Making Sense of Supplements

Ask Dr. Jen

Question:

Can someone make this more clear to me - are vitamins different from supplements? As in, a vitamin is something the body makes and requires and supplements are not? Is that correct? I've done a bit of research but it seems still a little unclear to me.”

-Via The Vajenda

***

Great Question! Thank you for asking.

Supplements include vitamins and minerals, but they also include herbal and botanical products, collagen, probiotics, Ayurvedic medicines, Traditional Chinese Medicine, and amino acids. They can be products recommended by evidence-based medicine, and they can be a pure grift, and they can be in a medical no man’s land supported only by mostly low-quality studies. Lumping everything together, products like multi-ingredient “Ovary Support” or “Liver Shield” into the same category as vitamin B12 for people who can’t get enough in their diet means the former two, which are not backed by robust science, benefit from the goodwill of the latter, which is a solid recommendation. So, I totally understand the confusion. 

How does a person wade through the morass and decide what is recommended and what is snake oil? And even more importantly, what is safe? Given the money to be made and the number of medical professionals with their own lines of supplements, it’s getting harder and harder to tell. 

With this in mind, I want to introduce you to my own classification system for supplements and some basic tools. This isn’t a formal classification system; it helps me organize my thoughts and evaluate claims more quickly.

Is this a Single Ingredient to Prevent or Treat a Nutritional Deficiency?

The keywords here are “nutritional deficiency,” so this class doesn’t include ginger for nausea, black cohosh for hot flashes, or taking vitamin E because you believe it is an antioxidant. These are vitamins and minerals used to make up a nutritional shortfall, and you should easily be able to find information about this from respective medical societies or your government (for example, the NIH, the CDC, Health Canada, or the NHS). Common examples are:

• Vitamin B12 for vegans and vegetarians, as B12 is only found in animal products.

• Iron, the heme iron in animal products, is easier to absorb than non-heme iron found in plants, so some vegetarians and vegans may need to supplement their diet.

• Calcium.

• Vitamin D.

There may also be very specific examples related to medications or medical conditions where supplementing the diet might be needed, for example:

• Vitamin B12 for people taking medications for gastroesophageal reflux disease (these medications reduce stomach acid, which affects absorption of vitamin B12).

• Vitamin B12 for people aged 50 or older who aren’t getting vitamin B12 from fortified foods. 

• Potassium for people taking a diuretic (water pill) that causes them to release extra potassium into the urine.

In the United States, the Office of Dietary Supplements is a good place to get information about what you need nutritionally in your diet and whether supplementing with a vitamin or a mineral might be recommended. They have fact sheets for most vitamins and minerals that you can find here. I find this site useful as it informs you about which foods are good sources of specific vitamins and minerals. The CDC also has good information about many nutrients and when supplements are indicated (just Google the name of the vitamin or mineral and CDC, which usually works). As recommendations can vary from country to country, finding your local equivalent is a good idea. For example, in the UK, table salt doesn’t usually have added iodine, but in the US it does, so if certain foods are or are not fortified with vitamins and minerals, it can change recommendations. I also find that Nutrition Source at the Harvard T.H. Chan website has good information that is easy to digest (#sorrynotsorry about the pun).

The recommendations are generally uniform here, so if you look up the vitamin or mineral that interests you, you should find essentially the same information across several sites. Just don’t use information from the providers or companies that sell supplements. 

Verdict: single ingredient vitamin or mineral supplements are recommended for people who can’t meet their nutritional needs. 

Choose a vitamin or mineral supplement that has been independently verified to contain what it claims and is free of certain contaminants. Look for either a USP Verified label, an NSF label, or one that has been verified by ConsumerLabs.com. Be careful because some supplements might put “USP” on their labels, but that is not the same as being USP-verified. Consumer Reports also posts information about testing. 

Is This a Fiber Supplement?

