Long before anyone knew what a vitamin was, people had noticed something odd: liver could help a person who could see in daylight but stumbled after sunset. Ancient Egyptian and Greek physicians recorded versions of that observation. They had the remedy, more or less, but not the molecule.
That took centuries. The story eventually led to vitamin A, a fat-soluble family of compounds involved in vision, immune function, and the normal growth and maintenance of tissues. For runners, the useful lesson is not that vitamin A is a secret performance booster. It is that essential nutrients tend to look boring right up until you do not have enough of them.
The night-blindness clue
In the 1800s, nutrition scientists thought a complete diet was fairly simple: protein, carbohydrate, fat, minerals, and water. Then carefully controlled feeding experiments kept producing animals that failed to grow, became ill, or developed eye problems even though those boxes had been checked.
Milk, butter, egg yolk, and cod-liver oil seemed to contain something the purified diets did not. In 1913, Elmer McCollum and Marguerite Davis at the University of Wisconsin, working independently of Lafayette Mendel and Thomas Osborne at Yale, described a fat-soluble factor needed for growth. It was first called “fat-soluble A,” then vitamin A. Not exactly a Hollywood title, but chemistry has always been better at discovery than branding.
The old night-blindness observations finally made chemical sense. Rod cells in the retina use a light-sensitive pigment called rhodopsin. Its light-catching component is made from retinal, a form of vitamin A. When vitamin A stores become severely depleted, low-light vision can fail before more serious eye damage appears. That is a deficiency outcome, not evidence that extra vitamin A gives a well-nourished runner owl vision.
Vitamin A is a family, not one molecule
“Vitamin A” is convenient shorthand for compounds the body can use as vitamin A. Animal foods provide preformed vitamin A, including retinol and retinyl esters. Plants provide provitamin A carotenoids, especially beta-carotene, which the body can convert into usable vitamin A.
Those forms matter. Preformed vitamin A is readily absorbed and stored. Beta-carotene must first be converted, and that conversion varies among people. Nutrition labels handle the differences with micrograms of retinol activity equivalents, or mcg RAE. It is a way to compare different chemical routes to the same biological job.
Why vitamin A matters to runners
Running does not create a special vitamin A requirement, but runners still depend on the systems vitamin A supports. It helps maintain normal vision, including adaptation to dim light. It also helps regulate immune function and supports epithelial tissues, the protective surfaces lining the respiratory and digestive tracts.
That makes vitamin A biologically important. It does not make it an ergogenic aid. There is no good human evidence that adding vitamin A above adequate intake makes a vitamin-A-replete runner faster, raises VO2 max, or shortens recovery. Correcting a deficiency and improving performance beyond adequacy are two different claims. The first is established nutrition. The second has not been demonstrated.
What the evidence can and cannot tell us
| Question | What the evidence supports |
|---|---|
| Is vitamin A essential? | Yes. It is required for normal vision, immune function, cell differentiation, and tissue maintenance. |
| Does deficiency matter? | Yes. Night blindness is an early clinical sign of depleted vitamin A stores; severe deficiency can damage the eye. |
| Does more improve running? | No runner-specific clinical evidence shows that extra vitamin A improves performance when intake and status are already adequate. |
| Can high doses be harmful? | Yes. Preformed vitamin A can accumulate, and high-dose beta-carotene trials found harm in current or former smokers and some asbestos-exposed workers. |
That last row deserves respect, not panic. The adult tolerable upper intake level is 3,000 mcg RAE per day for preformed vitamin A from food and supplements. It does not apply to beta-carotene in the same way. In two large trials, much larger beta-carotene regimens—20 mg daily in male smokers, or 30 mg beta-carotene plus 7,500 mcg RAE of retinyl palmitate in current or former smokers and asbestos-exposed workers—increased lung-cancer risk. Those were specific doses in specific high-risk populations, not a general claim that carrots are dangerous.
Food first: build a two-lane route
A practical diet uses both lanes. Eggs, dairy, fish, and liver provide preformed vitamin A. Sweet potatoes, carrots, pumpkin, spinach, kale, and other dark-green or orange produce provide carotenoids. Because vitamin A is fat-soluble, eating these foods with some dietary fat helps absorption. Olive oil on spinach or eggs beside roasted sweet potato is chemistry doing its job without making lunch complicated.
| Food | Typical vitamin A per serving | Easy runner use |
|---|---|---|
| Baked sweet potato, 1 whole | About 1,403 mcg RAE | Dinner side or post-run bowl |
| Raw carrots, 1/2 cup | About 459 mcg RAE | Lunch, snack, or chopped into a grain bowl |
| Cooked spinach, 1/2 cup | About 573 mcg RAE | Fold into eggs, pasta, or soup |
| Pickled Atlantic herring, 3 oz | About 219 mcg RAE | On toast or in a potato salad |
Liver is extraordinarily rich in preformed vitamin A: a three-ounce serving of beef liver can provide more than 6,500 mcg RAE. It can fit in a diet, but it is not a food to stack casually with high-dose retinol supplements. If you are pregnant, trying to become pregnant, taking a retinoid medication, or managing a condition that affects fat absorption, discuss vitamin A intake with a qualified clinician.
Why we include vitamin A in PEREGRUNE
Food should do the heavy lifting. Real life, however, includes early meetings, late practices, travel weekends, and the occasional dinner assembled from whatever survived the refrigerator. We include vitamin A in PEREGRUNE Runner Multivitamin as daily nutritional security alongside a varied diet.
A two-tablet serving provides 3,000 mcg RAE of vitamin A, with 67% from beta-carotene and 33% from retinyl palmitate. That split matters: about 990 mcg RAE is preformed vitamin A, while the balance is beta-carotene. We chose a mixed-form approach to provide vitamin A through both routes rather than treating every microgram as chemically identical.
This is a formulation rationale, not a claim that the finished multivitamin has been clinically shown to improve running performance. A multivitamin helps cover the nutritional bases. It does not replace vegetables, protein-rich foods, adequate calories, sleep, or the miles themselves.
FAQ
Should I take vitamin A before a run?
No special pre-run timing is needed. If you use a supplement containing vitamin A, take it with a meal that includes some fat and follow the serving directions.
Are carrots enough?
Carrots are an excellent beta-carotene source, but variety is useful. Combining orange and dark-green produce with eggs, dairy, or fish provides a broader mix of vitamin A forms and other nutrients.
Does vitamin A improve night running?
Correcting true deficiency can restore impaired dark adaptation. More vitamin A has not been shown to sharpen night vision in someone who is already adequate. Reflective gear and a good light still win that race.
The bottom line
Vitamin A earned its place in nutrition history by solving a problem people had recognized for thousands of years. For runners, its value is foundational: normal vision, immune function, and healthy tissues. Get it from a colorful, varied diet, use a thoughtfully formulated multivitamin as daily security, and resist the idea that essential automatically means more is better.
Supplement note: Dietary supplements are not intended to diagnose, treat, cure, or prevent disease. Follow the serving directions and talk with a qualified healthcare professional if you are pregnant, trying to become pregnant, use retinoid medications, smoke or formerly smoked, or have a condition that affects nutrient absorption.
Sources
- NIH Office of Dietary Supplements: Vitamin A and Carotenoids—Health Professional Fact Sheet
- Lanska DJ. Historical aspects of vitamin A deficiency disorders. Handbook of Clinical Neurology. 2010.
- Thomas DT, Erdman KA, Burke LM. Nutrition and Athletic Performance position statement. 2016.
- Omenn GS, et al. Beta carotene and vitamin A in high-risk adults (CARET). New England Journal of Medicine. 1996.
