The (Non) Sense of Nutritional Supplements

by Hrvoje Verži


It was bound to happen. As a professor I directed enough graduate students to eventually find one who was as eccentric and as provocative in dealing with me as I was in dealing with my major professors when I was a grad student. Hrvoje (Herbie) Verži was that student for me. He gave me a better appreciation of what my former professors faced. He turned out to be an excellent student completing a very challenging thesis on the complex chemistry behind pink discoloration of banana puree during heating.   

Choosing a nutritional supplement can be quite a challenge because there are so many different publications, recommendations, advisories and opinions about it. In addition, there are so many different suppliers and companies offering supplements it is very easy to just give up.

This is an attempt to sort things out for persons who are interested or wondering if they need to take supplements or maybe decide that they really do not need the supplements they are taking right now.

Here are some answers to important questions before starting to take nutritional supplements:

Is there a health value in taking nutritional supplements for a person in good health?

Great news, if you are a generally healthy adult, regardless of age you don’t need any dietary supplements. However, if you are prone to slightly elevated blood pressure, for example, you can profit from a magnesium intake. There are indications that magnesium by itself can significantly lower your blood pressure if your intake is 300-400 mg a day. Another example is the outcome of the Iowa Women’s Health Study which looked at 40,000 women and how their mortality differed when they took supplements. Apparently with calcium a life-extending effect was recorded, but supplemental iron seemed to increase total mortality risk.  However, in men other studies show more cardiovascular events after calcium supplementation.

Is there an age population that benefits from a nutritional supplement intake?

Babies and infants are recommended supplementation with vitamin D if they are breastfed. In the period from 4-6 months an iron supplementation is recommended until iron containing foods are introduced. Women during pregnancy should most importantly supplement with folic acid, other optional micronutrients include vitamin D, iron and calcium. For older adults (starting at 50+) there are indication that they might need vitamin B12 because of age related absorption deficiencies. Vitamin D, calcium and magnesium can be useful in preventing loss of bone mass.

Are there high-risk subgroups that benefit from supplements?

Some medical conditions demand a supplementation because the absorption of the nutrients is significantly reduced or blocked (1). These include

  • Anemia (iron)
  • Inflammatory bowel disease (multivitamin/multimineral formulations)
  • Osteoporosis (vit D, calcium, magnesium)
  • Macular degeneration (antioxidant vitamins, copper, zinc)
  • Long term use of medication (proton pump inhibitors)
  • Restricted/suboptimal eating patterns (multivitamins/multiminerals)

Is there a potential health risk in taking nutritional supplements?

That depends clearly on the vitamin or mineral you are about to take. Taking vitamin D in high dosages over a long period of time can cause kidney failure. Overdosing of vitamin A can lead to hip fractures and can be toxic to the liver. In contrast, the water soluble vitamins like vitamin C and all B vitamins (except B12) are not stored, so any excess is excreted. Vitamins A, D, E and K are fat-soluble and therefore stored over a longer period of time therefore a daily supplementation is not recommended. Minerals (calcium, magnesium) and trace elements (selenium) are also water-soluble and therefore are not stored in the body. Harmful overdoses can only occur if a very high dose is taken over a very long period of time.

How do I know I am choosing the right supplement?

Choosing the right supplement is a science in itself. Once you have decided to start taking a nutritional supplement, it should be worth your while to review what is on the market and how you can sort out the best brand for you. It is important to know that FDA does not certify supplements for safety or effectiveness the way it monitors drugs.The FDA doesn’t set potency or dosage standards, either. Manufacturers are left to police themselves. So where can you find information that is valid and not biased? Several consumer watchdog organisations like, US Pharmacopeia, NSF International, or UL are testing supplements on a regular basis and review the results. According to the most recent consumerlab multivitamin review 46%  of multivitamin/ multimineral supplements failed testing.

Are there other aspects to consider (interactions, absorption) with supplements?

And still if you have followed all the steps so far another thing can still go wrong and your whole analysis was for nothing. Are all multivitamins and multiminerals absorbed efficiently by the body? Are there reasons that does not happen? Yes, and there are plenty. For example, you need to take calcium with vitamin D otherwise only 10-15% of calcium is absorbed. New studies show that magnesium plays also an important role in calcium absorption. Another potential downfall is the correct and quick loss of nutrient potency in the supplement. Generally powdered forms are less likely to degrade than those stored as liquids. Some companies add sweeteners or sugars to their products to increase acceptability. However, sweeteners have been associated with blocking micronutrients from being absorbed into the body as well. High-fructose corn syrup may contribute to deficiencies in key minerals. Sucrose may block the absorption of vitamin C, calcium and magnesium.

Hrvoje Verži earned his Bachelors degree in Biochemistry (1996) and Masters in Food Science (1998) at the University of Georgia. As an undergraduate he was also NCAA indoor triple jump champion in 1995 and competed for Germany in the 90s.  A native of Croatia, he returned to Europe upon graduation. He is currently an Account Manager for Vaccines at Pfizer in Germany. He has also had positions as Product Coach and medical advisor for Wyeth Pharmaceuticals with the OTC and antibiotics business. He started his professional career with a position in sales for Cardiovascular Products.

Next week: Vitamins and Minerals 101


(1) Manson, J. and Bassuk, S.S. 2018. Vitamin and mineral supplements: What clinicians need to know. JAMA 319: 859-860.

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