Beware Deficiencies in Some Calcium, Vitamin D, Vitamin K Supplements

Bone health is essential to overall health and quality of life. Healthy bones provide the body with a frame that allows for mobility and for protection against injury. Bones also serve as a storehouse for minerals that are vital to the functioning of many other life-sustaining systems in the body. Unhealthy bones, however, perform poorly in executing these functions and can lead to fractures, which are by far the most important consequence of poor bone health, since they can result in disability, diminished function, loss of independence, and premature death.

Along with physical activity, there are several nutrients that are important for bone health. Adequate calcium is critical for building and maintaining strong bones, where 99 percent of the mineral is found in the body. The rest is present in the blood, extracellular fluid, muscle and other tissues, where it plays a necessary role in dilation of blood vessels, muscle contraction, nerve transmission and glandular secretions. Vitamin D is important for good bone health because it aids in the absorption and utilization of calcium. Vitamin K functions in the body to modify certain proteins that ensure proper calcium utilization in the bones. And while a well-balanced diet can provide the necessary amounts of these nutrients, many Americans, for a number of reasons, consume levels that are far below the amount recommended for optimal bone health—making supplementation a popular alternative.

Unfortunately, not all supplements are created equal, as ConsumerLab.com (CL) found in a large review of supplements relating to bone health. Their results appear in three separate Product Review reports: Calcium Supplements, Vitamin D Supplements,  and Vitamin K Supplements.  The reports cover 34 single-ingredient and combination products for adults as well as children including tablets, chewables, capsules, softgels, liquids, wafers, and powders. Twenty-two of the products were selected by CL, while 12 were tested at the request of their manufacturers or distributors.

Brands included in the reports are Adora, Allergy Research Group, Caltrate, Carlson, Citracal, DaVinci Laboratories of Vermont, Floradix, Garden of Life, GNC, Isotonix (Market America), Julian Whitaker MD, Kirkland (Costco), Lifetime, Li’l Critters, Nature’s Bounty, Nature Made, Nature’s Plus, Nature’s Life, Nutrition Now, OSCal, Puritan’s Pride, Physiologics, Pure Encapsulations, Quest, Rite Aid, Standard Process, Sundown, Trader Darwin’s (Trader Joe’s), Twinlab, Vitamin Shoppe, and Vitamin World, which were all tested to ensure they contained their labeled amounts, that they weren’t contaminated with metals such as lead, and their ability to break apart for proper absorption.

The tests revealed that 5 out of 22 provided only 52.5 to 89 percent of their listed amounts of calcium or vitamin K. CL also found important differences in absorption and potency among the available forms of these nutrients, such as calcium carbonate versus calcium citrate, vitamin D3 versus vitamin D4, and vitamin K1 versus two marketed forms of vitamin K2, as well as a wide variation in the suggested daily dosage across products, including a 50-fold variation in the dose of vitamin D (from 100 IU to 5,000 IU). “The new test reports help consumers understand which supplements are accurately labeled and which are not, as well as whether or not a supplement may help them and at what dosage,” said Tod Cooperman, M.D., President of CL.
   
CL is a leading provider of consumer information and independent evaluations of products that affect health and nutrition. The company is privately held and based in Westchester, New York and has no ownership from, or interest in, companies that manufacture, distribute, or sell consumer products. CL is affiliated with PharmacyChecker.com, which helps consumers evaluate online pharmacies and drug prices, and MedicareDrugPlans.com, which reviews and rates Medicare Part D plans. Subscription to ConsumerLab.com is available online.