Green, red, yellow and orange bell peppers can be the same plant at different ages. A red bell pepper is often just a ripened green one, though color also depends on the variety. Yellow, orange, brown, white and purple peppers exist, and the variety ‘Permagreen’ stays green when fully ripe. The red comes from pigments such as capsanthin and capsorubin, which are made only in red pepper.
Ripeness changes what is inside. In a Spanish sweet pepper, vitamin C rose from 107 mg per 100 g when green to 154 mg when red. In a separate lab analysis, the red fruit also had the most provitamin A, while immature green fruit had the most polyphenols.
A medium raw red pepper (119 g) has 31 calories and about 152 mg of vitamin C. That is 169% of the Daily Value (the amount on US food labels).
Bell peppers belong to the same species as many chili peppers, Capsicum annuum, yet they have no heat. In a 2005 study of the pungency (heat) gene Pun1, every non-pungent pepper tested carried a deletion in it.
Two carotenoids (plant pigments) also stand out. Raw red pepper has 490 µg (micrograms) of β-cryptoxanthin per 100 g in the USDA data. In a lab survey of 33 fruits and vegetables, orange pepper had the largest share of zeaxanthin.
Health benefits of bell peppers
The top findings from 20 studies, strongest evidence first
What the stars mean
- Strong. Several randomized trials, pooled in a meta-analysis, point the same way, or regulators (FDA or EFSA) have approved the claim.
- Moderate. Good randomized trials support it, but there are fewer of them, or their results vary.
- Limited. Small, short or single trials, or mixed results. Promising, but it needs confirmation.
Population and lab studies get no stars: they show a link or a mechanism, not proof.
How we rate evidence →- ★★Shorter colds, from vitamin C pillsAt 0.2 g a day or more, vitamin C pills made colds 8% shorter in adults and 14% shorter in children. They did not cut how often people caught colds, and these were pills: one medium red pepper has about 152 mg.
- ★★Lower blood pressure, from vitamin C pillsIn 29 short trials, vitamin C pills (median 500 mg a day for 8 weeks) lowered the top number by 3.84 points (mm Hg systolic). The bottom number fell by 1.48 mm Hg, and these were pills, not peppers.
- ★Little change in iron absorption over daysIn 12 people, 51 to 247 mg of vitamin C a day did not clearly change iron absorption over 5-day diets. The effect is strong in single meals but far less across a complete diet.
- ★No change in body fat from capsiateIn 24 young men doing weight training, 10 weeks of capsiate, a mild pepper compound, did not change body fat, appetite or strength. It was an extract, not whole peppers.
- Population studyLinked to a lower risk of Parkinson diseaseIn a study of 490 patients and 644 people without the disease, those who ate more peppers had a lower risk of Parkinson disease. The link was mostly seen in people who never used tobacco or smoked less than 10 years.
All 20 studies, strongest evidence first
Vitamin C pills shortened colds but did not cut cold numbers
This Cochrane review pooled placebo-controlled trials, where some people got a dummy pill. At 0.2 g a day or more, colds were 8% shorter in adults and 14% shorter in children, across 31 comparisons. For catching colds (29 comparisons, 11,306 people), the general community had 0.97 times the risk, but 598 marathon runners, skiers and soldiers had 0.48 times. These were supplements, and one medium red pepper has about 152 mg.
Vitamin C supplements lowered systolic pressure 3.84 mm Hg in short trials
This meta-analysis (a study that pools many trials) covered 29 randomized trials, each with 10 to 120 people. The median dose was 500 mg a day for a median of 8 weeks. Diastolic pressure (the bottom number) fell 1.48 mm Hg. The authors say long-term trials on blood pressure and clinical events are needed; these were pills, not peppers.
Paprika extract capsules raised blood β-cryptoxanthin and zeaxanthin; capsanthin never appeared
This double-blind, placebo-controlled trial gave 33 healthy adults 0, 20 or 100 mg a day of paprika oleoresin for 12 weeks. Paprika oleoresin is an extract of Capsicum annuum fruit. The carotenoid β-cryptoxanthin built up more than the others, and safety tests showed no adverse events. It was an extract, not whole peppers.
51 to 247 mg vitamin C did not clearly change iron absorption
In 12 people, iron absorption from a labeled wheat roll was measured over three 5-day diet periods. One diet was freely chosen, and two were changed to lower or raise daily vitamin C. Vitamin C raises iron absorption strongly in single meals, but the authors found the effect far less pronounced across a complete diet. The group was small.
Mild CH-19 Sweet pepper reduced energy intake in positive energy balance
This randomized trial included 27 people, who spent three weeks in negative and three weeks in positive energy balance. Positive balance means eating more calories than you burn. On ten test days they took capsaicin, green tea, CH-19 sweet pepper, capsaicin with green tea, or placebo. CH-19 Sweet is a special non-pungent cultivar, so the result may not apply to store-bought bell peppers.
