By: Andy De Santis, RD and Dr. Kathleen Regan, ND

Andy De Santis is a Registered Dietician practicing at Innate Wellness High Park. He focuses on creating diet plans for patients of Innate Wellness. If you are interested in having a customized nutrition program created for you, please call the High Park Clinic. 

Calcium is one of the most abundant minerals found in the human body. Most calcium is stored either in our bones or our teeth, leaving a small amount found in other tissues or circulating through our blood. The way our bodies use and absorb calcium depends on the presence of specific nutrients, such as Vitamin D, and specific hormones, such as parathyroid hormone and calcitonin. Calcium levels are also influenced by specific female hormones such as estrogen (which increases calcium absorption).

Declining levels of estrogen as women age, through menopause, after hysterectomy, or via estrogen reducing drugs such as Tamoxifen (post-breast cancer treatment) can dramatically affect calcium levels. Individuals who don’t consume dairy can also be at risk for calcium deficiency but they can obtain more than enough calcium from their diet if they know other calcium rich foods! What is most important to know is that supplementing with high levels of calcium can be unhealthy and even dangerous for the body. So if you are low in calcium or suffer from low bone density – you need a balance of diet and supplementation to achieve your daily intake.

When most people think calcium, they think bone health, but it’s important to realize that a number of other nutrients also make up the bone matrix, including phosphorous, magnesium, silicon, strontium and boron.

Calcium also serves a variety of critical functions in the human body beyond just supporting the formation of healthy bones and teeth. Calcium is also responsible for:

  • Muscle contraction
  • Nerve signaling
  • Blood vessel contraction and expansion

Perhaps most importantly, calcium works in combination with magnesium, sodium and potassium to regulate your blood, nerves, muscles – particularly the heart muscle.

When you think about it from a pure survival perspective, regulation of the heart muscle is much more important for life than bone formation, and so our bodies make it the physiological priority. This means that if your body detects low blood calcium levels, which can interfere with proper heart functioning, it will stimulate the release of calcium from your bones. This is why, in calcium deficient diets, such as the average nutritionally imbalanced North American Diet, osteoporosis has become a serious problem.

Osteoporosis, by definition, is a disease characterized by bones that have lost density ( largely due to calcium losses) to point that they are at a greatly increased risk of fracture. Owing to concerns over osteoporosis, and based on earlier studies that showed calcium intake was positively related to a reduced risk of heart disease, it became standard practice to recommend calcium supplementation, especially in post-menopausal women who are prone to lower bone-density due to dropping estrogen levels. 

So How Much Do You Need?

Recommended Daily Allowances acknowledge that calcium absorption changes as we age, with men and women between 19 and 50 years of age needing 1000mg per day, women between 50 and 70 years of age needing 1200mg per day, men between 50 and 70 years of age needing 1000mg per day and men over 71 years of age needing 1200mg per day.

More recent studies, including the Women’s Health Initiative, have found that women with an elevated intake of calcium (greater than 1000mg), particularly those individuals taking calcium supplements, were at an increased risk of experiencing cardiovascular events by 15-22%. Those women with supplemented/excessive calcium intakes were more likely to have elevated blood lipid levels related to blood clotting and increased calcium deposits in their arteries. In addition, high supplemental doses of calcium have been associated with an increased risk of kidney stones.

Why More Is Not Better

The idea that too much calcium is actually bad for you may be surprising but, as the saying going, there is such a thing as too much of a good thing, and that certainly applies to your calcium intake.

If you’re wondering why this is, the current state of science suggests that high dose supplemental calcium ( ~700-1000 mg) is not well broken down by the body. When the body takes on more calcium than it can handle, the excess is not well absorbed and ends up circulating in the blood leading to the cardiovascular issues described in the previous section.

For this reason above all else, it is highly recommended that the majority of people take their calcium in from dietary sources, intermittently throughout the day to ensure optimal absorption and excretion of excess calcium.

Where needed, much smaller dosage of supplemental calcium (150-400mg) can be added (pregnancy, lactation, post menopause, breast cancer treatment, osteoporosis).

 

It’s Not JUST About Calcium Though

So now you know what calcium does for you, how much you need and why too much can be dangerous, BUT it is also important to also realize that your body’s effective use of calcium is highly dependent on a number of factors, especially when it comes to bone health.

Here are just a few factors that can affect calcium absorption and bone density:

  • Poor absorption from certain foods
  • Age
  • Low stomach acid
  • Low dietary fat
  • Low dietary protein
  • A diet high in oxalic acids or phytic acids ( found in certain grains/veggies)
  • Vitamin D deficiency (needed for calcium absorption and metabolism)
  • Vitamin K deficiency (reduces calcification caused by calcium)
  • Vitamin E deficiency (associated with lower bone density)
  • Phosphorous in excess of calcium (reduced calcium absorption)
  • Magnesium deficiency (reduces calcification caused by calcium)

This list is extensive and serves as proof that if you are looking to improve your bone density, there are so many areas that you need to consider and it is never as simple as just taking a calcium supplement.

