Which multivitamin?

While many studies suggest multivitamin supplementation can reduce the risk of various chronic diseases, other studies indicate that supplementation may be toxic at higher levels. How much should you take and what should you look for in a quality multivitamin?

The 'how much' is a difficult question to answer. For example, in the United States consumers are aware of the United States Recommended Daily Allowance (USRDA) and strive to achieve 100% of this value in their supplement. There are many flaws to this approach, however. For example, RDAs should not be confused with nutritional requirements. Requirements differ from individual to individual due to many factors from genetics and environment to intensity of training and stress levels. Most agree that it's not harmful to consume two to three times the recommended levels of most vitamins and minerals. Many people regularly do this through a combination of foods and supplements. Some vitamins, such as Vitamins A and D, are exceptions to this as they are known to be toxic at higher intakes.

While it's impossible to quantify all of the possible nutrients that may appear in a multivitamin, we can estimate the quality by using a few reference ingredients.
To come up with our comparison, we started with the USRDA for our sample nutrients. This is really the bare minimum needed for survival. For example, the USRDA for Vitamin C was established based on the lowest amount with a reasonable margin of error that would prevent scurvy. Obviously, Vitamin C has many more uses than the prevention of scurvy, but this is the key factor in determining the RDA guidelines! In addition to the RDA, however, another guideline has been established for most nutrients by the Food and Nutrition Board (FNB - a U.S. organization established in 1940 to study issues pertaining to the safety and adequacy of the food supply.) This is the 'tolerable upper limit' which establishes the safe upper limit of intake. As you will see, there is a considerable gap between the recommended daily allowance and the tolerable upper limit. So where in this range should your intake fall?

Again, this is a matter of debate. Nutrition science is constantly changing, and we discover new information about vitamins, minerals, and other nutrients every day. We based our guidelines on a book by Lyle McDonald called, 'The Comparative Guide to Nutritional Supplements.' In this book, he surveyed several doctors known to specialize in nutrition and obtained their recommendations for daily vitamin supplementation. He then averaged these recommendations to create a weighted standard. The USRDA, suggested intake, and tolerable upper limits for some key vitamins and a sample mineral are listed below:



As you can see, there is quite a variance between the RDA, upper limit, and suggested amounts. These are by no means the total list of nutrients that should be found in a multivitamin, but a sample reference for comparing different products.

Before we start shopping for a multivitamin, the next thing to be aware of is the quality of ingredients. Laws in different countries differ with respect to how vitamins may be manufactured and distributed. In the United States, for example, supplement manufacturers are not required to adhere to a pharmaceutical level of testing. This means sometimes bottles are produced where the actual ingredients do not match the label claims. There are several consumer groups that regularly test and rate vitamins to help determine which adhere to the label claims. If you are purchasing from a U.S. supplier, make sure that the supplier adheres to the U.S. FDA guidelines for pharmaceutical grade supplements. If possible, obtain lab results from batches of the product that were tested by a third-party and not a lab owned by the manufacturer.

You also don't want to make the mistake of purchasing a supplement based on simple cost or convenience. Many of the cheap, one-a-day varieties fall far short of the suggested amounts.

As an example, consider one very popular 'one per day' multivitamin. It is one of the cheaper multivitamins on the market and promises that you only have to take one easy, convenient pill every day. Using our reference ingredients, we found the following: Vitamin B12 is 6mcg (3% of the suggested amount), Vitamin C is 60mg (5% of the suggested amount), Vitamin D is 400IU (2/3 of the suggested amount), and copper is 2mg (100% of the suggested amount). Everything but copper fell short of the mark! The higher quality multivitamin we examined comes in packets that contain multiple pills and is taken twice daily. For this product, the Vitamin B12 was 150mcg (75% of the suggested amount), Vitamin C was 2,000mg (160% of the suggested amount but within the tolerable upper limit), Vitamin D is 800IU (130% of the suggested amount and over the tolerable limit, but this was from two tablets which each taken separately is only 400IU), and copper is 3mg (150% of the suggested amount but well within the tolerable upper limit).

It is obvious that the second product had far more nutrients and higher potency than the original, so it's not good enough to compare simply based on total cost. The second product was also pharmaceutical grade and while it cost more than the cheaper product, it is still less than the cost of a nice dinner for a full month's supply and provided more overall value.

You will probably never find a multivitamin with the perfect amount of every nutrient, and one option is to purchase each vitamin separately and take this based on your personal preferences. A nutritionist may assist with determining what your optimal intakes of various nutrients should be. For most people, however, a quality multivitamin combined with quality, whole foods (lots of vegetables and fruit) should cover all bases and will be a more cost-effective approach. Simply look for a product from a reputable company that adheres to a high quality standard for production. Companies with quality products will stay informed of nutrition research and periodically reformulate their products as new information becomes available.

In conclusion, here is a reference list of ingredients to look for in a multivitamin. This is not to be considered a wholly comprehensive list and may change in the future as new nutrients are discovered and we learn more about existing ones.

The Basics

Beta carotene, Vitamin B2 (Riboflavin), Niacin, Vitamin B6, Folic Acid, Vitamin B12, Thiamin, Biotin, Pantothenic Acid, Vitamin C, Omega-3 (flax oil and or fish oil: EPA and DHA)

Use Caution (Harmful in higher amounts)

Vitamin A, Vitamin D, Vitamin E, Iron (heme-iron or animal-derived is safer than non-heme or plant-derived), Vitamin K (listed here because it is toxic for people with certain conditions)

Nice to Have

Choline, Inositol, Param-Aminobenzoic Acid, Iodine, Glutamic Acid, Natural Tocopherols, Bioflavanoids, N-acetyl L-cysteine, Alpha Lipoic Acid, Coenzyme Q10, Lutein, Lycopene

Minerals (Most should be chelated)

Calcium, Magnesium, Zinc, Selenium, Copper, Manganese, Chromium, Molybdenum, Boron, Silicon, Vanadium