12 mg capsiate daily did not change body fat, appetite or strength
This randomized trial gave 24 healthy untrained young men capsiate, a mild pepper compound, or placebo for 10 weeks. All followed the same resistance (weight) training. Both groups gained body mass, fat-free mass and strength, with no difference between them. Capsiate came as an extract of Capsicum annuum, not as whole peppers.
Mild CH-19 Sweet pepper briefly raised core temperature and oxygen use
This small study had 11 healthy volunteers eat CH-19 Sweet or a pepper cultivar with neither capsaicin nor capsiate. Core temperature was clearly higher with CH-19 Sweet, and neck temperature rose for about 20 minutes. Oxygen consumption was also clearly higher. It measured short-term heat output, not weight or health.
People who ate more peppers had a lower risk of Parkinson disease
This case-control study compared 490 newly diagnosed patients with 644 people without the disease (controls) in Washington State. The link with peppers was clear, and mostly seen in people who never used tobacco or smoked less than 10 years. All edible nightshades combined gave 0.81 times the risk per time a day, a result that could be chance. Diet was self-reported, and the authors ask for confirmation.
Frequent sweet peppers went with 34% lower odds of sarcopenia
This cross-sectional study (a single snapshot) used a food frequency questionnaire in 2,451 older adults, 16.1% of whom had sarcopenia. The odds were 0.73 times as high for once a week or less. For 2 to 3 times a week or more they were 0.66 times, with similar results for chilies. A cross-sectional study cannot show which came first.
Sweet peppers were not linked to handgrip strength, but chilies were
This cross-sectional study included 3,717 adults. In men, handgrip strength clearly rose with how often they ate chilies. The authors report that similar results were not seen with sweet peppers. It is a snapshot and cannot show cause.
High β-cryptoxanthin intake went with 21% lower osteoporosis odds
This meta-analysis of observational studies pooled 7 studies with 100,496 people. The odds were 0.79 times as high for osteoporosis and 0.71 times (29% lower) for hip fracture. The compound β-cryptoxanthin is a carotenoid in red bell pepper (490 µg per 100 g), but the studies were about the compound, not peppers. The authors say longer-term studies are needed to confirm cause.
Ripening raised vitamin C from 107 to 154 mg per 100 g
Lab tests on the Spanish ‘Fresno de la Vega’ pepper found 107.3 mg per 100 g at the green mature stage. It had 129.6 when turning and 154.3 when red. Ripe red peppers lost about 25% of their vitamin C in storage at room temperature, and about 15% in 20 days at 4°C. Blanching lost 12% and canning 20 to 25%; freezing kept 60%, or 87% if blanched first, in this one variety.
Green peppers led in polyphenols, ripe red in vitamin C, provitamin A
This lab analysis followed one sweet pepper cultivar (‘Vergasa’) through four stages: immature green, green, immature red and red. Polyphenol content fell 4 to 5-fold after the immature green stage. Ascorbic acid, the main form of vitamin C, rose as the pepper matured. It is one cultivar, not a study in people.
Oven, air-fryer and infrared cooking clearly cut vitamin C and phenolics
This lab test cooked red bell peppers at 170, 180, 190 and 200°C. Oven cooking kept the most antioxidant activity of the three methods. Acrylamide ranged from 93.67 µg per kg of dry weight (oven, 170°C) to 1,985.38 µg (air fryer, 200°C). These are measurements of cooked peppers, not a study in people.
Roasted or steamed yellow pepper lost over half its antioxidant activity
This lab test contact-grilled, roasted, roasted and microwaved, or steamed green, yellow and red bell peppers. In green peppers, contact grilling and roasting with microwaving raised polyphenols from 2.75 to about 15.2 to 15.4 mg GAE per gram of dry weight. Every method lowered reducing sugars in red peppers. The authors say the best heat treatment depends on ripeness.
Red pepper capsanthin was the most bioaccessible keto-carotenoid; heat and fat helped
This lab digestion model compared pigments from red bell pepper, mamey sapote and sockeye salmon. Capsanthin came out ahead of the sapote pigments, and salmon astaxanthin was lowest. Heat and added fat helped every food except salmon, which is naturally rich in fat. Bioaccessible means released during digestion, not proven to be absorbed.
Orange pepper had the highest zeaxanthin share, 37% of its carotenoids
This lab analysis covered 33 fruits and vegetables, two juices and egg yolk. Corn had the most lutein, and dark green leafy vegetables had very little zeaxanthin (0 to 3%). Lutein and zeaxanthin make up the pigment of the macula, the part of the eye for sharp central vision. But the study measured foods, not eye health.
