Vitamins are micronutrients human bodies need but don't naturally produce

Humans need vitamins, but research is mixed on taking supplements

When an organism needs an organic molecule to survive, but cannot synthesize enough of it itself, that molecule is called a vitamin. Typically, we consume vitamins through food, but many resort to supplements—a common and mostly unregulated practice.

Humans need higher levels of water-soluble vitamins that easily pass through the body

There are two types of vitamins: lipid soluble and water-soluble. Water-soluble vitamins like B vitamins and vitamin C are in the watery parts of fruits and easily pass through the human body before being taken up by the bloodstream or exiting your body. But lipid (fat) soluble vitamins must be absorbed through the intestinal wall, carried by proteins, and then may be stored in the liver and other body parts—meaning there is greater risk of overdosing.

What do vitamins actually do?

Vitamins are molecular tools the body needs to carry out regular cellular processes, such as wound healing. This 45-minute video dives into the science behind vitamins and their role in the body. There are 13 essential vitamins that must be...

Why is there a Vitamin K but no Vitamin F?

The first vitamin was identified in 1913 by an American scientist performing rat studies while investigating dairy cattle nutritional needs. Elmer Vernon McCollum called this first vitamin, found in butter and egg yolk, "fat-soluble factor A." This...

Most adults don't need a daily vitamin, and it won't extend your life

A 20-year study by the National Cancer Institute involving almost 400,000 people found that daily multivitamins did not help people live longer. In some cases, these vitamins also increased the risk of death. Although some subpopulations—such as those with documented vitamin deficiencies and pregnant individuals—should take vitamins, daily multivitamins should not be taken uniformly by adults. Instead, patients should discuss vitamins with their clinicians and consider baseline vitamin testing before starting vitamin regimens.

Supplements are only typically recommended for those with a proven deficiency

Blood tests and other dietary screening tools by clinicians and nutritionists can indicate whether someone is deficient in needed vitamins or minerals, and those results can then lead to a personalized care plan that may include supplements. Supplements can negatively interact with certain medications, so it's important to speak with your doctor about supplements before taking them.

Learn what the best foods are to survive on a limited diet

The human body can naturally synthesize 11 of the 20 amino acids needed to build the critical proteins required for function, but the nine missing ones can all be obtained from white potatoes. A bit of oatmeal can provide the molybdenum needed to process sulfites from potatoes, while other key vitamins and nutrients can be acquired from avocados, berries, milk, beans, and spinach.

Can you overdose on vitamins?

Many people pop a multivitamin supplement each day thinking that any excess nutrients won't hurt them. This article explains how chronic excess of any vitamin can cause toxic levels in the body. This condition is known as hypervitaminosis, and symptoms vary depending on what vitamins have achieved toxic levels of accumulation. According to this article, dietary supplements in the US are not required to submit to the FDA documentation supporting their efficacy or safety.

Do you need a multivitamin?

In 2013, several researchers declared multivitamins dead, stating that so-called supplements had no clear benefits and might be harmful. But the science isn't so clear-cut. This article explores the question of who would benefit from...

Vitamin A does not cure measles, but it helps reduce the symptoms

Also known as retinol, vitamin A plays a significant role in supporting the body’s immune system. The virus attacks the immune system, and studies have shown a correlation between vitamin deficiency and severity of measles symptoms. Supplemental vitamin A doses are now a part of recommended treatment for pediatric patients.

Vitamins can slow macular degeneration

Research published in 2022 affirmed that vitamin formulations containing vitamins C and E, copper, zinc, lutein, and zeaxanthin—but no beta carotene—can enhance eye health and slow the progression of macular degeneration.

The birth of the multivitamin

In 1912, biochemist Kazimierz Funk, often anglicized as Casimir Funk, proposed that there existed an essential nutrient in food that could prevent deficiency diseases, such as scurvy or rickets. This article explores the origin of the multivitamin, an invention that has garnished...

Yes, you can take too many vitamins and they can make you sick

Too much of vitamins A, D, E, and K (which are fat-soluble) can build up in the body and cause serious health problems, including liver damage, kidney stones, and blood clotting irregularities. Excess iron and calcium can also make it harder for the body to absorb other needed nutrients.

Vitamin D supplement pills are linked to rising cases of vitamin D toxicity in the US

Vitamin D deficiency is common. But taking Vitamin D supplements in doses exceeding 4,000 IU/day (a measurement of vitamin biological activity) for prolonged periods can raise bodily concentrations of this vitamin to dangerous values. US National Poison Data indicates that the annual average of vitamin D poisonings from 2000-05 was 196, but this rose by 1,600% to 4,535 per year for the period of 2005-11.

