Humans need vitamins, but research is mixed on taking supplements

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

Each vitamin is found in specific portions of a normal human diet and supports normal human functioning in distinct ways. Vitamin A is found in red meat, carrots, and potatoes and supports vision and skin health, while Vitamin D (common in fish and mushrooms) helps absorb calcium. See sources and uses of each vitamin with this chart.

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.

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...

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.

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.

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...

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...

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.)

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.

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.

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 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.

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.

Why don't we synthesize blood?

We're trying. Scientists are currently working on creating viable synthetic blood, an alternative to the presently relied-upon donations that manage to fall short of demand. More than half of the world's nations struggle to meet their population's need for blood. This article details current and historical efforts to develop synthetic blood, a venture that started more than 400 years ago.

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.

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.

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...

Gummy vitamins have candy-level sugar—and that sweetness is linked to overdoses

A typical gummy vitamin contains about the same amount of sugar in a single serving as one Sour Patch candy. It's linked to the increase in pediatric overdoses for products including multivitamins and melatonin. Gummy formulations also degrade quickly, so they often include much higher levels of the product in each serving than the label advertises—boosting overdose risks due to this unchecked variability. (Some users may experience a paywall.)

Reporting if supplements make you ill helps FDA know what products to investigate

The US Food and Drug Administration regulates supplements like foods and can only take action about a supplement if they learn that there are problems with it after it's on the market. This website allows consumers, industry, and others to file a complaint about a product that made them ill or raised other concerns.

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.

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 have become a multibillion-dollar industry

Beginning in our 20s, the amount of this protein in our skin, muscles, and connective tissue declines. But independent, high-quality studies—like those that are double-blind—have not yet shown a significant association between their use and evidence of it improving skin elasticity, reducing wrinkles, or combating hair loss. Some collagen supplements do seem to help with joint pain and knee function, but NPR cautions that studies on that purpose are industry-funded.

Supplements often have issues with impurities, toxins, and inaccurate labels

Consumer Reports' tests of more than 20 supplement powders and shakes in 2025 found that more than two-thirds of them contain unsafe levels of lead. Some contained 10 times the amount of lead that's considered acceptable to ingest in a day. The levels they found, in some cases, were even higher than when they tested the products 15 years earlier.

Search this citation-heavy database of nutrition and supplement research

Explore a reference site that aggregates and summarizes peer-reviewed studies on hundreds of supplements and dietary interventions. It is ad-free and funded by subscriptions, making it a health resource without a financial stake in what you buy.

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 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...

Instead of consuming water and carbon dioxide to produce oxygen and sugar, anoxygenic photosynthesis involves alternative reactants and products.

This 'Science Vs' episode checks the taste, health, and environmental claims about organic food against the actual research.

Organic food might be greener, but it’s not better for you

Weighing in on the ongoing debate surrounding organic versus “regular” foods, health experts explain whether organic foods offer significant health benefits. Studies suggest that organic foods have little additional nutritional value compared to...

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.

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.

Metabolism, a collection of chemical reactions at the cellular level, processes food and converts it into energy to power the body.

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.

Photoautotrophs, which include plants, algae, bacteria, and Euglena, are organisms at the base of the food web that convert light energy from the sun into chemical energy stored in sugars.

Biohacking to boost personal health has become a concept that encompasses everything from vitamin regimens and cryochambers to brain implants and red light therapy.

Supplement sales soared during the pandemic, alongside growing distrust of the health establishment, amplifying a trend that endures—even when some of the products don't even work.

Research studies can be conducted inside or outside of living samples

While "in vitro" experiments occur outside living organisms for cost-effectiveness, "in vivo" experiments take place inside them, providing real-life insights at a higher cost and with increased ethical concerns. Alternatively, "in silico" methods use computational simulations.

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.

What sleep is for and why you can’t live without it

Sleep is one of the most important needs that humans have. The body uses sleep as a time of restoration and rejuvenation, as body tissues repair themselves, growth hormones are released, and the process continues. Brain plasticity theorists believe that sleep is also used for the processing and consolidating of new memories.

The USDA does not claim that organic food is healthier than the alternatives

Although many believe organic food to be healthier, the USDA's organic label refers to methods used to grow the food rather than any potential health benefits. Still, a 2016 Pew Research Center study found that 76% of people purchased organic food for its health value.

Proof of 'natural' food claims are voluntary for most food products

Unlike the enforcement done by the USDA for meat, dairy and eggs, the FDA offers loose guidelines for using a "natural" food label on most foods, and following the guidelines is voluntary. As a result, many products labeled as "natural" can contain processed ingredients and synthetic additives.

Ultraprocessed foods include preservatives, dyes, sweeteners, and more

Processed foods are those that have been altered from their original state, which includes numerous processes that we consider natural, such as cooking or salting. Ultraprocessed foods contain at least one item that wouldn’t be found in a kitchen, like hydrogenated oils or high-fructose corn syrup. It’s estimated that nearly 75% of all foods consumed in the US are ultraprocessed, though that doesn’t mean that all of them are unhealthy. In fact, some, such as prepackaged whole wheat bread and soy milk, are recognized for their health benefits.

GMOs sound scary, but you eat them every day

Why are GMOs bad? They aren't. We've been eating them for decades with no ill effects, which makes sense, because a genetically modified organism is simply an organism, like every other organism, produces hundreds of thousands of proteins, but one or two of them are proteins that were chosen specifically by humans. Watch this 11-minute video for more.

What are universal vaccines?

As viruses mutate and develop, vaccines have to adapt, leading to regular recommended injections like flu shots. Researchers are working to develop universal vaccines that aim to protect against multiple virus variants if not entire virus families. These vaccines work by creating broadly neutralizing antibodies (bnAbs) that target aspects of viruses that don't typically mutate and are integral to the virus' survival.

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...

Fertilizers provide essential nutrients to plants for their growth, including nitrogen, phosphorus, and potassium, but an overabundance of these nutrients may also harm plants.

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.

Synthetic biology can prevent extinction by creating create disease-resilient plants and animals

Through gene editing and the deployment of artificial cells, scientists can leverage learnings from the genetic sequencing of animals with known resistances to protect endangered species. Gene editing of certain species, such as mosquitoes, can also reduce their ability to spread diseases like malaria between humans.

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.