While many healthy Americans are able to meet their daily vitamin and mineral needs through food sources, some may benefit from supplementation if they have specific deficiencies.
Vitamins are chemical compounds that are essential for normal body function. Because vitamins (with the exception of Vitamin D) cannot be created by our bodies, they must be ingested from dietary sources to meet our daily needs. There are 13 essential vitamins and the USDA has determined the recommended daily amounts (RDA) required for good health.
Minerals are naturally occurring inorganic substances used by the body to build bones, make hormones, and regulate muscle contraction among other important functions. There are two kinds of minerals: macrominerals (needed by the body in larger amounts) and trace minerals (the body needs very small amounts of trace minerals). Macrominerals include calcium, phosphorus, magnesium, sodium, potassium, chloride and sulfur. Trace minerals include iron, manganese, copper, iodine, zinc, cobalt, fluoride and selenium.
It’s important to note that vitamins and supplements are not regulated in the same manner as drugs by the Food and Drug Administration (FDA). However, manufacturers of dietary supplements are responsible for determining that their products are safe and are required to comply with Good Manufacturing Practices, a set of uniform standards established to ensure quality throughout the manufacturing, packaging, labeling, and holding of dietary supplement products. Independent reviews of supplement manufacturer quality may be obtained at several organizations including the United States Pharmacopeia, ConsumerLab.com, and NSF International. A seal of approval from one of these organizations provides assurance that the product was properly manufactured, contains the ingredients listed on the label, and does not contain harmful levels of contaminants.
Please note that the level of scientific evidence demonstrating a medical benefit varies among dietary supplement products. In some cases, including sports nutrition and weight loss supplements and with certain herbal products, there is no conclusive evidence. Those products will not be discussed here.
Overview of Key Vitamins
Vitamins are essential nutrients that people must acquire through their diets in order for their bodies to function properly. There are a total of 13 vitamins required by the human body. They are classified into two groups based on how they dissolve: four of them are fat soluble vitamins (absorbed through the intestines and stored in body fat) and nine of them are water soluble vitamins (absorbed through the stomach and intestines and removed in the urine).
Fat Soluble Vitamins
Because these vitamins are stored in fat cells and thus are not easily removed from the body , supplements containing vitamins A, D, E and K can accumulate in the body to harmful levels if too much is taken. Recommended daily amounts of vitamins for children and adults of different ages may be found here. Please click on the highlighted vitamin and mineral names for more in depth information about them.
- Vitamin A is important for healthy vision and immune function. It can be found in animal proteins including liver, kidney, eggs and dairy products. Carotenoids (which can be converted into Vitamin A inside the body) are found in dark green, leafy vegetables, as well as yellow vegetables and carrots.
- Vitamin D is important for maintaining healthy levels of calcium and phosphorus, which build strong bones. Vitamin D is found in fish, eggs, fortified milk and fish oils. The body can produce Vitamin D in skin cells exposed to sunlight.
- Vitamin E is an important antioxidant and helps to repair and protect cells from damage. Vitamin E is found in eggs, fortified cereals, fruit, green leafy vegetables, meat, nuts, nut oils, poultry, vegetable oils, argan oil, olive oil, wheat germ oil and whole grains.
- Vitamin K is important for blood clotting. Vitamin K is found in foods including green leafy vegetables, meat and dairy products.
Water soluble vitamins
Water soluble vitamins (also known as B and C vitamins) are removed from the body by the kidneys and urine. Since water soluble vitamins are not stored, a regular daily intake is required to meet our physical needs. There is less danger of harm from high doses of water soluble vitamins because excess B and C vitamins are readily removed from the body. However, people with kidney damage may have difficulty eliminating excess water soluble vitamins.
- Vitamin B-1 (also known as thiamine) plays an important role in many different body functions, including nerve and muscle functioning, enzyme processes and digestion of carbohydrates. Dietary sources of thiamine include beef, brewer’s yeast, legumes (beans, lentils), milk, nuts, oats, oranges, pork, rice, seeds, wheat, whole-grain cereals and fortified flours.
- Vitamin B-6 (also known as pyridoxine) is required for the production of certain neurotransmitters (signaling chemicals found in the brain and nervous system) as well as nerve health. Major food sources of vitamin B-6 include cereal grains, legumes, vegetables (carrots, spinach, peas, and potatoes), milk, cheese, eggs, fish, liver, meat and flour.
- Vitamin B-9 (also known as folic acid or folate) is required for fetal brain development and brain health in general. Dietary sources of folate include fortified cereals and flour, leafy vegetables (spinach, broccoli, lettuce), okra, asparagus, fruits (bananas, melons, lemons), legumes, yeast, mushrooms, organ meat (beef liver, kidney), orange juice and tomato juice.