Vitamin B1 is linked to gut motility—helping fight constipation—in 2026 research

A study published in early 2026 found a link between vitamin B1 and the successful movement of food through your GI tract, known as gut motility. The work incorporated genetic and survey data about poop frequency to identify genes associated with gut motility and then separately linked poop frequency data with how much vitamin B1 people ingested, theorizing that the vitamin supports the production of acetylcholine, a neurotransmitter that stimulates GI system contractions.

Collagen supplements typically come from animal sources like fish, pigs, or cattle

Eating collagen-rich foods won't lead to more collagen in the body because your digestive system breaks down consumed collagen into amino acids. Instead, eating a healthy diet of proteins and greens helps your body to produce collagen. Collagen supplements derived from animal skin and bones are typically sold in a prebroken-down peptide formulation called hydrolyzed collagen so they can be absorbed through the gut into the bloodstream.

The nutrients vegetarians and vegans need to keep in mind

Although most older Americans still enjoy their steaks and chicken, an estimated 2.5 million of those ages 55 and older have abandoned red meat and poultry in favor of a predominantly plant-based diet. Some people decide to go vegetarian or vegan...

See preferred supplements across different countries in 2025, by generation

Millennials and Gen Z typically took more supplements than other age groups across vitamins, proteins, minerals, and herbal supplements, according to 2025 data from a Global Consumer Insights Survey conducted in 55 countries. Roughly two-thirds of Gen Z respondents stated they'd taken vitamins in the past 12 months. (Some users may experience a paywall.)

The dietary market is worth more than $60B

Listen to this question and answer session with the US Food and Drug Administration about dietary supplements—vitamins, minerals, probiotics and similar products people may buy in liquid, pill, or powder form. They are categorized legally as a category of food and can be legally brought to market without the FDA even knowing about it, though consumers can tell FDA about issues with the products and FDA can take action to remove dangerous or unlawful items after they're available.

Proteins with limited light sensitivity prevent humans from seeing all types of light

Specialized photoreceptor cells in the retina called cones each possess photopigments that activate when exposed to three ranges of visible light. Other forms of electromagnetic radiation outside the activation range do not generate signals for processing in the brain, thereby limiting average human vision to approximately 10 million colors.

The FDA does not approve dietary supplements before they go to market

The US Food and Drug Administration does not regulate products including vitamins, probiotics, and herbal mixes as drugs due to the Dietary Supplement Health and Education Act of 1994, which amended the Federal Food, Drug, and Cosmetic Act. Because dietary supplements are regulated as a subcategory of foods, inspectors do not assess whether dietary supplements work as advertised before sale.

Unlike America's recommendations, Australian authorities don't encourage routine sunscreen use for darker skin tones—reasoning that melanoma risk is low, and it's better to get UV exposure to help the body naturally produce vitamin D.

Human anatomy 101: the body's systems

Human life is made possible by the body's ten major systems, which maintain homeostasis by responding to incoming sensory and biochemical input. Each system must work independently and collaboratively for the body to maintain health and respond appropriately to its internal and external environments. The bones of the skeletal system, for example, give the body its shape and protect organs while also facilitating movement with the muscular system.

Most Westerners don't need more protein, despite the protein boom

You can find the macronutrient in snack bars and pretzels, shakes, and more, even though most normal diets in the West are already protein-heavy with meat and milk. A mix of increased exercise culture and influencer sway has led to a market hungry for it.

In 2026, University of Cambridge researchers reported that a group of gut bacteria called CAG-170 may be a key marker of good health, occurring far more often in healthy individuals and less commonly in people with chronic diseases.

ConsumerLab is a watchdog site reviewing supplements for quality and recalls

The group purchases supplements and tests them for accuracy. When it tested 26 popular B vitamin supplements, it found five failed their tests because they provide either significantly less or much more of the ingredients than listed. This type of product-label mismatch can occur because the FDA does not regulate these products as it would a drug.

Remember: Not all fats are bad for you

Contrary to past dietary advice promoting low-fat diets, newer research shows that certain types of fats are both necessary and healthy. It all comes down to the type of fat you eat. Focus on getting "good" unsaturated fats from sources like nuts,...

Lack of Vitamin D seems to be one major factor fueling MS risk

Researchers believe that a combination of factors can elevate MS risk, including a lack of vitamin D exposure in different locales, genetic history, cigarette smoke exposure, and Epstein-Barr virus infection.

Each second, the human body produces 2 million to 3 million new red blood cells.

Optimal human functioning requires movement

There is now ample evidence to back the centuries-old hypothesis that exercise is critical to human health. This review article explores the latest discoveries in exercise science, including how exercise is intrinsic to maintaining our organ systems throughout life.

