Vitamins are either water-soluble or fat-soluble nutrients that the body needs to function optimally. Water-soluble vitamins require water for absorption and are excreted in urine, making it unlikely that you can take too much. There are nine water-soluble vitamins: vitamin C and the eight B vitamins (thiamin, riboflavin, niacin, vitamins B6 and B12, folate, biotin, and pantothenic acid). Fat-soluble vitamins require fat for absorption and are stored in fat tissue. There are four fat-soluble vitamins: vitamins A, D, E, and K. Because these vitamins are fat-soluble, making sure to get some fat within the same meal as these vitamins will allow your body to absorb the vitamins properly.¹

Vitamin A: Contrary to popular belief, there is not a single nutrient called "vitamin A." Rather, vitamin A comprises a broad group of related nutrients that form two major subsets of vitamin A-related nutrients. Carotenoids are the plant-based form of vitamin A, and retinol is the animal source of dietary vitamin A. Generally speaking, vitamin A-related nutrients help the production and activity of white blood cells as well as support growth and remodeling of bone. However, retinoids (from retinol) and carotenoids provide different health benefits.²

Retinoids are especially important to pregnancy, childbirth, childhood development, night vision, red blood cell production, and resistance to infectious disease. Carotenoids function as antioxidant and anti-inflammatory nutrients. It is important to note that while both retinoid (found in animal foods) and carotenoid (found in plant foods) nutrients are vital to health, healthy bodies are able to effectively convert carotenoids into retinoids, so you don't have to eat animal foods in order to obtain retinoid forms of vitamin A that are essential for health. The best sources of vitamin A-related nutrients, listed in order of percentage daily value per serving, are sweet potatoes, carrots, spinach, kale, mustard greens, collard greens, turnip greens, beet greens, Swiss chard, and winter squash.²

B Vitamins

Thiamine (B1): Also known as vitamin B1, thiamine is an essential nutrient that helps your entire body to function properly. Thiamine helps produce adenosine triphosphate (ATP), a molecule that transports energy within cells, boost your immune system, and alleviate digestive problems. Thiamine deficiency is rare in developed countries, but most food processing destroys this helpful B vitamin, so supplementation is not uncommon. However, you can avoid low B1 levels by consuming high amounts in dietary sources such as sunflower seeds, navy beans, black beans, barley, dried peas, green peas, lentils, pinto beans, lima beans, and oats.³

Riboflavin (B2): Also known as vitamin B2, riboflavin promotes energy production (riboflavin is crucial for the metabolism of fat molecules into useful energy), offers antioxidant protection against harmful free radicals, and promotes iron metabolism. Good dietary sources of vitamin B2 (ranked in order of % daily value per serving) include spinach, beet greens, mushrooms, asparagus, sea vegetables, eggs, cow's milk, broccoli, swiss chard, and green beans.⁴

Niacin (B3): Like other B-complex vitamins, niacin (also known as vitamin B3) is important for the conversion of dietary macronutrients (carbohydrates, fats, and proteins) into usable energy, and protecting your body against tissue damage from free radicals. The highest sources of B3 are animal-derived foods including tuna, chicken, turkey, and salmon, but there are many good plant sources as well including peanuts, green peas, root vegetables, leafy greens, cantaloupe, sunflower seeds, brown rice, and barley.⁵

Pyridoxine (B6): Vitamin B6 is necessary for creating heme, the nonprotein, insoluble, iron protoporphyrin constituent of hemoglobin. In other words, vitamin B6 is necessary for distributing oxygen in your body, the primary function of hemoglobin. Furthermore, vitamin B6 is involved in metabolizing carbohydrates, synthesizing (i.e. creating) vital messaging molecules in our nervous system and brain (called neurotransmitters), and liver detoxification. The importance of adequate dietary vitamin B6 has led many nutritionists to conclude that the Recommended Dietary Allowance (RDA) of 1.3 - 1.7 milligrams for healthy adults is on the low side. The Tolerable Upper Limit (TUL) of vitamin B6 is around 100 milligrams. Excellent sources of vitamin B6 include tuna, spinach, cabbage, bok choy, bell peppers, turnip greens, garlic, and cauliflower.⁶

Cobalamin (B12): Cobalamin, or vitamin B12, plays several important roles within your cardiovascular system. Like vitamin B6, vitamin B12 plays a key role in red blood cell production by providing a key building block for hemoglobin. Vitamin B12 also normalizes homocysteine levels in the blood. High levels of homocysteine are related to the early development of heart and blood vessel disease and considered an independent risk factor for heart disease. Beyond your cardiovascular system, vitamin B12 is necessary for the production of DNA and promotes brain and nervous system health. Generally, your body cannot store B vitamins well, but vitamin B12 is the exception. Several years' worth of vitamin B12 can be stored in your body. Only microorganisms like fungi and bacteria can produce vitamin B12. Since no plants or animals can make vitamin B12, the most common dietary sources are from animals that feed on microorganisms either directly (such as marine animals) or consume significant amounts of microorganism-rich soil while grazing (such as factory farm animals).⁷ However, the vast majority of factory farm animals receive vitamin B12 through supplementation and/or injection (more information found here). As such, the highest sources of dietary vitamin B12 are found in sardines, salmon, tuna, cod, lamb, scallops, shrimp, and beef. Vegans and vegetarians can easily maintain optimal vitamin B12 levels by using B12 supplements such as Deva's B12 Vitamin Supplement found here.