The recommended daily intake of fiber is about 25 g-30 g a day from food. A high-fiber diet is associated with a lower risk of colon cancer, breast cancer, heart disease, and type 2 diabetes, and, of course, helps prevent constipation. I see many people with pelvic floor issues and hemorrhoids related to constipation, so I talk a lot about fiber. Because many Americans don’t get the fiber they need, I ask my patients to track their intake for a couple of days to know how much they are getting. Since I was asking my patients to do this, I decided to track my intake for a few days, which was way lower than expected, so I kept tracking. I am NOT suggesting that you track your fiber intake daily; rather, I do this to remind myself when speaking with my patients that it can be hard to get the fiber you need. 

Verdict: While getting fiber from food is ideal, it’s not always possible, so fiber supplements can fill the gap when people have constipation. It is unclear whether fiber supplements have the same health benefits as fiber in food, so trying to increase fiber intake is ideal for the other health benefits. My big “fiber hack” is the cereal Bran Buds. I believe I have changed more lives by recommending it than with anything else. Look, everyone is happier when they are not constipated. Just 1/2 of a cup has 17 g of fiber, so you are more than halfway there! I often have a 1/4 cup mixed with 1/4 cup of raw oatmeal (think Quaker Oats) and some walnuts and blueberries topped with milk as a fast fiber-filled breakfast. 

Is This a Multivitamin?

A multivitamin typically contains 100% of the Recommended Daily Allowance of 26 or so vitamins and minerals. There are definitely situations where multivitamins are recommended, for example, prenatal vitamins or for people who have had bariatric surgery. In these situations, getting multiple nutrients might be difficult because of the body’s demands (pregnancy) or difficulties with absorption. A multivitamin may also be recommended if someone can’t get a nutritionally complete diet because of appetite or other medical conditions. Appetite can decrease as people age, but nutritional requirements don’t, meaning they may consume less food but still require the same amount of nutrients, resulting in shortfalls, so some people may need a multivitamin when they are older. 

However, a multivitamin isn't recommended if someone has a nutritionally complete diet. Here is a handy calculator from the USDA so you can figure out your daily nutritional needs (if that interests you) https://www.nal.usda.gov/human-nutrition-and-food-safety/dri-calculator.  If you want to read about how a multivitamin can negatively affect your health behaviors, read this fascinating piece from Outside Magazine. 

Verdict: If you need a multivitamin, find one that has been verified by a third party. Again, the recommendations should be pretty uniform across respected websites, such as the Office of Dietary Supplements, the Institute of Medicine, and the CDC.  

Single Ingredient Supplements for Specific Reasons

This category has products that range from those supported by good evidence to those with lower-quality studies where it’s a stretch to say “backed by research.” For example, helping with a neural connection in a mouse model for Parkinson’s does not mean a product can help a human get a better night’s sleep, and yet that is the type of “evidence” listed by some people who sell these products. 

This is a very broad category. Here are some examples:

• High doses of omega-three supplements to reduce triglycerides

• Magnesium for constipation

• D-Mannose for prevention of urinary tract infections

• Black Cohosh for hot flashes

• Relizen for hot flashes

• Magnesium for leg cramps

• Thiamine for PMS

• Probiotics to prevent yeast infections

• Melatonin for sleep

The Office of Dietary Supplements has fact sheets for many of these products, so you can look some of them up. When there is robust evidence, the supplement is typically recommended by the respective medical society’s guidelines. 

Verdict: There is no verdict here. For example, magnesium is effective for constipation, but probiotics are useless in preventing yeast infections. This means each individual claim needs to be evaluated. Some single-ingredient products are helpful when used appropriately, and it’s best to look for one that has been independently verified by third-party testing. Some are useless or have unknown long-term risks. Others can be adulterated and dangerous. For example, many tejocote root products were recently found to have yellow oleander, which is a poison. 

I’ll review some of these products related to menstrual and menopause health in later posts in this series.