The five most common chemicals found in modern food

Most modern processed foods rely on a number of preservatives to stay fresh from production to our plates. The most common include citric acid (preservative and flavor), sodium benzoate (preservative), xanthan gum (thickening and stabilizing), carrageenan (thickening), and red dyes 3 and 4 (for color).

What constitutes a 'healthy' diet?

A natural diet, typically high in plant-based foods and low in processed foods, appears to be the main contributor to a healthy, diverse gut microbiome.

It is recommended that humans consume 2.0 to 3.7 liters (about 4.2 to 7.8 pint glasses) of water daily to replace water lost through breathing, sweating, urination, and bowel movements.

On average, the human body produces about 100 watts of electricity—enough to power a light bulb—but some people can produce over 2,000 watts in short bursts, such as when sprinting.

How understanding a balanced diet can help you make good food choices

Eating a balanced diet—which includes a variety of foods from all food groups—is important for optimal health. It is also recommended to avoid ultra-processed foods, such as frozen meals, fast foods, soda, and flavored yogurt. The simplest way...

Explore the human and environmental resources needed to make an electric vehicle

The minerals needed to build batteries for electric vehicles are expensive and often take a human toll paid by the communities where they are mined. This interactive article details what minerals make up an electric vehicle battery, where they come from, and dangers posed by the mining process.

What is the rarest color in nature?

Plants, animals, or minerals found in nature bear almost every color imaginable. There are two factors that influence what hues you see in the wild: physics and evolution. So, which colors are you least likely to see in the natural world? Victoria Hwang explores one of nature's rarest spectacles.

Dietary supplements are regulated like foods

This hour-long 2016 documentary from Frontline, the Canadian Broadcasting Corporation, and The New York Times examined the safety of dietary supplements. It noted that this then-$30B industry (it's at least doubled since then) suffers from irregularities and impurities. It warned that many Americans are unaware of the lack of regulatory oversight over these products.

The strange endurance of consuming blood for health

Blood's importance to humanity is best summarized this way: without it, we die. This importance naturally begets assumptions about its medicinal properties, many of which appear accessible through drinking or eating the fluid connective tissue. This article details the history of blood drinking, from ancient Roman gladiators to modern-day sanguinarians.

Some animals, including certain tropical ants, have little or no microbial populations in their gut, upending the idea that all animals rely on this ecosystem to help maintain their health and proper functioning.

When processing light, the brain can perceive colors with no natural wavelength

While some animals are sensitive to many forms of light, humans possess receptors that are sensitive to red, green, and blue wavelengths. These receptors send signals to the brain, which are processed and mixed to produce the array of colors we observe, including magenta, pink, and "supercolors" that lack a corresponding natural wavelength in the visible spectrum.

Mineral and chemical sunscreens protect differently, but both guard against UV damage.

The term 'superfood' is a marketing construct with no scientific or medical definition

Encompassing at least 136 plants and animals, the concept has been criticized by nutritionists for its scientific value, which has been exploited by the wellness industry for profit. Although the label has encouraged the consumption of fruits and vegetables, food variety and minimal processing remain key to a healthy diet.

Molecules derived from algae can be found in foods such as ice cream, salad dressings, brownie mix, and gravies, as well as in products such as toothpaste, multivitamins, and egg substitutes.

Unlike fruits, the category of 'vegetables' is a culinary term, not a scientific one

Within botany, fruits are defined as the ripened ovaries of flowering plants, and include apples, grapes, tomatoes, avocados, green beans, peppers, and almonds. In the kitchen, "vegetables" is an umbrella term that encompasses many fruits and other parts of plants, such as leaves (lettuce, kale) and roots (carrots, beets).

Humans have taste receptors throughout the body, including in the testes and lungs, but we don't taste what they detect because those areas lack taste buds.

How humans digest food

Every day, the average human eats close to six pounds of food—all of which must be processed by the digestive system. Ten organs collaborate to transform food that the mouth chews into the energy needed to stay alive. (Stretched out, these organs...

What does blood do?

Blood's primary purpose is to ferry oxygen and nutrients to cells in need while collecting cell waste and byproducts for removal. It also enables the body's repair and immune systems to traverse our internal landscape to address cell damage or external invaders, such as viruses and parasites. Zooming out from the exact roles of blood's various cells, the fluid connective tissue also assists with maintaining homeostasis via temperature regulation and pH balance.

A human joint is any place in the human body where two bones connect, providing structure and stability.

Blood has evolved many times over hundreds of millions of years, resulting in different blood colors and compositions—and there are even some organisms that don't need blood at all.