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How to Check Dietary Supplement Quality

Article at-a-glance:

  • Nearly 80% of American adults take dietary supplements, but few know how to evaluate dietary supplement quality.
  • The FDA doesn’t regulate product formulations for quality, only manufacturing processes. This leaves consumers vulnerable to unscupulous companies.
  • In one study, 65% of dietary supplements tested had toxic metals.
  • Understanding how to evaluate dietary supplements can keep you safe and ensure you’re getting products do what they say they’ll do.

by Dr. John Neustadt

The dietary supplements industry is one of the largest direct-to-consumer health products industry in the country. A 2017 survey commissioned by the Council for Responsible Nutrition (CNR) reported that 76% of US adults take dietary supplements. Dietary supplement manufacturers and ingredient suppliers operate in all 50 states. The dietary supplement industry provides jobs for more than 750,000 Americans and generates $5.75 billion in state and local taxes and $9.2 billion in federal taxes. In the US alone, the dietary supplement industry generated $122 billion in revenue and continues to grow year after year.

Along with the growing interest in dietary supplements, there’s a growing need to make sure you’re getting the best value for your money and staying safe. The dietary supplement industry in the US is regulated by the FDA, but the FDA only regulates the manufacturing process. It does not regulate product formulation or raw material quality. This leaves consumers vulnerable to unscrupulous companies that misrepresent the research underlying their product formulations or include poor quality nutrients that your body can’t absorb and use.

Fortunately, with a little education, you can learn what to look for. This article provides helpful guidelines to help you start asking better questions of comapnies so you can spend your hard-earned money wisely, protect your family from potential toxic chemicals, get all the incredible health benefits that high-quality products provide, and be a smart, savvy shopper.

Supplements, Not Drugs

When shopping for dietary supplemetns, it’s improtant to understand what dietary supplements are, and what they are not. Dietary supplements are vitamins, minerals, herbs, and other substances meant to improve your health. They can come as pills, capsules, powders, and liquids. They’re not intended to replace an optimal diet, but rather to “supplement” the diet. Dietary supplements are not drugs and are not approved by the FDA to diagnose, treat, prevent or cure disease.

But that doesn’t mean they’re unregulated. Dietary supplements are regulated by the U.S. Food and Drug Administration (FDA) under the Dietary Supplement Health and Education Act of 1994 (DSHEA). Signed by President Clinton on October 25, 1994, DSHEA acknowledges that millions of consumers believe dietary supplements may help to augment daily diets and provide health benefits. And a large body of basic science and clinical trials support the health benefits of dietary supplements.

The provisions of DSHEA define dietary supplements as being:

  • A product (other than tobacco) that is intended to supplement the diet that bears or contains one or more of the following dietary ingredients: a vitamin, a mineral, an herb or other botanical, an amino acid, a dietary substance for use to supplement the diet by increasing the total daily intake, or a concentrate, metabolite, constituent, extract, or combinations of these ingredients.
  • Intended for ingestion in pill, capsule, tablet, or liquid form.
  • Not represented for use as a conventional food or as the sole item of a meal or diet.
  • Labeled as a “dietary supplement.”
  • Products such as an approved new drug, certified antibiotic, or licensed biologic that was marketed as a dietary supplement or food before approval, certification, or license (unless the Secretary of Health and Human Services waives this provision).

Should You Take Supplements

Most people would probably benefit from a high-quality dietary supplement. That’s because the vast majority of people don’t eat an optimal diet and are living high-stress lives. Both of those things increase someone’s risk for nutritional deficiencies in addition to just simply getting older or if you are or ever have been pregnant. A good dietary supplement is a smart insurance policy.

In theory, we should be able to receive all the nutrition we need from diet alone. But the fact is that people don’t.

  • Few of us eat the recommended five to eight servings of fresh fruits and vegetables a day.
  • Our food is often picked before it’s ripe and transported long distances.
  • The soil in which conventionally grown food is farmed has become depleted of nutrients.
  • We rely on quick, processed foods with our busy lifestyle.
  • We live in a highly toxic world.
  • We have individual health needs and challenges.

