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What To Look For In A Multivitamin.

Is Your Micronutrient Deficiency Holding Back Your Muscle Gains?

Posted by NutritionMax - January 4th, 2015

Many Americans are deficient in micronutrients (vitamins and minerals) on a daily basis due to poor dietary choices. Due to a fast paced lifestyle, convenience is attractive which makes for a diet abundant in energy dense and nutrient depleted foods. National surveys have revealed the prevalence of micronutrient insufficiency in Americans. One survey denoted that these type of diet is associated with suboptimal concentrations of vitamin C, vitamin E, vitamin A, folate and vitamin B12(1). Even deficiency of at least one micronutrient can impair immunity and increase susceptibility for chronic diseases like osteoporosis and cancer.

In order to fill in the nutritional gaps, daily multivitamins are advised as they are an inexpensive, easy and safe way to reach the daily value or more accurately speaking, the dietary reference intake (DRI). In fact, The Journal of the American Medical Association has published the recommendation that every person take a multivitamin daily saying that "suboptimal intake of some vitamins, above levels causing classic vitamin deficiency, is a risk factor for chronic diseases and common in the general population, especially the elderly." However, there are individual precautionary measures one must take when choosing the appropriate multivitamin. Let’s take a look in detail on what to factors need to be considered.

The composition of multivitamins varies greatly among brands as there are no true definitions. Many products contain 100% of the Daily Value of most micronutrients, except for calcium, potassium, magnesium and phosphorus. Some multis contain other beneficial phytonutrients, herbs and trace minerals such as silicon, vanadium, nickel and boron, but these are not essential as they can be commonly procured from diet. There is also no “one-size-fits-all” multivitamin because people who have a compromised health or genetic variation have an individualistic need for specific vitamins and minerals.

There is an unfathomable discrepancy between the basis for the quantity of a micronutrient on a supplement label and what the latest nutrient recommendations are. The Daily Values (DV), much like on food labels are based on archaic guidelines from 1968 and don’t reflect the current recommendations set forth by the United States Institute of Medicine. Generally, what this means is the amounts in the supplement are slightly higher than what the current DRI is. A perfect example is with Vitamin A. The Daily Value from 1968 used to say 5,000 IU was enough for optimal health. The contemporary recommendation known as the dietary reference intake (RDA) is 3,000 IU for men and 2,333 IU for women. Clearly, Vitamin A is in quantities above 100% of the RDA. These dosages are typically seen and are safe in general. It is usually not a concern for adverse effect as these higher amounts are still much less than the upper limit.

For the majority of the healthy population, multivitamins are safe; nevertheless, it is in the individual’s best interest to consult with their doctor the appropriateness of a certain multivitamin after analyzing their personal nutrient status, identifying deficiencies, considering health risks when a nutrient is consumed in excess as well as taking into account possible drug-nutrient interactions if one is taking pharmaceutical drugs.


Let’s examine some individual micronutrients that require attention for certain populations when selecting a multivitamin.

Vitamin A – The daily RDA for adult men: 900 mcg/3,000 IU.

The RDA for adult women: 700 mcg/2,310 IU (Pregnant: 770 mcg/2,565 IU)

Due to the risk for potential birth defects, vitamin A intake from a multivitamin above 5,000 IU as retinol is a contradiction for pregnant women. The same contraindication also applies to men and women of older age due to the increased risk for bone mineral density loss and osteoporosis. However, as beta-carotene there is no evidence of endangerment of bone health. Individuals who are at risk for vitamin A deficiency include fat malabsorption issues and alcoholics.

Vitamin B - The adult daily RDA for the 8 B vitamins are as follows:

Thiamin (B1) – Men: 1.2 mg; Women: 1.1 mg (Pregnant: 1.4 mg)

Riboflavin (B2) – Men: 1.3 mg; Women: 1.1 mg (Pregnant: 1.4 mg)

Niacin (B3) – Men: 16 mg; Women: 14 mg (Pregnant: 18 mg)

Pantothenic Acid (B5) – Men: 5 mg; Women: 5 mg (Pregnant: 6 mg)

Vitamin B6 – Men: 1.3; Women: 1.3 mg (Pregnant: 1.9 mg)

Biotin (B7) – 30 mcg for men, women and pregnant

Folate (B9) – Men: 400 mcg; Women: 400 mcg (Pregnant: 600 mg)

Vitamin B12 - Men: 2.4 mcg; Women: 2.4 mcg (Pregnant: 2.6 mcg)

Populations at risk for deficiencies include pregnant and lactating women (B6, folate), undernourished/very low calorie diets, older populations (B12), alcoholics (all b vitamins), vegans/vegetarians (B12) and certain medications like proton pump inhibitors (B12).

