The Different Purposes Of Vitamins Explained

Vitamins are raw materials your body uses to sustain life, according to HelpGuide. The roles they play number in the hundreds, and include boosting your immune system, healing wounds, and strengthening your bones. They're called micronutrients because you need only a small amount, but those small quantities are essential to ward off disease and maintain optimal health.

Vitamins are organic, unlike their inorganic counterpart minerals which hold their chemical structure and easily make their way from soil and water into your body. Their organic nature means vitamins are vulnerable to destruction by air, heat, or acid, and may also become depleted when foods in which they are contained are cooked in water (via Healthline). Despite these potential pitfalls, Harvard Health Publishing confirms that the best way to get the nutrients you need in the right amounts is a balanced, varied, and healthy diet.

Oregon State University explains that to be considered a vitamin, a compound must be organic and result in obvious deficiency symptoms when it's missing from your diet. Researchers have identified 13 such compounds that we call vitamins, which are either fat or water soluble and available via food or supplements.

It's not just a myth — carrots really can help your eye health, according to Harvard T.H. Chan School of Public Health. They're a source of beta-carotene, which your body converts on an as-needed basis into retinol, also known as vitamin A (via Mount Sinai). In addition to supporting eye health, vitamin A also helps your immune system and organs work properly (via the National Institutes of Health).

The human diet contains two primary types of vitamin A: preformed (retinol and retinyl esters), and carotenoids that your body converts to retinol (via Harvard T.H. Chan School of Public Health). Preformed vitamin A exists in fortified foods, like juices, cereals, and dairy products, as well as vitamin supplements and animal products. Plant sources provide the carotenoids like beta-carotene that are precursors to retinol. Beta-carotene exists in vitamin supplements, as well as fruits and vegetables like cantaloupe, sweet potatoes, broccoli, spinach, and lettuce in addition to carrots (via Mount Sinai).

The recommended daily amount of retinol activity equivalents for men aged 19 years and older is 900 micrograms (3,000 IU), and for women is 700 micrograms (2,333 IU). You likely won't need to worry about vitamin A toxicity if your diet contains mostly beta-carotene sources, since your body will convert only as much as it needs. However, if you take supplements, it's important to know the maximum safe limit for vitamin A from retinol is 3,000 micrograms (10,000 IU) daily (via Harvard T.H. Chan School of Public Health).

Mount Sinai explains that all the B vitamins assist in the conversion of food into fuel, and vitamin B2 is part of this function. Also known as riboflavin, this vitamin works as an antioxidant to fight free radicals that might otherwise damage your cells and DNA. As a result of this antioxidant action, vitamin B2 can help slow aging, and help to ward off potential perils like cancer and heart disease. Riboflavin may also support eye health, as well as reduce the frequency and duration of migraine headaches.

Organ meats, yogurt, milk, and eggs are among the animal dietary sources of vitamin B2. Plant sources include spinach, broccoli, Brussels sprouts, wild rice, whole grains, and almonds. Riboflavin is heat tolerant but may wash away during boiling or soaking, so steaming and roasting are preferable food preparation methods to preserve this nutrient. Mount Sinai cautions that light destroys vitamin B2, and that foods that contain it should be stored in a way that eliminates light exposure.

If your diet isn't balanced, you might benefit from a riboflavin supplement. The recommended daily dose for people aged 19 years and older is 1.3 milligrams for men and 1.1 milligrams for women. Pregnancy increases that recommended amount to 1.4 milligrams, and if you're breastfeeding, you should aim for 1.6 milligrams per day.

In addition to working with other B vitamins to convert food into glucose, vitamin B5 contributes to the formation of red blood cells, cholesterol, sex hormones, and stress hormones. It aids in the synthesis of coenzyme A, which the human body needs for cellular chemical messaging, liver toxin metabolism, and fatty acid synthesis. Pantothenic acid, as vitamin B5 is also known, helps your digestive system remain healthy, and makes it possible for your body to use other B vitamins. Vitamin B5 may also reduce facial acne, improve blood cholesterol, and ease arthritis symptoms (via Medical News Today).

"Pantou" is Greek for everywhere, which describes the availability of pantothenic acid. Most foods contain some of this vitamin, making deficiency a rare occurrence. Common food sources include beef, seafood, poultry, eggs, milk, vegetables, whole grains, chickpeas, and peanuts, according to National Institutes of Health (NIH).

