Multivitamins first hit the shelves in the 1940s as part of a post-war initiative to treat malnutrition. By the 1950s, consumers were being encouraged to take multivitamins daily, and more companies joined the supplement industry.
As research and regulations have evolved, so to have manufacturing processes and supplement formulas. Multivitamins have come a long way from their original formulas, and consumers now have an enormous range of products to choose from, all varying in terms of formulation, ingredients, and levels of efficacy.
How to choose a quality multivitamin
A quality multivitamin should not replace a healthy diet. It should only be used to help fill nutritional gaps that may be a result of malabsorption, dietary deficiencies, or any other reason that prevents you from obtaining the nutrients you need from foods.
Here’s a quick guide on how to choose a quality multi.
1. A multivitamin should have the nutrients that you need
A quality multivitamin should contain all or most of the 13 essential vitamins: A, C, D, E, K, and B vitamins, along with the major mineral’s magnesium, zinc, iodine, copper, selenium, and others.
These nutrients are not only required for the proper function of the mind and body but to act as cofactors. Most vitamins and minerals work as enzyme activators to support the primary functions of other nutrients.
People with malabsorption disorders or genetic polymorphisms (such as MTHFR) may require a methylated multivitamin
to ensure optimal absorption of the nutrients they would otherwise be unable to obtain from food.
The eight B vitamins (known as the B-vitamin complex) are involved in several steps of the energy-production system, namely in breaking down fats and carbohydrates into glucose for energy. B12 specifically is involved in helping to form red blood cells which deliver oxygen around the body. 
Iron is also key to energy due to its role in oxygen transport, cellular energy production, and immune function.  Vitamin C is required for the biosynthesis of carnitine, an essential cofactor for energy production. Magnesium has a predominant role in the production and utilization of ATP (adenosine triphosphate), the form of fuel used by every cell. 
3. Choose according to your age and life stage
Your nutritional needs will vary as you go through life. Older adults may be at a higher risk for insufficient nutritional intake due to medications, loss of appetite, malabsorption, medications, or medical conditions, and/or difficulty eating. They also have greater needs for highly bioavailable nutrients that support the heart, brain, and bones.
Younger individuals and pregnant women may need nutrients that support energy, focus, and fertility. A kid’s multivitamin should contain nutrients that assist with learning and development, such as calcium, fiber, and B vitamins.
Vegans will need to seek out a vegan multivitamin that contains no animal-derived products but provides nutrients missing from their diet, such as iron.
Antioxidants can provide valuable protection from oxidative stress. Oxidative stress is generated by unstable molecules known as free radicals, which are produced from exposure to environmental factors such as smoking, pollution, UV rays, and other toxins. Free radicals can damage the body’s cells, increasing the risk of chronic illnesses such as heart disease and cancer. 
Some antioxidants with clinically proven results include Coenzyme Q10 (CoQ10), lycopene, vitamin C, alpha-lipoic acid, vitamin E, selenium, and epigallocatechin gallate (EGCG).
5. Choose only bioavailable nutrients
The bioavailability of the vitamins and minerals within a supplement will reflect their benefits to your overall health. If a nutrient is not bioavailable, it will not be absorbed properly in the body, which means its benefits are nil.
Potential side effects of multivitamins
Everyone’s health circumstances are different, and a multivitamin may carry some element of risk in certain situations.
• Taking large amounts of minerals such as calcium, iron, magnesium, potassium, and/or zinc may have negative effects on heart rate, muscle function, urination, or cognition. Some side effects may include stomach bleeding, diarrhea, confusion, or muscle weakness. 
• Combining multivitamins with other supplements or fortified foods may lead to an excess intake of certain nutrients.
• Some ingredients in multivitamins may have contraindications with medications or certain medical conditions. If you have a medical condition or take medication, check with your health practitioner before starting any supplement regime.
• Always read the ingredients and dosage instructions.
Most importantly, check that the product has United States Pharmacopeia (USP) approval. This ensures that the product contains the exact ingredients and dosages on the label, and that it is free of contaminants (such as heavy metals and pesticides) and manufactured under sanitary and regulated conditions.
The best time to take multivitamins
Multivitamins that contain B-complex vitamins should be taken in the morning with breakfast, as they are designed to stimulate energy. All multivitamins should be taken with a meal to assist with absorption and reduce the risk of gastrointestinal side effects.
The right multivitamin is one that supports good health, particularly if you’re in need of certain nutrients to support a health condition or restore a deficiency. Your age, gender, and life stage (such as pregnancy) may also require additional nutrients that can’t be adequately obtained from food.
Always consult your doctor before beginning a new supplement, especially if you are pregnant, nursing, or have a health condition.