Vitamins are essential elements for normal human development. Vitamins are found only in plants and animals and are organic substances which generate hundreds of chemical reactions throughout the body. These include converting sugars and fats into energy and synthesizing proteins to create basic components of various cellular structures. Vitamins can also help in healing wounds and bolster the immune system. There are fat soluble vitamins – vitamins A, D, E, & K. These vitamins are stored in fatty tissues and liver until they are needed. The water-soluble vitamins are vitamin B1, B2, B3, B5, B6, vitamin C, biotin, and folic acid. Water soluble vitamins must be replenished daily, and any that does not get used by the body is excreted in the urine.
Vitamin A is important for normal vision, immune system and reproduction, and helps organs such as heart, lungs, kidneys, and other organs work properly. Sources include beef liver and other organ meats, some types of fish such as salmon, green leafy vegetables and other green, orange, and yellow vegetables i.e. broccoli, carrots, squash, and dairy products, cantaloupe, apricots, and mangos. The recommended dietary allowance for males 14 years and older is 900 mcg (micrograms) and for females 14 years and older it is 700 mcg.
Vitamin D helps build strong bones and helps the body absorb calcium and phosphorus from food and supplements. Too little vitamin D can cause rickets in children and osteomalacia in adults. The muscles, nerves, and immune system require vitamin D to properly function. Sources of vitamin D include fatty fish such as salmon, tuna, or mackerel, beef liver, cheese, egg yolks, mushrooms, fortified milk, and sunlight. Adults 19-70 years require 15 mcg or 600 IU (international units) daily and adults 70 years and older need 20 mcg or 800 IU daily.
Vitamin E is an antioxidant, boosts the immune system, widens the blood vessels and keeps blood from clotting. Sources include vegetable oils such as sunflower and safflower, nuts such as hazelnuts, almonds, and sunflower seeds, and green vegetables such as spinach and broccoli, fortified breakfast cereals, fruit juice, margarines and spreads. Adults require 15 mg (milligrams) f Vitamin E daily.
Vitamin K is essential for blood clotting and healthy bones. Sources include spinach, kale, broccoli, and other green leafy vegetables, fruits such as blueberries, and meat, cheese, eggs, and soybeans. Adult men 19 years and older need 120 mcg daily, and adult women 19 years and older need 90 mcg daily.
The B vitamins include vitamin B1 (thiamine), vitamin B2 (riboflavin), vitamin B3 (niacin), vitamin B5 (pantothenic acid), vitamin B6 (pyroxidine), vitamin B12 (cyanocobalamin), and folic acid.
Vitamin B1 helps turn food into energy and is important for growth, development, and function of cells. Sources include whole grains and fortified breads and cereals, meat (especially pork) and fish, legumes, seeds, and nuts. The recommended dietary allowance for females is 1.1 mg and males is 1.2 mg daily.
Vitamin B2 helps turn food into energy and is important for growth, development, and function of cells. Sources include eggs, organ meats (kidneys and liver), lean meats, low fat milk, fortified breads and cereals, and green vegetables such as asparagus and spinach. Males 19 years and older need 1.3 mg, and females 19 years and older need 1.1 mg daily.
Vitamin B3 helps turn food into energy and is important for the development and function of cells. Sources include poultry, beef, pork, fish, enriched and fortified breads and cereals, and some types of legumes, nuts, and grains. Males 19 years and older need 16 mg and females require 14 mg daily.
Vitamin B5 helps turn food into energy and makes and breaks down dietary fats. Sources include beef, poultry, seafood, organ meats, eggs, milk, mushrooms, avocadoes, potatoes, broccoli, whole grains, peanuts, sunflower seeds, and garbanzo beans. Males and females 19 years and older need 5 mg daily.
Vitamin B6 is essential for enzyme reactions involved in metabolism, and it also helps with essential brain development during pregnancy and infancy as well as immune function. Sources include poultry, fish, organ meats, potatoes, and fruit other than citrus. Adults 19 to 50 years 1.3 mg daily, Males 51 years and older need 1.7 mg and females 51 years and older 1.5 mg daily.
Vitamin B12 keeps the body’s nerve and blood cells healthy. It helps make DNA (the genetic material in all cells). Vitamin B12 also helps prevent a type of anemia called megaloblastic anemia. Sources include beef liver, clams, fish, poultry, eggs, milk, and other dairy products, fortified breakfast cereals and nutritional yeast. The recommended dietary allowance for all adults is 2.4 mcg daily.
Folic acid is a B vitamin that makes DNA and other genetic material. It is responsible for cell division and is important for pregnant women. Sources include beef liver, asparagus, broccoli, spinach, mustard greens, orange juice and oranges, nuts, beans, and peas, fortified breakfast cereals and breads. Adults 19 years and older need 400 mcg daily. Biotin is a B vitamin that turn carbohydrates, proteins, and fats in food into energy. Sources include meat, fish, eggs, organ meats, and seeds and nuts. Adults 19 years and older need 30 mcg daily.
Lastly vitamin C is an antioxidant that helps protect cells from damage caused by free radicals and helps with the production of collagen, a protein to help wounds heal. Vitamin C improves absorption of iron from plant-based foods and helps the immune system work properly. Sources include citrus fruits such as oranges and grapefruits, kiwifruit, tomatoes, and red and green peppers. Adult males need 90 mg and adult females need 75 mg daily.
Dietary Reference Intakes RDA and Adequate Intake, Food and Nutrition Board, Institute of Medicine, National Academics, 2011.
White, Beverly, PhD, RD, Institute for Natural Resources, Health Update, Essential Vitamins, May 2008.