The NIH recommends that everyone aged 14 years and older consume 5 milligrams of vitamin B5 daily. People who are pregnant should increase their daily intake to 6 milligrams, and then again to 7 milligrams if they breastfeed.

Biotin is part of the B vitamin team that breaks down substances like carbohydrates and fats (via WebMD). Thinning hair is one of the symptoms of low biotin, which may be why this vitamin is a popular treatment for hair loss, as well as brittle nails. The Mayo Clinic includes amino acid metabolism and blood cholesterol level regulation among biotin's beneficial effects.

According to the National Institutes of Health (NIH) you can get the biotin you need by eating foods like liver, meat, fish, eggs, nuts, seeds, and some vegetables including spinach, broccoli, and sweet potatoes. Most people get enough biotin through dietary sources, although there are certain people at risk for a deficiency. They include those who use alcohol excessively, who are pregnant or breastfeeding, and who live with the genetic disorder biotinidase deficiency.

The NIH recommends that adults aged 19 years and older, plus pregnant teens and women, consume 30 micrograms of biotin daily. Breastfeeding teens and women should increase their daily intake to 35 micrograms.

The Mayo Clinic describes vitamin B12 as having an essential role in cell metabolism, DNA production, nerve function, and the formation of red blood cells. Without this key nutrient, you're at risk for complications that include anemia, nerve damage, fatigue, muscle weakness, dementia, low cognitive function, mood disturbances, and intestinal problems.

Vitamin B12 occurs naturally in animal food sources like dairy, poultry, meat, and fish. In addition, there are fortified breakfast cereals that contain this vitamin. B12 isn't present in the types of plant foods people commonly eat, which means that if you're vegan or vegetarian you'll have to proactively look for this nutrient. WebMD suggests fortified foods, nutritional yeast, seaweed, and shiitake mushrooms as vegan-friendly sources.

The Mayo Clinic recommends that adults consume at least 2.4 micrograms of vitamin B12 each day. Vegans and vegetarians can meet the recommended daily allowance with a vitamin B12 supplement since dietary plant sources are scarce and may not be readily available in necessary quantities.

Your bones and teeth need vitamin D for growth and development (via Healthline). Other benefits of this fat-soluble vitamin include disease resistance, calcium and phosphorus absorption, and immune system regulation. According to a study in PLoS One, vitamin D may help to downgrade pathological autoimmune responses by boosting the quantity and function of T regulatory cells. Healthline also lists easier management of mood and body weight among the benefits of vitamin D.

You may have heard vitamin D referred to as the sunshine vitamin because of the way your body produces it from sunlight exposure. To fill in the gaps when you can't spend time in the sun, choose from fortified foods and those with naturally occurring vitamin D, like seafood, egg yolk, beef liver, and mushrooms grown in ultraviolet light, explains Healthline. It may help to add a vitamin D supplement to your routine since it may not be convenient to rely on sunlight or food sources to acquire this nutrient.

According to Healthline, the recommended daily amounts of vitamin D increase after age 70, when all adults should aim for 20 micrograms (800 IU) daily. Between the ages of 18 and 70, all adults including those who are pregnant or breastfeeding need 15 micrograms (600 IU) of daily vitamin D. It's possible to experience vitamin D toxicity from supplements, so it's wise not to exceed the dose recommendation by much.

Vitamin K contributes to bone metabolism, blood calcium levels, and blood clotting (via Medical News Today). Though rare, a severe deficiency in this vitamin can result in slower clotting time, resulting in excessive bleeding. Newborn babies typically receive a vitamin K injection to safeguard against potentially fatal brain bleeds, and people who take blood thinning medication need their doctor's clearance before increasing their intake of this nutrient. Vitamin K may also protect bone health, improve episodic memory in adults who are older, and reduce blood pressure by preventing arterial mineralization.

Leafy green vegetables like kale and Swiss chard are rich in vitamin K, according to Medical News Today. Other sources include meat, dairy, eggs, Japanese natto, parsley, collard greens, spinach, soybean oil, grapes, and hard-boiled eggs.

Experts believe that most adults in the United States consume enough vitamin K through their diet. Deficiencies in this nutrient are common for newborn infants but rare for adults, according to WebMD. You might have an increased risk of low vitamin K levels if you live with a disease that impacts digestive absorption like irritable bowel disease, are significantly malnourished, use alcohol excessively, or take medication that interferes with vitamin K absorption. WebMD indicates that the recommended daily amount of vitamin K for adults aged 19 years and older is 120 micrograms for men and 90 micrograms for women, regardless of their pregnancy or breastfeeding status.