FAQ about Multivitamins, Calcium and Vit D Supplements

FAQ about Multivitamins, Calcium and Vit D Supplements

This week I am answering a few more nutrition related questions from my friends at the Get Back Up Today Team. Who are the Get Back Up Today Team? They are the first national team composed of people who all live with foot drop. The team includes a triathlete, a marathoner, a teacher and a wounded veteran. Each member has a unique story and different cause of foot drop, including Charcot-Marie-Tooth disease, Multiple Sclerosis, FSHD Muscular Dystrophy and spinal injury. Today I will answer some of their questions about multivitamins as well a s a few questions about calcium and vitamin D.


Are multivitamins necessary?

Before I answer this question there are a few things I will say first. Taking a multivitamin does not offer a guarantee of optimal health and it will not compensate for a poor diet. A healthy diet including a wide variety of colorful fruits and vegetables, whole grains, legumes and lean proteins is the best source of vitamins, minerals and other nutrients.


In 2006, an expert panel conducted a comprehensive evidence-based review of the relationship between studies on vitamins and their impacts on health and concluded that “the present evidence is insufficient to recommend either for or against the use of multivitamins by the American public to prevent chronic disease”.


In other words it may not hurt to take a multivitamin approximating the recommended intake but it may not help either. It will cost money and there is currently no standard regulatory definition for what a multivitamin must contain or at what levels.

Product claims vary widely and many are unsubstantiated. As I have said before, the FDA does not regulate supplements the same as they do food. It is important to know what is and is not in what you are putting into your body.

If you do decide to take a multivitamin first take a look at what you ARE eating to see what nutrients you may be getting adequately in your diet. If you frequently consume fortified breakfast cereals, sports bars  or meal replacement bars you may be getting more nutrients than you think from these foods. The combination of whole foods, fortified foods and supplements can raise the intake of of some nutrients beyond the safe upper levels and potentially be harmful.

It is a good idea to know the Tolerable Upper Limit (The highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase) of any vitamins and minerals you are taking and to check the nutrition labels of foods you regularly consume to make sure your food choices are not enriched or fortified with the same nutrients. Information on the TUL of vitamins and minerals can be found be clicking the DRI calculator link provided below.


Who Should Consider an Multivitamin?

  • If you have numerous food allergies that limit your food choices you may be missing nutrients
  • If you are pregnant or contemplating pregnancy you will want to choose a vitamin that provides at least 400 mcg of Folate to protect against birth defects like spina bifida.
  • By consuming less than 1200 calories per day, you may not be consuming enough nutrients in your diet.
  • If you are vegetarian or vegan you will want to choose a vitamin with 2.4 mcg of vitamin B-12.
  • If you are over 50 you may benefit from from calcium, vitamin D, vitamin B-12( the body is often less able to absorb this nutrient with age)
  • Anyone who is a heavy smoker or drinker.


What to Look For and What to Avoid:

  • Avoid products that provide greater than 100% of the RDA for any nutrients. There is a limit to what the body can absorb and unabsorbed water soluble B and C vitamins are generally excreted in the urine. Expensive urine! Excess fat soluble vitamins can build up over time and pose a greater danger of toxicity.
  • Avoid high doses of multiple minerals in one product as they can compete for absorption and cancel out the benefits of either.
  • If you are an otherwise healthy male or a post menopausal female you may not need a multivitamin with iron.
  • Avoid supplements with high cost botanical ingredients and extracts that are of questionable benefit.
  • Look out for unexpected ingredients like caffeine, guarana or other stimulants. Also look for non-nutritive sweeteners and or sugar.
  • Ignore wild manufacturer claims that are intended to separate you from your money. Check with a third party testing service like ConsumerLab or USP. Here is the USP label to look for on supplement bottles, go here to see what it stands for.

What to look for in a supplement

Are there vegetarian alternatives to gel-caps? Are gummy vitamins as effective as other forms of vitamins?

Gel-caps and Gummy vitamins typically contain gelatin, which is derived from animal collagen. Vegan alternatives to gelatin based capsules are often made with cellulose. This information is provided on the product label.  There are vegan Gummy vitamin products available on the market as well. As to the efficacy of Gummy vitamins (with gelatin or otherwise) or any other form of vitamin it varies by product and formulation. A third party testing service can help you to determine the quality of any product you may be considering.


What is vitamin D? There are several forms of vitamin D, what is the difference?

