Vitamins: Overview
Vitamins are a group of organic substances found in plants and animals that the human body cannot produce on its own, or only produces it in insufficient amounts, so has to get it from food. There are 13 recognized vitamins that come in two types: fat-soluble and water-soluble.
Fat-Soluble Vitamins
Fat-soluble vitamins dissolve in fat. They require fat in order to be absorbed and can be stored in the fat tissues of the body as well as liver. They include vitamins A, D, E, and K.
Vitamin A
Vitamin A is used primarily in the production of retinal. Retinal is used within the eye to sense light. Without it, we would not be able to see. Vitamin A is also important in maintaining healthy skin, bone development, and immune function.
They are available in both animal and plant foods, including liver, fish, dairy, sweet potatoes, carrots, spinach, kale, apricots and red bell peppers. In animal foods, it is found as retinol, also known as preformed vitamin A, while in plant foods it is found as carotenoids. The body then converts these into vitamin A. To convert carotenoid beta-carotene into a usable form of vitamin A, the body requires bile salts. Bile salts are produced by the liver when you consume fat, so adding good fats to a vegan or plant-based meal is essential.
Vitamin D
Vitamin D promotes the absorption of calcium and phosphorus. This helps the body to form and maintain bones, as well as play a role in immunity and cell growth. Unlike other vitamins, the body can manufacture its own vitamin D through sunlight. Frequent exposure to sunlight will promote sufficient amounts of vitamin D, without the risk of getting too much, since your body will only produce what it needs.
Food sources of vitamin D include leafy green vegetables such as spinach, some mushrooms, and herbs such as eyebright, alfalfa, and fenugreek. Many people claim that vitamin D can only be found in animal products, but this isn’t true. Most animal products such as dairy and eggs only contain vitamin D because it is added in; not because it is naturally occurring. This is also true for fortified soy milk. The process of adding nutrients to foods is known as “food fortification.” The problem with fortified foods is that the nutrients are not as easily absorbed by the body.
Vitamin E
Vitamin E works as an antioxidant and protects vitamin A and C, red blood cells, and essential fatty acids from destruction. It is available in a number of foods including fruits (kiwifruit and avocado), leafy green vegetables, vegetable oil, nuts (almonds and hazelnuts), seeds (sunflower), and whole grains.
Vitamin K
Vitamin K is important for blood clotting and stopping bleeding as well as building bone health. There are two naturally occurring forms: vitamin K1 and vitamin K2. Vitamin K2 is produced by the bacteria in the large intestines, while vitamin K1 is obtained through food. These foods include: parsley, kale, tomatoes, broccoli, spinach, cabbage, cauliflower, and olive oil. Animal foods are generally limited in vitamin K.
Water-soluble Vitamins
Water-soluble vitamins dissolve in water. They are not stored for long as the body takes what it needs and excretes the rest as waste. Because of that, you need a continuous supply. They include: vitamin C and B-complex vitamins thiamin (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), cobalamin (B12), vitamin B7 (biotin), vitamin B9 (folate or folic acid), and vitamin B5 (pantothenic acid). B-complex vitamins are a group of vitamins that help the body metabolize fats and protein and help in nervous system and brain function.
Vitamin C
Vitamin C, also known as ascorbic acid, has many important functions including working with vitamin E as an antioxidant, neutralizing free radicals throughout the body, helping protect vitamins A and E as well as fatty acids from oxidation, and the production of collagen, which is the connective tissue that holds muscles, bones, and other tissues together.
Foods high in vitamin C include: oranges, kiwi fruits, sweet red pepper, Kakadu plum, camu camu fruit, asparagus, broccoli, cabbage, tomatoes, blackberries, grapefruit, mangoes, melons, pineapples, spinach and strawberries.
Vitamin B1 (Thiamin)
Vitamin B1 helps the body convert food (carbohydrates) into energy (glucose). Not only does it boost energy, it also improves the body’s immune system and, as a result, helps against anxiety and stress.
They can be found in grain, sunflower seeds, brown rice, asparagus, kale, cauliflower, potatoes, and oranges.
Vitamin B2 (Riboflavin)
Vitamin B2 helps break down proteins, fats and carbohydrates and absorb other nutrients and maintain tissue. It also helps convert amino acid tryptophan into niacin, another B-vitamin, and helps in the proper absorption and activation of iron, folic acid, and vitamins B1, B3, and B6.
Sources for B2 include liver, eggs, whole grains, wild rice, mushrooms, soybeans, broccoli, brussels sprouts, chard, okra, green beans, and spinach.
It is important to note that ultraviolet light can destroy vitamin B2.
Vitamin B3 (Niacin)
Like other B-vitamins, vitamin B3 is needed for the metabolism of food, and of turning sugars and fats into energy. It also helps in proper enzyme function, boost HDL “good” cholesterol, and regulate the nervous and digestive systems.
