Calcium is the most abundant mineral in the body and makes up roughly two whole pounds of body weight! We often associate calcium with strong bones and in fact, ninety-nine percent of calcium is located in the skeleton (teeth included). The remaining one percent is found in blood and tissues, where it plays a role in muscle contraction, assists Vitamin K in blood clotting activities, and is required for the transmission of nerve impulses.

Why Calcium is Crucial

Let’s get into the specifics about how our normal heart rhythm and blood pressure also rely on calcium. When not enough calcium is consumed, the parathyroid glands send signals to release the parathyroid hormone (PTH) and activate Vitamin D in the kidneys. This active form of Vitamin D (calcitriol) increases calcium absorption in the small intestine. PTH and Vitamin D then stimulate the release of calcium from bones and decrease urinary excretion of calcium. This ensures the body has what it needs for heart function, muscle contraction, and nerve impulses. When the body has enough calcium, the parathyroid gland stops its production of PTH, which allows the kidneys to excrete any extra calcium in the urine.

When you understand how this works, it’s easy to see that not eating enough calcium-rich foods over time can cause hypertension, cardiac arrhythmias, and osteoporosis. In some cases, certain medications (including diuretics) or a low functioning parathyroid gland can cause low blood calcium levels, which can lead to problems.

There are not any minor symptoms of calcium deficiency to give you a heads up that you may be low in this nutrient until hypertension, cardiac arrhythmias, and bone loss have already occurred. For this reason, it’s important to make sure your diet contains enough calcium…and Vitamin D to assist its absorption!

Calcium’s Absorption Issues

Things that interfere with calcium absorption are:

  • Phytates found in unsoaked grains, legumes, nuts, and seeds can bind to calcium and block its absorption.
  • Oxalic acid found in spinach, rhubarb, tea, and cranberries can interfere with calcium utilization (but only if consumed in large amounts).
  • Sugar throws off the calcium/phosphorus ratio in blood more than any other single factor. Sugar also stresses the adrenal glands, which can upset the hormone balance and affect calcium metabolism.
  • Caffeine in large amounts will increase the loss of calcium in urine.
  • Excessive fluoride replaces calcium in bones and can cause them to become brittle and weak.
  • Sodium in excess increases calcium loss in urine.
  • Coffee increases excretion of calcium from the body, while alcohol inhibits calcium absorption, so those beverages are best avoided by people with low calcium levels.

Helpful Tip: As we age, absorption naturally declines, so our intake of calcium should be increased.

Calcium Supplements

There are many forms of calcium supplements, from coral calcium to oyster shell calcium. While I can’t visualize myself going out and chewing on a piece of coral or oyster shell, these calcium supplements are in fact, considered to be “safe.” However, many nutritional therapists, including myself, emphasize the importance of getting this nutrient from food because most calcium supplements contain lead which can be very harmful.

The two main forms of calcium in supplements are calcium carbonate and calcium citrate. Side effects from supplementation include gas, bloating, constipation, or a combination of these symptoms. Calcium carbonate appears to cause more of these side effects than calcium citrate.

Calcium Carbonate

Due to its dependence on the presence of stomach acid for absorption, calcium carbonate is absorbed best when taken with food. Since it can neutralize stomach acid, calcium carbonate is often found in over-the-counter antacids, such as Rolaids® and Tums®, which can actually negatively affect digestion over time.

Calcium Citrate

Calcium citrate is a better choice for those with poor digestion, hypochlorhydria (lack of stomach acid), or other absorption disorders. Calcium citrate is absorbed well when taken with or without food and does not appear to interfere with digestion. Absorption appears to be highest in 500 mg doses, which is the amount in a typical calcium supplement. If a person takes 1,000 mg/day of calcium from supplements, it is a good idea to split the dose and take 500 mg two separate times during the day.

Use caution with calcium supplementation. What the body doesn’t need, it may deposit into tissues like the muscles and kidneys. High doses of supplemental calcium are associated with calcification of soft tissues and kidney stones. It can also prevent the absorption of other important nutrients such as iron and zinc.

Minerals are synergistic, so adding in calcium alone is not the best way to treat a calcium deficiency. Supplementing your diet with isolated minerals is only begging for trouble. As with vitamins, each mineral is a part of an intricate “dance” and adding or removing one leaves the others unable to perform optimally. Minerals are naturally in balance when obtained from whole foods, so getting your minerals from food is more beneficial than supplementation. For instance, liver is rich in calcium, iron, magnesium, potassium, sodium, and zinc in ideal ratios that the body can use readily.