Folate (B9): This critical B complex vitamin is a critical nutrient for the health of our cardiovascular and nervous systems. Within our cardiovascular system, folate works with vitamin B12 to regulate homocysteine blood levels, functions as a part of the enzyme dihydrofolate reductase (DHFR) which contributes to the production of nitric oxide synthase (NOS) which balances levels of nitric oxide (NO) in the blood, and aids in the production of red blood cells. Nitric oxide is a gas that helps relax blood vessels (thereby supporting healthy blood pressure levels) and improves blood circulation (thereby supporting healthy arterial function and heart health). Within our nervous systems, folate works alongside vitamin B6 to support the production of neurotransmitters. Most notably, researchers have verified a close connection between the availability of folate and the body's ability to properly produce multiple neurotransmitters, especially serotonin and dopamine. Green plant foods, including spinach, turnip greens, bok choy, parsley, and romaine lettuce, are among the richest sources of folate.⁸

Note: Folic acid is the synthetic source of folate and commonly found in enriched cereals and grains. Some people have trouble processing folic acid, so it is encouraged to get your folate from natural food sources such as lentiles, pinto beans, garbanzo beans, asparagus, spinach, navy beans, black beans, kidney beans, turnip greens, and broccoli.

Biotin (B7): Although misunderstood for nearly the entire 20th century, biotin serves many important roles. Biotin helps balance blood sugar by contributing to the production of insulin and promotes skin health by building healthy fats in the skin that keeps skin looking youthful. Biotin deficiencies are known to cause skin rashes, leaving the skin flaky and irritated. Biotin-packed foods (ranked in order of % daily value per serving) include peanuts, tomatoes, almonds, eggs, onions, carrots, Romaine lettuce, cauliflower, sweet potato, oats, walnuts, and salmon.⁹

Pantothenic Acid (B5): Historically known as vitamin B5, pantothenic acid (PA), or pantothenate, is extremely vital to your health. Coenzyme A (CoA), one of the most important chemicals needed to sustain life, is a large biochemical molecule required for the synthesis and oxidation of fatty acids. In other words, your body needs BoA to metabolize carbohydrates, fats, and proteins. CoA biosynthesis requires PA, making PA a vital nutrient that makes energy metabolism possible. Without it, we wouldn't exist. Thankfully, PA is commonly found in many foods and PA deficiencies in developed countries are quite rare. The best sources of PA (ranked in order of % daily value per serving) include mushrooms, cauliflower, sweet potato, broccoli, beet greens, asparagus, turnip greens, bell peppers, cucumber, celery, and avocado.¹⁰

Vitamin C: Most people can name a few good dietary sources and benefits of this well-publicized vitamin. Vitamin C is a powerful antioxidant that keeps chemical reactions in our body in check, improves the body's ability to absorb iron (because of this, it is beneficial to consume vitamin C-rich foods alongside iron-rich foods), enables collagen production, and promotes nervous system health. Collagen is the main structural protein that forms various connective tissues in our bodies. Collagen literally holds our body together, so people with severe vitamin C deficiency lose teeth, bone strength, and bleed easily. As for the nervous system, our bodies need vitamin C to produce serotonin, a hormone that plays a critical role in managing our moods, daily bodily rhythms (such as our sleep cycles), stress, and pain. Your body needs serotonin to maintain a positive, happy, low-stress life. Like most vitamins, the best dietary sources of vitamin C are plant foods. For vitamin C, these foods include papaya, bell peppers, broccoli, brussels sprouts, strawberries, pineapple, oranges, kiwi, cantaloupe, cauliflower, kale, and cabbage (listed in order of % daily value of vitamin C per serving).¹¹

Vitamin D: Vitamin D is a fat-soluble vitamin that is largely responsible for maximizing absorption of calcium, iron, magnesium, phosphate and zinc. There are several types of Vitamin D, but the ones most important to our health and well-being are Vitamin D3 (also called cholecalciferol) and D2 (ergocalciferol). Food sources of Vitamin D include salmon, sardines, tuna, eggs, and cow's milk. A major source of Vitamin D is sunshine, where it is synthesized in the skin. It's hard to find recommendations on how much time in the sun is optimal for Vitamin D consumption when you factor in that any time in the sun increases your risk of skin cancer.¹²

Vitamin E: A fat-soluble vitamin necessary for a strong immune system, healthy skin, and eyes. Many studies show that Vitamin E is beneficial in preventing cancer, heart disease, diabetes, Alzheimer's and cataracts. Deficiencies in Vitamin E are rare but usually occur in people with digestive disorders, cystic fibrosis and sometimes people that have very low-fat diets. The best sources of Vitamin E include vegetable oils, green leafy vegetables (specifically spinach), fortified cereals, eggs, and nuts.¹³

Vitamin K: Vitamin K is comprised of a group of fat-soluble vitamins that are necessary for proper blood clotting. Deficiencies of Vitamin K can cause uncontrolled bleeding and weakening bones. Vitamin K includes Vitamin K1 and K2. K1 is synthesized by plants and found in most green, leafy vegetables. There are 3 synthetic types of Vitamin K – these included K3, K4, K5. The best sources of Vitamin K include kale, spinach, mustard greens, collard greens, and chard.¹⁴