Sources for vitamin B3 include anchovies, beef, whole grains, beans, cheese, chicken, eggs, lamb, mushrooms, sunflower seeds, legumes, green peas, avocados, dates, and leafy vegetables.
Vitamin B6 (Pyridoxine)
Vitamin B6 aids in protein metabolism and red blood cell formation, regulates levels of the amino acid homocysteine, and helps in the production of insulin and hemoglobin. It also helps with mood and sleep by assisting in the production of serotonin, melatonin, and norepinephrine.
Food sources for B6 include chicken, turkey, salmon, lentils, sunflower seeds, brown rice, carrots, watermelon, bananas, whole grains, and green leafy vegetables.
Vitamin B12 (Cobalamin)
Vitamin B12 is unique in that it is the only vitamin that contains a metallic ion, the mineral cobalt. To be absorbed by the body, vitamin B12 is first separated from the protein by hydrochloric acid. It then combines with a protein made in the stomach called intrinsic factor and is absorbed by the body. Because of this, B12 is not as easily absorbed as other B-vitamins. Also unlike other B-vitamins, many years worth of vitamin B12 can be stored in the body.
No plant or animal can produce biologically active vitamin B12. Only microorganisms such as bacteria, archaea, and fungi have the enzymes necessary. Animals are often told to be the only source of B12. They have the bacteria in their rumen (stomach) that are needed to synthesize B12. This bacteria-synthesized B12 is then passed down and absorbed by the small intestines.
However, what most people don’t realize that that the human gut also contains B12-synthesizing bacteria, from the mouth to the intestines. Most of our intestinal B12 is produced in the colon, where there is the greatest number of bacteria in the body. Due to its location, most of the vitamin is not available for absorption.
Many people believe that the vitamin B12 produced in the intestines is too far down to be absorbed. Recent research has shown otherwise. Some vitamin B12 is also excreted in the bile and then reabsorbed. The effectiveness of this absorption can be influenced by many factors due to the vitamin’s complexity and the process it requires for proper absorption. If any one of the multiple factors in the process is impaired, such as in the case of low stomach acid, imbalances of intestinal bacteria, and the absence of intrinsic factor, then so is the ability of B12 to be absorbed.
This also applies to people who consume meat. They are equally at risk of becoming B12 deficient.
Studies and findings have also revealed that animal foods are not the only sources for vitamin B12. The vitamin can also be found in some mushrooms, algae, and fermented plant foods such as tempeh or miso.
Again, it is important to remember that no foods, neither plant nor animal, naturally contain vitamin B12. It is only produced by microorganisms, or certain bacteria and archaea (a single celled organism similar to bacteria). Many factors, such as pollution and stress, can affect our body’s absorption and store of vitamin B12. Whether you are a meat-eater or vegan, you may need to consider adding natural supplements.
Vitamin B7 (Biotin)
Vitamin B7, also known as vitamin H, is, like the other B-vitamins, involved in the metabolism of protein, fats, and carbohydrates. It also helps the body process glucose, produce fatty acids and amino acids, and helps activate protein/amino acid metabolism in the hair roots and fingernail cells. It plays a crucial role in the health of hair, skin, and nails. Like vitamin B5, bacteria in the intestines produce vitamin B7.
It can be found in small quantities in a number of food. Some of them include: liver, cheese, salmon, avocado, raspberries, oats, and fresh vegetables, particularly bean sprouts and raw cauliflower.
Vitamin B9 (Folate or Folic Acid)
Folic acid works with vitamin B12 for the synthesis of DNA, the breakdown of protein, and the formation of hemoglobin in red blood cells. It also aids in rapid cell division and growth and enhances brain health. It plays a critical role in the production and maintenance of DNA and RNA. Like the other B-vitamins, it also plays a key role in nerve function.
Sources of vitamin B9 include asparagus, cabbage, cauliflower, green peas, spinach, oranges, chickpeas, lentils, broccoli, Brussel sprouts, cabbage, papaya, kiwi fruit, parsnips, and sunflower seeds. Make sure not to overcook any vegetables, as it can cause the folic acid content to drop.
Vitamin B5 (Pantothenic Acid)
Vitamin B5 is involved in the breakdown of carbohydrates, lipids (fats), and some amino acids, as well as aids in the formation of hormones. It is used in the production of enzymes and has been shown to lower cholesterol. It plays an essential role in the rebuilding of tissue, muscles, and organs.
It is found in small quantities in nearly all foods. The word “pantothenic” comes from the Greek pantothen, which means “from everywhere.” As a result, sources include anything from whole grains to broccoli, avocado, royal jelly, peas, mushrooms, and legumes. It is also made by intestinal bacteria.