium for only some women, and only at modest dosages. When it comes to BONE HEALTH…is adequate vitamin D, …, and Weight-bearing Exercise,…I endorse the advice of Walter Willett, M.D., Dr. P.H., who chairs the department of nutrition at the Harvard School of Public Health: ‘If you want to prevent fractures, don’t drink the milk, but take your cow for a walk!’”
A- Dairy Products:
- Two glasses of milk per day provide 1,000- 1,200mg.
However, it is not essential to have dairy products, as there are many other sources. But if you insist, make sure you use only hormone-free, organic dairy products to reduce your exposure to the antibiotics and hormones found in many dairy products.
B- Non Dairy Products:
- Broccoli: steam broccoli for a high-calcium side dish
- Almonds: they contain almost 100 mg of calcium per ounce. Also Brazil nuts and Hazelnuts are good sources.
- Oatmeal: it provides a significant amount of calcium. Just one packet of instant oatmeal provides about 100mg
- Orange juice: enjoy a glass of orange juice with your breakfast and boost your calcium. Calcium-enriched orange juice will provide even more of your daily needs.
- Kale: it is high in calcium, other minerals and antioxidants. Cook as a side dish or add to your salad as a calcium boost.
- Black Eyed Peas: they are a good source of calcium, potassium, folate and other nutrients.
- Blackstrap Molasses: they can replace sugar in some recipes to increase calcium and iron intake. Molasses contains even more calcium than milk
- Many Peas & Beans (Pinto, adzuki and soybeans) are excellent sources of calcium
- Salmon: This fish is loaded with essential fatty acids and rich in calcium and other minerals
- Figs: fresh figs are a good source of calcium. Four of them will give you more than 100 mg of calcium
- Sesame Seeds: sprinkle them on cereal or salads. Sesame seeds are not just high in calcium, but also provide fiber and unsaturated fat.
- Cauliflower, Sardines, cooked collard greens, Kale, Bok Choy, Turnip greens, Sunflower seeds, Tofu, raisins, dried fruits and Citrus fruits have modest amounts of calcium.
For Bone Health, Andrew Weil M.D., recommends that:
- All women supplement with 500 to 700 mg of calcium taken with meals, for a total daily calcium intake of 1000-1200 mg from all sources.
- For men, he suggests 500mg from all sources and better not to supplement because higher amounts have been linked to increased risk of prostate cancer.
- Do not use Bonemeal or Dolomite as your source of calcium supplement. The Food and Drug Administration has issued warnings that they could be dangerous because these products may contain
- Men and Women should take 1000 to 2000 IU of Vitamin D3 to facilitate calcium absorption and promote bone mineralization- as well as for protection from many forms of cancer and other serious diseases.
- Magnesium is also an important mineral in the bone matrix and is usually provided with calcium to offset some of its constipating effects. The dose should be half of your calcium dose.
Supplements of calcium and magnesium are often taken at night before bed to help absorption and to prevent the extra loss of body calcium that can occur during the night. Also, it is a good evening tranquilizer.
Monique Helou, RHN
– Staying Healthy with Nutrition by Elson M. Haas, Md and Buck Levin, Ph.D., RD
– Nutrition & Diet Therapy by Peggy S. Stamfield and Y.H. Hui
– Krause’s Food & Nutrition Therapy by L. Kathleen Mahan and Sylvia Escott- Stump
– Nutritional Influences on Illness “A sourcebook of Clinical research” by Melvyn R. Werbach, M.D.
– www.drweil.com by Andrew Weil, M.D.