If you do choose supplementation, be sure that your calcium supplement is labeled “lead free” and contains magnesium and Vitamin D to facilitate absorption and availability.

The Problem with Milk As a Calcium Source

For years, milk products have been promoted as a good source of calcium. While they are, there is food with even higher levels of calcium. Who would have thought! Almonds, white beans, and canned salmon with bones have more calcium than dairy and are alternatives for those who are lactose intolerant or sensitive to the protein casein in milk.

The problem with milk today is that it is fortified, pasteurized, and homogenized. This milk often comes from sickly cows that are fed growth hormones, antibiotics, genetically-modified corn, and other substances unnatural to their native diet. So no matter how many minerals and Vitamin D this milk contains, it is not ultimately going to “do you body good”, as the catchy 80’s slogan would like us to believe.


Pasteurization is a method of heat sterilization that kills many live enzymes and bacteria that produce lactic acid, a substance that naturally protects us against dangerous pathogens. Pasteurization also makes it easier to justify low standards of cleanliness on the huge dairy farms that supply most of America with milk. In raw milk, the important amino acids lysine and tyrosine remain stable. This allows them, along with 22 other amino acids, to be available to the body upon consumption. This is not the case with pasteurized milk.


In the “good old days,” a sign of good quality milk was the layer of cream at the top. The thicker the layer, the better the milk. If the layer of cream was thin, then the milk was considered to be lacking. Homogenization was developed in an effort to hide the cream within the milk. This newly created milk tasted bland, but had a creamier texture. The homogenization process takes a huge amount of milk and forces it, at a very high pressure, through a mechanism with tiny holes so that the fat globules are dispersed throughout the liquid as teeny tiny fat particles; changing the structure of the milk. All of this is done so you won’t have to shake milk before you drink it. Some claim that the fat particles are absorbed directly into the bloodstream instead of being digested properly, which may play a role in heart disease. I have not found any studies to support this claim nor have I found any to discredit it either.

If you choose to get your calcium from dairy sources, Good Decisions recommends local, organic, raw milk. If you are not a fan of raw milk, the next best thing is local or organic cultured buttermilk, yogurt, and kefir. It is also important to make sure you are not sensitive to milk products before consuming them. Also be sure to avoid any ingredients other than milk and live cultures in dairy products like yogurt (additives like carrageenan are often added, which has been linked to digestive problems).

If anything, choose organic. It is not as flavorful as raw milk but it is a much better decision than conventional milk, which lacks both flavor and nutrients. By choosing organic you avoid growth hormones, antibiotics, and other things fed to cows on those sad, cramped feedlots.

Are you someone who always reaches for skim or 1% milk? You may not realize that choosing these non-fat or low-fat varieties is similar to drinking sugar water! I have actually heard that skim milk is fed to pigs to help them gain weight. Switch to plain, whole milk versions to make sure you get those fat-soluble vitamins that ensure calcium absorption.

Recommended Daily Allowance (RDA)

Adults 19 and older – 1000 mg/day
Upper Level Dosage (UL) – 2,500 mg/day

Food Sources of Calcium

Animal sources: sardines, caviar, roe, cod, whitefish, and fish with bones (salmon and sardines). Dairy products and bone-rich broths used to make soups and stews are also good sources of calcium.

1 can salmon sockeye with bones – 882 mg
1 oz dried smelt – 448 mg
1 can of sardines with bones – 351 mg

1 cup cultured buttermilk – roughly 300 mg
1 cup yogurt – roughly 290 mg
1 cup kefir – roughly 267 mg

Plant sources: sea vegetables, legumes, sunflower seeds, pumpkin seeds, sesame seeds, dark leafy greens such as collard greens, and other green vegetables

1 cup raw winged beans – 801 mg
1 cup raw white beans – 485 mg
1 cup raw kidney beans – 359 mg
1 cup dry-roasted almonds – 457 mg
1 oz sesame seeds – 277 mg
1 oz agar (seaweed) – 175 mg
1 cup kale – 205 mg
1 cup turnip greens -104 mg

Some foods rich in other nutrients increase calcium absorption and availability. These include Vitamins A and D, which makes fatty fish ideal. In fact, 3.5 ounces of whitefish provides 810 mg of calcium, along with magnesium, potassium, and fat-soluble Vitamins A, E, and K, which, synergistically, makes it an ideal source of calcium. Try swapping a cheese-heavy dinner with our light, calcium-rich White Fish Poached in Coconut with Lime Ginger and Cilantro. SO delicious!