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Certified Clinical Densitometrist and Bone Health Expert

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Calcium is a Doubled-Edged Sword

Friday, September 16, 2011
 
Calcium is a Doubled-Edged Sword

Insufficient calcium leads to bone loss, muscle cramps and insomnia. Too much calcium may result in calcium being deposited in unwanted areas of the body such as the arteries. So, where is the sweet spot for calcium intake? The chart at the end of this article from the National Institute of Health (NIH) lists the recommended daily allowance for calcium needed to insure good health for all ages. Following is some information about calcium to help you understand this vital mineral:

  • According to the NIH adults need about 1,000 – 1,200 mg. of calcium each day, from all sources! That means foods and supplements. I think this range is good for most people, unless there is some reason that an individual is not absorbing calcium. Osteoporosis is one example of a condition where higher amounts of calcium may be needed.
  • Calcium absorption is increased by as much as 50% if you have enough vitamin D on board. I have covered vitamin D in past articles but a blood level of 45-55 ng/ml is a good amount. Most people do need supplemental vitamin D to obtain this amount. Without testing, 2,000 IU is safe for healthy people. Unhealthy people may need more or less vitamin D depending on their condition and should be tested.
  • Too much calcium can cause constipation.
  • Magnesium is needed to balance calcium. There are different opinions ranging from a 2:1 ratio (calcium / magnesium) to 1:1. I favor somewhere in between depending on the patient. Too much magnesium can cause loose stools. Since most people I see suffer from constipation the added magnesium to the diet is usually a welcome relief.
  • Calcium is best when taken in smaller, more frequent doses and taken with meals.
  • Calcium supplements – calcium citrate or calcium malate is absorbed better than calcium carbonate because it has an acid component and you need acid to digest calcium.
  • If you do take a calcium supplement only take as much as you would get from a serving of yogurt or a glass of milk – 200-300 mg. at one time.
  • Only about 30% of the calcium we ingest is absorbed

Elemental calcium and magnesium

Supplemental calcium comes in the form of a compound. The most common calcium supplement is calcium carbonate. Calcium carbonate is 40% calcium by weight and calcium citrate is 20-25% calcium by weight. Some supplements list elemental calcium and some do not. This is important because a supplement stating 500 mg. calcium may only contain 200 mg. of elemental calcium. On the other hand, if it is elemental, then 500 mg. is a hefty dose – too much for one dose. Know your source.

Are you getting too much calcium?

I have found that many of my patients do consume too much calcium – especially those who eat a lot of dairy. On top of this some are taking very high doses of calcium supplements thinking if the RDA is 1,200 mg. then they should take 1,200 mg. of supplemental calcium. Remember 1,000 – 1,200 mg. total, from all sources.

Some people with malabsorption problems do need higher doses but this should be worked out with someone who knows nutrition.

Calcium Sources

Dairy is high in calcium, however a lot of people are lactose intolerant or allergic to dairy. One 6 – 8 ounce serving of yogurt or milk contains ~ 300 mg. of calcium. Some of my favorite non-dairy calcium rich sources include: Sardines, salmon, sesame seeds, almonds, collard greens and figs. The herb nettles is an amazing source of calcium – If you are interested in making infusions of nettles there is an article on my website under osteoporosis articles. Tahini (sesame seeds) dressing is loaded with calcium and great for salads and veggies.

The International Osteoporosis Foundation has a food chart to look up foods that contain calcium www.iofbonehealth.org    search – calcium-rich foods

Supplemental Calcium

As noted above, calcium citrate absorbs better than calcium carbonate because it has an acid component – you need acid to digest calcium. Calcium carbonate is not the best for most people because you need to take it with food and it dilutes the acid needed not only for calcium absorption but also for protein and other foods that need acid to break down. Many people take the antacid Tums as their supplement. This practice may actually lead to bone lose years down the road. Remember that you must balance your calcium with magnesium. The best supplemental magnesium source is magnesium citrate or magnesium glycinate.

What is the best time to take calcium?

I am dairy-free and a light eater so I do take a calcium and magnesium supplement. I found a liquid product of calcium citrate and magnesium citrate. One tablespoon = 250 mg. calcium and 170 mg. of magnesium. I always take one tablespoon before bed. Why before bed? Bone loss occurs more during the night and I have low bone mass. Calcium and magnesium also help with sleep. As mentioned above, small amounts throughout the day of calcium rich foods is the best and adding a supplement if necessary.

Who should be concerned about getting enough calcium?

  • People who have been diagnosed with osteoporosis or low bone mass.
  • Those who consume a diet high in foods that increase acidity in the body are at risk of not absorbing enough calcium. The top foods to avoid, are the same ones we hear about all the time: Sugar and processed carbohydrates – you know these non-foods. When considering sugary drinks, just say NO! Also, a diet high in protein, especially animal protein can leach calcium from bone.
  • People with low vitamin D in their blood – vitamin D increases calcium absorption by as much as 50%.
  • Malabsorption – gastrointestinal problems that impact absorption such as celiac disease and Crohn’s disease.
  • Those who lack stomach acid either from medications or because their body does not produce adequate amounts of stomach acid.
  • Dairy-free diet – while it is true that greens contain abundant calcium it still may be difficult for some to get enough calcium from their diet.
  • Excessive intake of any of the following can inhibit calcium absorption or utilization: protein, caffeine, alcohol and sugar.
  • Phytic acid and oxalic acid are found naturally in some plants; both bind with calcium and inhibit calcium absorption. High levels of oxalic acid can be found in spinach, collard greens, sweet potatoes, rhubarb, and beans. Foods high in phytic acid are fiber-containing whole-grain products such as wheat bran, beans, seeds, nuts, and soy isolates. These are healthy foods and should not be totally avoided. This is why eating a diet with a wide variety of foods is so important, making sure you eat plenty of greens daily.

If you have any questions regarding calcium please leave it in the comments section - I actually read my comments.
The National Institute of Health recommends the following RDA for Calcium intake:

Table 1: Recommended Dietary Allowances (RDAs) for Calcium [1]

Age

Male

Female

Pregnant

Lactating

0–6 months*

200 mg

200 mg

   
7–12 months*

260 mg

260 mg

   
1–3 years

700 mg

700 mg

   
4–8 years

1,000 mg

1,000 mg

   
9–13 years

1,300 mg

1,300 mg

   
14–18 years

1,300 mg

1,300 mg

1,300 mg

1,300 mg

19–50 years

1,000 mg

1,000 mg

1,000 mg

1,000 mg

51–70 years

1,000 mg

1,200 mg

   
71+ years

1,200 mg

1,200 mg

   
  • Adequate Intake (AI)

Resources and references
Office of Dietary Supplements
Heaney RP, Recker RR, Stegman MR, Moy AJ. Calcium absorption in women: relationships to calcium intake, estrogen status, and age. J Bone Miner Res 1989;4:469-75. [PubMed abstract]
•  Massey LK, Whiting SJ. Caffeine, urinary calcium, calcium metabolism, and bone. J Nutr 1993;123:1611-4. [PubMed abstract]
•  Hirsch PE, Peng TC. Effects of alcohol on calcium homeostasis and bone. In: Anderson J, Garner S, eds. Calcium and Phosphorus in Health and Disease. Boca Raton, FL: CRC Press, 1996:289-300.


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