Vitamin C – The daily RDA for adult men: 90 mg. The RDA for adult women: 75 mg. (Pregnant: 85 mg)

Vitamin C adequacy can be easily achieved through diet as just a few servings of fruits and vegetables can put you around 200 mg. Vitamin C is a very safe and highly effective antioxidant, antimicrobial, antibiotic, antihistamine, and antiviral. Therefore, a total intake the 400+ range satisfies cellular saturation. Those at risk of vitamin C deficiency include obese populations, smokers and those who are on medications that interfere with absorption and metabolism of ascorbic acid like aspirin.

Vitamin D – The daily RDA for adult men and women: 800 IU. (Pregnant: 600 IU)

These values are arguably too low considering it is insufficient in a about 82% of Americans. Studies show that even consumption of up to 10,000 IU is very improbable of inducing toxicity in healthy individuals(3). Elderly people (ages 65+) may require further supplementation of 400 IU. There are specific groups that are at an increased risk of deficiency such as breast-fed infants who rely solely on breast milk for vitamin D. The American Academy of Pediatrics advises supplementation of 400 IU per day for all infants. Additionally, dark skin people, overly clothed individuals and complete avoidance of the sun, fat malabsorption conditions (i.e. cystic fibrosis and cholestatic liver disease), inflammatory bowel diseases (i.e. Crohn’s), pregnancy women, vegans/vegetarians and obese individuals.

Vitamin E – The daily RDA for adult men and women: 15 mg/22.5 IU. (Pregnant: 22.5 IU)

Vitamin E from food sources has been suggested to be unreliable in reaching the RDA, as 90% of Americans consume less than 15 mg from food alone. Consequently, the Linus Pauling Institute recommends a preference of a multivitamin or specific vitamin E supplement that contains at least 30 IU(4). Otherwise, true vitamin E deficiency risk is seen in those who have genetic mutations in alpha-tocopherol transfer proteins, fat malabsorption conditions, extreme malnutrition and smokers.

Vitamin K – The daily AI for adult men: 120 mcg.

The daily AI for adult women: 90 mcg (Pregnant: 90 IU)

Vitamin K is prevalent in many foods and therefore results in a incidence of deficiency. People are real risk for deficiency include fat malabsorption disorders, IBD, cystic fibrosis, liver disease and those who take vitamin K antagonistic drugs that counteract its assimilation. Individuals who are on anticoagulants like warfarin (Coumadin) are advised not to increase their vitamin K intake as it can oppose the drug’s effects.

Calcium - The daily RDA for adult men: 1000 mg. The RDA for adult women: 1000 mg, 1200 mg (51 years of age+) (Pregnant: 1000 mg)

Calcium deficiency is related to kidney failure, lack of vitamin D and low magnesium levels rather than from insufficient dietary calcium. Therefore, low blood levels of calcium (hypocalcemia) can be masked by a deficiency of vitamin D and/or magnesium. Vegans and vegetarians are at an increased risk for deficiency; however, many foods these days are fortified with calcium.

Calcium in multivitamins or as an independent supplement are commonly found in forms such as calcium carbonate, calcium citrate, calcium lactate, calcium gluconate and calcium citrate malate. Calcium carbonate being the most economically friendly form that is best taken with meals at no more than 500 mg at a given time for optimal absorption. Other forms like citrate and citrate malate are acceptable at anytime during the day, even without a meal. One caveat with calcium supplementation is the risk for hypercalcemia, especially in conjunction with antacids. Ingesting massive amounts of calcium can cause extremely high calcium blood levels inducing vomiting, nausea and abdominal pain in its mildest form.

