A vitamin is an organic compound required as a vital nutrient in limited amounts. Your body can’t make vitamins in sufficient quantities, so you must obtain them from your diet or from supplements.

Each vitamin comprises one or more vitamer compounds grouped under a letter of the alphabet, such as “vitamin A”, which includes the compounds retinal, retinol, and about 50 carotenoids. Your body can convert vitamers to the active form of the vitamin, and sometimes to other vitamers, as well.

Vitamins have many functions. Some have hormone-like functions as regulators of mineral metabolism (e.g., vitamin D), or regulators of cell and tissue growth and differentiation (e.g., some forms of vitamin A). Others function as antioxidants (e.g., vitamin E and vitamin C). The largest number of vitamins (e.g., B complex vitamins) help enzymes in their work in metabolism.

The value of eating a certain food to maintain health was recognized long before vitamins were identified, and the discovery of vitamins was a slow and fairly recent process. Vitamin deficiencies can cause diseases such as goiter, scurvy, osteoporosis, immune deficiencies, metabolic disorders, cancer, premature aging, and eating disorders, among many others. Excess of some vitamins, especially fat-soluble vitamins such as vitamin A, can be toxic.

Vitamins are classified as either water-soluble or fat-soluble. In humans there are 13 vitamins: 4 fat-soluble (A, D, E, and K) and 9 water-soluble (8 B vitamins and vitamin C). Your body can use most vitamins for multiple functions.

Dr. T. Colin Campbell argues that vitamin A as retinol isn’t a true vitamin, because the human body can manufacture retinoids out of the true essential vitamin, the carotenoids. He also asserts that vitamin D isn’t a true vitamin, because the human body can synthesize it from the action of sunshine on the skin.

Water-soluble vitamins dissolve easily in water and, in general, your body can readily excrete them in urine. Because you can’t readily store them, you need to consume them more consistently. Bacteria synthesize many types of water-soluble vitamins.

• Thiamine (vitamin B1) maintains your energy supplies, coordinates the activity of nerves and muscles, supports proper heart function, and is critical for brain cell and cognitive function. Get 1.1 milligrams per day* from yeasts, asparagus, crimini mushrooms, spinach, flax seeds,  peas, Brussels sprouts, whole grains, wheat germ, navy beans, kidney beans, and peanuts.
• Riboflavin (vitamin B2) helps protect cells from oxygen damage, supports cellular energy production, and maintains your supply of other B vitamins. Get 1.1 milligrams per day* from crimini mushrooms, spinach, summer squash, asparagus, chard, shiitake mushrooms, green beans, mustard greens, broccoli, collard greens, and turnip greens.
• Niacin (vitamin B3) helps lower cholesterol levels, stabilizes your blood sugar, supports genetic processes in your cells, helps your body process fats, and protects against Alzheimer’s disease and age-related cognitive decline. Get 14 milligrams per day* from yeast, rice and wheat bran, paprika, peanuts, sun-dried tomatoes, crimini mushrooms, shiitake mushrooms, and asparagus.
• Pantothenic acid (vitamin B5) helps turn carbohydrates and fats into usable energy, improves your ability to respond to stress by supporting your adrenal glands, and ensures adequate production of healthy fats in your cells. Get 5 milligrams per day* from crimini and shiitake mushrooms, cauliflower, cucumber, avocado, asparagus, broccoli, celery, grapefruit, turnip greens, sweet potato, collard greens, chard, bell peppers, and corn.
• Vitamin B6 (Pyridoxine) supports a wide range of activities in your nervous system, promotes proper breakdown of sugars and starches, and helps lower levels of homocysteine, an amino acid that is an intermediate product in an important metabolic cycle. Elevated blood levels of homocysteine are a risk factor for heart attack, stroke, or peripheral vascular disease. Get 1.5 milligrams per day* from brewer’s yeast, dulse, potatoes, pistachios, sunflower seeds, spinach, bananas, lentils, avocados, sweet potatoes, winter squash, yams, peas, sesame seeds, bell peppers,turnip greens, summer squash, shiitake mushrooms, collard greens,chickpeas, garlic, leeks, cauliflower, Brussels sprouts, onions, hazelnuts, kale, pineapples, and carrots.
• Biotin (vitamin B7) supports healthy skin through proper fat production, helps your body make efficient use of sugar, and maintains an energy supply in your nerve cells. Get 30 micrograms per day* from Chard, carrots, almonds, walnuts, strawberries, raspberries, onions, cucumbers, and cauliflower.
• Folate (vitamin B9) acts as a co-factor for enzymes involved in the synthesis of DNA; supports red blood cell production and helps prevent anemia, lowers your risk of cardiovascular disease and cancer by preventing build-up of homocysteine in your blood, supports cell production, especially in your skin, allows nerves to function properly, helps prevent neural tube defects in fetuses, helps prevent osteoporosis-related bone fractures, and helps prevent dementias including Alzheimer’s disease. Get 400 micrograms per day* from Romaine lettuce, spinach, asparagus, turnip greens, mustard greens, parsley, collard greens, broccoli, cauliflower, beets, lentils, summer squash, black beans, navy beans, kidney beans, pinto beans, chickpeas, papaya, strawberries, green beans, sea vegetables, cabbage, bell peppers, Brussels sprouts, leeks, fennel, tomatoes, and peas.
• Vitamin B12 (Cyanocobalamin) supports production of red blood cells and prevents anemia, allows nerve cells to develop properly, and helps your cells metabolize protein, carbohydrate, and fat. Get just 2.4 micrograms per day* from nori, fortified foods, or supplements. (Neither plants nor animals make vitamin B12; it is made by bacteria.)
• Vitamin C (Ascorbic acid) helps produce collagen, which supports strong bones, muscles, blood vessels, gums, mucous membranes, corneas, joints, and other supporting cells and tissues; functions as an antioxidant and prevents oxygen-based damage to your cells; helps return vitamin E to its active form; helps prevent cancer by neutralizing volatile oxygen free radical molecules and preventing damage to your DNA that can lead to cancer and by destabilizing a tumor’s ability to grow under oxygen-starved conditions: helps you absorb iron and calcium; supports your immune system; processes toxins for elimination; and acts as an antihistamine. Get 75 milligrams per day* from papaya, bell peppers, strawberries, broccoli, pineapple, Brussels sprouts, kiwifruit, oranges, cantaloupe,  kale, cauliflower, starfruit, bok choy, grapefruit, turnip greens, mustard greens, collard greens, raspberries, chard, napa cabbage, lemon and lime juice, cabbage, tomatoes, Romaine lettuce, sweet potato, winter squash, peas, summer squash, spinach, potatoes, yams, avocados, watercress, blueberries, watermelon, and green beans.