In addition to consuming adequate calcium, you must also carefully consider your current intake of magnesium, vitamin K and vitamin D, at the very least. This is why a balanced calcium supplement or ‘bone density’ supplement should contain 500mg or less of calcium per day as well as a range of healthy bone nutrients. At a minimum it should contain magnesium and vitamin D. If you come to Innate Wellness looking for bone support, you will notice we don’t carry isolated calcium and this is why.

What about the rest of your daily calcium? This should come from food! We have attached a list of calcium rich foods based on realistic daily consumption.

You will notice that, at first glance, that dairy is the richest source of dietary calcium among conventional foods. You could theoretically have a cup of yogurt and 2 cheese slices and already be at 80% of your calcium goal. There’s a catch though. Dairy is not an ideal source of calcium for everyone, and certainly not those individuals who are lactose intolerant or have some other form of sensitivity to dairy products, which can affect their absorption of calcium from those types of foods. Dairy can also be a problematic food for those with hormonal imbalance or estrogen dominant health conditions such as breast cancer (Read more).

With this mind, the list below is meant to offer you a path to obtaining 1000mg of calcium daily, with or without dairy.

If you are older than 50 or post-menopausal, you may need an additional 200mg of calcium daily and if you are pregnant or breastfeeding you may need an additional 200-400mg.

 

Top Sources Of Calcium

Based on Canadian Nutrient File 2015 data

 

Dairy

Milk – 310 mg per cup

Cottage Cheese – 150-250 mg grams per cup, depending on variety

Yogurt/Kefir – 175-275 mg per ¾ cup, depending on variety

Cheese – 250-500 mg of per 50 grams, depending on variety

 

Leafy Greens

Per 1 Cup Raw

Kale – 106 mg

Spinach – 30 mg

 

Per ½ cup, cooked ( from frozen/fresh)

Collard Greens – 189/142 mg

Spinach – 154/129 mg

Turnip Greens – 134/104 mg

 

Per 10 sprouts , cooked

Brussels Sprouts -75 mg

 

Per 1 medium stalk, cooked

Broccoli – 75 mg

 

Starchy Vegetables

Per 1 medium

Sweet Potato – 40 mg

Squash – 30-50 mg, depending on variety

 

Nuts/Seeds

Per ¼ cup

Almonds – 97 mg

Hazelnuts – 39 mg

Walnuts, Sunflower Seeds, Pumpkin Seeds – ~20 mg

 

Dairy Alternatives

Per 1 cup (250 ml)

Fortified Soy Milk – 325 mg

Enriched Rice/Almond/Cashew Milk – 175 to 325 mg, depending on variety.

Soy Yogurt – 250 mg

 

Legumes

Per 1 cup ( 250 ml) fresh, cooked*

Soy Beans – 185 mg

White Or Navy Beans – 150 mg

Chickpeas, Pinto Beans – 85 mg

Kidney Beans – 65 mg

Lentils – 40 mg

* Canned varieties have slightly higher calcium levels

  

Fish/Seafood

Per 75 grams canned with bones ( about ½ can)

Sardines – 180-280 mg, depending on variety

Salmon – 175-215 mg, depending on variety

Mackerel, Anchovies – 175 mg

 

Fruit

Per 1 medium fruit

Orange – 65 mg

 

Per 8 pieces, dried

Fig – 100 mg

 

Other Foods

Per 1 tbsp

Blackstrap Molasses –   179 mg

 

Per 2 tbsp

Sesame Seed Butter (Tahini) – 130 mg

 

Per ½ brick

Tofu/Tempeh – 325+ mg, depending on variety.

 

Per 1 cup

Fortified Orange Juice – 310 mg

 

References

  1. Anderson, J. et al. Calcium Intake From Diet and Supplements and the Risk of Coronary Artery Calcification and its Progression Among Older Adults: 10‐Year Follow‐up of the Multi‐Ethnic Study of Atherosclerosis (MESA)Journal of the American Heart Association. 2016;5
  1. Bolland MJ, Grey A, Reid IR. Calcium supplements and cardiovascular risk: 5 years on. Therapeutic Advances in Drug Safety. 2013;4(5):199-210. doi:10.1177/2042098613499790
  1. Maresz K. Proper Calcium Use: Vitamin K2 as a Promoter of Bone and Cardiovascular Health. Integrative Medicine: A Clinician’s Journal. 2015;14(1):34-39.
  1. Wawrzyniak A, Klimczyk P, Woźniak A, Anyżewska A, Leonkiewicz M. Assessment ofdifferences in nutrients consumption in women diagnosed with osteoporosis as compared to a healthy control group. Rocz Panstw Zakl Hig. 2017;68(2):143-149.