Dietary supplements don’t replace a good diet. There are compounds in food that just can’t be replaced by a pill. Evidence shows that a good diet is still your best tool for staying healthy. However, high-quality dietary supplements can play an important role in a larger health strategy.

Evaluate Manufacturing Quality

There are three things to look for in evaluating dietary supplements. First, they should be manufactured at an FDA-registered facility that is also GMP-certified. Manufacturers don’t advertise this on their product labels, so you’ll need to check their website or sales literature for this. 

GMP refers to Good Manufacturing Practice Regulations promulgated by the US Food and Drug Administration (FDA) under the authority of the Federal Food, Drug, and Cosmetic Act. These regulations require manufacturers take steps to ensure that their products are safe and pure. GMP regulations require a quality approach to manufacturing, enabling companies to minimize or eliminate instances of contamination, mix-ups and errors. This in turn protects the consumer from purchasing a product that has only what’s on the label, in the amounts listed on the label.

This process requires manufacturers test raw materials for contaminants and quarantine the materials throughout the manufacturing process. Failure of firms to comply with GMP regulations can result in very serious consequences, including recall, seizure, fines, and jail time. GMP regulations address issues including recordkeeping, personnel qualifications, sanitation, cleanliness, equipment verification, process validation, and complaint handling.

Additionally, the highest-quality manufacturers will also have inspections and certifications from third-party organizations, such as the Natural Products Association (NPA), NSF International, Quality Assurance International and potentially government agencies such as Health Canada.

Products manufactured overseas and imported into the United States may not adhere to the higher US standards. Many herbal products have been shown to contain toxic metals. This is unfortuantley a situation of unscrupulous companies using tainted raw materials that put consumers at risk.  It’s buyer beware. Consmers need to become educated and proactive to ensure they’re getting their money’s worth, but also to protect themselves from poisoning from toxic metals and other contaminants.

A 2006 survey of Ayurvedic dietary supplements produced in South Asia and sold in 20 stores in the Boston area revealed that 20% of the dietary supplements (14 of 70 Ayurvedic supplements) contained heavy metals. Of those with heavy metals, 13 contained toxic amounts of lead 6 tested positive for arsenic, and 6 contained mercury. Based on the EPA established reference doses (RfDs) for oral chronic exposure of arsenic and mercury, people consuming those products were ingesting nearly 29 times the EPA-determined safe dose of arsenic and 1,348 times the safe dose of mercury. Chronic lead exposure, in any amount, is considered toxic.

An earlier 2002 case report documented lead poisoning from Ayurvedic medicine in a 41year-old male. He complained of malaise, weakness, abdominal pain, and weight loss. His blood lead level was 78 μg/dL and it was anemic (hemoglobin 7.9 g/dL). He had traveled to India where he was treated with Ayurvedic medicine for oligospermia (decreased sperm number). Analysis of the dietary supplements revealed high concentrations of lead—13,084 μg/g in one pill and 1,917 μg/g in another pill. It was estimated that during the course of his treatment he had ingested 1.26 g of lead.

Another 2002 case report described arsenic toxicity in a 39 year-old woman taking the dietary supplement Chitosan, derived from chitin, a polysaccharide found in shellfish. Chitosan is believed to help people lose weight by blocking the absorption and storage of fat. The woman reported to the emergency room complaining of fatigue, headache, and weakness for the previous 6 months. She had been taking 6 capsules daily of the “fat blocker” pills for a year. A 24-hour urine collection revealed 186 μg/L arsenic (normal is considered 0–50 μg/L). Analysis of the pills revealed an arsenic concentration of 135.5 ng/g/capsule. Shellfish is a known reservoir of arsenic, and no other sources could be identified.

It’s not only products and raw plant materials coming from India that pose risks for being contaminated with toxic metals. Raw materials coming out of China can also be tainted. A meta-analysis of 22 case reports, case series, and epidemiological research concluded, “heavy metal (particularly lead) poisoning through traditional Chinese medicine use has been reported with some regularity.”

