Vitamins Galore - Which To Choose?

Multivitamins efficacy varies for many reasons

/ Author:  / Reviewed by: Joseph V. Madia, MD

Vitamins and minerals are essential for proper functioning — whether it's to meet daily requirements or for disease prevention. But where to begin with so many choices?

Multivitamins consist of all the vitamins and minerals the body needs. Essential vitamins and minerals are those the body can't make on its own. They're only available from an outside source like food or supplements.

Multivitamins and dietary supplements are only needed when you're missing nutrients in your diet. Choosing the right multivitamin depends on factors, like:

  • Age
  • Gender
  • Diet
  • Health

The Institute of Medicine (IOM) established Daily Reference Intakes (DRI). The purpose is to provide health professionals and the public nutritional values for supplements that are deemed appropriate for healthy living, while accounting for all the factors above.

DRI consist of the recommended daily allowance (RDA), adequate intake (AI), upper tolerable intake level (UL) and estimated average requirement (EAR). Unless otherwise directed by your physician, consumers only need to focus on RDA and AI. Both values are goals per day.

In addition to deciding which dietary supplement or multivitamin is best for you and your family, there are also these challenges:

  • A supplement testing company, ConsumerLab, found 10 out of 38 multivitamin brands were listing an incorrect amount of nutrients on the label
  • Price doesn't affect the quality of the multivitamin
  • There is no standard vitamin for each individual
  • The National Institute of Health says there isn't enough evidence to support the use or disuse of multivitamins
  • A study from the American Journal of Epidemiology didn't find multivitamin use effective in preventing or treating diseases like cancer and cardiovascular disease

Many experts agree that too many people aren't getting enough vitamins and minerals from the food they eat. These common nutrients are:

Folate/Folic acid:

Folate is sometimes used interchangeably with folic acid. Folate is the natural form of this B vitamin and is found in many dark green leafy vegetables like spinach, asparagus, broccoli, beans and legumes.

Folic acid is the man-made form of folate and is found in multivitamins, dietary supplements and fortified foods like breakfast cereals. It's better to consume folic acid because it is more stable than folate and can be completely absorbed by the body.

Folate or folic acid is needed to prevent certain types of anemia and pregnancy-related birth defects.

RDA values vary by age:

  • 1-3 years - 150 micrograms/day
  • 4-8 years - 200 micrograms/day
  • 9-13 years - 300 micrograms/day
  • 14+ years - 400 micrograms/day
  • Pregnant women need 600 micrograms per day to prevent birth defects
  • It can also benefit mothers-to-be before conception

Vitamin B-12:

The body needs vitamin B-12 for normal blood formation and proper brain functioning. Vitamin B-12 deficiencies can lead to anemia and brain problems. It can be found in fish, meat, poultry and some dairy products like milk. Beef liver and clams are the best sources of vitamin B-12.

RDA values depending on age:

  • 0-6 months - 0.4 micrograms/day
  • 7-12 months - 0.5 micrograms/day
  • 1-3 years - 0.9 micrograms/day
  • 4-8 years - 1.2 micrograms/day
  • 9-13 years - 1.8 micrograms/day
  • 14+ - 2.4 micrograms/day
  • Pregnant women - 2.6 micrograms/day
  • Breastfeeding women - 2.8 micrograms/day
  • As you age you need more B-12 because the body can't absorb it as well
  • Vegans and vegetarians need to consume supplemental B-12 since the main sources of this vitamin are animal products


Calcium is a key mineral in bone and dental health, nerve function, muscle contraction and many other bodily functions. Calcium deficiency can lead to brittle, fragile bones.

The mineral can be found in dairy products like milk, yogurt and cheese. Other calcium-rich foods include leafy green vegetables, some fish and most grains.

RDA is not available, but AI is:

  • 0-6 months - 200 milligrams
  • 7-12 months - 260 milligrams
  • 1-3 years - 700 milligrams
  • 4-8 years - 1,000 milligrams
  • 9-18 years - 1,300 milligrams
  • 19-50 years - 1,000 milligrams
  • Men 51-70 years - 1,000 milligrams
  • Women 51-70 years - 1,200 milligrams
  • 71+ years - 1,200 milligrams
  • Pregnant and breastfeeding teens - 1,300 milligrams
  • Pregnant and breastfeeding adults - 1,000 milligrams

Vitamin D:

Vitamin D is commonly known as the sunshine vitamin and can only be found in very few foods. Exposing your body to direct sunlight is the best way to get vitamin D, but salmon, tuna and mackerel are the best food sources. The body produces vitamin D when sunlight hits the skin.

Vitamin D is essential because it assists in absorption with calcium and phosphorus to maintain bone health. Inadequate levels of vitamin D can result in soft bones, which is a condition known as rickets in children and osteomalacia in adults.

RDA values depending on age:

  • 0-12 months - 400 IU
  • 1-70 years - 600 IU
  • 71+ - 800 IU
  • Pregnant and breastfeeding women - 600 IU
  • Requirement can be met with 5-30 minutes of direct sun exposure at least twice a week
  • The toxicity level of vitamin D is 2,000 IU per day
  • Too much vitamin D can cause hypercalcemia (too much calcium in the blood)
  • Warning: sunscreen may block UV rays needed to make vitamin D in the body

Vitamin A:

Vitamin A is one of the nutrients important for normal vision, growth, immune function and other important bodily functions. Vitamin A can be found in many colorful fruits and vegetables as well as eggs, milk and liver.

RDA values vary depending on age:

  • 1-3 years - 1,000 IU
  • 4-8 years - 1,320 IU
  • 9-13 years - 2,000 IU
  • Male 14+ years - 3,000 IU
  • Female 14+ years - 2,310 IU
  • Pregnant teen - 2,500 IU
  • Breastfeeding teen - 4,000 IU
  • Pregnant adult - 2,565 IU
  • Breastfeeding adult - 4,300 IU
  • The UL is 2,000 IU for children, but the daily value listed on many multivitamins is 5,000 IU

There is no one brand or type of multivitamin that will work for everyone. It is important that you educate yourself on the proper use of vitamins and minerals and read labels to help you decide.

Be sure to speak with a health professional for more personal nutrient needs before starting a new supplemental regimen.

Some supplements can react with prescription medicine, so be sure to inform your doctor of any vitamins and minerals you're already taking or plan on taking.

Reviewed by: 
Review Date: 
July 12, 2011
Last Updated:
July 25, 2011