Vitamin D is a fat soluble vitamin that is sometimes called the sunshine vitamin because the skin produces it via sunlight exposure. It is then “activated” in the liver and kidneys.Vitamin D is a fat soluble vitamin naturally present in very few foods. These include:

  • Salmon
  • Tuna
  • Mackerel
  • Fish Liver Oils
  • Fortified foods like Milk and Juice

Smaller amounts found in:

  • Beef Liver
  • Cheese
  • Egg Yolks
  • Some Mushrooms

“Vitamin D” is sometimes used as an umbrella term that includes vitamins D-2 and D-3. Vitamin D-2, or ergocalciferol, is the form made by mushrooms from exposure to sunlight. Finally, Vitamin D-3, which is also called cholecalciferol, is the type that’s made in your skin. Both D-2 and D-3 are available in supplements and research is mixed about which is the best absorbed.  However (in case it matters to you) D-2, ergocalciferol is vegan and D-3 cholecalciferol is not as it is often produced from lanolin in sheep’s wool. 


How does vitamin D work with Calcium?

  • Vitamin D promotes calcium absorption in the gut and maintains adequate calcium and phosphorus levels in the blood.
  • It is required for bone growth and helps to prevent osteoporosis.
  • Vitamin D also has a role as an immune function regulator.


Who should supplement vitamin D?

Vitamin D deficiency is thought to impact over 75% of Americans. As I have said vitamin D is found naturally in very few foods but it can be found in some fortified foods. Many people may benefit from taking a vitamin D supplement, but especially:

  • Individuals with a vitamin D deficiency
  • Adults over 50
  • Individuals with limited sun exposure
  • People with very dark skin
  • Individuals with conditions causing fat malabsorption (such as Crohn’s )
  • Individuals who have had significant gastric surgeries such as gastric bypass


I am a female endurance athlete, do I need calcium and vitamin D above the DRI?

There have been limited studies on vitamin D and athletic performance but given the important role that calcium and vitamin D play on muscle and bone health, the regulation of electrolyte metabolism, protein synthesis and immune function it is important that female athletes get adequate amounts of these nutrients but not in excess of the DRI. Check this handy DRI calculator to see what is recommended for you. Have your blood level of vitamin D checked annually.

For answers to more questions about calcium and how to get it from diet check out my blog post on the subject here.



  • Armas LAG, Hollis BW, Heaney RP. 2004. Vitamin D2 is much less effective than vitamin D3 in humans. J Clin Endocrinol Metab 89:5387-91.
  • Benardot, D. Advanced Sports Nutrition, Second Edition. Human Kinetics, Champaign Il. 2012.
  • Clark, N. Nancy Clark’s Sports Nutrition Guidebook, Fifth Edition. Human Kinetics, Champaign Il. 2014.
  • Ginde A.A., Liu M.C., Camargo C.A. Demographic differences and trends of vitamin D insufficiency in the U.S. population, 1988–2004. Arch. Intern. Med. 2009;169:626–632.
  • Holick MF, Biancuzzo RM, Chen TC, et al. 2008. Vitamin D2 is as effective as vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D. J Clin Endocrinol Metab 93:677-81.
  • Huang H-Y, Caballero B, Chang S, Alberg AJ, Semba RD, Schneyer C, et al. Multivitamin/Mineral Supplements and Prevention of Chronic Disease. Evidence Report/Technology Assessment No. 139. (Prepared by The Johns Hopkins University Evidence-based Practice Center under Contract No. 290-02-0018). AHRQ Publication No. 06-E012. Rockville, MD: Agency for Healthcare Research and Quality. May 2006.
  • National Institute of Health Office of Dietary Supplements. Multivitamin/mineral Fact Sheet for Health Professionals.  https://ods.od.nih.gov/factsheets/MVMS-HealthProfessional/
  • National Institute of Health Office of Dietary Supplements. Vitamin D Fact Sheet for Health Professionals. https://ods.od.nih.gov/factsheets/VitaminD-HealthProfessional/
  •  Ogan D, Pritchett K. Vitamin D and the Athlete: Risks, Recommendations, and Benefits, Review. Nutrients 2013, 5:1856-1868.


I am a Registered Dietitian Nutritionist living in Greensboro, North Carolina. I help people overcome nutrition obstacles and help them meet their nutrition and wellness goals.

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Hi, I’m Mona. I have been living with Relapsing Remitting Multiple Sclerosis (RRMS) for over ten years. As a registered dietitian nutritionist (RDN) I help others with MS to navigate the nutrition superhighway and make sustainable progress toward their unique wellness goals.

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