Given these risks, it’s crucial that you ensure companies follow the highest industry manufacturing standards. This includes testing all raw materials for contiminants such as toxic metals, yeast and mold. Additionally, after the raw materials are manufactured into their finished products, companies should be putting the products in quarantine and testing them for contaminants such as yeast, mold and bacteria that could have contaminated the products during manfuacturing.

Determine Formulation Quality

When discussing dietary supplements formulations, the details are important. Whether you are evaluating a multiple vitmain and mineral supplement, or dietary supplements to help with specific health concerns, such as for promoting bone health, for cardiovascular support, to help with supporting healthy blood sugar or to enhance memory and energy the approach to looking at the products is slightly different.

When evaluating a multivitamin and mineral supplement you should look for two things on the label.

  1. Is it a one-a-day multivitamin? If it is, then you’re pretty much guaranteed that it contains poor absorbed nutrients. You can verify this by seeing if there are any “-oxide” minerals.
  2. Are any of the minerals listed as “-oxide”? Manufacturers list each ingredient in the Supplement Facts Panel on a product label. On the Supplement Facts Panel, find magnesium, zinc, and copper. If any minerals are in an “oxide” form, then the manufacturer has put cheap, poorly absorbed raw materials into the formula. This is because these minerals are very poorly absorbed in their “oxide” form.For example you can only absorb only about 4% of the magnesium as magnesium oxide. This means that 96% of what you put in your mouth is just passing right through you and being eliminated in your stool. In fact, magnesium oxide is so poorly absorbed that it’s used in higher amounts as a laxative. Companies use the oxide form of minerals because they’re inexpensive. But you’d be better off eating a few spinach leaves than wasting your money on a dietary supplement that contains minerals in their oxide forms.

And if you’re looking for dietary supplements other than a multiple vitamin and mineral to help promote health in specific areas of your life, such bone health, cardiovascular health neurological health, etc, look for dietary supplement formulas that:

  1. Have human clinical trials conducted on the nutrients in the product.
  2. Contain both the dose and form of nutrients used in the studies they cite for their product.

Since the FDA doesn’t approve dietary supplement formulas, manufacturers can claim their products promote health, and use studies to support their claims. But sometimes companies will then put into their formulations a lower amount of the nutrient than what was used in the studies. Or they might also put a different form of the nutrients than what was used in the studies and shown to work. Therefore, it’s important to make sure the manufacturer has both the dose and form of nutrients used in studies they’re citing to support their products.

Buy Only the Best

There are better forms of individual nutrients than others. You get what you pay for. Many lower-cost products will use cheaper forms of vitamins and minerals. Unfortunately, many times cheaper forms also mean the nutrients are poorly absorbed or not usable by the body.