- Vitamin B-12 (also known as cobalamin) is required for protein and DNA synthesis. Major food sources include fish, shellfish, meat, eggs and dairy products.
- Vitamin C is required for the production of collagen (in skin), as well as bones, cartilage, muscle and blood vessels. Vitamin C also assists with iron absorption in the intestine. Good food sources of Vitamin C include fruits (especially citrus) and vegetables.
Overview of Key Minerals
Minerals are inorganic elements that come from soil and water and are absorbed by plants. Animals and humans absorb minerals from the plants they eat and use them for important body processes. While there are many different minerals that exist in trace amounts in the body, only the most important minerals will be discussed here.
- Calcium – Calcium is the most abundant mineral in the body and is required for building bones and teeth, for blood vessel health, muscle function, nerve transmission, intracellular signaling and hormone secretion. Good dietary sources of calcium include dairy products, sardines, fortified juice, green leafy vegetables and soy products.
- Magnesium – Magnesium helps to regulate many chemical reactions in the body including protein synthesis, energy production, muscle and nerve function, blood glucose control and blood pressure regulation. It helps to build strong bones and is important for normal heart rhythm. Major food sources of magnesium include green leafy vegetables, legumes, nuts, seeds and whole grains. In general, foods containing dietary fiber provide magnesium.
- Iron – Iron is critical for the production of red blood cells, which carry oxygen to all the tissues of the body. Iron also helps to regulate cell growth and development. Foods richest in iron include animal sources such as red meats, fish, and poultry. Iron can also be found in plant sources such as lentils and beans.
- Zinc – Zinc is important for immune function, protein and DNA production, wound healing, cell division, and plays a role in our senses of taste and smell. A daily intake of zinc is required to maintain minimum levels because the body has no specialized zinc storage system. Excellent food sources of zinc include oysters, red meat, poultry, beans, nuts, crab and lobster, whole grains, fortified breakfast cereals and dairy products.
Specific Groups Who May Benefit From Supplementation
While eating a daily variety of nutrient-dense foods generally provides sufficient intake of key vitamins and minerals, the US dietary guidelines recommend supplementation (or eating foods fortified with vitamins and minerals) under the following circumstances:
- Women who may become pregnant should get 400 micrograms per day of folate from either food or supplements or both. Adequate folate intake reduces the risk of birth defects.
- Women who are pregnant should take a pre-natal vitamin supplement that includes iron. This reduces the risk of birth defects, vitamin deficiencies and anemia.
- Adults age 50 or older should eat foods fortified with vitamin B-12 or take a multivitamin that contains B-12 or a separate B-12 supplement.
Dietary supplements may also be appropriate in the following cases:
- Strict calorie restriction or vegetarian diet. Adults who consume fewer than 1,600 calories per day or those who follow a vegan or vegetarian diet may be at higher risk for vitamin and mineral deficiencies.
- Digestive problems. Adults and children who suffer from intestinal disorders that cause malabsorption syndromes (such as chronic diarrhea, celiac disease, inflammatory bowel disease, food intolerances and allergies or consequences of gastric bypass surgery) may require vitamin and mineral supplementation.
- Bleeding disorders. Those who have chronic bleeding problems (such as hemophilia, heavy menstrual bleeding, gastrointestinal bleeds or clotting disorders) may benefit from iron supplementation.
- Osteoporosis. Older adults at risk for weaker bones may benefit from calcium and vitamin D supplementation.
- Wounds. Those recovering from significant wounds (including burns, recent surgeries and diabetic ulcers) may benefit from Vitamin C and zinc supplementation.
- Macular degeneration. Specific anti-oxidant vitamins in combination with zinc may help to reduce the risk of developing this age-related eye problem.
- Alcohol abuse. Individuals who regularly drink alcohol in excess are prone to Vitamin B and folate deficiencies.
- Specific deficiencies. Various vitamin and mineral deficiencies can occur sporadically as a result of lack of sufficient exposure to sunlight (Vitamin D), as a side effect of medications (such as diuretics), from genetic disorders and from excessive sweat loss from certain endurance sports (such as triathlon, marathon and Ironman training).
If you want to be sure you are meeting your daily vitamin and mineral needs, talk with your healthcare professional about whether supplementation may benefit you. Keep in mind that vitamins and minerals have extremely important effects on the body and that overdoses may be as harmful as deficiencies. Consuming a diet rich in lean protein, dairy, fruits, grains, nuts, seeds and vegetables is the best first step for insuring that you obtain your optimal daily amounts of vitamins and minerals.