Phytol in red, yellow pepper fats became available in a digestion model
In this lab study, the phytol came from phytyl esters in red and yellow bell pepper. The same group earlier found these esters in all 14 red and 6 yellow peppers tested, and in none of 3 green ones. One 150 g portion could use up to 81% of the daily limit for people with Refsum’s disease. That is a rare inherited condition that blocks the breakdown of phytanic acid, and it is no concern for others.
Steamed green pepper bound bile acids 7% as well as a drug
This lab digestion model measured binding on a dry-matter basis. Green bell pepper bound 7% as much as the cholesterol drug cholestyramine, against 13% for kale and collard greens and 10% for broccoli. Steaming improved binding compared with earlier values for the raw vegetables. Binding in a test tube does not show lower cholesterol in people.
Red pepper pigments cut UVB DNA strand breaks in skin cells
This lab study treated human skin fibroblasts in a dish with 1 µM capsanthin, capsorubin or lutein. Capsanthin and capsorubin are pigments made only in red pepper. All three lowered DNA strand breaks after UVB light and reduced one marker of cell death, while another was unchanged. It was done in cells, and eating peppers has not been shown to protect skin.
Who should be careful with bell peppers
Most people can eat bell peppers freely. Take a little care if one of these applies:
- Irritable bowel syndrome. Monash University lists green bell pepper as low in FODMAPs (carbs that can trigger gut symptoms) at one 75 g serving. Check the Monash app for the current limits on red and yellow peppers.
- Pepper or pollen allergy. Allergy to peppers is rare, but it has been reported in people allergic to latex and to some pollens, such as Japanese cedar. If you have reacted to peppers, ask an allergist.
How to choose, store and eat bell peppers
- Color: red had the most vitamin C in one Spanish cultivar, 154 mg per 100 g against 107 mg for green. Immature green had the most polyphenols.
- Cooking: in lab tests of red pepper at 170 to 200°C, oven cooking kept the most antioxidant activity and made the least acrylamide. Air-frying at 200°C made the most.
- With a little oil: heat and added fat helped release capsanthin from red bell pepper in a digestion model.
Choose peppers that are firm, bright and tight-skinned. Keep them unwashed in a plastic bag in the fridge for up to a week. Ripe red peppers lost about 15% of their vitamin C in 20 days at 4°C in one lab test. So use them sooner rather than later.
In USDA tests of 328 sweet bell pepper samples in 2021, none had a residue above the legal limit. In 2020, 6 of 675 did.
Sources
- Low FODMAP shopping list. Monash FODMAP blog. 2025.
- Takei M, Nin C, Iizuka T, et al. Capsicum allergy: involvement of Cap a 7, a new clinically relevant gibberellin-regulated protein cross-reactive with Cry j 7, the gibberellin-regulated protein from Japanese cedar pollen. Allergy Asthma Immunol Res. 2022.
- García-Menaya JM, Cordobés-Durán C, Bobadilla-González P, et al. Anaphylactic reaction to bell pepper (Capsicum annuum) in a patient with a latex-fruit syndrome. Allergol Immunopathol (Madr). 2014.
- Krauß S, Hammann S, Vetter W. Phytyl fatty acid esters in the pulp of bell pepper (Capsicum annuum). J Agric Food Chem. 2016.
- Krauß S, Michaelis L, Vetter W. Phytyl fatty acid esters in vegetables pose a risk for patients suffering from Refsum’s disease. PLoS One. 2017.
- Martínez S, López M, González-Raurich M, Bernardo Alvarez A. The effects of ripening stage and processing systems on vitamin C content in sweet peppers (Capsicum annuum L.). Int J Food Sci Nutr. 2005.
- Marín A, Ferreres F, Tomás-Barberán FA, Gil MI. Characterization and quantitation of antioxidant constituents of sweet pepper (Capsicum annuum L.). J Agric Food Chem. 2004.
- Zhao W, Xu Y, Kim J, et al. Effects of cooking methods on antioxidant activity and acrylamide formation in red bell pepper (Capsicum annuum L.). Food Sci Biotechnol. 2024.
- Chacón-Ordóñez T, Esquivel P, Jiménez VM, Carle R, Schweiggert RM. Deposition form and bioaccessibility of keto-carotenoids from mamey sapote (Pouteria sapota), red bell pepper (Capsicum annuum), and sockeye salmon (Oncorhynchus nerka) filet. J Agric Food Chem. 2016.
- Bell peppers. University of Nebraska–Lincoln Extension.
- Pesticide Data Program annual summary, calendar year 2021. USDA Agricultural Marketing Service.
- Pesticide Data Program annual summary, calendar year 2020. USDA Agricultural Marketing Service.
History of bell peppers
Peppers are a food of the Americas. Starch grains from chili peppers turn up at seven archaeological sites, from the Bahamas to southern Peru. The sites date from 6,000 years ago to European contact.
