A new calcium study has created a lot of confusion and consternation. To refresh your memory: a randomized trial of calcium supplements has revealed an unexpected complication (Gut, March 1, 2018). Doctors have been recommending calcium pills both to strengthen bones and to lower the risk of colorectal cancer. The new calcium study of more than 2,000 Americans showed that people taking 1,200 mg of calcium daily were more rather than less likely to develop precancerous colon polyps years later.
Calcium alone more than doubled the risk, while calcium with vitamin D nearly quadrupled it in comparison to placebo. This complication didn’t show up until six to ten years after starting supplementation.
More Details on the New Calcium Study:
For a bit more background and an in-depth analysis of the new data, here is our most recent article on this topic:
Should You Worry About Calcium Side Effects Like Colon Polyps?
Readers Are Confused:
Joyce in San Antonio, Texas, worries about stopping calcium:
“My question is are there any side effects or complications to suddenly stop taking the calcium supplement after taking it daily for literally over 20 years?”
Joseph is concerned about calcium buildup in the bloodstream:
“I believe calcium supplements (other than calcium citrate) do not enter bones but stay in bloodstream which can contribute to plaque in blood vessels more so than cholesterol.”
Fran in West Palm Beach, Florida, wants to know about vitamin K2 and calcium:
“Do these studies take into account the role of vitamin K2? I understand that without a sufficient quantity of K2, calcium ends up in the wrong places in our bodies, such as our arteries, and perhaps the colon, and not to our bones. I’d appreciate your addressing how vitamin K2 affects the results of our calcium intake.”
Larry in Raleigh, North Carolina, makes an interesting point:
“What is with these people and their simplistic solutions?
“’Your bone density is low. Bones are calcium. Eat lots of calcium and your bones will be denser. No, we didn’t bother to test it. Isn’t it obvious?’
“Similarly:
“’You have too much cholesterol. Cholesterol is in beefsteak, milk, cheese, and butter. Don’t eat those things and your cholesterol will go down. No, we didn’t consider that cattle are mammals, that cattle eat only a grain diet, that cattle must manufacture cholesterol, or that humans are also mammals and also manufacture cholesterol. Just stop eating those things. Isn’t it obvious?’
“Doesn’t anyone think these things through anymore?”
Tina in North Palm Beach, Florida, wants to know about a natural plant formula vs. pure calcium supplements:
“Your article only refers to calcium carbonate. I’m curious as to what side effects a whole food plant formula based calcium might have.
“I’ve been on a regimen of a popular raw, whole plant based, calcium with 756 mgs calcium and 1,600 IU of D3 for years with no side effects thus far. It also contains magnesium derived from algae and Dead Sea minerals, and organic fruits and vegetables. It’s about as natural as any supplement can be.”
Linda in North Carolina describes a serious GI problem with calcium:
“My aunt fell and broke her ankle at age 68. She was prescribed calcium supplements during recuperation. Then at home she developed a severe intestinal blockage that resulted in her having emergency surgery and a colostomy. She died from complications at age 70. Beware!”
People’s Pharmacy Perspective:
Calcium supplements, especially calcium carbonate, can cause pretty serious constipation. For an older person this can be uncomfortable or even something worse, as Linda describes above.
Calcium citrate may be less constipating, but some supplements are a bit pricey. There is also less absorbable elemental calcium in each pill compared to some other calcium salts.
We’re not sure that plant-derived calcium would be substantially safer than other forms of “natural” calcium. For example, some of the calcium carbonate supplements are derived from coral, limestone, eggshells or oyster shells. We have a sneaky suspicion that it is the large bolus of calcium found in supplements that may overwhelm the body’s regulatory system. Smaller doses found in food might be absorbed more gradually and thus be safer.
Vitamin K2 and Calcium:
Fran wanted to know more about the relationship between vitamin K2 and calcification. Most people are not familiar with vitamin K2. Fran’s question is of substantial interest, though.
Crash Course in Vitamin K:
There are two forms of vitamin K. One (literally, vitamin K1 aka phylloquinone) is found in dark green leafy vegetables like kale, spinach, collard greens, Brussels sprouts and broccoli. It is known as the coagulation nutrient because it is essential for making proteins that aid in blood coagulation. It was named vitamin K for the German word Koagulationsvitamin.
Vitamin K2 is known as menaquinone. There are actually a number of menaquinones (MKs) and they are created in part by fermentation. Foods and beverages like sauerkraut, miso, tempeh, kimchi, kefir, kombucha, natto (fermented soybeans popular in Japan), Gouda and Brie cheeses have varying amounts of vitamin K2. This nutrient is also made by bacterial living in the human intestines.
Can vitamin K2 help prevent calcification of arteries and plaque buildup while helping build stronger bones? This question remains controversial. An article in the European Review for Medical and Pharmacological Sciences (Sept. 2013) concluded:
“Vitamin K2 deficiency has recently been recognized as a protagonist in the development of vascular calcification and osteoporosis. Data reported so far are promising and, dietary supplementation seems a useful tool to contrast these diseases. However, large studies or solid clinical correlations regarding vitamin K2 deficiency and its pathologic consequences are needed to confirm these preliminary experiences.”
That’s doctorspeak. In essence they are suggesting that low levels of vitamin K2 increase the risk for both calcified plaque buildup and weakened bones. An article in Integrative Medicine: A Clinician’s Journal, Feb. 2015) proposes:
“Vitamin K2 promotes arterial flexibility by preventing accumulation of arterial calcium and supplementation with it could correct calcium amounts in the body that are out of balance. Thus, calcium in tandem with vitamin K2 may well be the solution for bringing necessary bone benefits while circumventing an increased risk for heart disease.”
As intriguing as this idea may be, we are lacking large, well-controlled clinical trials that establish the role of vitamin K2 in preventing calcification of soft tissue and building strong bones. Until we have more data we’re sorry we don’t have a good answer for Fran.
Stopping Calcium?
Joyce wanted to know if someone could stop calcium suddenly after years of supplement use. The answer is not obvious, since few studies have studied the impact of sudden cessation. When in doubt, check with a health professional and consider gradual tapering. Make up the difference with dietary sources of calcium. You will find good food sources of calcium in this article.
New Calcium Study found in:
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