Multi-ingredient Supplements with Claims about Medical Benefits

Several vitamins, minerals, botanicals, amino acids, etc., are combined together to provide a product that is almost always for a nebulous benefit because, in the United States, no actual medical claim can be made. They are usually sold under names like “boost,” “support,” and “enhance,” which sound important but are medically meaningless. These products are often for the immune system, “hormone health,” or the metabolism. 

This is a huge buyer-beware category. These products are rarely, if ever, tested. It often seems like someone just looked through a list of ingredients and decided to throw things together that “sound good,”  like the “liver shield” supplement I reviewed last year. There is a huge explosion of menopause supplements in this category, so I will be taking a look at some of those in later posts. 

These products are MASSIVE moneymakers. There is no real research and development, so there are no upfront costs. The company that makes “Liver Shield,” something two liver specialists and a toxicologist advise against taking, claims they are on track to be at “8 figures” in 2024. They started in June 2022. 

These products haven’t been studied, so they are hard to evaluate, and we do not know if they work. Often, there isn’t even meaningful testing to see if the ingredients can be used safely together. In my opinion, these products are best avoided, but the biggest red flags that you are dealing with something that is just absurd or risky include the following:

• Claims about “cleanses” or “detox.” These are synonyms for scam. This is gibberish. Do you want to trust your health to someone writing in gibberish?

• Any product that claims to contain Ayurvedic medicines, as there is about a 20% chance they are contaminated with lead.

• Any product with “proprietary blend” on the label. This is basically “a secret recipe,” it’s impossible to know how much of each ingredient is in the product if the ingredients are even listed.

• Avoid products designed to boost metabolism, burn fat, or “enhance” sports performance or libido, as they are the ones that are most likely to be adulterated. 

The Department of Defense has a supplement checker, which is something to use for these products. You can find it here. It’s not a validated tool but picks up some riskier issues and introduces some good ways to think about these products.

Verdict: These products are all really buyer-beware. Read more here about how many of these products are contaminated with other, sometimes harmful, ingredients. In one study, 12% of “sports enhancers” contained ingredients banned by the FDA. 

Finally

Do not assume supplements are benign (aside from contamination issues). For example, one study showed that among women with breast cancer who were receiving chemotherapy, the ones taking antioxidant supplements were more likely to have a recurrence. The hypothesis was the antioxidants might be fueling the cancer (a multivitamin did not have this same risk). We don’t know what we don’t know about unstudied supplements that are taken for supposed health benefits (this doesn’t include those taken to make up a dietary insufficiency). 

And don’t get information about the supposed medical benefits of supplements from anyone who sells them. If I sold birth control pills, you would rightly be suspect of my advice about contraception methods, ya know?

Some supplements definitely have their place, which makes it all confusing—something those who make untested products are likely counting on.

1. Skulas-Ray, Wilson PWF, Harries WS, et al. Omega-3 Fatty Acids for the Management of Hypertriglyceridemia: A Science Advisory From the American Heart Association. Circulation 2019;140. https://www.ahajournals.org/doi/10.1161/CIR.0000000000000709

2. Should I take a Daily MultiVitamin/ Harvard T.H. Chan School of Public Health https://www.hsph.harvard.edu/nutritionsource/multivitamin/

3. Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B(6), Folate, Vitamin B(12), Pantothenic Acid, Biotin, and Choline. Washington, DC: National Academies Press; 1998.

4. National Acadmeies Science Medicine and Engineering, Dietary Reference Intakes. The Essential Guide to Nutrient Requirements. 2006. Institute of Medicine; Jennifer J. Otten, Jennifer Pitzi Hellwig, and Linda D. Meyers, Editors. 

5. Cohen PA. The Supplement Paradox: Negligible Benefits, Robust Consumption. JAMA. 2016;316(14):1453–1454. doi:10.1001/jama.2016.14252.

6. Christine B. Ambrosone et al., Dietary Supplement Use During Chemotherapy and Survival Outcomes of Patients With Breast Cancer Enrolled in a Cooperative Group Clinical Trial (SWOG S0221). JCO 38, 804-814(2020).

   DOI:10.1200/JCO.19.01203.