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Health & Exercise Forum

The truth about vitamins: Part 2 of 2

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Dec 16, 2019
Robin Tanner, MD3

Guest Author: Robin Tanner MD3, 3rd Year Medical Students at Geisinger Commonwealth School of Medicine (GCSOM)

Robin Tanner MD3 is a third year medical student at Geisinger Commonwealth School of Medicine. Originally from Danville, Pennsylvania, Robin received her bachelor’s degree from Auburn University in Auburn, Alabama. Aside from studying medicine, she enjoys learning about World War II, politics, classical literature and new languages. She volunteers with different pediatric organizations including the Make-A-Wish Foundation and Camp Victory. She hopes to pursue a career that incorporates medical education, pediatrics and global health.

It’s routine to be asked, while visiting a doctor’s office “what medications are you taking?”  You give the doctor a list of medications and are ready for the next question at your visit. Wait, what about those vitamins you have been taking?  He probably doesn’t need to know that right? They are gummies with smiley faces on them. Why would a doctor care if you eat a gummy every day? About 48% percent of adults take some sort of supplementation as a part of their daily routine.  Vitamins show minimal significant benefits in healthy individuals and can even cause negative side effects when taken with specific medications.

Last week’s article discussed the purpose of vitamin supplementation and how it applies to the average healthy individual.  Although it is not needed in individuals who eat a well-balanced diet, there are many people who can benefit from vitamins and people who should stay away from them.  

Many diseases and conditions which benefit from vitamin supplementation are due to higher demands on the body, decreased levels in vitamin stores in the body or poor absorption from food.  Depending on the disease or condition, a vitamin supplementation may provide symptomatic relief or prevent progression of the disease. On the other hand, some vitamins can react with specific medications to cause additive effects, counteract the medication’s effects, or even potentiate side effects.  The following are some circumstances where vitamins may or may not be beneficial.



Women who are pregnant or are planning to become pregnant are strongly suggested to use prenatal vitamins.  An important component of prenatal vitamins is folic acid (vitamin B9). In fetal development, the neural tube will grow to become the brain and spinal cord.  Folic acid is important in helping to prevent neural tube defects such as anencephaly (a condition where the baby is born without major portions of the brain) and spina bifida (where a baby is born with an opening in the spinal cord exposing the nerves). 

Infants and children

Children who are nursed should receive vitamin D supplements until weaned to whole milk containing vitamin D.  Children who are nursed also benefit from iron supplementation until iron-containing foods (such as spinach, broccoli or meats) are introduced into the diet.  For children who use formula, they typically reach their daily requirements due to supplementation in the formula itself.  


Anemia occurs when there is a decrease in the amount of red blood cells circulating in the blood.  Symptoms include fatigue, dizziness and shortness of breath. Anemia can be due to a deficiency of vitamin B12, folate (B9) or iron.  These substances help red blood cells divide and function properly. When the body is lacking, there is a decrease in the amount of functioning red blood cells to carry oxygen to the body.  A blood test at a doctor’s office can help determine the cause of the anemia and will lead to appropriate supplementation.  


As women age, the levels of estrogen decrease in the body which leads to an increased in bone breakdown. This is a common complication in postmenopausal women and can lead to bone pain and fractures.  Vitamin D and calcium supplementation can help improve bone health and decrease the risk of bone fractures in this population.  

Digestive diseases (Chron disease, bariatric surgery)

Certain digestive disease such as Chron disease or other inflammatory bowel diseases cause impairment in the absorption of some molecules.  Supplementation with iron, B vitamins, vitamin D, zinc and magnesium could be beneficial to maintain the recommend daily intake.    


Long term metformin use can lead to a B12 deficiency.  Although B12 deficiency takes years to develop (due to large amounts stored in the body), the symptoms may be confused with diabetic neuropathy.  B12 supplementation may prevent nerve damage due to the deficiency. Levels are commonly monitored in these patients for such a reason. 


Medications that Mimic Supplements

The retinoids are a class of drugs similar to vitamin A.  A commonly prescribed retinoid is isotretinoin, commonly called Accutane, used in the treatment of acne.  Increased levels of vitamin A from supplementation and drug administration can increase the risk of vitamin A toxicity which can lead to nausea, vomiting and vision changes.  


Warfarin (Coumadin) is a commonly prescribed drug to decrease the risk of blood clot formation. Warfarin prevents clotting by inhibiting and enzyme which requires vitamin K to function. Using supplementation of vitamin K while using Warfarin to prevent clots can reverse the effects of Warfarin and thus increase the likelihood of developing blood clots.  

Increased risk of side effects

Niacin (vitamin B3) can affect cholesterol levels, lowering LDL cholesterol (“bad cholesterol”) and increasing HDL cholesterol (“good cholesterol”).  Statins are one of the most prescribed drugs in the United States. They decrease the amount of cholesterol made by the liver thus decreasing blood cholesterol levels.  However, research has shown that when combining these two medications, there is no increased benefit. Niacin may even cause a small increase in risk for muscle pain and breakdown, a statin side effect. 


Vitamin supplementation has the potential to be beneficial and harmful.  Therefore, it is important to disclose to medical professionals all current medications along with any supplementation one may be taking.  This is especially true when considering adding a new drug to daily regimens. If you have been diagnosed with a medical condition or are taking medications, it is important to talk to your medical provider before beginning over the counter supplementation.  So yes, your doctor does want to know if you are eating a smiley face gummy every day.


National Institutes of Health (NIH) - Office of Dietary Supplements (ODS) – Fact Sheet for Health Professionals

Blumberg, J., Frei, B., Fulgoni, V., Weaver, C., & Zeisel, S. (2017). Impact of frequency of multi-vitamin/multi-mineral supplement intake on nutritional adequacy and nutrient deficiencies in US adults. Nutrients, 9(8), 849.

Medical Reviewer: James W. Joseph, MD, Geisinger Family Practice, Elysburg, PA and GCSOM Family Medicine Practice Clerkship Director

Visit your doctor regularly and listen to your body.

NEXT MONDAY – Read Dr. Paul J. Mackarey “Health & Exercise Forum!”

This article is not intended as a substitute for medical treatment. If you have questions related to your medical condition, please contact your family physician. For further inquires related to this topic email:

Paul J. Mackarey PT, DHSc, OCS is a Doctor in Health Sciences specializing in orthopaedic and sports physical therapy. Dr. Mackarey is in private practice and is an associate professor of clinical medicine at Geisinger Commonwealth School of Medicine (formerly The Commonwealth Medical College).