  • Vitamin D
    The most absorbable form of viamin D is vitamin D oil. Many manufacturers will sell capsules containing vitamin D powder or mix the powder into oil and sell it as a softgel. When combined with other minerals, such as calcium, using vitamin D powder may technically be the only way to manufacture the product. However, when shopping for a Vitamin D3 standalone product, make sure it’s made using vitamin D3 oil. NBI’s Vitamin D3 uses non-GMO vitamin D3 oil in a small softgel with extra virgin olive oil, vitamin E and rosemary extract to preserve its potency and enhance its absorption.
  • Vitamin E
    The best form of Vitamin E is d-alpha tocopherol with mixed tocopherols (d-alpha, gamma, beta, and delta). The synthetic form of Vitamin E is dl-alpha tocopherol. Note that the difference in labeling is “d” vs. “dl” before the alpha—“dl” is not a healthy choice.
  • Vitamin B12
    The best form of Vitamin B12 is methylcobalamin. Cyanocobalamin is the form in most vitamins and is usually fine for most people. If someone has chronic disease, however, a methylcobalamin form is recommended.
  • Vitamin B6
    The active form of B6 is pyridoxine 5-phosphate. This is usually designated at P-5-P.
  • Iron
    The reason why iron supplements case cramping and constipation is becuase they’re not absorbed well enough. Look for a chelated, highly absorbable form of iron, like FerroSolve, that doesn’t create the GI issues like so many other products.
  • Other Minerals
    There are many forms of minerals which are bonded to compounds; the physical form of a mineral is usually designated by the last word of the name. Example: magnesium citrate or magnesium oxide. Each form has different amounts of the basic elemental mineral as compared to the size of the whole compound and will determine how absorbable the mineral is. The most absorbable forms of minerals will be the amino acid chelated forms, or those listed as citrate, aspartate, asparotate, glycinate and malate. For example: calcium carbonate (this includes coral calcium) requires stomach acid for absorption. As poeple get older stomach acid production can decrease. It can also decrease when someone has an autoimmune diesease or if they are taking an acid-blocking medication. When there isn’t enough stomach acid, the calcium stays attached to the carbonate, which means the calcium cannot be absorbed. This can cause gastrointestinal discomfort. In contrast, calcium citrate does not require stomach acid for absorption so there isn’t the risk with calcium citrate that exists with calcium carbonate. Similarly, magnesium oxide is poorly absorbed and causes water to stay in the intestines, which can cause diarrhea. Thus, magnesium oxide can be useful to treat occasional constipation. Alternatively, magnesium citrate is a better choice because it is more easily absorbed.

Avoid bad “other ingredients”

Before you read what active ingredients are in the product, read the label for “other ingredients.” Many supplements contain extra ingredients that may cause side effects or impair absorption. If you have lots of unnecessary “other ingredients,” it doesn’t matter how much active ingredients you have, the dietary supplement is probably a poor choice. It’s a good idea to research any ingredient that’s unfamiliar to you.

The following is not a comprehensive list. Some “other ingredients” to avoid:

  • Glucose, fructose, dextrose, maltodextrose, corn syrup, sucrose, lactose. These are sugars and unless these are added for flavor in children’s chewable vitamins, they are not needed. As soon as possible, wean your child from a chewable to a capsule to minimize their dependence on sugar and risk to their teeth.
  • Sorbitol. This is a sugar alcohol, and although is not purely sugar, it is not beneficial in a vitamin. For diabetics this is an absolute must for avoidance! Sorbitol can also cause diarrhea.
  • NutraSweet, Equal, Aspartame, Sucralose, Splenda. These are artificial sweeteners and are not beneficial to the body.
  • Polyethylene glycol. Although non-toxic, this chemical, when used in large dosages, is a treatment for constipation. It is unnecessary for use in highly absorbable vitamins.
  • Mineral Oil. Mineral oil is derived from petroleum and prevents absorption of nutrients. Given these two facts, taking a vitamin with mineral oil does not seem a good choice.
  • Canuba Wax. Canuba wax may inhibit the digestion of the ingredients and make it less absorbable. This is especially true if digestive weaknesses are already present.
  • Dextrin. This is a binding product, making the nutrients less available for digestion.
  • Di-calcium phosphate. Di-calcium phosphate is an excipient (an inactive ingredient) and is not available to the body as calcium. A vitamin labeling both calcium and phosphorus may be counting the di-calcium phosphate as calcium, but it really doesn’t add much to the calcium content nutritionally.
  • Any coloring
  • Any pharmaceutical glaze

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Dietary Supplement Usage Increases, Says New Survey. 2017; Council for Responsible Nutrition. Accessed November 20, 2017. [report]

Economic Impact of the Dietary Supplement Industry. 2016; Council for Responsible Nutrition. Accessed November 20, 2017. [report]

Ernst E, Thompson Coon J. Heavy metals in traditional Chinese medicines: a systematic review. Clin Pharmacol Ther. 2001;70(6):552-560. [article]

Firoz M, Graber M. Bioavailability of US commercial magnesium preparations. Magnes Res. 2001;14(4):257-262. [article]

Saper RB, Kales SN, Paquin J, et al. Heavy Metal Content of Ayurvedic Herbal Medicine Products. JAMA. 2004;292(23):2868-2873. [article]

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