A 2014 study combined genetics, language history, archaeology and climate models. It placed the domestication of Capsicum annuum, the species of bell peppers, in Mexico, most likely the central-east. There, chili remains from before pottery were found in the Tehuacán Valley.
Europeans called them peppers because of their bite, which resembled black pepper, although the two plants are not related. Seeds reached Spain by 1493, and the Spanish and Portuguese then spread peppers to Africa and Asia. The earliest recorded use of the name “bell pepper” is from 1683.
The gentle bell pepper is a matter of genes. Pungency depends on the gene Pun1, and every non-pungent pepper tested carried a deletion in it.
In Central Europe, peppers had been known in Hungary since 1569. But the paprika grown there stayed hot until the 1920s. Then a breeder in Szeged found a plant with sweet fruit that led to the sweet varieties.
Szeged is also where red peppers made scientific history. Albert Szent-Györgyi had run short of a substance called hexuronic acid, which he had been extracting from cattle adrenal glands. In October 1932 he tested red paprika peppers and found they were an excellent source.
That fall his team processed 500 kg of peppers into nearly 500 g of crystalline vitamin C. In 1933 they processed 3.3 tons and obtained more than 3 kg.
The pure vitamin C let researchers confirm that hexuronic acid and vitamin C were the same substance. Szent-Györgyi received the 1937 Nobel Prize in Physiology or Medicine for his work on biological combustion, with special reference to vitamin C.
Who deserves the credit for first identifying it has been disputed. Charles King of Pittsburgh reported the same conclusion in Science two weeks before Szent-Györgyi’s note in Nature.
Sources
- Kraft KH, Brown CH, Nabhan GP, et al. Multiple lines of evidence for the origin of domesticated chili pepper, Capsicum annuum, in Mexico. Proc Natl Acad Sci U S A. 2014.
- Perry L, Dickau R, Zarrillo S, et al. Starch fossils and the domestication and dispersal of chili peppers (Capsicum spp. L.) in the Americas. Science. 2007.
- Stewart C Jr, Kang BC, Liu K, et al. The Pun1 gene for pungency in pepper encodes a putative acyltransferase. Plant J. 2005.
- Bell pepper. Wikipedia.
- Capsicum. Wikipedia.
- Paprika. Wikipedia.
- Earning the Nobel Prize. University of Szeged Klebelsberg Library, Szent-Györgyi exhibition.
- Albert Szent-Györgyi. Science History Institute.
- The Nobel Prize in Physiology or Medicine 1937. NobelPrize.org.
Frequently asked questions about bell peppers
Are bell peppers good for you?
For most people, yes. Raw red bell pepper has 26 calories, 128 mg of vitamin C and 2.1 g of fiber per 100 g. Vitamin C supplements lowered systolic blood pressure by 3.84 mm Hg in a meta-analysis. People who ate more peppers had a lower risk of Parkinson disease in one case-control study.
No pepper finding here reaches strong evidence, and the Parkinson finding is a link, not proof.
Which color bell pepper is healthiest?
No study here compared all the colors head to head. In lab analyses, ripe red fruit had the most vitamin C and the most provitamin A. In one cultivar, red had 154 mg of vitamin C per 100 g against 107 mg for green.
Immature green fruit had the most polyphenols. Orange pepper had the largest share of zeaxanthin in a survey of 33 foods. A mix of colors covers each.
Are bell peppers nightshades?
Yes, the Capsicum genus belongs to the nightshade family, Solanaceae. In a case-control study of 490 patients, eating more peppers went with a lower risk of Parkinson disease. No study here tested whether nightshades worsen joint pain or gut problems, and allergy to peppers is rare.
Are raw or cooked bell peppers healthier?
Neither is simply better, though cooking lowered vitamin C in the lab tests here. Oven, air-fryer and infrared cooking of red pepper clearly cut vitamin C and phenolics, and air-frying at 200°C made the most acrylamide. Heat and added fat did help release capsanthin in a digestion model.
How much vitamin C is in a bell pepper?
A medium raw red pepper (119 g) has about 152 mg, or 169% of the Daily Value, and 100 g has 128 mg. Green peppers have less: 107 mg per 100 g against 154 mg for red in one Spanish cultivar. Ripe red peppers lost about 25% of their vitamin C in storage at room temperature, so keep them in the fridge.
Are bell peppers good for weight loss?
No study here tested weight loss with bell peppers. Raw red pepper has 26 calories and 2.1 g of fiber per 100 g, so it fills a plate cheaply. The mild CH-19 Sweet cultivar lowered energy intake in a 27-person trial. But 12 mg a day of capsiate did not change body fat in another trial of 24 men.
Can bell peppers cause gas?
They can in some people, and no trial here measured gas directly. Monash University lists green bell pepper as low in FODMAPs at one 75 g serving. If peppers bother you, try that amount first and check the Monash app for red and yellow.