Magnesium - The daily RDA for adult men: 400 mg, 420 mg (31 years old+). The RDA for adult women: 310 mg, 320 mg (31 years old+) (Pregnant: 350 mg, 360 mg (31 years old+)

In healthy populations who have a sound diet, magnesium deficiency is not common. Low serum magnesium can induce a calcium deficiency. Individuals with gastrointestinal conditions like Crohn’s, celiac, ulcerative colitis or other inflammatory bowel diseases are at an elevated risk for magnesium deficiency. Additionally, a poor diet, older populations with increasing age and those with diabetes and kidney disorders.

Iron - The daily RDA for adult men: 8mg. The RDA for adult women: 18 mg (Pregnant: 27 mg)

Iron deficiency is the most prevalent nutrient deficiency in the country. Heme iron is the form that is most bioavailable to the body, whereas, nonheme iron has a weak absorption rate, which is what is found in supplements like a multivitamin. Therefore, only a fraction of iron is absorbed from a supplement depending on the salt the iron is bound to. For example, ferrous sulfate (heptahydrate) contains 22% of actual elemental iron, ferrous sulfate (monohydrate) has 33%, ferrous gluconate has 12% and ferrous fumarate has 22% of elemental iron(5). The amount of absorbed iron is usually accounted for and displayed on the product.

There are a number of specific groups of people who are at risk of greater iron deficiency. These include pregnant and lactating women, acute blood loss, adolescence, menstruation, children between the ages of 6 months and 4 years of age, celiac disease and h. plylori infection patients, athletes involved in long endurance training, individuals who have had gastric bypass surgery and vegetarians and vegans. With attention towards the latter, plant foods provide little bioavailable iron as nonheme). To account for this diminished absorption, adjusted RDA values are set as 14 mg for adult men and postmenopausal women, 33 mg for premenopausal women and 26 mg for adolescent females(6). Multivitamins or separate iron supplementation is contraindicated for men and postmenopausal women due a decreased risk of a deficiency, unless your physician as instructed you otherwise.

Specific populations who are at a greater risk for numerous micronutrient deficiencies include those suffering from eating disorders, eat very low calorie diets (below 1200 calories), live in an impoverished environment or have a low socioeconomic status, people who have bariatric surgery and as mentioned earlier, a large portion of Americans who do not eat a nutrient-dense diet(2).

In general, multivitamins regarded as a very safe supplement in healthy populations given the micronutrient dosages listed on the specific product. If any additional single nutrient supplement is a part of your regimen, total intake of that nutrient should be accounted for when deciding on a multivitamin. Please consult with your doctor or a qualified health practitioner before using any supplements, especially if pharmaceutical drugs are involved due to the chance of drug-nutrient interactions.

When looking for a high quality multivitamin, there are a few things to keep in mind.

To ensure a product meets the criteria for purity, identity and appropriate manufacturing, look for the verification mark Current Good Manufacturing Practices (CGMP). However, some products can meet this criteria for good standards, yet be absent of a verification mark(2).

For confirmation and further details about a product of interest, visit organizations like or NSF International where you can find complete evaluations. Be aware also that there are high potency vitamins, which contain higher than usual amounts of some nutrients for a specific health target such as the heart or immune system.

Time-released multivitamins have not been adequately proven to be more beneficial than non-time-released. Lastly, some vitamins in capsule form may be derived from gelatin, which is something to consider for the vegetarian/vegan individual.

Multivitamins are designed to “cover your bases” and ensure daily adequacy of each micronutrient is met for optimal health. However, a sound whole foods diet should always be the priority as this is the blueprint for a healthy body.



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posted by NutritionMax
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NASM CPT, Master's in Human Nutrition
Precision Nutrition Sports & Exercise Nutritionist

Justin Janoska is a professional fitness coach and a clinical nutritionist who specializes in helping people with challenging diseases. He runs an online coaching platform where he helps people like you reach build muscle or lose weight.

For an intimate coaching experience, visit

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Vitamin D deficiency is the most overlooked.  It is really a hormone rather than a vitamin and your body has thousands of Vitamin D receptors throughout the body.  I found out I was grossly deficient - 9 Ng when normal ranges should be in the 50-75 Ng range - back in 2011.  I have been taking 2000IU of D3 everday since.  2000 - 5000IU is safe for those with deficiencies.  Too much Vitamin D can lead to calcification of the kidneys and cause sudden cardiac arrest.


Great article Justin!  I love how technical you are!  Very impressive as usual!