Fat-soluble vitamins are absorbed through your intestinal tract with the help of lipids (fats). Because they are more likely to accumulate in the body, they are more likely to lead to overdose diseases than are water-soluble vitamins.

• Vitamin A (made from many carotenoids) is needed for vision, healthy skin and mucous membranes, bone and tooth growth, and immune system health.  Get 700 micrograms per day* from carrots, winter squashes (acorn, butternut, pumpkin), sweet potatoes, cantaloupe, apricots, spinach, kale, turnip greens, broccoli, red bell peppers,  and greens.
• Vitamin D helps optimize calcium and phosphorus metabolism; prevents type 2 diabetes, insulin resistance, high blood pressure, heart attack, congestive heart failure, stroke, falls, muscle weakness, and osteoporosis; maintains bone integrity; helps regulate insulin activity, blood sugar balance, immune system responses, muscle composition and  function, and blood pressure; reduces risk of  excessive inflammation and  some bacterial infections; supports cognitive function and mood stability; and helps prevent chronic fatigue as well as bladder, breast, colon, ovarian, prostate, and rectal cancer. Get 15 micrograms per day* from sunlight or from Mushrooms exposed to ultraviolet light.
• Vitamin E protects your skin from ultraviolet light, prevents cell damage from free radicals, allows your cells to communicate effectively, and helps protect against bladder cancer, prostate cancer, and Alzheimer’s disease. Get 15 milligrams per day* from Spinach, turnip greens, chard, mustard greens, cayenne pepper, sunflower seeds, almonds, bell peppers, asparagus, collard greens, kale, tomatoes, cranberries, broccoli, Brussels sprouts, papaya, raspberries, and carrots.
• Vitamin K allows your blood to clot normally, helps protect your bones from fracture, helps prevent postmenopausal bone loss, helps prevent calcification of your arteries, and provides possible protection against liver and prostate cancer. Get 90 micrograms per day* from parsley, kale, spinach, Brussels sprouts, chard, green beans, asparagus, broccoli, kale, mustard greens, turnip greens, collard greens, thyme, Romaine lettuce, sage, oregano, cabbage, celery, sea vegetables, cucumber, leeks, cauliflower, tomatoes, and blueberries.

*You can estimate your requirements here.

A well-rounded diet based on unrefined plant foods provides an abundance of most vitamins. The only exception may be vitamin B12 for most of us who wash away dirt and bacteria from food, and vitamin D for most of us in temperate climates in winter months. A daily multivitamin/multi-mineral supplement usually ensures adequate levels of these nutrients. You can have your blood levels of vitamin D and vitamin B12 checked when you have your cholesterol checked to ensure that you are absorbing adequate levels and know whether you need to supplement further.

Stay healthy!

This blog uses the latest nutritional data available from the USDA (United States Department of Agriculture), and the FDA (United States Food and Drug Administration), as well as nutritional data provided by food growers and manufacturers about their products. We believe the information on this blog to be accurate. However, we are not responsible for typographical or other errors. Nutrition information for recipes is calculated by Living Cookbook based on the ingredients in each recipe based on statistical averages. Nutrition may vary based on methods of preparation, origin and freshness of ingredients, and other factors.

This blog is not a substitute for the services of a trained health professional. Although we provide nutritional information, the information on this blog is for informational purposes only. No information offered by or through this blog shall be construed as or understood to be medical advice or care. None of the information on this blog should be used to diagnose or treat any health problem or disease. Consult with a health care provider before taking any product or using any information on this blog. Please discuss any concerns with your health care provider.